AMCA Publication 203 R2007

AMCA Publication 203-90(R2007) Field Performance Measurement of Fan Systems ASSOCIATION INTERNATIONAL, INC. The International Authority on Air System Components AIR MOVEMENT AND CONTROL AMCA PUBLICATION 203-90 (R2007) Field Performance Measurement of Fan Systems Air Movement and Control Association International, Inc. 30 West University Drive Arlington Heights, IL 60004-1893 © 2007 by Air Movement and Control Association International, Inc. All rights reserved. Reproduction or translation of any part of this work beyond that permitted by Sections 107 and 108 of the United States Copyright Act without the permission of the copyright owner is unlawful. Requests for permission or further information should be addressed to the Executive Director, Air Movement and Control Association International, Inc. at 30 West University Drive, Arlington Heights, IL 60004-1893 U.S.A. However. the second edition. designed. Aerovent. IL 60004-1893 U.S. It was reaffirmed July. Inc. Barry Blower/SnyderGeneral Corp. For information on procedures for submitting and handling complaints. Berkshire RG10 9TH United Kingdom Acme Engineering & Manufacturing Corp. TLT-Babcock. 2007. AMCA 203 Review Committee Robert H. These examples provide sufficient guidance for the proper field testing of most fan system installations. components or systems tested. Jolette Disclaimer AMCA uses its best efforts to produce standards for the benefit of the industry and the public in light of available information and accepted industry practices. The intent of this publication is to provide information from which test procedures can be developed to meet the conditions and requirements encountered in specific field test situations. applicable field test examples shown in Annex A. AMCA does not guarantee. AMCA Staff .Forward The original edition of Publication 203 was released in 1976. Authority AMCA Publication 203 was approved by the Air Movement Control Association Membership in 1990. Milley Lane. installed or operated in accordance with AMCA standards or that any tests conducted under its standards will be non-hazardous or free from risk. Saunders Erling Schmidt Gerald P. or AMCA International. certify or assure the safety or performance of any products. Numerous examples of actual field tests are presented in detail in Annex A. Inc. New axial fan System Effect Factors were established based on a test project conducted and underwritten by AMCA. These factors were incorporated in their respective. Chairman Narsaiah Dasa James L. updates much of the information that was presented. will consider and decide all written complaints regarding its standards. Hare Hatch Reading. Novenco. This. Objections to AMCA Standards and Certifications Programs Air Movement and Control Association International. or interpretations thereof. Incorporated c/o Federation of Environmental Trade Associations 2 Waltham Court.A. Inc. Inc. Smith Jack E. certification programs. They include the proper procedure for determining various System Effect Factors. write to: Air Movement and Control Association International 30 West University Drive Arlington Heights. Annex K (estimating the power output of three phase motors) and Annex L (estimating belt drive losses) were rewritten and adjusted based on new information received from motor and drive manufacturers. Over four hundred belt drive loss tests were analyzed. Zaleski. AMCA 201-02 and AMCA 203-90 are companion documents. Publication 200 . are listed for various configurations. Discussion is limited to systems where there is a clear separation of the fan inlet and outlet and does not cover applications in which fans are used only to circulate air in an open space.Related AMCA Standards and Publications AIR SYSTEMS System Pressure Losses Fan Performance Characteristics System Effect System Design Tolerances Air Systems is intended to provide basic information needed to design effective and energy efficient air systems. System Effect Factors. Publication 202 TROUBLESHOOTING System Checklist Fan Manufacturer's Analysis Master Troubleshooting Appendices Troubleshooting is intended to help identify and correct problems with the performance and operation of the air moving system after installation. Publication 201 FANS AND SYSTEMS Fan Testing and Rating The Fan "Laws" Air Systems Fan and System Interaction System Effect Factors Fans and Systems is aimed primarily at the designer of the air moving system and discusses the effect on inlet and outlet connections of the fan's performance. which must be included in the basic design calculations. AMCA 203-90 and AMCA 201-02 are companion documents. Publication 203 FIELD PERFORMANCE MEASUREMENTS OF FAN SYSTEMS Acceptance Tests Test Methods and Instruments Precautions Limitations and Expected Accuracies Calculations Field Performance Measurements of Fan Systems reviews the various problems of making field measurements and calculating the actual performance of the fan and system. . . . . . . . . . . . . . . . . . .13 11. . . . . . . . . . . . . . . . . . . . . . . . .6 Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Location of traverse plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Fan Flow Rate . . . . . . . . . . . . . . . . . .9 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Pressure measuring instruments . . . . . . . . . . .4 Power transmission losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Types of Field Tests . . . .5 Flow rate calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3. . . . .7 9. . . . . . . . . . . . . . . . . . . . .13 . . . . . . . . . . . . . . . . Static Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Static pressure calculations . . . . . . . . . . . . . . . . . . . 2. . . . . . . . . . . . . . .3 Static pressure measurements . . . . . . . . . . . . . . . . . . . . . . . .1 Alternatives to Conducting Field Tests . . . . . . . . . . . . . . . . . . . .11 11. . .2 Velocity measuring instruments . . . . . . . . . . . . . . . . .2 Power measurement methods . . . . .5 Accuracy . . . . . . . . . . . . . .2 Referenced Planes . .8 10. . . . . . . . . . . . . . . . . . . . . . . . .9 10. . . . . . . . . . . . . . . . . . . . . .8 10. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 9. . . . . .4 9. 4. . . . . . . . . . . . . . . . . . .8 10. . . . . . . . . . . . . . 5. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 9. . . . . . . . . . . . . . . . . . . .2 System Effect Factors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 11. . . . . . . . . . . . . . . . . . . . 7. . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Power Input . . . . . . . . . . . . . . . . . . . . . .1 General . . . . . . . . . 6. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .10 10. . . . .2 Fan Performance . . 9. . . . . . . . .TABLE OF CONTENTS 1. . . . . . . . . . . . . . Introduction . . . . .1 General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 The traverse . . . .3 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .12 11. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 9. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. . . . . . . . . . . . . . . . . . . . . . . . .2 Symbols and Subscripts . . . . . . . . . . . . . . . . . . .3 Power measuring instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .17 17. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 Ducted inlet. . . . . . . . . . . . . .14 13. . . . Densities . . . . . . . . . . . . . . ducted outlet fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11. . . . . Conversion Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ducted outlet fans . . . . . . . . . . . . . . . . . . . .4 Density values . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .16 16. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 Accuracy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . free outlet fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 17. . . . . . . . . . .14 12. . . . . . . . . . . . . . . . . . . . . . . . .98 Pitot-Static Tube Holder . .19 17. . . . . . . . . . . . . . . . . . . .101 Manometer Data . . . . . . . . . . . .14 13. . . . . . . . . . . . . . .19 17. . . . . . . Test Preparation . .3 Ducted inlet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 14. . . . . . . . . . Fan Speed .19 17. . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Free inlet. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .99 Static Pressure Tap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 13. . . . .3 Additional data . . . . . . . . . . .1 Locations of density determinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .15 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 Data required at each location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97 Double Reverse Tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Accuracy . . . . . . . . . . . . .21 Pitot-Static Tubes . . . . . . . . . . . . . .16 15. . . . . . . . . . . free outlet fans . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 13. . . . . . . . . . . . . . . . . . .5 Air handling units . . . . . . . . . . . . . . . . . . . . . . .14 12. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 13. . . . . . . . . . . . . . . . . .102 Distribution of Traverse Points . .100 Pitot-Static Tube Connections . . . . . . . Typical Fan-System Installations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6 Barometric pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .14 13. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Free inlet. . . . . . . . . . . . . . .2 Speed measurements . . . . . . . . . .5 Temperatures . . . . . . . . . . . . . . . . . . . . . . . . . .19 Annex A Annex B Annex C Annex D Annex E Annex F Annex G Annex H Field Test Examples . . . . . Precautions . . . . . . . . . . . . .1 Speed measuring instruments . . . . . . . . . . . .18 17. . . . . . . . . . . . . . . . . . . . . . . . . . .126 Typical Format for Field Test Data . . . . . . . . . . . . . . . . .130 Uncertainties Analysis . . . . . . . . .117 Diffusion at Fan Outlets . . . . . . . . . . . . . . . . . . . . . . . . . . . .131 Annex L Annex M Annex N Annex P Annex R Annex S Annex T . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .112 Density Charts and Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .110 Density Determinations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Annex J Annex K Instrumentation Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .106 Phase Current Method for Estimating the Power Output of Three Phase Fan Motors . . . . . .108 Estimated Belt Drive Loss . . . . . .125 Diffusion at Fan Outlets . . . . . . . . . . . . . . The effects of system conditions on fan performance is discussed in Section 5. these examples are based on actual tests which have been conducted in the field. In the case of large fans used in industrial applications and of mechanical draft fans used in the electrical power generation industry the performance of a field test may be part of the purchase agreement between the fan manufacturer and the customer. AMCA Standard 803 Site Performance Test Standard-Power Plant and Industrial Fans defines the conditions which must be met to achieve higher accuracy of measurement. very few fans are installed in conditions reproducing those specified in the laboratory standard. vibration. Although the word air is used when reference is made in the general sense to the medium being handled by the fan. Annex A includes examples of a number of different field tests. it is not practical to write one standard procedure for the measurement of the performance of all fan-systems in the field. it is desirable to include a suitable measuring section in the design. In new installations of this type. In North America. etc.Troubleshooting AMCA Standard 210 . This means that. mechanical draft. dust collection. Agreement must be reached on the test method to be used prior to performance of the test. in assessing the performance of the installed fansystem.3 and 10. sudden changes of area. In addition to Publication 203. drying. air conditioning. exhaust. gases other than air are included in the scope of this publication. ventilating. Sections 9. and stress levels are not within the scope of this publication. and more completely in AMCA Publication 201. it is strongly recommended that the following AMCA publications be carefully reviewed: AMCA Publication 200 . A major problem of testing in the field is the difficulty of finding suitable locations for making accurate measurements of flow rate and pressure. As acceptance and proof of performance tests are related to contract provisions. 1 . C) Proof of Performance Test . conveying.Fans and Systems AMCA Publication 202 .Laboratory Methods of Testing 2. INC. Because of the wide variety of fan types and systems encountered in the field.3 outline the requirements of suitable measurement sections. Before performing any field test. B) Acceptance Test .A test specified in the sales agreement to verify that the fan is achieving the specified performance. In most cases. This publication offers guidelines to making performance measurements in the field which are practical and flexible enough to be applied to a wide range of fan and system combinations. Types of Field Tests There are three general categories of field tests: A) General Fan System Evaluation .Air Systems AMCA Publication 201 . axial. Scope The recommendations and examples in this publication may be applied to all types of centrifugal. Introduction Performance ratings of fans are developed from laboratory tests made according to specified procedures on standardized test setups. and mixed flow fans in ducted or nonducted installations used for heating.A test in response to a complaint to demonstrate that the fan is meeting the specified performance requirement. In actual systems in the field.A measurement of the fan-system’s performance to use as the basis of modification or adjustment of the system. air cleaning. Fans and Systems. etc. Measurement of sound. industrial process. Because these problems and others will require special consideration on each installation. including elbows. 3. obstructions in the path of the airflow. AMCA 203-90 (R2007) Fans for Rating Field Performance Measurement of Fan Systems 1. they are usually subject to more stringent requirements and are usually more costly than a general evaluation test. the standard is ANSI/AMCA Standard 210 / ANSI/ASHRAE 51 Laboratory Methods of Testing Fans for Rating. consideration must be given to the effect on the fan’s performance of the system connections.AMCA INTERNATIONAL. Examples of the application of SEFs in determining the results of field tests are included in Annex A. This will usually require the installation of special ductwork. or other conditions influencing fan performance when installed in the system. In this case. Alternatives to Field Tests In some cases. The fan air density is the density at the fan inlet. Fan total or static efficiencies may be included. System Effect Factor (SEF) is a pressure loss which recognizes the effect of fan inlet restrictions. This is done for the purpose of allowing direct comparison of the test results to the design static pressure calculation.Ps1 – Pv1 + SEF 1 + SEF 2 + …+ SEF n 2 . fan total or static pressures. Thus. These locations are designated as follows: Plane 1: Plane of fan inlet Plane 2: Plane of fan outlet Plane 3: Plane of Pitot-static tube traverse for purposes of determining flow rate Plane 4: Plane of static pressure measurement upstream of fan Plane 5: Plane of static pressure measurement downstream of fan The use of the numerical designations as subscripts indicate that the values pertain to those locations. In field tests of fan-system installations in which system effects have not been accounted for. 5. Referenced Planes Certain locations within a fan-system installation are significant to field tests. fan outlet restrictions. C) Testing a reduced scale model of the complete fan and system using the test methods outlined in this publication. Where SEFs are not applied in the fan selection process. deals in detail with the effect of system connections on fan performance. the full size fan can be tested at the installation site in accordance with AMCA Standard 210. it is important that their sources be recognized and their magnitudes be established prior to testing. The effect can range from a minor amount to an amount that results in the fan-system performance being completely unacceptable. The effect on fan performance as a result of swirl at the inlet is impossible to estimate accurately as the system effect is dependent upon the degree of swirl. SEFs must be applied in the calculations of the results of field tests. Fan Performance Fan performance is a statement of fan flow rate. considerations such as cost and problems of making accurate measurements may make the following alternative methods of testing worth investigation: A) Testing the fan before installation in a laboratory equipped to perform tests in accordance with AMCA Standard 210.AMCA 203-90 (R2007) 4. for a field test. The fan flow rate is the volume flow rate at the fan inlet density. This alternative course of action is recommended when swirl exists at the fan inlet (see Publication 201. 7. Power Plant Fans – Establishing Performance Using Laboratory Methods. SYSTEM EFFECT FACTORS (SEFs) ARE INTENDED TO BE USED IN CONJUNCTION WITH THE SYSTEM RESISTANCE CHARACTERISTICS IN THE FAN SELECTION PROCESS. Tests conducted in accordance with AMCA Standard 210 will verify the performance characteristics of the fan but will not take into account the effect of the system connections on the fan’s performance (see Section 5). B) Testing a reduced scale model of the fan in accordance with AMCA Standard 210 and determining the performance of the full size fan as described in AMCA Publication 802. System Effect Factors AMCA Publication 201. Limitations in laboratory test facilities may preclude tests on full size fans.8). Figure 9. It gives system effect factors for a wide variety of obstructions and configurations which may affect a fan’s performance. Fans and Systems. The alternative to dealing with a large magnitude SEF is to eliminate its source. the fan static pressure is defined as: Ps = Ps2 . 6. and fan power input at stated fan speed and fan air density. This requires revisions to the system. Fan Flow Rate 9.. wg lbm/ft3 lbm/ft3 ----DESCRIPTION 9. as appropriate Plane 1 (fan inlet) Plane 2 (fan outlet) Plane 3 (plane of Pitot-static traverse for purpose of determining flow rate Plane 4 (plane of static pressure measurement upstream of fan) Plane 5 (plane of static pressure measurement downstream of fan) . provided certain precautions are employed (see Section 15). It is adjusted by changing the slope to any of the various fixed settings and by changing the range scale accordingly. Inclined manometers are available in both fixed and adjustable range types..3 Inclined manometers. wg in. Area of cross-section Diameter Equivalent diameter Full load amps Fan power input Power transmission loss Motor power output Electrical power Length Speed of rotation No load amps Nameplated horsepower Nameplated volts Fan static pressure Static pressure at Plane x Fan total pressure Total pressure at Plane x Fan velocity pressure Velocity pressure at Plane x Barometric pressure Saturated vapor pressure at tw Partial vapor pressure Absolute pressure at Plane x Fan flow rate Interpolated flow rate Flow rate at Plane x System effect factor Torque Dry-bulb temperature Wet-bulb temperature Velocity Pressure loss between Planes x and x’ Pressure loss across damper Fan gas density Gas density at Plane x Summation sign Airflow direction 9. The flow rate at the traverse plane is calculated by converting the velocity pressure to its equivalent velocity and multiplying by the area of the traverse plane. wg in. shown in Annex C. 3 SUBSCRIPT c r x 1 2 3 4 5 Value converted to specified conditions Reading Plane 1.2. Both types require calibration. Hg in. The double reverse tube is used when the amount of particulate matter in the gas stream impairs the function of the Pitot-static tube. Each setting provides a different ratio of the length of the indicating column to its indicated height.2. 20:1. or dirt. wg lb-in. .2 Velocity measuring instruments Use a Pitot-static tube of the proportions shown in Annex B or a double reverse tube. and density at the traverse plane and the density at the fan inlet.2. The Pitot-static tube is connected to the inclined manometer as shown in Annex F. Symbols and Subscripts SYMBOL A D De FLA H HL Hmo kW L N NLA NPH NPV Ps Psx Pt Ptx Pv Pvx pb pe pp px Q Qi Qx SEF T td tw V ∆Px.1 General Determine fan flow rate using the area. velocity pressure.. wg in. and an inclined manometer to measure velocity pressure. Hg in. 9. water. wg in.AMCA 203-90 (R2007) 8. and intermediate ratios are available (see Figure 10 in Annex G). It is suited for use in relatively clean gases. The adjustable range type is convenient in that it may be adjusted at the test site to the range appropriate to the velocity pressures which are to be measured. The double reverse tube requires calibration. The velocity pressure at the traverse plane is the root mean square of the velocity pressure measurements made in a traverse of the plane. The double reverse tube is connected to the inclined manometer as shown in Annex C. Hg cfm cfm cfm in. Adjustable range type manometers in which the slope may be fixed at 1:1. wg in. It is important that the double reverse tube be used in the same orientation as used during calibration. 3.1 Pitot-static tube. The velocity pressure at a point in a gas stream is numerically equal to the total pressure diminished by the static pressure. The Pitot-static tube is considered to be a primary instrument and need not be calibrated if maintained in the specified condition. wg in.2 Double reverse tube. °F °F fpm in. 9. wg in. 9. Mark the double reverse tube to indicate the direction of the gas flow used in its calibration. 2. It may be used in gases that contain moderate levels of particulate matter such as dust. Hg in.x’ ∆Ps ρ ρx Σ DESCRIPTION UNIT ft2 ft ft amps hp hp hp kilowatts ft rpm amps hp volts in. Also. free outlet fan flow rate by measuring other parameters and interpreting certified ratings performance (see Section 17. This corresponds to a velocity of approximately 600 fpm for air of 0. consider the range.3 Location of traverse plane For field tests. When suitable locations are not available. corrosive. recommendations regarding alternate test procedures and instrumentation for use for velocities less than 600 fpm are not presented in this publication. In some installations. 5) The traverse plane should be located to minimize the effects of gas leaks between the traverse plane and the fan. and some are not suited for use in high temperature. Normally. When locating the traverse plane close to the fan. Determine velocities in the very low range more accurately by using a manometer with a slope of 20:1.AMCA 203-90 (R2007) The accuracy of the manometer used in the measurement of velocity pressures is of prime importance. the procedure for its use. or explosive atmospheres. the system designer should provide a suitable traverse plane location in the system. The graph in Annex G indicates the effect of expected resolution of manometer readings on the accuracy of velocity determinations.6. Therefore. scale graduations. Due to practical limitations in length. note that the traverse plane and area is located at the tip of the Pitot-static tube. its use is restricted to measurements where the velocities are very low. wg. indicating fluid of the instrument and the range of the velocity pressures to be measured.1) 2) The flow streams should be at right angles to the traverse plane.1). Select a manometer that will provide an acceptable degree of accuracy. than 75% of the velocity pressure measurements are greater than 1/10 of the maximum measurement (see Figure 9. Proper distribution of traverse points and accurate determination of the area of the traverse plane are difficult to achieve when the airway does not conform closely to a regular shape. A location well downstream in a long. When the divergence or convergence of the airway is irregular or more than moderate in degree.2. 4) The cross-sectional shape and area of the airway should be uniform throughout the length of the airway in the vicinity of the traverse plane. Descriptions of various types of instruments used to determine range velocities are presented in Annex J. If it is necessary to use one of these instruments. 3) The cross-sectional shape of the airway in which the traverse plane is located should not be irregular. free outlet fan by the addition of a temporary duct. The uniformity of distribution is considered acceptable when more 4 . 6) When it is necessary to locate the traverse plane in a converging or diverging airway (not recommended). Estimate free inlet. as is often done in order to minimize the effect of leakage. A Pitot traverse plane suitable for the measurements used to determine flow rate are as follows: 1) The velocity distribution should be uniform throughout the traverse plane. When a field test is anticipated. quality. Variations from this flow condition as a result of swirl or other mass turbulence are considered acceptable when the angle between the flow stream and the traverse plane is within 10 degrees of a right angle. flow conditions upstream of the fan are usually more suitable. the 9. velocities encountered in the field test situations are well in excess of 600 fpm. suitable test measurement station locations must be provided in the system. and the expected accuracy of results should be agreed upon by all interested parties.023 in. When the fan is ducted outlet and the traverse plane is to be located downstream from the fan. The angle of the flow stream in any specific location is indicated by the orientation of the nose of the Pitot-static tube that produces the maximum velocity pressure reading at the location. dirty. free outlet fan to a ducted inlet. errors in velocity determinations made by using a Pitot-static tube and manometer exceed normally acceptable values at velocity pressure readings less than 0. more than one traverse plane may be required in order to account for the total flow (Annex A contains examples). convert a free inlet. The basis for this graph is described in Section 9.4 Low velocity instruments. wet. Most of the instruments require frequent calibration. 9. significantly nonuniform flow conditions may exist. consider making temporary or permanent alterations to the ducting for improved test accuracy. slope. For free inlet. particularly when the requirement for a field test is an item in the specifications. free outlet fans.075 lbm/ft3 density. straight run of uniform cross-section duct will usually provide acceptable conditions for the Pitot traverse plane. its calibration. 1 .Typical Velocity Pressure Distributions Encountered in Velocity Pressure Measurement Planes in Fan-System Installations 5 . MAY BE UNSATISFACTORY FOR FLOW INTO INLET BOXES .AMCA 203-90 (R2007) Pv MAX 10 Pv MAX Pv MAX 10 Pv MAX A: IDEAL Pv DISTRIBUTION B: GOOD Pv DISTRIBUTION (ALSO SATISFACTORY FOR FLOW INTO FAN INLETS.MAY PRODUCE SWIRL IN BOXES) Pv MAX 10 Pv MAX Pv MAX 10 Pv MAX 60% 80% C: SATISFACTORY Pv DISTRIBUTION .MORE THAN 75% OF Pv READINGS GREATER THAN: Pv MAX 10 (UNSATISFACTORY FOR FLOW INTO FAN INLETS OR INLET BOXES) D: DO NOT USE UNSATISFACTORY Pv DISTRIBUTION LESS THAN 75% OF Pv READINGS GREATER THAN: Pv MAX 10 (UNSATISFACTORY FOR FLOW INTO FAN INLETS OR INLET BOXES) Pv MAX 10 Pv MAX Pv MAX 10 40% Pv MAX 35% 20% E: DO NOT USE UNSATISFACTORY Pv DISTRIBUTION LESS THAN 75% OF Pv READINGS GREATER THAN: P MAX v 35% F: DO NOT USE UNSATISFACTORY Pv DISTRIBUTION LESS THAN 75% OF Pv READINGS GREATER THAN: P MAX v 10 (UNSATISFACTORY FOR FLOW INTO FAN INLETS OR INLET BOXES) 10 (UNSATISFACTORY FOR FLOW INTO FAN INLETS OR INLET BOXES) Figure 9. but not less than 12 in. MIN. Y WHERE: De = 4YZ π INLET BOX DAMPERS Z Note: The measurement plane should be located a minimum of ½ De from the inlet cone. Figure 9.AMCA 203-90 (R2007) MEASUREMENT PLANE De MIN.2 STACK VELOCITY PROFILE Note: Spiral vortex may form when fan discharges directly into a stack or similar arrangement. 2 12 in. from the leaving edge of the damper blades. Figure 9.3 6 . In some instances. Annex P provides guidance for the location of the traverse plane in these cases. the velocity pressure measurements indicated by the manometer will fluctuate. When the inlet side of the fan is not ducted but is designed to accept a duct.5 / number of readings]2 7 . This is particularly important at measurement points near the walls of the airway (see Annex A-1A). increase the number of measurement points in the traverse to improve accuracy. orient the nose of the Pitot-static tube such that it coincides with the anticipated line of the flow stream. 9. On occasion. Regions where unacceptable levels of swirl are usually present.1 Flow rate at traverse plane. When it is necessary to locate the traverse plane in a converging or diverging airway.3. 9. an undesirable traverse plane location is unavoidable. This short length of duct should produce no significant addition to the system resistance.1 Inlet box location.5 Flow rate calculations 9. but in some cases it may alter the pattern of flow into the fan impeller. Since the flow at a traverse plane is never strictly steady. This course of action is recommended for acceptance tests and proof of performance tests. In such cases. depending on the specific conditions encountered. No appreciable effect on Pitot-static tube readings occur until the angle of misalignment between the airflow and the tube exceeds 10 degrees. consider installing a short length of inlet duct to provide a suitable traverse plane location. 9. The location of the traverse plane on the inlet side of the fan should not be less than ½ equivalent diameter from the fan inlet.5. Where the duct is small. In the case of double inlet fans. Regions immediately downstream from elbows. If the flow conditions at the traverse plane are less than satisfactory. The modifications may be temporary. obstructions and abrupt changes in airway area are not suitable traverse plane locations. permanent. Swirl may form when a fan discharges directly into a stack or similar arrangement (see Figure 9. Any velocity pressure measurement that appears as a negative reading is to be considered a velocity pressure measurement of zero and included as such in the calculation of the average velocity pressure.3. When the traverse plane must be located within an inlet box.4 The traverse Annex H contains recommendations for the number and distribution of measurement points in the traverse plane. and thereby affect the performance of the fan slightly. its length may necessarily be greater than 2 equivalent diameters in order to ensure that the tip of the Pitot-static tube is a minimum of 1½ equivalent diameters from the duct inlet.2). or each of a limited number of prospective locations lacks one or more desirable qualities. should be avoided. traverses must be conducted in both inlet boxes in order to determine the total flow rate. 9. minor or extensive. the estimated accuracy may indicate that the results of the test would be meaningless. Do not locate traverse points in the wake of individual damper blades. The traverse plane should be located a minimum of ½ equivalent diameters from the fan inlet and not less than 1½ equivalent diameters from the inlet of the duct. 2) Provide a suitable location by modifying the system.3). the plane should be located a minimum of 12 inches downstream from the leaving edges of the damper blades and not less than ½ equivalent diameter upstream from the edge of the inlet cone (see Figure 9.5 ρ3 = the density at the traverse plane Pv3 = the root mean square velocity pressure at the traverse plane = [∑(Pv3r)0. such as the region downstream from an axial flow fan that is not equipped with straightening vanes. This duct should be of a size and shape to fit the fan inlet. a minimum of 2 equivalent diameters long and equipped with a bell shaped or flared fitting at its inlet. The flow rate at the traverse plane is calculated as follows: Q3 = V3A3 Where: A3 = the area of the traverse plane V3 = the average velocity at the traverse plane = 1096 (Pv3/ρ3)0.AMCA 203-90 (R2007) traverse plane should be situated a sufficient distance downstream from the fan to allow the flow to diffuse to a more uniform velocity distribution and to allow the conversion of velocity pressure to static pressure.2 Alternative locations. Each velocity pressure measurement should be mentally averaged on a time-weighted basis. the alternatives are: 1) Accept the most suitable location and evaluate the effects of the undesirable aspects of the location on the accuracy of the test results. particularly in acceptance tests and proof of performance tests. an uncertainty of 15% in the determination of the flow rate in a branch duct that accounts for 20% of the total flow rate for the system affects the accuracy of the total flow rate determination by only 3%. this uncertainty can be controlled by selecting a manometer with a slope suited to the velocity pressures to be measured and by avoiding regions of very low velocity in the selection of the traverse plane location. multiple traverse planes.075 lbm/ft3 density.5. This includes instances in which the conditions at the Pitot traverse plane do not conform to all of the qualifications indicated in Section 9. Improve the accuracy of the flow rate determination by avoiding these conditions in the selection of the traverse plane location. Where a single traverse plane is used. As indicated in the graph.3.2 Continuity of mass. These include nonuniform velocity distribution.. swirl.1 determinations. It is important that the calibration of the double reverse tube be applied correctly. it is assumed that no mass is added or removed from the gas stream between the traverse plane and the fan inlet. However.e. In the general application. This corresponds to a velocity of approximately 600 fpm for air of 0. and applicable System Effect Factors. Generally. The graph in Annex G provides guidance for improving the accuracy of the flow rate 8 10. and other mass turbulence. providing the density at this location is known and the assumption noted above is valid. This effect is shown for several manometer slope ratios. other conditions may exist at the traverse plane which can significantly affect the accuracy of the flow rate determination. its determination is based on the fan flow rate. + Q3n (ρ3n/ρ1) 9. wg. The uncertainty analysis presented in Annex T indicates that the uncertainties in flow rate determinations will range from 2% to 10%. single traverse plane. Fan Static Pressure 10. ducts are sized for velocities considerably in excess of 600 fpm. The calculations of fan flow rate are based on considerations of continuity of mass.023 in. and as such. wg in a manometer with slope ratio of 1:1. The use of System Effect Factors in the determination of fan static pressure is described in Section 5. corrected for the calibration of the double reverse tube. In some instances.4 Fan flow rate. Every effort should be made to improve the accuracy of the flow rate determination. but these sections can usually be avoided.6 Accuracy The performance item of major concern in most fansystem installations is the flow rate. and the fan inlet area.5. the calculation of the fan flow rate is: Q = Q1 = Q3 (ρ3/ρ1) Where: Q3 and ρ3 = as described in Section 9. in the fan-system installation may be calculated.5. corrected for manometer calibration and where applicable. the density at the fan inlet. ρ1 = the density at the fan inlet 9. having determined the flow rate and density at the traverse plane. and ventilating units.3 Fan flow rate. the uncertainties incurred in the determinations of low velocity flows may be acceptable. This graph indicates the effect of expected resolution of velocity determinations. the expected resolution used as a basis for the graph is the length of indicating column equivalent to 0. Velocities less than 600 fpm may exist in certain sections of the system in some installations. For example. reading resolution uncertainty can be significant. i. The static pressures at the fan inlet and outlet may be obtained directly by making pressure measurements at these locations.05 in. and as such. The use of the calibration of the double reverse tube is described in Annex C. This range is based on considerations of the conditions that are encountered in most field test situations.: Qx = Q3 (ρ3/ρx) 9. or they may be .1 General Determine fan static pressure by using the static pressures at the fan inlet and outlet. In addition to low range velocities. 9. For all ratios.AMCA 203-90 (R2007) Pv3r is the velocity pressure reading.. When it is necessary to use more than one traverse plane in order to account for the total flow: Q = Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) + . (x). heating. Do no use a Pitot-static tube and manometer to determine velocities in the low ranges associated with filters and cooling coils in air conditioning. or improve the conditions by modifying the system.5. the velocity pressure at the fan inlet. The velocity pressure at the fan inlet is the calculated average velocity pressure at this location. Reading resolution uncertainties exceed normally acceptable values at velocity pressures less than 0. the flow rate at any location. When the change in area is moderate and gradual. the determinations must account for the effects of velocity pressure conversions and pressure losses. Use no fewer than four taps located 90 degrees apart.2. a double reverse tube as shown in Annex C. It is important that the inner surfaces of the duct in the vicinities of the pressure taps be smooth and free from irregularities. and indicating fluid necessary to minimize reading resolution errors. and that the velocity of the gas stream does not influence the pressure measurements. See Annex P for guidance in locating the measurement plane in these cases. 10. range. particularly in aligning the nose of the tube with the lines of the flow streams. or a side wall pressure tap as shown in Annex E. The static pressure at this location is difficult to measure accurately with a Pitot-static tube due to the existence of turbulence and localized high velocities. 10. and considerations of velocity pressure conversions and calculations of pressure losses for duct fitting and other system components can be avoided.2.2. upstream and downstream of the fan. the pressure loss of the component must be calculated and credited to the fan. If there is a change in area between the measurement plane and the plane of interest. The location of the static pressure measurement 9 10. scale graduations. When a system component is situated between the measurement plane and the plane of interest. as may occur between the measurement planes and the planes of interest. and a manometer to measure static pressure. If the surface conditions or the velocities at the duct walls are unsuited for the use of pressure taps. a pressure tap should be installed near the center of each wall. In general. 10. The calculation of the pressure loss is usually based on the component’s performance ratings. Inclined manometers used to measure static pressures require calibration and should be selected for the quality. In rectangular ducts. and this atmospheric pressure be that for which the barometric pressure is determined. 10.3 Static pressure measurements It is important that all static pressure measurements be referred to the same atmospheric pressure. The double reverse tube cannot be used to measure static pressure directly. This assumes that the duct friction loss between the two planes is negligible.AMCA 203-90 (R2007) determined by making pressure measurements at other locations.1 Pitot-static tube. Instruments for use in the other measurements involved in the determination of fan static pressure are described in Section 13. the loss is considered to be equivalent to the velocity pressure in the smaller area.2 Double reverse tube.4 Manometers. and the static pressure at the plane of interest is considered to be the same as the static pressure at the measurement plane. the static pressure measurement plane downstream of the fan should be situated a sufficient distance from the fan outlet to allow the flow to diffuse to a more uniform velocity distribution and to allow the conversion of velocity pressure to static pressure. slope. In the latter case. When the change in area is an abrupt and sizable enlargement. Use a Pitot-static tube of the proportions shown in Annex B. This assumes that the velocity pressure in the larger area and the duct friction loss are negligible. then a Pitot-static tube must be used with extreme care. 10. The comments that appear in Section 9. It must be connected to two manometers and the static pressure for each point of measurement must be calculated. The pressure tap does not require calibration.2 Pressure measuring instruments This section describes only the instruments for use in measuring static pressure.3. and where the airway . then the calculation of the static pressure at the plane of interest must account for velocity pressure conversion and include any associated pressure loss. Then the duct friction loss between the measurement plane and the plane of interest is usually insignificant.2. 10.1 Location of the measuring plane.3 Pressure tap. the conversion of velocity pressure is considered to occur without loss and the static pressure is calculated on the basis of no change in total pressure between the measurement plane and the plane of interest. A manometer with either vertical or inclined indicating column may be used to measure static pressure. as in a duct leading into a large plenum. Make static pressure measurements near the fan inlet and the fan outlet. which may be obtained from the manufacturer of the item. When the fan is ducted outlet.2 regarding the use and calibration of the Pitot-static tube are applicable to its use in the measurement of static pressures. pressure taps should be used if it is necessary to measure static pressure in the immediate vicinity of the fan outlet. between the measurement plane and the plane of interest is straight and without change in crosssectional area. Both the manometer connections and the method of calculation are shown in Annex C. 2. is derived as follows: Pt4 = Pt1 + ∆P4. as indicated in Section 9.Pv1 . negative. Ps2. the alternatives are to accept the best qualified locations and evaluate the effects of the undesirable aspects of the conditions on the accuracy of the test results or provide suitable locations by modifying the system. Regions immediately downstream from elbows. obstructions. for static pressure at the fan outlet. and abrupt changes in airway area are generally unsuitable locations. By substitution and rearrangement: Ps1 = Ps4 + Pv4 . In most cases. positive values are those measured as being greater than atmospheric pressures.4. Ps1.Pv2 + ∆P2. other system components. duct fittings. Although ∆P represents a loss in all cases. respectively. In the case of double inlet fans.2 When using a Pitot-static tube or a double reverse tube to measure static pressure.1 Where: Pt4 = the total pressure plane of measurement Pt1 = the total pressure at the fan inlet ∆P4. In general. A long. Ps2: Pt2 = Pt5 + ∆P2. a single measurement at each of the taps located at the plane is sufficient. Use Annex H to determine the number and distribution of the measurement points.3. the values of static pressures must be entered with their proper signs and combined algebraically. negative values are those measured as being less than atmospheric pressure. By definition. it is considered a positive value as used in the equations in this publication.3: 1) The velocity distribution should be uniform throughout the traverse plane. If in any fan-system installation the prospective locations for static pressure measurement planes lack one or more desirable qualities.4. The static pressure at the fan inlet. 10.1 = the sum of the pressure losses between the two planes These losses (∆P) include those attributable to duct friction. In all of the equations in this publication. In the event that static pressure measurements must be made in an inlet box.5 10. These static pressure measurements are designated Ps4 and Ps5. a number of measurements must be made throughout the plane.4 Static pressure calculations Static pressure measurements may be positive or 10 . the measurement plane should be located as indicated in Figure 9.1 Static pressure at measuring planes. but at locations a relatively short distance upstream from the fan inlet and downstream from the fan outlet. straight run of duct upstream of the measurement plane will usually provide acceptable conditions at the plane.2 Static pressure at fan inlet or outlet. 3) The cross-sectional shape of the airway in which the plane is located should not be irregular. may be measured directly in some cases. When using pressure taps. the qualifications for a plane well suited for the measurement of static pressure are the same as those for the measurement of velocity pressure. The static pressure at a plane of measurement (x) is calculated as follows: Psx = ∑P sxr number of readings Where: Psxr = the static pressure reading.1 Similarly.5 Ps2 = Ps5 + Pv5 . Ps1. 5) The plane should be located such as to minimize the effects of leaks in the portion of the system that is located between the plane and the fan. static pressure measurements must be made in both inlet boxes in order to determine the average static pressure on the inlet side of the fan.∆P4.AMCA 203-90 (R2007) plane upstream of the fan should not be less than ½ equivalent diameter from the fan inlet. 10. 4) The cross-sectional shape and area of the airway should be uniform throughout the length of the airway in the vicinity of the plane. Regions where unacceptable levels of turbulence are present should be avoided. and changes in airway area. Static pressure at the fan inlet. and the static pressure at the fan outlet. 2) The flow streams should be at right angles to the plane. corrected for manometer calibration 10. the static pressure measurements for use in determining fan static pressure will not be made directly at the fan inlet and outlet. .. The equation for fan static pressure is: Ps = Ps2 . pressure losses associated with velocity pressure conversions are often difficult to determine accurately. Determinations of other pressure losses occurring between the measurement planes and the fan inlet or fan outlet. and the equations for Ps1 and Ps2 reduce to the following: Ps1 = Ps4 + Pv4 . and as such. SEF n = System Effect Factors that account for the various System Effects that are uncorrected and exist at the time of the field test.Pv2 These equations may be used when changes in area between the measurement planes and the planes of interest are moderate and gradual. and the pressure losses associated with conversions of velocity pressure to static pressure are negligible.5 Accuracy The uncertainty analyses in Annex T indicate that the uncertainties in fan static pressure determinations are expected range from 2% to 8%. This range is based on considerations of the conditions expected to be encountered in most field test situations.AMCA 203-90 (R2007) Where: The velocity pressures at the various planes can be determined from the following general equations for the velocity pressure at a plane of measurement (x): Pvx = Pv3 (A3/Ax)2 (ρ3/ρx) Or: Pvx = (Qx/1096Ax)2 ρx Locate the static pressure measurement planes such that the pressure losses between the measurement planes and the planes of interest are insignificant. Determinations of the values of System Effect Factors. Improve the accuracy of the fan static pressure determination by avoiding static pressure measurement plane locations where turbulence or other unsteady flow conditions will produce significant uncertainties in the mental averaging of pressure readings.Pv1 + SEF 1 + SEF 2 + .. then the equations are further reduced to: Ps1 = Ps4 Ps2 = Ps5 These equations may also be used when the only losses between the measurement planes and the planes of interest are those associated with changes in area that are abrupt and sizable enlargements in the direction of flow. This includes pressure losses in ducts. SEF 2. . are subject to uncertainty. + SEF n Where: SEF 1. • 10. This assumption may not be valid. The uncertainty analyses in Annex T and the resulting anticipated uncertainty range do not account for uncertainties that may occur in the following: • Determinations of velocity pressure conversions occurring between the measurement planes and the planes of the fan inlet or fan outlet. The area and density values that are involved in these determinations are usually obtained without significant uncertainties.Pv1 Ps2 = Ps5 + Pv5 . The calculations of these losses are based on the assumption of uniform flow conditions.. Generally.3 Fan static pressure. in addition to the losses being negligible there are no changes in the areas between the measurement planes and the respective planes of interest. If. and other system components. This assumes that the velocity pressure in the larger area is negligible. These determinations are based on limited information.4. 10. This requires alterations to the system.Ps1 . 11 . static pressure measurements are much greater in magnitude than velocity pressure measurements. • Avoid situations requiring these determinations. However. and the selection of a manometer that will provide reasonably good accuracy is not usually a problem. thereby eliminating them as sources for uncertainties. The uncertainties involved in determining the values of System Effect Factors can be avoided only by correcting the causes of the System Effects. and the calculated pressure loss values may be significantly inaccurate. This will eliminate the uncertainties involved in the determination of the pressure losses. Other reading resolution uncertainties are not as significant in the fan static pressure determination as in the determination of flow rate. duct fittings. AMCA 203-90 (R2007) 11. The phase current method is convenient and sufficiently accurate for most field tests. The method. it may also involve the measurements of the no load phase currents. 2) Given the typical motor performance chart of watts input versus torque output and speed at a stated voltage.2. is the value in the typical motor performance data that corresponds to the field test measurement of watts input to the motor. 11. In this method. Hmo. Since fan motors are normally selected for operation at or near the full load point. and the typical motor performance data values of power factor (pf) and motor efficiency. These methods are intended to provide economical and practical alternatives for dealing with various levels of accuracy requirements. For belt driven fans. Typical motor performance data may be used to determine fan power input. 12 3) Given the typical motor performance chart of watts input versus motor efficiency at a stated voltage.2 Typical motor performance data.2. the motor power output is calculated as: Hmo = T ×N 63025 11. Since the results of field tests are usually compared to the rated performance characteristics of the fan. which are referred to as typical in that the data and the actual performance of the motor are expected to correspond closely. Use the field test measurement of watts input and the corresponding typical motor performance data value of motor efficiency. requires measurements of the phase currents and voltages supplied to the motor while driving the fan. and the average should be withing 2% of the voltage indicated in the performance data. the closer the actual phase current is to the motor nameplate value of full load amps. The data provided can be in a variety of forms. the power transmission loss. This method for estimating the power output of three phase motors is based on the relationship of motor current and motor power output. this method provides a reasonably accurate estimate of the power output of the fan motor. where applicable. motor power output is determined by one of the following methods: 1) Given the typical motor performance chart of watts input versus motor power output at a stated voltage. when a power transmission loss occurs. the loss will have to be determined and subtracted from the motor output in order to obtain the fan power input. Depending on the operating load point of the motor.1 General Fan power input data included as part of the fan performance ratings are normally defined and limited to either: • • power input to the fan shaft the total of the power input to the fan shaft and the power transmission loss The losses in fan shaft bearings are included in either case. These data. The phase voltage should be stable and balanced. 11. It is important that the power supplied to the motor during the field test be consistent with that used as the basis for the motor performance data. The information regarding the basis of the rated fan power input accompanies the rating data or is otherwise available from the fan manufacturer. field test values of fan power input should be determined on the same basis as that used in the fan ratings. Use the field test measurement of watts input and the corresponding typical motor performance data values of torque output and speed. the greater the accuracy. corresponding to the measured amps input.1 Phase current method. the rated fan power input may or may not include belt drive losses. Fan Power Input 11. the motor power output is calculated as: Hmo = watts input × motor efficiency 746 4) Given the typical motor performance chart of amps versus power factor and motor efficiency at a stated voltage. Use the field test measurements of amps input and volts. can usually be obtained from the motor manufacturer. described in Annex K.2 Power measurement methods In view of the fact that accuracy requirements for field test determinations of fan power input vary considerably. the motor power output is calculated as: . Depending on the form of the typical motor performance data. Determine fan power input by using the motor power output and. a number of test methods are recommended. but are sufficient to determine motor power output based on electrical input measurements. In most instances. 4 Power transmission losses Several types of power transmission equipment are used in driving fans. When intending to use this method.2 for use with typical motor performance data. Normally. a graph is included in Annex L for this purpose. the length of the shut down time and the revisions to site conditions required for its installation are usually undesirable.3 Calibrated motors. belt drive loss. the fan manufacturer may be able to calibrate a motor. is included in many of the examples in Annex A. The use of a torquemeter requires some prearrangement with the purchaser. A calibrated motor may be used to determine fan power input.2. In many cases. 11. This type of instrument is available with accuracies of 1% full scale for volts. This graph is based on the results of over 400 drive loss tests provided to AMCA by drive manufacturers. 11. amps and volts are the field test measurement values and. This is due mainly to is high cost and the cost of its installation. 11. and power factor can be obtained by using an industrial type power analyzer of good quality. The graph serves as a reasonable guide in evaluating belt drive losses. instead of being merely typical.3 Power measuring instruments Measurement of current. and 2% full scale for watts. where applicable. The phase voltage should stable and balanced. 11. Information as to whether the fan power input ratings include power transmission losses is included in the published performance ratings or is otherwise available from the fan manufacturer. It is important that the power supplied to the motor during the field test be consistent with that used in its calibration. for three phase motors: Hmo = (3)0. and the average should be within 2% of the voltage at which the motor was calibrated. watts. In most cases. but may include data for operation at voltages 10% greater and 10% less than nameplate voltage.4. In addition. Electrical input data and other data sufficient for the determination of power output are obtained in the calibration. The fan power input is the motor power output minus the power transmission loss.5 × amps × volts × pf × motor efficiency 746 In both equations. the higher levels of accuracy requirements can be met by using this type of instrument. the cost of the calibration is a limiting factor in the use of this method in field tests. Another method to determine fan power input involves the use of a torquemeter installed between the fan and the driver. accuracy level requirements will permit the use of a clip-on type ammeter-voltmeter. decreases with increasing motor power output and increases with increasing speed. The torquemeter is extremely limited in field test application. in the case of three phase motors. However. the calibration data represent the performance of a specific motor. The motor is calibrated over a range of operation. it is not normally used in cases where the fan is belt driven and where the fan impeller is installed directly on the motor shaft. The fan power input is the motor power output minus the power transmission loss. voltage.2. fan power input ratings do not include power transmission losses. A calibrated motor provides accurate data to determine motor power output. gear boxes.2. expressed as a percentage of motor power output. where applicable. Calibration data are similar to typical motor performance data with the exception that. For low horsepower applications. As indicated in the graph. and electromechanical couplings. who would normally have specified such equipment. are the averages of the measured phase values. 13 . For practical considerations.4. It is important that this be established and that the fan power input be determined accordingly in order to provide a valid comparison of field test results to the fan performance ratings. Clip-on instruments with accuracies of 3% full scale are available. so that site conditions can be altered to 11. The calibration normally provides data for operation at nameplate voltage. In view of the lack of published information available for use in calculating belt drive losses. amps and power factor.1 Estimating belt drive losses. it is usually necessary to specify in the motor purchase arrangements that the motor be calibrated since an additional cost is normally involved. The calculation of belt drive loss. using this graph. The field test measurements and the calculations involved in the determination of motor power output are the same as those described in Section 11.AMCA 203-90 (R2007) amps × volts × pf × motor efficiency 746 accommodate its installation. Those in which power transmission losses should be considered in the determination of fan power input include belt drives. based on a test of the motor. Hmo = Or. Torquemeters. fluid drives. providing the measurements are well up on the scales. AMCA 203-90 (R2007) 11.4.2 Estimating other transmission losses. For other types of power transmission equipment, consult the fan manufacturer to establish whether transmission losses are included in the fan ratings, and if so, request the magnitudes of the losses allowed in the ratings. Otherwise, it will be necessary to consult the manufacturer of the power transmission equipment for the information regarding transmission losses. determination is required. The pressures at Planes 1 and 2 are based on the static pressure measurements made for the purpose of determining the fan static pressure. The pressure at Plane 3 is obtained by averaging static pressure measurements made concurrent with the velocity pressure measurements made in a traverse of Plane 3. The absolute pressure at a plane is calculated by using the static pressure at the plane and the barometric pressure. For this reason, it is important that the barometric pressure be determined for the atmosphere to which static pressure measurements are referred. The temperatures used in density determinations are measured at the planes of interest. 11.5 Accuracy The uncertainty analyses presented in Annex T indicate that the uncertainties in fan power input determinations are expected to range from 4% to 8%. This range is based on considerations of the conditions encountered in most field test situations, estimated accuracies of the various test methods presented in this publication and allowances for uncertainties in the determinations of power transmission losses. 13.3 Additional data Additional data required in the determination of density depends on the gas stream as indicated below: 1) For air, the wet-bulb temperature is required unless it is otherwise known that the air is saturated with water vapor or that the water vapor content of the air is insignificant. It should be noted that incorrect assumptions as to whether the air is dry or saturated can result in substantial errors in density determinations. 2) For gases other than air, the normal procedure is to rely on process personnel for the data necessary to determine the density of the gas. The information provided will include density or data sufficient to calculate the density, which should be for stated conditions of temperature and pressure. 12. Fan Speed 12.1 Speed measuring instruments Measure speed with a revolution counter and chronometer, a stroboscopic tachometer, an electronic counter-timer, or any other precision type tachometer which has a demonstrated accuracy of 0.5% of the measured value. Friction driven and magnetic type pickups should not be used in low fan power ranges where they can influence speed and fan power input measurements. 12.2 Speed measurements Establish the speed by averaging a minimum of three measurements made during the test determination period. The variation in the measurements should not exceed 1% for any single point of operation. 13.4 Density values Gas stream density can be established when the pressure, temperature, and additional data, as indicated in Section 13.3, have been obtained. Procedures for establishing density are described in the examples in Annex M and are further illustrated in the field test examples in Annex A. Although the pressure and temperature of the gas stream must be obtained for each plane at which a density value is required, it is usually necessary to obtain additional data, such as the wet-bulb temperature, for only one plane in order to establish the densities at all planes. The densities at the planes for which the additional data is not obtained can be calculated, providing the gas stream does not change composition or undergo a change in phase between planes. The calculation is based on density being directly proportional to absolute pressure and 13. Densities 13.1 Locations of density determinations Determine the densities of the gas stream for Plane 1, the fan inlet; and for Plane 3, the velocity pressure measurement plane. In addition, the density at Plane 2, the fan outlet, must be determined whenever the fan total pressure, the fan velocity pressure, or an SEF at the outlet side of the fan is required. 13.2 Data required at each location The pressure and temperature of the gas stream must be obtained for each plane at which a density 14 AMCA 203-90 (R2007) inversely proportional to absolute temperature. 13.4.1 Example calculation - ρ3 from ρ1. Use Figure N.1 of Annex N to establish the density of air at Plane 1 based on the test determinations of barometric pressure, pb, and the following Plane 1 values: Ps1, static pressure, in. wg td1, dry-bulb temperature, °F tw1, wet-bulb temperature, °F The following data are obtained for Plane 3: Ps3, static pressure, in. wg td3, dry-bulb temperature, °F Calculate the density at Plane 3 as follows:  P + 13.6 pb   t d1 + 460  ρ3 = ρ1  s3    13.6 p1   t d3 + 460  Where: thermometer should be accurate within 5°F of the measured value and readable to 5°F or finer. The temperature determination should be representative of the average temperature of the gas stream throughout the plane of interest. When the temperature varies with time or temperature stratification exists at the measurement plane, several temperature measurements may be necessary in order to obtain a representative average. At elevated temperatures, the thermometer may have to be shielded to prevent radiation effects from exposed heat sources. Locate the wet-bulb thermometer downstream from the dry-bulb thermometer in order to prevent the drybulb temperature measurement from being adversely affected. The wet-bulb thermometer wick should be clean, closely fitted, and wetted with fresh water. The velocity of the air over the wick should be between 700 and 2000 fpm. Use a sling psychrometer to obtain dry and wet-bulb air temperature measurements at the fan inlet for free inlet fans. 13.6 Barometric pressure p1 = the absolute pressure, in. Hg at Plane 1, calculated as follows: p1 = pb + (Ps1/13.6) In this manner, ρ3 can be calculated without having to measure the wet-bulb temperature at Plane 3. These equations can be used for gases other than air and can be adapted for use in calculations involving any two planes, subject to the limitations noted earlier. In the example calculation of ρ3, pb is determined for the atmosphere to which the measurements of Ps1 and Ps3 are referred. Refer static pressure measurements to a common atmosphere. When the pressures cannot be referred to a common atmosphere, the absolute pressure for each plane is calculated by using the static pressure measurement at the plane and the barometric pressure for the atmosphere to which the static pressure measurement is referred. However, for the purposes of accuracy, static pressure measurements that are used in the determination of fan static pressure must be referred to a common atmosphere. Use a portable aneroid barometer for field test determinations of barometric pressure when an acceptable site barometer is not available. The barometer should be accurate within 0.05 in. Hg of the measured value. Determine the test value of barometric pressure by averaging measurements made at the beginning and end of the test period. When the test value of barometric pressure is to be based on data obtained from a nearby airport, it is important that the data include the barometric pressure for the airport site and the elevation for which the pressure was determined (often the barometric pressure is corrected to sea level). This pressure value must then be corrected to the test site elevation. Barometric pressure decreases approximately 0.1 in. Hg for every 100 ft increase in elevation 13.7 Accuracy As indicated in Annex T, uncertainties in density determinations are expected to be less than 3%. However, care must be exercised in obtaining representative test measurements in order to prevent the uncertainties from exceeding this value. 13.5 Temperatures Measure temperatures with mercury-in-glass, dial, or thermocouple type thermometers. For temperatures through 220°F, the thermometer should be accurate within 2°F of the measured value and readable to 1°F or finer. For temperatures above 220°F, the 14. Conversion Calculations Generally, the test fan will be operating at a speed and inlet density that are somewhat different from the 15 AMCA 203-90 (R2007) fan performance rating values of fan speed and inlet density. In order to provide a common basis for comparing the field test results to the fan performance ratings, each of these two items must be the same in both sets of data. This can be accomplished by converting the results of the field test to the speed and density conditions of the fan performance ratings. The equations for the conversion are as follows. Qc = Q (Nc / N) Psc = Ps (Nc / N)2 (ρc / ρ) Ptc = Pt (Nc / N)2 (ρc / ρ) Pvc = Pv (Nc / N)2 (ρc / ρ) Hc = H (Nc / N)3 (ρc / ρ) Where the subscript c designates values converted to specified conditions, and items without the subscript c are field test values. These conversion equations do not account for the effect of the compressibility of the gas stream. However, since the test fan usually operates at conditions of speed and inlet density that are reasonably close to the quoted fan performance, the conversion calculations usually result in small changes from field test values and the effect of the compressibility of the gas stream is considered to be negligible. Where test conditions are considerably different than design conditions, the effect of compressibility may need to be considered. Work required to measurements (drilling installation of static thermometer wells, etc.) prior to the test date. accommodate test of traverse holes, pressure taps and should be completed 4) System Effect Factors, if any, must be established prior to the conduct of the test. 5) The expected test uncertainties must be agreed upon prior to the test (see Annex T). 6) Responsibility for the cost of the test or any fansystem modifications required as a result of the test should be established. 7) Prior to testing, an inspection must be made to ensure that the fan is installed in accordance with the fan manufacturer’s recommendations. The duct system should also be inspected for compliance with design specifications, conditions of filters, abnormal duct restrictions, etc. 8) The majority of fan field performance tests cover a single point of operation, namely, the design duty. If it is deemed necessary to cover several points of operation, provision must be made in advance for changing the system resistance. The means used to vary the system resistance must not cause adverse flow conditions in the vicinities of the fan and measurement planes. If the fan cannot be tested at the quoted system design point, then it is sufficient for the evaluation of fan field performance to establish the proximity of the field test point to any portion of the fan performance rating curve within the limitations of the uncertainty analysis (see Annex T). 9) It must be established that the system remains constant for the duration of the test. Modulating dampers should be set in a fixed position, no process changes shall be undertaken, etc. Variable inlet vane controls or inlet box dampers must be set in the full open position for the duration of the test, except when testing for control characteristics. 10) All precautions to ensure the safety of test personnel must be observed. 11) The fan-system should be operated for a length of time sufficient to ensure steady state conditions prior to the start of the test. 12) It is advisable that representatives of all parties interested in the test results be present at the time of the test to cover their areas of responsibility. 15. Test Preparation 15.1 The following items should be agreed upon by all interested parties prior to the start of a field performance test: 1) AMCA Publication 200, Air Systems, AMCA Publication 201, Fans and Systems, and AMCA Publication 202, Troubleshooting, should be reviewed and implemented before starting the field test. 2) Personnel conducting field tests on fans must be technically competent and fully conversant with all four parts of the AMCA Fan Application Manual. The person responsible for conducting the test should be designated and agreed upon by all parties. 3) The test instrumentation and locations of test measurement planes should be established. 16 Since fan pressure readings are never strictly steady. the following equipment be taken to or be otherwise available at the job site: 1) Pitot-static tubes of suitable lengths for the maximum duct size to be traversed. tape. corrosive or explosive atmospheres. Clear plastic tubing is ideal from this standpoint. 7) Sling psychrometer for obtaining dry-bulb and wet-bulb temperatures. immediately remove the Pitot-static tube and clean the inside of the tubing and Pitotstatic tube before proceeding with the test. 13) Complete AMCA Fan Application Manual containing Publications 200. 5) When making measurements in wet gas streams. inlet boxes. absence of fluctuations is an indication of a plugged Pitot-static tube. 9) Measure temperatures on both sides of double inlet fans as temperature differences may exist between each side. 6) Thermometers to cover the range of anticipated temperatures. 202. continually check for the presence of moisture in the tubing. Release both legs of the tubing simultaneously after the Pitotstatic tube is inside the test duct and properly oriented. calculator. 6) Before performing any work inside a fan. ductwork. 2) Static and total pressure manometer tubing must be “pinched off” prior to inserting or removing the Pitot-static tube from the test duct. 8) Clip-on ammeter-voltmeter. and necessary drawings.” 7) The area at the plane of flow measurement should be measured internally to account for internal insulation or other obstructions.e. and 203. Typical Fan-System Installations A fan assembly may include any number of appurtenances: variable inlet vanes. wet.. instruments should be selected for suitability for such atmospheres. 10) Aneroid barometer.2 It is recommended that as a minimum. When using Pitot-static tubes in dirty. Check visually. or other system components. 8) Do not rely on damper control indicators to ensure that dampers are fully open. whether the pressures are positive or negative.AMCA 203-90 (R2007) 15. 5) Tubing couplings and “T” type tubing connectors. coveralls. 4) The Pitot-static tube is intended for measuring pressures in relatively clean gases. 2) Manometers suitable for measuring static pressures. Manometer fluids other than water are acceptable. make certain that the fan motor starter is “locked out. 17. 9) Fan speed measurement instrument. and the magnitudes of pressures. 3) Loop the manometer tubing well above the manometer so that any fluid which is inadvertently blown from the gauge will drain back into the manometer. 3) Inclined manometer suitable for measuring velocity pressures. Failure to release simultaneously may result in manometer fluid being blown from the manometer. 12) Test data sheets. 11) Flashlight. 10) When measuring in high temperature. etc. 16. inlet 17 . 4) Flexible tubing of suitable length to enable manometers to be installed at a convenient location. or other suitable electrical measurement instruments for the determination of fan power input. Considerations should be given to the use of a double reverse tube in dirty atmospheres. If moisture collects in the tubing. or corrosive atmospheres. hand tools. Precautions The following precautions should be observed when conducting a field test: 1) Connect the Pitot-static tube to the manometers according to anticipated pressures. both legs of the Pitot-static tube must be cleaned out frequently during the test. power analyzer. i. A spare bottle of manometer fluid is advisable. Consider using a double reverse tube in these situations. 201. measuring rule. provided the specific gravity is known. 17. the calculation of the loss is based on the performance ratings for the damper. d) The use of interior doors that my restrict the flow of air from areas normally expected to be ventilated. If the assembly includes an inlet box. belt guards. the fan inlet is the inlet to the inlet box. a built-up unit. The performance ratings for a fan that includes inlet box dampers. the field test procedure will depend on whether the equipment is a factory assembled central station unit.Ps1. The locations of the fan inlet and fan outlet depend on whether specific appurtenances are considered to be a part of the fan assembly. inlet screens. free outlet fan. In order to determine the fan static pressure. free outlet fan. fan speed. diffusers (evasés). the loss through the damper must be calculated. For the laboratory test. The fan performance ratings may be assumed to include the appurtenances that are established as being a part of the fan assembly. outlet dampers. The most obvious problem is the lack of a suitable location for the velocity pressure measurement plane. In order to be able to compare the field test results to the fan performance ratings. conducted in accordance with AMCA Standard 210.4). in the case of ventilators that supply or exhaust air from a buildingthe most commonly encountered applications of free inlet. ventilating. In these cases. and airconditioning equipment. In the case of heating. it is essential that these items be fixed in their full open positions for the duration of the test. In this method for testing a free inlet. particularly in conjunction with the item immediately above and as it may affect the flow of air from the outlet of the ventilator. For a fan assembly that includes a diffuser. c) The velocity and direction of the wind outside the building. air conditioning equipment. In order to determine the proper field test procedure and to provide a valid basis for comparing field test results to the fan performance ratings. free outlet fans It is difficult to achieve an accurate field test of a free inlet. other fans. furnaces. when the loss through a damper must be calculated. and the density of the air at the fan inlet. In addition. determine the fan performance by using one of the following methods: 1) Make field test measurements sufficient for determining fan static pressure. but not be a part of the fan assembly. Determine the fan air flow rate by entering this curve at the test values of fan static pressure and fan power input (see Example 5C in Annex A). the fan outlet is the outlet of the diffuser. set. or a packaged unit (see Section 17. the fan static pressure is calculated as the static pressure on the outlet side of the fan less the static pressure on the inlet side of the fan: Ps = Ps2 . fan power input. it is important to establish which of these items are considered a part of the fan and which are considered a part of the system. Using the fan manufacturer’s certified performance ratings. it is essential that the damper blades be fixed in their full open positions during the test since this is the condition on which the damper pressure loss ratings are based. free outlet fans-it is extremely difficult to define. The effect is most significant when large doors that are normally closed are kept open for extended periods such as in loading operations. b) The use of doors providing access to the building. and maintain for the duration of the test the “normal” system condition. Items affecting the system include: 18 . Assuming that these difficulties can be resolved and the desired system is fixed for the duration of the test. inlet bells. Alternately.AMCA 203-90 (R2007) box dampers.1 Free inlet. the fan must be set up in a manner that duplicates the field installation conditions. paint booths. these items may be included in the fan-system installation. all appurtenances must be in place and any restrictions or obstructions to the free flow of air into the fan inlet and away from the fan outlet must be accurately duplicated in the laboratory test setup. a) The operations of ovens. 2) Use the method as described above with the exception that the performance curve is established by a laboratory test of the fan. and similar items that may supply or exhaust air from the building in intermittent or modulating fashions. which is not considered a part of the fan is located between a static pressure measurement plane and the fan. That is. draw a performance curve for the fan for operation at the test values of fan speed and entering air density. This consideration arises when a damper. In addition. The static pressure measurements involved must be referred to the same atmospheric pressure and made at locations sufficiently distant from the fan inlet and outlet so as to be unaffected by the velocity of the air entering and leaving the fan. variable inlet vanes or outlet dampers cover operation of the fan with these items in the full open positions. ducted outlet fans In this type of fan-system configuration. 17. Since Ps1 + Pv1 = 0. 17.Pv1 + SEF 1 + SEF 2 + .. The velocity pressure measurement plane should be located a minimum of 1. See Examples 4C and 4D in Annex A. The air performance ratings for this type of unit are based on the operation of the fan section assembly only. + SEF n 17. humidifiers. 17. these equipment assemblies may include any number of combinations of coils. and air-conditioning applications. the sum of the static pressure at the fan inlet. but in changing the pattern of the flow of air into the fan inlet. Pv1. should be selected on the basis of minimizing its interference with the flow of air into the fan inlet while providing velocity pressure of magnitudes that can be accurately measured.3 Ducted inlet. ducted outlet fans In the calculation of fan static pressure for this type of fan-system configuration. mixing boxes.. at a point sufficiently distant from the fan inlet as to be in still air.Ps1 . Pvx. ventilating. The effect of this duct on the system is negligible.Pv1 + SEF 1 + SEF 2 + .(Ps1 + Pv1) Ps = Ps2 + SEF 1 +SEF 2 + . it may affect the performance of the fan slightly. free outlet fan are the same as those required for a fan with a ducted inlet and a free outlet. and the velocity pressure at the fan inlet. etc. there is no special consideration in the calculation of fan static pressure. and built-up units. The equation for calculating fan static pressure for this configuration is: Ps = Ps2 . Ps1. and the velocity pressure. At this point.. + SEF n 17. is considered to be equal to the sum of the static pressure.AMCA 203-90 (R2007) 3) Install a duct on the inlet side of the fan for the purpose of providing a location for the velocity pressure measurement plane. the gas stream may be discharging from the fan into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred.5. and the entrance to the duct should be flared in order to reduce the entrance loss.. it is essential that the static pressure measurements in the region of the fan outlet be referred to the same atmospheric pressure as used in all other pressure measurements. The cross-sectional shape and area of the duct. which is temporarily installed for purposes of the test..2 Free inlet. dampers. Applications of this method of test are presented in Examples 5A and 5B in Annex A. factory assembled central station units. Air handling units include packaged units. The length of the duct should be a minimum of twice its diameter or equivalent diameter.5 Air handling units This category consists of draw-through and blowthrough types of equipment assemblies used in heating.2 Factory assembled central station units. charges to the fan the losses incurred in accelerating the air into the fan inlet and eliminates inaccuracies which may occur in any attempt to measure velocity pressure and static pressure at the fan inlet. referred to the atmospheric pressure in the region of the fan outlet. However. When this possibility exists. The static pressures at the inlet and outlet to the assembly and the velocity pressure at the inlet to the assembly are used in calculating the static pressure generated by this type of air handling unit.5. Psx. Ps = -Ps1 . It is important that the field test method correspond to the rating method in each case. Ps2. This type of unit is supplied and rated by the manufacturer as an assembly. filters. and the velocity pressure in still air is zero. Ps1 + Pv1 = Psx + Pvx = 0 This consideration. All of the test measurements and calculations in this method for testing a free inlet.4 Ducted inlet. The equation for this calculation is: Ps = Ps2 . which is the same as that used in the methods for testing fans for performance rating purposes. The basis used in establishing the air performance ratings for each of these unit types is described below.. free outlet fans In this type of fan-system configuration. the equation for calculating fan static pressure for this configuration is: 17.1 Packaged units. the flow conditions on the inlet side of the fan are usually more favorable for the location of the velocity pressure measurement plane. but include the effects of the air flow conditions 19 .5 diameters or equivalent diameters downstream from the duct inlet. + SEF n In this configuration. In addition to fans. is zero gauge pressure. the static pressure at the fan outlet. access sections. the static pressure is zero. except that in built-up units. In the field test determination of the performance of the fan. 17.3 Built-up units. the components are normally obtained from a number of equipment suppliers and the unit is assembled at the installation site.AMCA 203-90 (R2007) entering and leaving the fan section which are created by accessory equipment such as plenums. The fan section assembly includes the fan and the cabinet in which the fan has been installed. unencumbered by the cabinets in which they are installed. are used in calculating the static pressure generated by the fan section assembly. which coincides with the fan outlet.5. Built-up units are similar to factory assembled central station units. The accessory items are considered to be included in the system in which the fan section operates. the static pressure and velocity pressure at the fan inlet and the static pressure at the fan outlet are used in calculating the fan static pressure. The fans which are used in built-up units are rated as free-standing. filters. See Example 4A in Annex A. coils. An SEF that accounts for the effect of the cabinet is normally included in this calculation. mixing boxes. and it may be necessary to include an SEF to account for the conditions at the fan outlet. The static pressure and the velocity pressure at the inlet of the fan section and the static pressure at the fan section outlet. See examples 4B and 4E in Annex A. etc. 20 . FREE OUTLET 5A: 5B: 5C: Free Inlet. The examples are presented in detail and cover several types of fansystem combinations.AMCA 203-90 (R2007) Annex A. EXAMPLES OF FANS. Factory Assembled Draw-Through Type Packaged Air Conditioning Unit Packaged Air Conditioning Unit Central Station Air Conditioning Unit. but it is expected that the examples will provide sufficient guidance for dealing with those cases not covered. Factory Assembled Blow-Through Type EXAMPLES OF FANS. Not all of the possible fan-system combinations are included in the examples. Free Outlet Roof Ventilator as installed 21 . Portions of the procedures are typical for all fan-system installations. DUCTED OUTLET 1A: 1B: 1C: 1D: Centrifugal Forced Draft Fan Centrifugal Forced Draft Fan with Inlet Silencers Axial Forced Draft Fan with Inlet Silencers Centrifugal Fans in Parallel EXAMPLE OF FANS. INSTALLATION TYPE D: DUCTED INLET. Free Outlet Roof Ventilator with temporary duct Free Inlet. INSTALLATION TYPE C: DUCTED INLET. INSTALLATION TYPE A: FREE INLET. FREE OUTLET 3A: 3B: 3C: 3D: Centrifugal Fan in an Exhaust System Axial Fan in an Exhaust System Centrifugal Fan in a Scrubber System Centrifugal Roof Ventilator with Ducted Inlet EXAMPLES OF AIR HANDLING UNITS 4A: 4B: 4C: 4D: 4E: Centrifugal Fan in a Built-up Air conditioning Unit Central Station Air Conditioning Unit. Field test procedures are illustrated in a variety of situations. Field Test Examples This annex contains examples of field tests. Other portions of the procedures demonstrate methods for dealing with the more difficult features encountered in some installations. Free Outlet Propeller Fan with temporary duct Free Inlet. INSTALLATION TYPE B: FREE INLET. DUCTED OUTLET 2A: 2B: 2C: 2D: 2E: 2F: 2G: Utility Fan in a Ventilating System Centrifugal Fan in a Sawdust Conveying System Axial Fan in a Dryer System Centrifugal Fan in a Scrubber System Centrifugal Fan in a Process System Axial Fan in a Ventilation System High Pressure Centrifugal Fans in Series EXAMPLES OF FANS. If the motor power output is to be estimated by using the phase current method described in Annex K. 4. Ps1. A3. Measure td1 and tw1 in the path of the air flowing into the fan inlets. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. 6. In order to calculate the value of SEF 1. Determine the area of the traverse plane. including volts (NPV) and full load amps (FLA). it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point (refer to Annex K). At this point. the static pressure is zero. and the blast area of the fan. it is necessary to measure the length of the outlet duct. In order to be able to compare the test results to the fan performance ratings. Pvx. All of these measurements are used in the determination of densities at the various planes of interest. Measure the fan speed and the motor amps. A2. 3. the outlet area of the fan.4. as shown in the diagram. at the inlets of a fan with unrestricted inlets is considered to be equal to the sum of the static pressure. volts.AMCA 203-90 (R2007) EXAMPLE 1A: CENTRIFUGAL FORCED DRAFT FAN SEF 1 DIFFUSER 3 2 L VARIABLE INLET VANES SIDE VIEW OUTLET SIDE VIEW A2 A3 LOCATIONS OF PLANES 2 AND 3 ORIENTATION OF PITOT TUBE COMMENTS 1. The sum of the static pressure. Determine pb for the general vicinity of the fan. 2. however. Psx. as shown in the diagram. it is essential that the inlet vanes be fixed in their full open positions for the duration of the test. However. Determine Ps3 by averaging the static pressure measurements made in the same traverse. particularly near the walls of the diffuser. It is recommended that the Pitot-static tube be oriented so that its nose is aligned with the anticipated flow streams. Measure td3 in Plane 3. In addition. which is located at the tip of the Pitot-static tube. and. Pv1. and 22 . located near the end of the fan diffuser (evasé). These velocity pressure and static pressure measurements are susceptible to error due to the turbulence existing in the region of the fan outlet. at a point sufficiently distant from the fan inlets as to be in still air. and velocity pressure. SEF 1 is due to the effect of insufficient length of duct at the fan outlet. no other more suitable location for Plane 3 exists in this example. Performance ratings for fans with inlet vanes cover operation with the inlet vanes in their full open position. not at the location of the Pitot-static tube access holes in the diffuser. 5. watts. if possible. The variable inlet vanes are considered part of the fan. and the velocity pressure. L. it is undesirable to have Plane 3 located in a diverging airway. Procedures for the traverse are described in Section 9. Record all pertinent motor nameplate data. it is not necessary to measure motor watts. To calculate the fan static pressure: Ps = Ps2 . Use Figure N.5 = 5064 fpm Q3 = V3A3 = 5064 × 11.0712/0.1 in Annex N to obtain ρ1 = 0.AMCA 203-90 (R2007) the velocity pressure in still air is zero. In this case. In order to compare the test results to the quoted fan curve drawn for operation at 1780 rpm and 0.52 in.6 × 28.91     556  = 0.Ps1 .0712)0.91 in. FLOW RATES V3 = 1096 (Pv3/ρ3)0.4 + 13. which is the same as that used in the methods for testing fans for performance rating purposes.6 p1   t d3 + 460   14. the test conditions are identical to the specified conditions and no calculations are required. 163 163 av.4 in. MOTOR NAMEPLATE DATA 200 hp.52/0.6 × 28. 166. wg Pv3 = 1. 572 567 av. it is necessary to convert the results to the specified conditions. 560. MEASURED MOTOR DATA Volts = = Amps = = 570.0701 lbm/ft3 density.76 ft2 L = 3 ft.90 = 90% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 200 hp motor operating at 90% FLA.0712 lbm/ft 3 In this case. Hg td1 = 85°F tw1 = 63°F td3 = 96°F Ps3 = 14. FAN POWER INPUT Measured amps/FLA = (163/181) = 0.94 ft2 A3 = 11.3 = 57223 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 57223 (0. Hg OBSERVATIONS SITE MEASUREMENTS pb = 28.0701   13. Ps1 + Pv1 = Psx + Pvx = 0 This consideration. 181 FLA 23 .(Ps1 + Pv1) + SEF1 Since: Ps1 + Pv1 = 0 Ps = Ps2 + SEF 1 7.3 ft2 Blast Area = 7.0701 lbm/ft3 The density at Plane 3:  P + 13.Pv1 + SEF 1 = Ps2 . charges to the fan losses incurred in accelerating the air into the fan inlets and eliminates the inaccuracies which arise in any attempt to measure the velocity pressure and static pressure at the fan inlets.91 in. CALCULATIONS DENSITIES For fan inlet conditions of: td1 = tw1 = p1 = = 85°F 63°F pb 28. ρ2 is considered to be equal to ρ3.0701) 58121 cfm GENERAL VIVs in full open positions.6 pb   t d1 + 460  ρ3 = ρ1  s3    13. Fan direct connected to motor. wg N = 1780 rpm A2 = 11. 60 hertz 575 volts.5 = 1096 (1. 1800 rpm. 3 phase. 160.91   545  = 0. 94 ) / π = 3. Figure 8. and 16% effective duct length. Ps = Ps2 + SEF 1 = 14.6 in. However.65 For blast area ratio of 0.76/11. wg 24 .7 ft L in % effective duct length = (L/18.7) 100 = (3/18. there may be some conversion of velocity pressure to static pressure between Planes 3 and 2. Figure 8.7) 100 = 16% Blast area ratio = Blast Area/A2 = 7.97 in. Ps2 is considered equal to Ps3.1 shows SEF 1 = 0. Figures 7. At 0.65.9 (4793/1000) = 18.075) = 0.94 = 0. For 4793 fpm velocity and curve U. wg H 178 hp SYSTEM EFFECT FACTOR AMCA Publication 201-90.9 ft.075 lbm/ft3. Therefore. Figure 7.3 indicate the following calculations: Q2 = Q3 (ρ3/ρ2) = 57223 (0. SEF 1 = 0.97 in.3 shows that for velocities over 2500 fpm. 100% effective duct length is one duct diameter per 1000 fpm.57 in. wg at 0.94) = 4793 fpm Duct diameter equivalent to the diffuser outlet area: De2 = 4 A2 / π = ( 4 × 11. wg CONVERSION TO SPECIFIED CONDITIONS Qc = = Psc = = Hc = = Q 58121 cfm Ps 14.3 shows System Effect Curve U applies.4 + 0.6 (0.0712/0.0712) = 57223 cfm V2 = (Q2/A2) = (57223/11. the amount of conversion will be very small relative to the static pressure measured at Plane 3 and ignoring any change in static pressure from Plane 3 to Plane 2 will have no appreciable effect on the test results. = De2 (V2/1000) = 3.57 = 14.0712 lbm/ft3.AMCA 203-90 (R2007) Hmo = 200 (163/181) (567/575) = 178 hp Since the fan is direct connected to the motor: H = Hmo = 178 hp FAN STATIC PRESSURE Since A2 is greater than A3.1 and 8.0712/0. 2. All of these measurements are used in the determination of densities at the various planes of interest.4. however. Determine Pv3a and Pv3b by using the root mean square of the velocity pressure measurements made in traverses of Planes 3a and 3b. 7. Performance ratings for fans with inlet vanes cover operation with the inlet vanes in the full open positions. includes the variable inlet vanes and inlet boxes. as shown in the diagram. If the motor power output is to be estimated by using the phase current method described in Annex K. but does not include the silencers. The ducts should be a minimum of one equivalent diameter in length. Determine Ps2 by averaging the pressure measurements at each of four static pressure taps located near the end of the fan diffuser (evasé). Ps3a and Ps3b are used in determining the density at the traverse plane. In order to be able to compare the test results to the fan performance ratings. and the blast area of the fan. Refer to Annex K. Measure td3 and tw3 near the inlet ducts. In order to calculate the value of SEF 1. Measure Ps1a and Ps1b at locations close to the entrances to the inlet boxes and in planes which are substantially equal in area to the planes of the entrances to the inlet boxes (Plane 1). 6. Procedures for traverses are described in Section 9. it is necessary to measure the fan outlet area. as supplied and rated by the manufacturer. 4.AMCA 203-90 (R2007) EXAMPLE 1B: CENTRIFUGAL FORCED DRAFT FAN WITH INLET SILENCERS TEMPORARY DUCT DIFFUSER STATIC PRESSURE TAPS 3a 0. including volts (NPV) and amps (FLA). Measure td2 in Plane 2. it is not necessary to measure motor watts. To calculate the fan static pressure: 25 .5 De 3b SILENCERS 1 A2 SEF 1 SIDE VIEW 2 COMMENTS OUTLET SIDE VIEW VARIABLE INLET VANES 1. Determine pb for the general vicinity of the fan. it is essential that the inlet vanes be fixed in their full open positions for the duration of the test. See Annex E for details of static pressure taps. Determine Ps3a and Ps3b by averaging each of the two sets of static pressure measurements made in the same traverses. Record all pertinent motor nameplate data. volts. SEF 1 is due to the effect of there being no duct at the fan outlet. 5. A3a and A3b are the areas traversed. and have flared inlets to reduce entrance losses and provide more uniform velocity profiles at the pressure measurement planes. This fan. A location for Plane 3 measurements may be obtained by installing ducts on each silencer inlet. A2. watts. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. Measure the fan speed and the motor amps. and if possible. 3. 6) 29.62/0.70)/2 -0. 455.31   545  = 0.0712 lbm/ft3 It is assumed that the temperature at Plane 1 are the same as those at Plane 3.0711 lbm/ft 3 The density at Plane 2:  P + 13.70 in.6 pb   t d3 + 460  ρ1 = ρ3  s1    13. 3 phase 60 hertz 460 volts.6 × 29. wg = 0.31   545  = 0.5 ft2 MEASURED MOTOR DATA Volts = = Amps = = 460.0712)0.31 + (-0.Ps1 . 26 .5 = 1096 (0.6 × 29.1 in Annex N to obtain ρ3 = 0.5 = 1096 (0. Hg = 93°F = 85°F = 58°F = -1. The basis for the calculations is described in Section 14.Pv1 + SEF 1 Where: Pv1 = (Q/1096A1)2 ρ1 8.25 + 13.5 = 40100 cfm V3b = 1096 (Pv3b/ρ3)0. wg = -0.0712     13. wg = -0.89.6 × 29. wg pb + (Ps3/13. The density at Plane 1:  P + 13.AMCA 203-90 (R2007) Ps = Ps2 .5 ft2 A2 = 18 ft2 A3a = A3b = 12.20 in. wg = 1180 rpm = A1b = 12.6 p3   t d2 + 460   10. Hg CALCULATIONS OBSERVATIONS SITE MEASUREMENTS pb td2 td3 tw3 Ps1a Ps1b Ps2 Ps3a Ps3b Pv3a Pv3b N A1a = 29.1 in. 256.26 in.5 = 3208 fpm Q3a = V3aA3a = 3208 × 12.5 = 3234 cfm Q3b = V3bA3b = 3234 × 12. wg = 0.65 .6) 29.0712)0. The motor manufacturer advises that this motor type has a peak efficiency of 91% at a power factor of approximately 0.65 in. it is necessary to convert the results to the specified conditions.075 lbm/ft3 density.30 in.5 ft2 Blast Area = 13.6 × 29.6 p3   t d1 + 460   −1.675 in. Fan direct connected to motor.61 in. wg = -1. DENSITIES For Plane 3 conditions of: td3 = 85°F tw3 = 58°F Ps3 = = = p3 = = = (Ps3a + Ps3b)/2 (-0.0712    545  13.6 pb   t d3 + 460  ρ2 = ρ3  s2    13.31 in.62 in.1 + 13. 258 257 av Use Figure N. 465 460 av 257.0721 lbm/ft 3 FLOW RATES V3a = 1096 (Pv3a/ρ3)0. 1180 rpm. In order to compare the test results to the quoted fan curve drawn for operation at 1180 rpm and 0.26    = 0.61/0.0.675/13. 285 FLA GENERAL VIVs in full open positions.26   553  = 0.5 = 40425 cfm MOTOR NAMEPLATE DATA 200 HP. wg = 10. wg Ps = Ps2 . Figure 7.1 and 8. Figure 8. using the motor efficiency data and the appropriate equation in Section 11.1 .1 shows SEF 1 = 0. the power factor and efficiency may be less.0712/0.075/0.0721) = 79520 cfm (Q2/A2) FAN POWER INPUT Measured amps/FLA = (257/285) = 0.89 × 0.33 (0.62 = 11.65 in.3 shows System Effect Curve T applies.25) .075/0.62 in. this is a reasonable check.2: 3 × 257 × 460 × 0. wg FAN STATIC PRESSURE Pv1 = (Q1/1096 A1)2 = (80638/1096 × 25)2 0. However. wg Hc = 224 (0.0721/0. which would reduce Hmo as calculated using the second method.33 in. At 0.AMCA 203-90 (R2007) Q3 = Q3a + Q3b = 40100 + 40425 = 80525 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 80525 (0.075) = 0. Figures 7. Hmo = 250 (257/285) (460/460) = 225 hp As a check of this value.0711 = 0.0711) = 11. and no duct.75.95 in.Ps1 .91 746 = 222 hp = (79520/18) = 4418 fpm Blast area ratio = Blast Area/A2 = 13.0711) 80638 cfm SYSTEM EFFECT FACTOR AMCA Publication 201-90.0712/0.Pv1 + SEF 1 = 10.62 in.3 indicate the following calculations: Q3 (ρ3/ρ2) = 80525 (0.2.90 = 90% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 250 hp motor operating at 90% FLA. For 4418 fpm velocity and curve T.65 (0.075 lbm/ft3. and: H = Hmo = 224 hp 27 .(-1.0.0711) = 236 hp Hmo = Since the motor is not fully loaded.0720 lbm/ft3: SEF 1 = 0.5/18 = 0. there is no drive loss. wg at 0. wg CONVERSION TO SPECIFIED CONDITIONS Qc = Q = 80638 cfm Psc = 11.75 For a blast area ratio of 0.62 + 0. The value of Hmo is selected to be the average of the two results: Hmo = 224 hp Since the fan is direct-connected to the motor. and if possible. A2. it is not necessary to measure motor watts. Determine pb for the general vicinity of the fan. Determine Ps5 by averaging the pressure measurements at each of four static pressure taps located near the end of the fan diffuser. Record all pertinent motor nameplate data. If the motor power output is to be estimated by using the phase current method described in Annex K. It is essential that the blade pitch angle be fixed for the duration of the test. SEF 1 is due to the effect of insufficient length of duct between the diffuser outlet and the elbow downstream of the diffuser. Measure td5 in Plane 5. L. A temporary short duct is installed upstream of the silencer to establish Plane 3 in which more uniform pressures can be obtained. and have a flared inlet to reduce entrance losses and provide a more uniform velocity profile at the pressure measurement plane. but does not include the silencer. volts.5 De INLET BOX 1 SIDE VIEW L GUIDE VANES COMMENTS 1. Measure Ps1 at a location close to the entrance to the inlet box and in a plane which is substantially equal in area to the plane of the entrance to the inlet box (Plane 1).AMCA 203-90 (R2007) EXAMPLE 1C: AXIAL FORCED DRAFT FAN WITH INLET SILENCER PLANE 3 LOCATION 3 TEMPORARY SHORT DUCT STATIC PRESSURE TAPS SILENCER TRANSITION DIFFUSER SECTION INNER CYLINDER 5 2 0. 5. watts. The duct should be a minimum of one equivalent diameter in length. . Measure td3 and tw3 near the entrance to the short inlet duct. Motor performance data. it is necessary to measure the length of the transition. This blade angle should be agreed upon by all interested parties. In order to calculate the value of SEF 1. 6. 28 See Annex E for details of static pressure taps. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. 4. In this example. supplied by the motor manufacturer. Measure the fan speed and the motor amps. All of these measurements are used in the determination of densities at the various planes of interest. 3. Procedures for traverses are described in Section 9. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. Ps3 is used in determining the density at the traverse plane. are used in the determination of motor power output for this example. includes the inlet box and diffuser section.4. and the outlet area of the diffuser. The fan assembly. 2. Ps2 is considered to be equal to Ps5. however. Ps3 is determined by averaging the static pressure measurements made in the same traverse. as supplied and rated by the manufacturer. including volts (NPV) and full load amps (FLA). This is a variable pitch axial flow fan. 3/0.6 × 29.0744 lbm/ft3 It is assumed that td1 = td3.5 = 1096 (1.Ps1 .70   548  = 0.6 p3   t d1 + 460   −1.0744)0.6 × 29. wg = -1. it is necessary to convert the results to the specified conditions. wg = 880 rpm = 170.0740 lbm/ft3 density. To calculate the Fan Static Pressure: Ps = Ps2 .80 in.8 + 13.8 in.3 ft2 = 176 ft2 = 170. wg = 1.0743 lbm/ft 3 The density at Plane 2: CALCULATIONS ρ 2 = ρ5  P + 13. wg = 20. 29 .70   528  = 0. In order to compare the test results to the quoted fan curve drawn for operation at 880 rpm and 0.8   528  = 0.88 power factor.6 p3   t d5 + 460   20. 9. the test conditions are identical to the specified conditions and no calculations are required. 3 phase 60 hertz 4000 volts.40/13.6 pb   t d3 + 460  = ρ3  s5    13. 4000.8 + 13. 448 448 av MOTOR NAMEPLATE DATA 4000 hp.3 ft2 = A2 = 15 ft DENSITIES For Plane 3 conditions of: td3 = 68°F tw3 = 62°F p3 = pb + (Ps3/13. In this case.8 in.Pv1 + SEF 1 Where: Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) 8.70 in. The density at Plane 1:  P + 13.3 = 780144 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 780144 (0.0756 lbm/ft 3 FLOW RATE V3 = 1096 (Pv3/ρ3)0. Hg Use Figure 20 in Annex N to obtain ρ3 = 0.6) = 29. as supplied by motor manufacturer: 0. 4100 4033 av 450.6 × 29.30 in.0744     13. 95% efficiency. 445. Motor performance data at operating load. Hg = 68°F = 62°F = 88°F = -1.AMCA 203-90 (R2007) 7.0744/0. Axial fans are often rated in Fan Total Pressure. Computation of Fan Total Pressure is illustrated in the CALCULATIONS section of this example.6 × 29. 520 FLA GENERAL Fan direct connected to motor. OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 td5 Ps1 Ps3 Ps5 Pv3 N A1 A2 A3 A5 L = 29.0743) 781194 cfm MEASURED MOTOR DATA Volts = = Amps = = 4000.0744     13.40 in.5 = 4581 fpm Q3 = V3A3 = 4581 × 170.6) = 29.8   528  = 0.6 pb   t d3 + 460  ρ1 = ρ3  s1    13.8 + (-1. 900 rpm. 0756 lbm/ft3.20 22.00 .82 in.3/176)2 (0.8 + 1. wg Pt2 = Ps2 + Pv2 = 20.1.50) + 0.20 = 22. At 0. wg FAN TOTAL PRESSURE AMCA Publication 201-90. and 8. wg at 0.1.8 + 1. wg CONVERSION TO SPECIFIED CONDITIONS Qc = = Psc = = Ptc = = Hc = = Q 781194 cfm Ps 21.32 = 22.20 in.0743) = 1. wg Pv2 = Pv3 (A3/A2)2 (ρ3/ρ2) = 1. For 4362 fpm velocity and curve V.0756/0.43) 100 = (15/65. there is no drive loss.0756) = 1. Figure 8.32 in.62 in. 100% effective duct length is one duct diameter for every 1000 fpm: = De2 (V2/1000) = 15 (4362/1000) = 65.62 + 1. Figures 7. wg Pt 22. wg FAN STATIC PRESSURE Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) = 1.4 shows System Effect Curve V applies.AMCA 203-90 (R2007) FAN POWER INPUT Hmo = = 3 × volts × amps × power factor × efficiency 746 SEF 1 = 0. Figure 7.Pt1 + SEF 1 = 22.32 (0.3)2 (0. 8.0744/0. wg Ps = Ps2 .32 = 21.50 in.1 shows SEF 1 = 0.3 (170.30 + 0.00 in.95 746 = 3507 hp Since the fan is direct connected to the motor.82 in. wg Also: Pt = Pv = = Pt = = 3 × 4033 × 448 × 0.1 shows that for velocities over 2500 fpm.3 (170.1. Ps + Pv Pv2 1.43) 100 = 23% For 23% effective duct length and a vaneaxial fan with a 2 piece elbow.0756) = 767761 cfm V2 = (Q2/A2) = (767761/176) = 4362 Duct diameter equivalent to the diffuser outlet area: De2 = 4 A2 / π = Pt1 = Ps1 +Pv1 = -1.43 ft. wg Pt = Pt2 . L in % effective duct length = (L/65.30 = -0.4 indicate the following calculations: Q2 = Q3 (ρ3/ρ2) = 780144 (0. wg 21.3/170. wg H 3507 hp 30 .0744/0.30 in.8 . wg Ps2 = Ps5 = 20.(-1.8 in.80) .(-0.Pv1 + SEF 1 = 20.0744/0. Figure 8.075) = 0.075 lbm/ft3.62 in.Ps1 .88 × 0.82 in.32 in.20 in. and: H = Hmo = 3507 hp SYSTEM EFFECT FACTOR ( 4 × 176 ) / π = 15 ft. 6. 4. including volts (NPV) and full load amps (FLA). 5. Measure td3 in Plane 3. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. assume that each fan delivers a flow rate proportional to its actual speed. Determine Ps3 by averaging the static pressure measurements made in the same traverse. 3. For each fan. In this example. Procedures for traverses are described in Section 9. and if possible. In this case. A2. Measure the fan speed and the motor amps. All of these measurements are used in the determination of densities at the various planes of interest. there are no suitable locations for traverse planes for use in determining directly the flow rate for each fan. volts. In order to be able to compare the test results to the fan performance ratings it is essential that the outlet dampers be fixed in the full open positions for the duration of the test. includes an outlet damper.AMCA 203-90 (R2007) EXAMPLE 1D: CENTRIFUGAL FANS IN PARALLEL 3 STATIC PRESSURE TAPS OUTLET DAMPER 2 SEF 1 PLENUM 1 PLAN VIEW 1 SIDE VIEW COMMENTS 1. located near the end of a straight run of duct. Measure td2 in Plane 2 for each fan. Ps3 is used in determining the density at the traverse plane. however. which is located at the tip of the Pitot-static tube. If the motor power outputs are to be estimated by using the phase current method described in Annex K. the duct length is so short as to be judged equivalent to there being no duct at all. Each of the fans. Performance ratings for fans with outlet dampers cover operation with the outlet damper in the full open position. Record all pertinent motor nameplate data. The alternative is to determine the total flow rate and since the fans and their operating speeds are alike. In order to calculate the value of SEF 1. Determine Ps2 for each fan by averaging the pressure measurements at each of four static pressure taps located in the short length of duct between the outlet damper and the plenum. Measure the area of traverse plane. it is necessary to measure the outlet areas of the fans. it may be necessary to disconnect the drives and measure the no load amps (NLA) if the motors are not operating at or near their full load points. measure td1 and tw1 in the path of the air flowing into the fan inlet. 2. and their blast areas. it is not necessary to measure motor watts. watts for each fan. A3.4. Determine pb for the general vicinity of the fans. as supplied and rated by the manufacturer. 31 . Refer to Annex K. See Annex E for details of static pressure taps. SEF 1 is due to the effect of insufficient length of duct between the outlet of each fan and the plenum. such as shown in the diagram. (Ps1 + Pv1) + SEF 1 Since Ps1 + Pv1 = 0: Ps = Ps2 + SEF 1 8. In order to compare the test results to the quoted fan curve drawn for operation at 1900 rpm and 0. 1780 rpm. 60 hertz 575 volts. 17 16.1 in Annex N to obtain ρ1 = 0. the static pressure is zero.05 in. 60 hertz 575 volts.25 ft2 RH Fan td1 = 75°F tw1 = 57°F td2 = 79°F 32 . 3 phase. 573 574 av 15. Ps1 + Pv1 = Psx + Pvx =0 This consideration.Pv1 + SEF 1 = Ps2 . RH fan speed A2 = 3. and the velocity pressure.7 av 7. and the velocity pressure in still air is zero.4 ft2 575. To calculate the Fan Static Pressure: Ps = Ps2 . and the velocity pressure.AMCA 203-90 (R2007) Ps2 = 6.075 lbm/ft3 density.Ps1 . LH fan speed A2 = 3. 16. Psx.2 ft2 Blast Area = 2. wg N = 1910 rpm. which is the same as that used in the methods for testing fans for performance rating purposes. At this point. at a point sufficiently distant from the inlet as to be in still air.0 575.4 in. at the inlet of a fan with an unrestricted inlet is considered to be equal to the sum of the static pressure. 17. The sum of the static pressure. 3 phase. it is necessary to convert the results to the specified conditions.25 ft2 MEASURED MOTOR DATA LH Fan Volts = = Amps = = NLA = RH Fan Volts = = Amps = = NLA = 7. 1780 rpm. 23 FLA RH Fan 25 hp. wg N = 1890 rpm.6 in. CALCULATIONS DENSITIES For inlet conditions for both fans of: td1 = 75°F tw1 = 57°F p1 = pb = 29. The basis for the calculations is described in Section 14.0718 lbm/ft3 The density at Plane 2: LH Fan td1 = 75°F tw1 = 57°F td2 = 79°F Ps2 = 6. wg 7.47 in. OBSERVATIONS SITE MEASUREMENTS pb = td3 = Ps3 = Pv3 = A3 = 29. 572. 16 15. 23 FLA GENERAL Outlet dampers in full open positions.05 in.4 in. Fans connected to motors through belt drives. Pv1.2 ft2 Blast Area = 2. Hg 78°F 5. Ps1. 574.0 MOTOR NAMEPLATE DATA LH Fan 25 hp. wg 0. Hg Use Figure N. 578 575 av 16. Pvx.7 av 7. charges to the fan losses incurred in accelerating the air into the fan inlet and eliminates the inaccuracies which arise in any attempt to measure the velocity pressure and static pressure at the fan inlet. 31 .6 pb   t d1 + 460  ρ2 = ρ1  s2    13.7)] (575/575) = 15.04 hp Figure L.0724) = 10385 cfm V2 = (Q2/A2) = (10385/3.6 + 13.7)/(23 .77 hp H = Hmo .AMCA 203-90 (R2007)  P + 13.6 × 29.4 + 13.6 × 29.6 × 29.0.83 hp H = Hmo .05 × 16.7)/(23 .05   538  = 0.0724 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.6 × 29.66 = 0.0724/0.57)/2 = 15.0718     13.0718     13.5 = 2792 fpm Q3 = V3A3 = 2792 × 7.7/23) = 0.0718) = 20834 cfm Assume that the air flow rate for each fan is proportional to its speed.16 hp Hmo = (18.05 Hmo = 0.0724)0.0724 lbm/ft 3 The density at Plane 3:  P + 13.66 .04 + 13. LH Fan Eqn A = 25 (16.HL = 15.47/0.15 + 15.66 hp Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 25 hp motor operating at approximately 70% FLA.16)/2 = 16.54 hp SYSTEM EFFECT FACTOR AMCA Publication 201-90.05 × 15.6 p1   t d2 + 460   6.1 in Annex L indicates estimated belt drive loss of 5% for each fan.4 = 20661 cfm Q = Q1 = Q3 (ρ3/ρ1) = 20661 (0.83 hp RH Motor HL = 0.15 hp RH Fan Eqn A = 25 (15.7/23) (575/575) = 18.57 hp Hmo = (17.05   535  = 0.5 = 1096 (0. Figures 7.77 = 14.05 Hmo = 0.7/23) = 0.6 p1   t d3 + 460   5.3 indicate the following calculations: LH Fan Q2 = Q1 (ρ1/ρ2) = 10472 (0.7 .HL = 16.05   539  = 0.7)] (574/575) = 13. LH Fan Q = Q1 = 20834 [1910/(1910 + 1890)] = 10472 cfm RH Fan Q = Q1 = 20834 [1890/(1910 + 1890)] = 10362 cfm FAN POWER INPUT LH Fan Measured amps/FLA = (16.1 and 8.73 = 73% RH Fan Measured amps/FLA = (15.83 = 15.31 = 0.68 = 68% Eqn B = 25 [(15.31 hp Eqn B = 25 [(16. LH Motor HL = 0.0.6 pb   t d1 + 460  ρ3 = ρ1  s3    13.7/23) (574/575) = 17.2) = 3245 fpm 33 .05   535  = 0.0718/0.7 . 0718) = 7.0724 lbm/ft3: SEF 1 = 0.5 in.43 hp 34 .075 lbm/ft3.2 = 0.70 RH Fan Q2 = Q1 (ρ1/ρ2) = 10362 (0.48 = 6. Figure 8.075/0.075/0.075) = 0.0724) = 10276 cfm V2 = (Q2/A2) = (10276/3. wg CONVERSION TO SPECIFIED CONDITIONS LH Fan Qc = 10472 (1900/1910) = 10417 cfm Psc = 6. wg at 0.2 = 0.3 shows System Effect Curve S applies. wg Hc = 15. wg RH Fan Ps = 6.0718) = 16. wg FAN STATIC PRESSURE Ps = Ps2 + SEF 1 LH Fan Ps = 6.4 + 0.88 in.11 in.075/0.AMCA 203-90 (R2007) Blast area ratio = Blast Area/A2 = 2.25/3.25/3.7 and no duct.54 (1900/1890)3 (0.4 + 0. wg Hc = 14.88 in.1 shows SEF 1 = 0.26 in.88 (1900/1910)2 (0.83 (1900/1910)3 (0.2) = 3211 fpm Blast area ratio = Blast Area/A2 = 2.88 (1900/1890)2 (0.0718) = 15.0718) = 7. At 0.0724/0. Figure 7.075/0. For each fan with velocities of 3245 fpm and 3211 fpm and curve S.70 For a blast area ratio of 0.48 = 6.28 hp RH Fan Qc = 10362 (1900/1890) = 10417 cfm Psc = 6.48 in.5 (0.0718/0. Determine Ps1 by averaging the pressure measurements at each of four static pressure taps in the collar connection at the fan inlet. Determine Ps2 by averaging the pressure measurements at each of four static pressure taps located near the fan outlet. 35 . Measure the fan speed and the motor amps. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. Procedures for traverses are described in Section 9. 4. located near the end of a straight run of duct. In order to compare the test results to the quoted fan curve drawn for operation at 1880 rpm and 0. it is necessary to measure the inlet area and the outlet area of the fan. SEF 2 is due to the effect of insufficient length of duct between the fan outlet and the elbow downstream of the fan. watts. In order to calculate the values of the SEFs.Ps1 . such as shown in the diagram. Determine pb for the general vicinity of the fan. volts. 2.AMCA 203-90 (R2007) EXAMPLE 2A: UTILITY FAN IN A VENTILATION SYSTEM 3 STATIC PRESSURE TAPS 1 PLAN VIEW 2 L SIDE VIEW SEF 2 OUTLET SIDE VIEW 3-PIECE ELBOW R/D = 1 SEF 1 COMMENTS 1. Record all pertinent motor nameplate data. 5. Determine Ps3 by averaging the static pressure measurements made in the same traverse. Measure the area of the traverse plane. Measure td2 in Plane 2. L.075 lbm/ft3 density. SEF 1 is due to the effect of the elbow located at the fan inlet. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. including volts (NPV) and full load amps (FLA). and if possible. Assume td1 is equal to td3. 3.4.Pv1 + SEF 1 + SEF 2 Where: Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) 7. which is located at the tip of the Pitot-static tube. To calculate the Fan Static Pressure: Ps = Ps2 . the length of the outlet duct. The basis for the calculations is described in Section 14. Measure td3 and tw3 in the traverse plane. 6. however. it is necessary to convert the results to the specified conditions. it is not necessary to measure motor watts. All of these measurements are used in determining densities at the various planes of interest. A1 and A2. Refer to Annex K. Ps3 is used in determining the density at the traverse plane. If the motor power output is to be estimated by using the phase current method described in Annex K. A3. and the blast area of the fan. 6 × 29.20 in. 60 hertz 230 volts.7 ft2 L = 0.20   532  = 0.4 10.6) = 29. wg Ps3 = -1. wg N = 1730 rpm A1 = 1.0719    532  13.65 hp Eqn B = 5 [(10.06 in.1 The density at Plane 1:  P + 13.06    = 0.5 = 2742 fpm Q3 = V3A3 = 2742 × 1.6 × 29.07 ft2 Blast Area = 0.1)] (228/230) = 2.35 in.83 ft MEASURED MOTOR DATA Volts = = Amps = = NLA = 227.07 = 2934 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 2934 (0.07 ft2 A2 = 1.18 in.5 = 1096 (0.98 hp 36 . 1750 rpm.0719 lbm/ft3 It is assumed that td1 = td3 FAN POWER INPUT Measured amps/FLA = 10.3/14) (228/230) = 3.20   532  = 0.3 .6 p3   t d2 + 460   0.3 av 7.2. 14 FLA GENERAL Fan connected to motor through belt drive.3.18 + 13. 229. 3 phase.7. 228 228 av 10.3/14 = 0. wg Pv3 = 0.6 pb   t d3 + 460  ρ2 = ρ3  s2    13.95 in.0719    532  13.30)/2 = 2.74 = 74% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 5 hp motor operating at 74% FLA.45/0.6 × 29.6) = 29.0718 lbm/ft 3 The density at Plane 2:  P + 13.30 hp Hmo = (3. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 72°F tw3 = 66°F p3 = pb + (Ps3/13.0718) 2938 cfm MOTOR NAMEPLATE DATA 5 hp.65 + 2. 10. wg Ps2 = 0.7.0719/0.AMCA 203-90 (R2007) OBSERVATIONS SITE MEASUREMENTS pb = 29. Eqn A = 5 (10.0723 lbm/ft FLOW RATES V3 = 1096 (Pv3/ρ3)0.95/13. Hg Use Figure N.35 + 13. Hg td2 = 72°F td3 = 72°F tw3 = 66°F Ps1 = -2.6 pb   t d3 + 460  ρ1 = ρ3  s1    13.1)/(14 .1 in Annex N to obtain ρ3 = 0. 10.6 × 29.6 p3   t d1 + 460   −2.06    3 = 0.45 in.17 ft2 A3 = 1.0719)0.20 + (-1. 07/1.7/1.0719/0. 27% effective duct length and elbow position C.05) 100 = (0.17 = 0. wg For SEF 2.18) . wg Hc = 2.075) = 0.05 in.1.53 + 0.0.0723/0.0723 lbm/ft3: SEF 2 = 0.35 .55 (0. AMCA Publication 201-90.22 = 3.67 = 3.19 = 2.5 indicate the following calculations: Q2 = Q3 (ρ3/ρ2) = 2934 (0. and with no duct between the elbow and the fan inlet.065 × 2.79 hp SYSTEM EFFECT FACTORS To determine the value of SEF 1.45 + 0.075/0.1 shows SEF 1 = 0. 8.05) 100 = 27% Blast area ratio = Blast Area/A2 = 0.0718) = 3.07)2 (0. Figure 7.53 in.Ps1 . At 0. calculate the velocity at the fan inlet: V1 = Q1/A1 = 2938/1. wg at 0.98 .7 in.5 × 1.065 Hmo = 0.Pv1 + SEF 1 + SEF 2 = 0.28 in. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 2938 (1880/1730) = 3193 cfm Psc = 3. Figures 7. For 2494 fpm velocity and curve P . wg FAN STATIC PRESSURE Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) = 0.98 = 0.17/π)0.075 lbm/ft3.0723) = 2918 cfm V2 = (Q2/A2) = 2918/1.05 ft L in % effective duct length = (L/3.0718) = 4.22 ft Figure 8.0718) = 0.0. System Effect Curve R applies.79 (1880/1730)3 (0.Q. At 0.67 in.45 (1. HL = 0. Figure 7.1 in Annex L indicates estimated belt drive loss of 6.45 in.075 lbm/ft3. wg at 0.5 shows System Effect Curve P . and 8.19 hp H = Hmo .(-2.28 (1880/1730)2 (0.075) = 0.7 (0.1 shows SEF 2 = 0.07 = 2746 fpm AMCA Publication 201-90.5 = (4 × 1. Figure 9.17 = 2494 fpm Duct diameter equivalent to the fan outlet area: De2 = (4A2/π)0.075/0.6 For blast area ratio of 0.0718 lbm/ft3: SEF 1 = 0.5 = 1. Figure 8.5%. the 100% effective outlet duct length is 2.5 duct diameters.74 hp 37 .0718/0.5 indicates that for a three piece elbow with radius to diameter ratio of 1.83/3.AMCA 203-90 (R2007) Figure L.55 in.HL = 2. For 2746 fpm velocity and curve R.Q applies.1. = 2.1 shows that for velocities of 2500 fpm or less. wg Ps = Ps2 .6.0719/0. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3.4. volts. Determine Ps1 by using a Pitot-static tube or static pressure taps in the duct connection at the fan inlet. 5. referred to the atmospheric pressure in the region of the duct outlet. In situations such as this example. In this case. and if possible. The friction loss in the short length of outlet duct is assumed to be negligible. 4. which is located at the tip of the Pitot-static tube. referred to the same 38 atmospheric pressure as used in all other pressure measurements. the pressure was measured as 0. and Ps2 is considered to be equal to the static pressure at the duct outlet. wg. SEF 2 is due to the effect of insufficient length of duct at the fan outlet. . A3.AMCA 203-90 (R2007) EXAMPLE 2B: CENTRIFUGAL FAN IN A SAWDUST CONVEYING SYSTEM 1 SEF 1 4-PIECE ELBOW R/D = 1 SEF 2 2 L2 L1 3 OUTLET SIDE VIEW SIDE VIEW COMMENTS 1. Measure td1 and td2. A1 and A2. it is not necessary to measure motor watts.1 in. When this possibility exists. it is essential that the static pressure in the region of the discharging air be measured. it is necessary to measure the inlet area and the outlet area of the fan. Record all pertinent motor nameplate data. SEF 1 is due to the effect of insufficient length of duct between the fan inlet and the elbow upstream of the fan. If a Pitot-static tube is used. Procedures for traverses are described in Section 9. the air may be discharging from the duct into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred. Determine Ps3 by averaging the static pressure measurements made in the same traverse. and the blast area of the fan. 3. Refer to Annex K. Determine pb for the general vicinity of the fan. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. however. 2. All of these measurements are used in determining densities at the various planes of interest. In order to calculate the values of the SEFs. Ps3 is used in determining the density at the traverse plane. If the motor power output is to be estimated by using the phase current method described in Annex K. Measure the fan speed and the motor amps. located near the end of a straight run of duct. The static pressure at the outlet of the duct is zero gauge pressure. the lengths of the inlet connection and the outlet duct. L1 and L2. watts. such as shown in the diagram. including volts (NPV) and full load amps (FLA). Measure td3 and tw3 in the traverse plane. Measure the area of the traverse plane. it should not project into the upstream elbow but be located well within the length of the duct connection as shown in the diagram. 6°F 91.0705)0.0705/0.5.83    = 0.6 pb   t d2 + 460  ρ1 = ρ2  s1    13.5 = 4596 fpm Q3 = V3A3 = 4596 × 1.0 ft MEASURED MOTOR DATA Volts = = Amps = = NLA = 460.0714 lbm/ft3 The density at Plane 1:  P + 13.6) = 29. wg 0.82   551. 3 phase.6 × 29. To calculate the Fan Static Pressure: Ps = Ps2 .3°F 70. 60 hertz 460 volts.6 × 29.Pv1 + SEF 1 + SEF 2 Where: Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) 7.Ps1 .4 in. wg 1. In order to compare the test results to the quoted fan curve drawn for operation at 2075 rpm and 0.4°F p2 = pb + (Ps2/13.075 lbm/ft3.6 p2   t d1 + 460  4 + 13. The basis for the calculations is described in Section 14.4 = 0. 26 26 av 11.3 MOTOR NAMEPLATE DATA 30 hp.3°F tw2 = 70.1 in Annex N to obtain ρ2 = 0. 36 FLA GENERAL Fan connected to motor through belt drive.0714    546  13.40 ft2 1.24/0.0714    546.6  13.6 pb   t d2 + 460  ρ3 = ρ2  s3    13. 1750 rpm.57 ft2 DENSITIES For Plane 2 conditions of: td2 = 91. 459 460 av 26.72 = 72% 39 . OBSERVATIONS SITE MEASUREMENTS pb td1 td2 tw2 td3 Ps1 Ps2 Ps3 Pv3 N A1 A2 A3 = = = = = = = = = = = = = 29.82 in.6 p3   t d3 + 460   −8. Hg 86. fan speed 1.24 in.9 in. wg 2120 rpm. it is necessary to convert the results to the specified conditions.5. Hg Use Figure N. wg -8. 460.0700 lbm/ft 3 The density at Plane 3:  P + 13.6 × 29.3   −11.6) = 29.4°F 86°F -11.83 in.26 ft2 L1 = 1.6 × 29.82 + (0.40 ft2 1.57 = 7216 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 7216 (0. 25.5 = 1096 (1.0700) 7268 cfm CALCULATION Blast Area = 1.3  = 0.0705 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0. FAN POWER INPUT Measured amps/FLA = (26/36) = 0.AMCA 203-90 (R2007) 6.33 ft L2 = 3.82   551.83    = 0.9 + 13.1 in.1/13. 1 .9 For blast area ratio of 0.11. Eqn A = 30 (26/36) (460/460) = 21.0700 lbm/ft3: SEF 1 = 1. and with a length of duct between the elbow and the fan inlet equal to 1 equivalent diameter. calculate the velocity at the fan inlet: V1 = (Q1/A1) = (7268/1.3)/(36 .13 (2075/2120)2 (0.85 hp Hmo = (21. wg 40 .075/0. wg Figure L. At 0.57/1.0 AMCA Publication 201-90.8%.40/π)0.5 = 1.33/1.3 (0.5 = 1.95 = 18.075) = 1.40) = 5191 fpm The diameter of the fan inlet: D1 = (4A1/π)0.95 hp H = Hmo .0. Figure 8. wg CONVERSIONS TO SPECIFIED CONDITIONS Qc = 7268 (2075/2120) = 7114 cfm Psc = 11. System Effect Curve S applies.40/π)0.85)/2 = 19.81 hp SYSTEM EFFECT FACTORS To determine the value of SEF 1.0700) = 1.26/1. AMCA Publication 201-90.AMCA 203-90 (R2007) Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 30 hp motor operating at 72% FLA. The length of the duct between the elbow and the fan inlet in terms of D1: = (L1/D1) = (1.34 ft.5 indicates that for a four piece elbow with a radius to diameter ratio of 1.3 shows no System Effect Curve applies and SEF 2 = 0.0/6.34) = 1.76 hp For SEF 2.24 (1.1 in Annex L indicates estimated belt drive loss of 4. HL = 0.2 in.76 .Pv1 + SEF 1 + SEF 2 = 0.57 in.1.0700) = 11.0714) = 7125 cfm V2 = (Q2/A2) = (7125/1.40) = 5089 fpm Duct diameter equivalent to the fan outlet area: De2 = (4A2/π)0.3)] (460/460) = 17.3 shows that for velocities over 2500 fpm.42 in.075 lbm/ft3. For 5191 fpm velocity and curve S.76 = 0.5 = (4 × 1.(-11.67 + 17.9 and 44% effective duct length.40 = 0.34 ft Figure 8. 100% effective duct length is one duct diameter per 1000 fpm: = D2 (V2/1000) = 1.4) .82 ft The length of the outlet duct in % effective duct length: = (L2/6.0700/0.HL = 19. FAN STATIC PRESSURE Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) = 1.0705/0.67 hp Eqn B = 30 [(26 .2 + 0 = 11. wg Ps = Ps2 .40)2 (0. Figure 9.Ps1 .13 in.34 (5089/1000) = 6.82) 100 = 44% Blast ratio area = Blast Area/A2 = 1. wg at 0.11. Figure 7.57 + 1.5 = (4 × 1.3 in.048 Hmo = 0.048 × 19.82) 100 = (3.1 shows SEF 1 = 1.0705/0. Figure 8.3 indicates the following calculations: Q2 = Q3 (ρ3/ρ2) = 7216 (0. 0700) = 18.90 hp 41 .AMCA 203-90 (R2007) Hc = 18.81 (2075/2120)2 (0.075/0. watts. Measure td3. It is recommended that the Pitot-static tube be oriented so that its nose is aligned with the anticipated flow streams. not at the location of the Pitot-static tube access holes. determine Ps5 at a location near the fan outlet. particularly near the walls of the diffuser. However. The purpose of presenting this example is to illustrate the not uncommon instance in which a test must be conducted in order to provide performance information. 3. Measure the fan speed and the motor amps. Procedures for traverses are described in Section 9. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. it is not necessary to measure motor watts. no other more suitable location for Plane 3 exists in this example. . Determine Ps4 by averaging the pressure measurements at each of four static pressure taps located near the fan inlet. located as shown in the diagram. as shown in the diagram. including volts (NPV) and full load amps (FLA). which is 42 located at the tip of the Pitot-static tube. the cross-sectional areas of the airways at Planes 4 and 5. the judgments required in determining the values of the SEFs are susceptible to error. 2. Determine Ps3 by averaging the static pressure measurements made in the same traverse. This type of installation is normally classified as one in which a satisfactory test cannot be conducted. but there are no other more suitable locations for these planes in this installation. 5. tw3. it is undesirable to have Plane 3 located in a diverging airway.4. Determine pb for the general vicinity of the fan. and if possible. 4. It is undesirable to have pressure measurement planes located in converging and diverging airways. even though the results will be innaccurate to a degree which is not normally acceptable. These measurements are used in the determination of densities at the various planes of interest. These velocity pressure and static pressure measurements are susceptible to error due to the turbulence existing in the region of the fan outlet. Refer to Annex K. Determine the area of the traverse plane. If the motor power output is to be estimated by using the phase current method described in Annex K. Record all pertinent motor nameplate data. In addition. there are no locations at which reasonably accurate pressure measurements can be made. In the same manner. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. and td4. Measure A4 and A5. Due to the configurations of the airways. In addition.AMCA 203-90 (R2007) EXAMPLE 2C: AXIAL FAN IN A DRYER SYSTEM 4 1 2 5 STRAIGHTENING VANES SEF 2 3 STATIC PRESSURE TAPS A3 SEF 1 PLAN VIEW INNER CYLINDER LOCATION OF PLANE 3 SIDE VIEW COMMENTS 1. A3. volts. however. 0694 lbm/ft3 The density at Plane 4:  P + 13. 24.01 in.8 = 26015 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 26015 (0.0 ft2 = 29.57 + 13. the rapidly diverging transition fitting downstream of the fan is considered equivalent to no duct at the fan outlet.57 in. 8.5°F tw3 = 75.AMCA 203-90 (R2007) 6. wg = 1. it is assumed that ρ5 = ρ2 = ρ3. SEF 1 = 0. 31 FLA GENERAL Fan connected to motor through belt drive CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 86.22 in. will result in an error which is considered negligible. In order to compare the test results to the quoted fan curve drawn for operation at 1580 rpm and 0. Therefore. Hg Use Figure N. A2. 25. Although an elbow is located a short distance upstream of the fan.8 ft2 = 12. 4.044 in. The basis for the calculations is described in Section 14. wg = 0. and assuming ρ1 = ρ4.6 pb   t d3 + 460  ρ 4 = ρ3  s4    13.0694    545  13.6 ft2 p3 = pb + (Ps3/13. 448 449 av 25.0694/0.Ps1 .0. Ps = Ps2 .6 p3   t d4 + 460   −1.6) = 28.5°F = 85°F = 1. 1750 rpm. 60 hertz 460 volts.5°F MEASURED MOTOR DATA Volts = = Amps = = NLA = 450.5  = 0.4 .044/0.6) = 29. and the calculated velocity pressures at Planes 1.90   546.0 24.0690 lbm/ft3 density.0691) 26128 cfm 43 MOTOR NAMEPLATE DATA 25 hp.6 × 29. Ps5.6 × 28. By similar reasoning.90 + (1. 3 phase. it is considered to produce no system effect since it is equipped with turning vanes and the average velocity through the elbow will be relatively low due to its large cross-sectional area. In judging SEF 2.8 av 9.01    = 0.5. 2. it is necessary to convert the results to the specified conditions. FLOW RATES V3 = 1096 (Pv3/ρ3)0.0691 lbm/ft 3 It is assumed that td1 = td4 and at the low pressure levels which exist at Planes 1 and 4. wg = 1590 rpm = A2 = 8. 449.5°F = 75.1 from Annex N to obtain ρ3 = 0. the difference between these pressures will be small. To calculate the Fan Static Pressure.5/13. and 5. In order to calculate the value of SEF2.0694)0. Hg = 86.5 = 873 fpm Q3 = V3A3 = 873 × 29. wg = -1. OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 td4 Ps3 Pv3 Ps4 Ps5 N A1 A3 A4 A5 = 28. it is necessary to measure the outlet area of the fan.4 ft2 = 9.Pv1 + SEF 1 + SEF 2 Where: Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) Ps1 and Ps2 are calculated on the basis of total pressure considerations.5 in. 7.5 = 1096 (0.90 in. using Ps4. CONVERSION TO SPECIFIED CONDITIONS Qc = 26128 (1580/1590) = 25964 cfm Psc = 2.0691) = 0.24 = 2.61 in.0690/0.044 (29. wg Ps2 + Pv2 = Ps5 + Pv5 Ps2 = Ps5 + Pv5 .24 in.044 (29. wg at 0.40)/2 = 18.26 .8/8.92 in.0691) = 2. wg Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) = 0.4)] (449/460) = 17.049 × 18.0.46 hp FAN STATIC PRESSURE Pv4 = Pv3 (A3/A4)2 (ρ3/ρ4) = 0.4)/(31 . wg Pv2 = Pv3 (A3/A2)2 (ρ3/ρ2) = 0.80 = 80% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 25 hp motor operating at 80% FLA.56 hp SYSTEM EFFECT FACTORS SEF 1 = 0 See item 6 under COMMENTS.0694/0.6)2 (0.21 hp Figure L.049 Hmo = 0. SEF 2 = 0.58 in.HL = 18.58 (1580/1590)2 (0.0694/0.42 .0691) = 17.03 .61 = 1.0691) = 0.61 + 0 + 0.52 + 17.40 hp Hmo = (19.044 (29.46 . wg 44 . wg Hc = 17.26 in. using 3252 fpm and curve U.2 indicates that a vaneaxial fan with no outlet duct will use System Effect Curve U. Q2 = Q3 (ρ3/ρ2) = 26015 (0.0)2 (0.8/31) = 0.54 in.0690/0.Pv1 = -1.8/31) (449/460) = 19.8 . wg Ps1 + Pv1 = Ps4 + Pv4 Ps1 = Ps4 + Pv4 .Ps1 .61 = -1.8/8.0694/0. AMCA Publication 201-90.Pv2 = 1.0.075) = 0.56 (1580/1590)3 (0. At 0.8/9.0) = 3252 fpm From Figure 7.0.57 + 0.26 (0. wg Pv5 = Pv3 (A3/A5)2 (ρ3/ρ5) = 0. To determine the value of SEF 2.9%. wg Losses between Planes 1 and 4 and between Planes 2 and 5 have been ignored.9. HL = 0.52 hp Eqn B = 25 [(24.0694/0.1 in Annex L indicates estimated belt drive loss of 4.9.0694/0.0694 lbm/ft3: SEF 2 = 0.(-1.92) .90 hp H = Hmo .8/12.03 in. Figure 8.42 in.075 lbm/ft3.AMCA 203-90 (R2007) FAN POWER INPUT Measured amps/FLA = (24.0694) = 0.4)2 (0.0.61 in.0694/0.0)2 (0.46 = 0.0694) = 0.044 (29.0694) = 26015 cfm V2 = (Q2/A2) = (26015/8. Eqn A = 25 (24.26 in.22 + 0. wg Ps = Ps2 .Pv1 + SEF 1 + SEF 2 = 1.1.90 = 17. as supplied and rated by the manufacturer. 6. Procedures for traverses are described in Section 9. 5. the area of the traverse plane. the conditions which exist at Plane 3 are assumed to exist at Plane 1. Record all pertinent motor nameplate data. 2. Measure td3 and tw3 in the traverse plane. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. located at the tip of the Pitot-static tube and A1. watts. includes the inlet box damper and the inlet box. and if possible. Determine Ps2 by averaging the pressure measurements at each of four static pressure taps located near the end of the fan outlet. Measure td2 in Plane 2. including volts (NPV). To calculate the Fan Static Pressure: Ps = Ps2 . 3.Ps1 . it is necessary to measure the length of the outlet duct. Determine Ps3 by averaging the static pressure measurements made in the same traverse. the fan outlet area. See Annex E for details of static pressure taps. In order to compare the test results to the quoted fan curve drawn for operation at 1780 rpm and 0.AMCA 203-90 (R2007) EXAMPLE 2D: CENTRIFUGAL FAN IN A SCRUBBER SYSTEM INLET BOX DAMPER STATIC PRESSURE TAPS SEF 1 3 1 L INLET BOX 2 DIFFUSER SIDE VIEW OUTLET SIDE VIEW COMMENTS 1. Determine pb for the general vicinity of the fan. These measurements are used in the determination of densities at the various planes of interest. and the blast area of the fan. and full load amps (FLA).059 lbm/ft3 density. SEF 1 is due to the effect of insufficient length of duct at the fan outlet. In order to calculate the value of SEF 1. 4. Refer to Annex K. it is necessary to convert the results 45 . Therefore. A2. If the motor power output is to be estimated by using the phase current method described in Annex K. 8. Measure the fan speed and the motor amps. Measure A3. Ps1 = Ps3 and Pv1 = Pv3. volts.Pv1 + SEF 1 Since Plane 1 is located shortly downstream of Plane 3 in an airway of uniform cross-section (A1 = A3). it is not necessary to measure motor watts. the area of the inlet to the damper. Performance ratings for fans with inlet box dampers cover operation with the dampers in the full open positions.4. located shortly upstream of the inlet damper. In order to be able to compare the test results to the fan performance ratings. This fan. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. it is essential that the damper be fixed in the full open position for the duration of the test. L. 7. however. 5513 in.5 ft2 Blast Area = 1.5 = 3550 fpm Q3 = = = Q = = V3A3 3550 × 6. Hg Use the modified Apjohn equation.6 × 29.28   557  = 0.0610 lbm/ft 3 Consider ρ1 to be equal to ρ3.5 ft2 A2 = 5. 3 phase.0610     13. pe = 0.3257 ( 24.6 p3   t d2 + 460   1. 4150.44   523  = 0.2 in Annex N to calculate the density at Plane 3. wg Ps3 = -70.1 + 13.1 in.50 ft MEASURED MOTOR DATA Volts = 4160.89 ft2 L = 2.378 pp ) t d3 + 460 1.28 in.2. 52 = 51 av NLA = 14 MOTOR NAMEPLATE DATA 500 hp.44 + (-70.tw3)/2700] = 0. Fan direct connected to motor.6 × 24.2/13.[p3 (td3 .5513 ) 63 + 460 = 0.62)/2700] = 0.64/0. 51. wg Pv3 = 0. 4150 = 4153 av Amps = 50. described in Section M. Hg pp = pe .28 − 0.0696 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.14)] (4153/4160) = 393 hp Hmo = (417 + 393)/2 = 405 hp 46 . 61 FLA GENERAL Inlet box damper in full open position.14)/(61 .6 pb   t d3 + 460  ρ2 = ρ3  s2    13.2 in.378 × 0. Eqn A = 500 (51/61) (4153/4160) = 417 hp Eqn B = 500 [(51 . Hg ρ3 = = 1.6) = 29.AMCA 203-90 (R2007) to the specified conditions.28 (63 . The basis for the calculations is described in Section 14.6) = 24.3257( p3 − 0. wg N = 1790 rpm A1 = 6.5 23075 cfm Q1 = Q3 23075 cfm FAN POWER INPUT Measured amps/FLA = 51/61 = 0.5603 .5 = 1096 (0.44 in. 60 hertz 4160 volts. and the table in Figure N.32 ft2 A3 = 6. 1785 rpm. The density at Plane 2:  P + 13.3 in Annex M.[24. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 63°F tw3 = 62°F p3 = pb + (Ps3/13. Hg td2 = 97°F td3 = 63°F tw3 = 62°F Ps2 = 1.64 in. OBSERVATIONS SITE MEASUREMENTS pb = 29.84 = 84% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 500 hp motor operating at 84% FLA.5603 in.0610)0. 3 indicate the following calculations.64 + 0.1 . there is no drive loss.70. wg Pv3 0.36.89) 100 = (2. and: H = Hmo = 405 hp SYSTEM EFFECT FACTOR AMCA Publication 201-90.60 ft Figure 8.64 in.059/0.0696) = 20224 cfm V2 = Q2/A2 = 20224/5. Figure 8.1 shows SEF 1 = 0.5 = (4 × 5. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 23075 (1780/1790) = 22946 cfm Psc = 71.33 in.075 lbm/ft3.1 and 8.60 (3802/1000) = 9.50/9.0 (1780/1790)2 (0.0.059/0.9 in. wg Ps2 . At 0. wg FAN STATIC PRESSURE Ps1 = = Pv1 = = Ps = = = Ps3 .89/5.36 (0. Figures 7.0696/0.5 = 2.3 shows that for velocities over 2500 fpm 100% effective duct length is one duct diameter for every 1000 fpm: = De2 (V2/1000) = 2.0610/0.33 71.0 in.3 shows System Effect Curve U applies.075) = 0.32/π)0.89) 100 = 25% Blast area ratio = Blast Area/A2 = 1. Q2 = Q3 (ρ3/ρ2) = 23075 (0. L in % effective duct length: = (L/9.AMCA 203-90 (R2007) Since the fan is direct-connected to the motor.36 in.0610) = 67. and 25% effective duct length. wg at 0.32 = 3802 fpm Duct diameter equivalent to the diffuser outlet area: De2 = (4A2/π)0.89 ft.2 in.Pv1 + SEF 1 1.(-70.36 For a blast area ratio of 0. wg Hc = 405 (1780/1790)3 (0.0610) = 385 hp 47 .0696 lbm/ft3: SEF 1 = 0.32 = 0. For 3802 fpm velocity and curve U.Ps1 .2) . Figure 7. Since flue gas is being handled by the fan. it is essential that the outlet damper and the inlet dampers be fixed in their full open positions. Measure td3a.AMCA 203-90 (R2007) EXAMPLE 2E: CENTRIFUGAL FAN IN A PROCESS SYSTEM STATIC OUTLET DAMPER PRESSURE TAPS 5 2 INLET BOXES INLET BOX DAMPERS 1a 3a 1b 3b SIDE VIEW OPPOSITE OUTLET SIDE VIEW COMMENTS 1. Determine pb for the general vicinity of the fan. it is not necessary to measure motor watts. Procedures for traverses are described in Section 9. however. Record all pertinent motor nameplate data. supplied by the motor manufacturer. 2. To calculate the Fan Static Pressure: Ps = Ps2 .4. watts. Measure the fan speed and the motor amps. includes the inlet box dampers and the inlet boxes. the areas of the inlets to the inlet dampers. Performance ratings for fans with inlet box dampers cover operation with the dampers in the full open positions. but does not include the outlet damper. the Orsat apparatus is used by process personnel to determine the density of the gas. 6. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. Determine Ps3a and Ps3b by averaging each of the two sets of static pressure measurements made in the same traverses. If the motor power output is to be estimated by using the phase current method described in Annex K. Determine Pv3a and Pv3b by using the root mean square of the velocity pressure measurements made in Planes 3a and 3b. These data are used in the determination of densities at the various planes of interest. Motor performance data. including volts (NPV) and full load amps (FLA). the areas of the traverse planes and A1a and A1b. 5. Measure A3a and A3b. 4. the duct downstream of the outlet damper is of sufficient length. 7. as supplied and rated by the manufacturer. This fan. Determine Ps5 by averaging the pressure measurements of each of four static pressure taps located downstream of the outlet damper. volts. In order to be able to compare the test results to the fan performance ratings. td3b. and td5. 3. are used in the determination of motor power output for this example. Also.Ps1 . and no SEF applies. performance ratings for items such as the outlet damper are for operation in the full open position.Pv1 48 . In this example. and if possible. 880 rpm.0725    819  13.6 in. The basis for calculations is described in Section 14.6 × 29. Hg = 345°F = 359°F = 363°F = -18.0451 lbm/ft 3 It is assumed that ρ1a = ρ3a and ρ1b = ρ3b. Pressure loss data supplied by manufacturer of outlet damper.92 in.053 in.0468 lbm/f ft It is assumed that ρ2 = ρ5. as determined by Orsat analysis. wg = -18.0725    805  13. MEASURED MOTOR DATA Volts = = Amps = = kW = 4300.92   t d5 + 460   −1. the conditions which exist at the traverse planes are assumed to exist at the inlets to the inlet dampers.0725  s3b    13.6 × 30. wg = 2.5 = 7338 fpm Q3a = V3aA3a = 7338 × 60.7 ft2 A2 = 115 ft2 A3a = A3b = 60. wg = 2. 385 FLA GENERAL Inlet box dampers and outlet damper in full open positions. Fan direct connected to motor. 4200 4250 av 378.92   t d3b + 460   −18.92   t d3a + 460   −18.8 + 13. it is necessary to convert the results to the specified conditions.0725  s3a    13.6 pb   70 + 460  ρ5 = 0. wg = 892 rpm = A1b = 60. FLOW RATES V3a = 1096 (Pv3a/ρ3a)0. 380 378 av 2519 pb td3a td3b td5 Ps3a Ps3b Pv3a Pv3b Ps5 N A1a MOTOR NAMEPLATE DATA 3000 hp.12   530  = 0.92    = 0.7 = 445417 cfm 49 . wg = -1.6 × 29.0725 lbm/ft3 at 29.12   530  = 0.6 pb   70 + 460  ρ3a = 0.0458 lbm/ft 3  P + 13.8 in. 376. the outlet damper pressure loss. CALCULATIONS DENSITIES The densities at Planes 3a and 3b are:  P + 13.6 × 30.3 in.6 × 29.6 × 29.0725  s5    13. Hg and 70°F.6 × 29.7 ft2 A5 = 140 ft2 Blast Area = 80 ft2 The density of the gas.6 × 30.6 × 29. In order to compare the test results to the quoted fan curve drawn for operation at 880 rpm and 0.6 pb   70 + 460  ρ3b = 0.0458)0. OBSERVATIONS SITE MEASUREMENTS = 30. Pv1 = (Q1/1096A1)2 ρ1 8.92    3 = 0.5 = 1096 (2.053/0. Motor efficiency data supplied by motor manufacturer. and the calculated velocity pressures at Planes 2 and 5.028 in. 3 phase.0725    823  13.049 lbm/ft3 density.6 + 13.12 in.12   530  = 0.92    = 0. Ps1 = Ps3 = (Ps3a + Ps3b)/2 Pv1 is calculated using the total flow rate and the total area at the inlets to the inlet dampers. The density at Plane 5:  P + 13. 60 hertz 4000 volts.AMCA 203-90 (R2007) Ps2 is calculated on the basis of total pressure considerations using Ps5. is 0. 4250.3 + 13. Since the inlets to the inlet dampers (Planes 1a and 1b) are located shortly downstream of the traverse planes (Planes 3a and 3b) in an airway of uniform cross-section. 0455/0.028/0.5 = 7349 fpm Q3b = V3bA3b = 7349 × 60. Since the fan is direct connected to the motor.(-18.8 .4/140)2 (0.0455/0. and: H = Hmo = 3174 hp Ps = Ps2 .0451)0.0455) 891501 cfm FAN POWER INPUT Measured amps/FLA = (378/385) = 0.4/115)2 (0.Ps1 .18.0468) = 1.7 = 446084 cfm Q3 = Q3a + Q3b = 445417 + 446084 = 891501 cfm Since the air is divided evenly between the two inlet boxes: FAN STATIC PRESSURE Pv1 = (Q1/1096A1)2 ρ1 = (891501/1096 × 121. wg Pv5 = Pv1 (A1/A5)2 (ρ1/ρ5) = 2. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 891501 (880/892) = 879508 cfm Psc = 14.5 = 1096 (2.21 = -1.66 in.55 in.0458 + 0.57 in.746 = 3174 hp The more accurate method of estimating the motor power output is assumed to be the latter. Using this information: Hmo = (2519 × 0. wg Ps1 = = = = Ps3 (Ps3a + Ps3b)/2 (-18.AMCA 203-90 (R2007) V3b = 1096 (Pv3b/ρ3b)0. wg Hc = 3174 (880/892)3 (0. there is no drive loss.2.04 = 14.4)2 0.04 (121.75 .49 + 0.2.49 in.6 + 1.049/0.0468) = 2.Pv2 = -1.94)/0.55) .3)/2 -18. wg Pv2 = Pv1 (A1/A2)2 (ρ1/ρ2) = 2.049/0. wg Ps2 + Pv2 = Ps5 + Pv5 + Damper Loss Ps2 = Ps5 + Pv5 + Damper Loss .94 (880/892)2 (0.0455) = 15.57 .04 in.21 in.0455 = 2. Hmo = 3000 (378/385) (4250/4000) = 3130 hp The data supplied by the motor manufacturer indicate motor efficiency of 94% at the measured power input of 2519 kW.94 in.0455) = 3282 hp 50 .Pv1 = -1.0455/0.98 = 98% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 3000 hp motor operating at 98% FLA.0455 lbm/ft3 Q = = = = Q1 Q3 (ρ3/ρ1) 891501 (0.0451)/2 = 0. wg ρ1 = ρ3 = (ρ3a + ρ3b)/2 = (0.04 (121. Measure A4 and A5. it is necessary to measure the inlet area and the outlet area of the fan. and the lengths of the inlet and outlet duct connections. Determine pb for the general vicinity of the fan. Also. watts. 51 . 5. Measure td3 and tw3 in the traverse plane. such as shown in the diagram. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. volts. and if possible. as they are in this example. Unless the degrees of divergence and convergence are moderate. A3. SEF 2 is due to the effect of insufficient length of duct between the fan outlet and the elbow downstream of the fan. 2. Measure the area of the traverse plane. L1 and L2.4. Measure td4. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. The unusual duct arrangement in this example makes it very difficult to obtain accurate pressure measurements. These measurements are used in determining densities at the various planes of interest. motor amps. 6. supplied by the motor manufacturer. located well downstream in a straight run of duct. 4. Record all pertinent motor nameplate data. including volts (NPV) and full load amps (FLA).AMCA 203-90 (R2007) EXAMPLE 2F: AXIAL FAN IN A VENTILATION SYSTEM 3 GUIDE VANES 4 SEF 1 STATIC PRESSURE TAPS 5 2-PIECE ELBOW (TYPICAL) L1 1 INNER CYLINDER 2 L2 SEF 2 COMMENTS 1. SEF 1 is due to the effect of insufficient length of duct between the fan inlet and the elbow upstream of the fan. however. the cross-sectional areas of the duct connections at the static pressure taps. Measure the fan speed. Ps3 is used in determining the density at the traverse plane. A1 and A2. Procedures for traverses are described in Section 9. are used in the determination of motor power output for this example. Determine Ps4 by using static pressure taps in the duct connection at the fan inlet. Motor performance data. the use of a diverging inlet fitting and a converging outlet fitting with this fan can pose additional problems. In order to calculate the values of the SEFs. Determine Ps5 by averaging the pressure measurements at each of four static pressure taps located near the end of the duct connection at the fan outlet. the fan performance will be adversely affected. 3. and this fact should be understood before testing begins. it is not necessary to measure motor watts. Determine Ps3 by averaging the static pressure measurements made in the same traverse. If the motor power output is to be estimated by using the phase current method described in Annex K. 6 p3   t d4 + 460   −1. 60 hertz 52 .075 lbm/ft3 density. Motor efficiency data supplied by motor manufacturer. 24. Hg 82. The density at Planes 1 and 4: ρ1 = ρ 4  P + 13. The basis for the calculations is described in Section 14.0. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 82. The measured amps indicate that the motor is operating very close to the full load condition.5/13.8°F 57.0 ft 3.76 in. It is assumed ρ2 = ρ5 = ρ3.2°F p3 = pb + (Ps3/13. shown above. In order to compare the test results to the quoted fan curve drawn for operation at 1750 rpm and 0. wg A2 7. Fan speed measurement was not obtained due to the closed duct arrangements on both sides of the fan.80    = 0. wg 0.Ps1 .82 in.0728    540  13.5 ft 460 volts. 461.6 × 29.80 in. wg -1.1 in Annex N to obtain ρ3 = 0.5 = 1096 (0.0729) 17623 cfm MEASURED MOTOR DATA Volts = = Amps = = kW = 460.1 in. 1760 rpm.0728 lbm/ft3.1 ft2 A5 4.6 pb   t d3 + 460  = ρ3  s4    13.8°F tw3 = 57. To calculate the Fan Static Pressure: Ps = Ps2 .91 ft2 6.Pv1 + SEF 1 + SEF 2 Where: Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) Ps2 and Ps1 are calculated using measured static pressure values and constant total pressure considerations.91 = 17647 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 17647 (0.0728)0. Hg Use Figure N.0.76   542.5 = 3594 fpm Q3 = V3A3 = 3594 × 4.76 + (0.9 av 18. 8.5 in.6 FLA GENERAL Fan direct connected to motor. it is necessary to convert the results to the specified conditions.8  = 0. 3 phase.6) = 29.2 ft2 3. wg 0. 459 460 av 25. 25.783/0.0729 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.2°F 80°F 0. OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 td4 Ps3 Pv3 Ps4 Ps5 A1 A3 A4 L1 L2 = = = = = = = = = = = = = = = 29.0728/0.0 MOTOR NAMEPLATE DATA 20 hp. Ps1 + Pv1 = Ps4 + Pv4 Ps2 + Pv2 = Ps5 + Pv5 Where each velocity pressure is calculated in a manner similar to the calculation of Pv1.8 24. 24.6 × 29. so the rpm was assumed to be the motor nameplate value of 1760.6) = 29.783 in.1 + 13.AMCA 203-90 (R2007) 7. AMCA 203-90 (R2007) FAN POWER INPUT The data supplied by the motor manufacturer indicate motor efficiency of 87.53) 100 = 46% From Figure 8.0 × 0.37 in.00 AMCA Publication 201-90.25 (0.01 ft The length of the duct between the elbow and the fan inlet in terms of the fan inlet diameter: = (L1/D1) = (3. for a vaneaxial fan with a 46% effective duct length between its discharge and a two piece elbow.1.0.1 + 0.98 in. wg Pv2 = Pv3 (A3/A2)2 (ρ3/ρ2) = 0.0728) = 0.91/4.075) = 0.1 shows that for velocities of 2500 fpm or less.1 = 2485 fpm FAN STATIC PRESSURE Pv5 = Pv3 (A3/A5)2 (ρ3/ρ5) = 0.00 diameter System Effect Curve S-T applies.0728) = 0.1/π)0.91/7. For a velocity of 2482 fpm and curve S-T.1.2 indicates that for a two piece elbow with a length of duct between the elbow and the fan inlet equal to 1. and is considered negligible.0728) = 17647 cfm V2 = Q2/A2 = 17647/7.0728/0.1 in. 8.5 = 3. and 8. the 100% effective duct length is 2.0728/0. Figure 7.0728/0. wg For SEF 2.075 lbm/ft3.783 (4.1/π)0.783 in.91/7.746 = 21. there is no drive loss.49 .5 = (4 × 7.25 in. wg Ps1 + Pv1 = Ps4 + Pv4 Ps1 = Ps4 + Pv4 .24 in.1 hp Since the fan is direct connected to the motor. AMCA Publication 201-90. wg Pv1 = Pv3 (A3/A1)2 (ρ3/ρ1) = 0.1) = 2482 fpm Diameter of the fan inlet: SEF 2 = 0. wg Ps2 + Pv2 = Ps5 + Pv5 Ps2 = Ps5 + Pv5 .91/6. Figure 9. Using this information: Hmo = (18. wg Diameter of the fan outlet: D2 = (4A2/π)0. At 0.5 diameters: = 2.37 = -0.82 + 0.01 = 7.37 = 1.37 in.0.23 in.Pv1 = -1. From Figure 7.01) = 1.0/3.783 (4.0728/0. System Effect Curve W applies.01 ft Figure 8. Figures 7.783 (4.4.0729 lbm/ft3: SEF 1 = 0.5 × 3.4 indicate the following calculations: Q2 = Q3 (ρ3/ρ2) = 17647 (0. and: H = Hmo = 21.5% at the measured power input of 18.91)2 (0.0729) = 0.875)/0.Pv2 = 0.1)2 (0. calculate the velocity at the fan inlet: V1 = (Q1/A1) = (17623/7.1 shows SEF 1 = 0.1 for 2485 fpm velocity and curve W.0729/0.5 = 3.783 (4.0 kW.53 ft The length of the outlet duct in % effective duct length: = (L2/7.1)2 (0.53) 100 = (3.00 D1 = (4A1/π)0. wg at 0. SEF 2 is less than 0.5/7.49 in.1 hp SYSTEM EFFECT FACTORS To determine the value of SEF 1.783 . wg Pv4 = Pv3 (A3/A4)2 (ρ3/ρ4) = 0.2)2 (0.5 = (4 × 7.0729) = 0.0728/0. 53 . wg Hc = 21.23 .08 in. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 17623 (1750/1760) = 17523 cfm Psc = 2.24 + 0 = 2.AMCA 203-90 (R2007) Ps = Ps2 .0729) = 2.(-0.1 (1750/1760)3 (0.12 in.Ps1 .075/0.37 + 0.98) .08 (1750/1760)2 (0.3 hp 54 .075/0.Pv1 + SEF 1 + SEF 2 = 1.0729) = 21.0. This example is no exception. however. Determine the static pressures at Planes 1a. and if possible. Procedures for traverses are described in Section 9. volts. Ps3 is used in determining the density at the traverse plane. The two single inlet fans in this example have been rated by the manufacturer as a two stage assembly. it may be necessary to disconnect the drives and measure the no load amps (NLA) if the motors are not operating at or near their full load points. watts for each fan. such as the one shown in the diagram. In each case. In this example. Although rated as an assembly. and td2b. 5. These measurements are used in determining densities at the planes of interest. a watts input measurement is made for 55 . 3. The damper downstream of the second fan is not included as part of the rated assembly. A3. Determine pb for the general vicinity of the fan. Therefore. tw3. which is located at the tip of the Pitot-static tube.AMCA 203-90 (R2007) EXAMPLE 2G: HIGH PRESSURE CENTRIFUGAL FAN IN A SERIES 3 2b STATIC PRESSURE TAPS 1b 2a 1a FAN B DAMPER INLET BOX FAN A SIDE VIEW INLET BOX COMMENTS 1. due to the turbulence existing in the regions of the outlets of the fans. In virtually all cases in which an air flow control damper. and 2b. Measure td3. Measure the fan speed and the motor amps. sufficient measurements are made to provide performance data for each fan. the conditions which exist at the plane of measurements are assumed to exist at the respective plane of interest because of the close proximity and the fact that the two planes are equal in area. The static pressure at each plane may be determined by averaging the static pressure measurements at each of four static pressure taps. it is recommended that static pressure taps be used at Planes 1b-2a and 2b. these planes are located shortly downstream of the inlets and outlets of the fans. it is not necessary to measure motor watts. which are the planes of interest. Record all pertinent motor nameplate data. td1a is assumed to be equal to td3. Determine Ps3 by averaging the static pressure measurements made in the same traverse. is included in the system. 2. or by averaging the static pressure measurements made in a Pitot-static tube traverse of the plane. including volts (NPV). As shown in the diagram. 1b2a.4. it is essential that the damper be fixed in its full open position for the duration of the test. If the motor power outputs are to be estimated by using the phase current method described in Annex K. td1b. and full load amps (FLA). 4. However. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. the point of operation of major interest and for which the fan has been selected is at the maximum air flow rate. 61 in. Hg pp = pe − p3 (t d3 − t w3 ) 2700 17. 7.5.5 in. Hg 35°F 33°F td2a 95°F 147°F 0. and the data in Figure N.5 FLA MEASURED MOTOR DATA First Stage Volts = = Amps = = kW = ρ3 = = 4000. supplied by the motor manufacturer. 1790 rpm. 4040. wg -150 in.5. In order to compare the test results to the performance quoted for the two stage assembly for operation at 1780 rpm and 0. 4020 = 4047 av Amps = 44.Ps1a .3257 (17. 45 = 44.5 in.5 av kW = 272 MOTOR NAMEPLATE DATA Data identical for each stage: 350 hp. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 35°F tw3 = 33°F p3 = pb + (Ps3/13.1879 in.61(35 − 33) = 0.1749 ) Second Stage Volts = 4080. Therefore: 56 .1879 − 2700 = 0.045 lbm/ft3 density.6 ft2 4. 6.3257( p3 − 0. wg 1790 rpm. 45. pe = 0.378 × 0. 45. 4040. 44. it is necessary to convert the results to the specified conditions. 3 phase. 44.378 pp ) t d3 + 460 1.1749 in.6) = 17.61 − 0.64 in.AMCA 203-90 (R2007) each motor and motor performance data. second stage fan speed A2a = A1b = A2b 5. To calculate the static pressure for the two stage assembly: Ps = Ps2b . wg 0. 60 hertz 4000 volts.6) = 28.92 ft2 Fans direct connected to motors. OBSERVATIONS SITE MEASUREMENTS = = = = = td2b = Pv3 = Ps3 = Ps1b = = Ps2b = Na = Nb = A1a = = A3 = pb td3 tw3 td1b 28.0470 lbm/ft 3 Any conversion of velocity pressure to static pressure which may occur between Planes 3 and 1a can be ignored with no significant effect on the accuracy of the test results.5 45 av 278 35 + 460 = 0. wg Ps2a -79. first stage fan speed 1790 rpm. both of which are described in Annex M. Hg 1.Pv1a GENERAL Where: Pv1a = Pv3 (A3/A1a)2 (ρ3/ρ1a) 8.745 in.64 + (-150/13. Motor efficiency data supplied by motor manufacturer. are used in determining motor power outputs. 4080 4040 av 44. The basis for the calculations is described in Section 14. The SEF which would normally be attributed to insufficient length of duct at the outlet of the first stage fan does not apply in this case because the fans have been rated as an assembly. Hg Use the modified Apjohn equation for partial vapor pressure and the density equation based on perfect gas relationships.2 in Annex N to calculate the density at Plane 3. 5 .0470) 21471 cfm Q2a Q3 (ρ3/ρ2a) 21471 (0.0470/0.0470) = 0.9 in.0470     13.6 × 28.0543) 18584 cfm Hb FAN STATIC PRESSURE Pv1a = Pv3 (A3/A1a)2 (ρ3/ρ1a) = 0.92 = 21471 cfm Q = = = = Q1a Q3 (ρ3/ρ1a) 21471 (0.0. additional density values are calculated as follows: ρ1b = ρ2a  P + 13.9 in. wg Assuming no change in temperature between Planes 3a and 1a: FAN POWER INPUT At the measured power input values of 278 kW and 272 kW.0470    555  13. wg Psc Hac = 354 (1780/1790)3 (0.0543 lbm/f  P + 13.0470/0.0624) = 16172 cfm 57 .6 × 17.746 = 354 hp Hmob = (272 × 0.575 in.0470) = 326 hp Q1b = = = = Q2b = Q3 (ρ3/ρ2b) = 21471 (0.0470) = 141.045/0.95)/0.745/0. the data supplied by the motor manufacturer indicate efficiency of 95% for each motor. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 21471 (1780/1790) = 21351 cfm = 149.045/0.0470 lbm/ft3 To provide information regarding the flow rates between stages and leaving the second stage.5 + 13.0470/0.AMCA 203-90 (R2007) Ps1a = Ps3 = -150 in. Hmoa = (278 × 0.9 (1780/1790)2 (0.6 pb   t d3 + 460  = ρ3  s1b    13.61    ft 3 = 0.(-150) .64   495  = 0. there are no drive losses and: Ha = Hmoa = 354 hp = Hmob = 346 hp ρ1a = ρ3 = 0.92/5.Pv1a = 0.6 pb   t d3 + 460  ρ2b = ρ3  s2b    13.95)/0.5 = 4364 fpm Q3 = V3A3 = 4364 × 4.745 (4.5 = 1096 (0.0470)0.6 × 28.Ps1a . wg The static pressure for the two stage assembly: Ps = Ps2b .0470) = 333 hp Hbc = 346 (1780/1790)3 (0.0624 lbm/ft t3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.6 p3   t d4 + 460   −79.045/0.0470/0.5 + 13.6 × 17.746 = 346 hp Since each fan is direct connected to its motor.6 p3   t d2b + 460   0.575 = 149.64   495  = 0.61   607  = 0.6)2 (0. the static pressure at the fan inlet may be determined by averaging the static pressure measurements at each of four static pressure taps or by averaging the static pressure measurements made in a Pitot-static tube traverse of Plane 1. a measurement plane which provides a satisfactory velocity profile cannot be located within the short length of duct between the point of connection of the branch ducts and the fan inlet. The velocity pressure for each branch is determined by using the root mean square of the velocity pressure measurements made in the traverse. The alternative. Measure the fan speed and the motor amps. Normally. Measure the area of Plane 1 for use in calculating Pv1. Record all pertinent motor nameplate data. The static pressure at each traverse plane is determined by averaging the static pressure measurements made in the same traverse. Procedures for traverses are described in Section 9. as supplied and rated by the manufacturer. In this example. the air may be discharging from the damper into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred. 2. referred to the atmospheric pressure in the region of the outlet of the backdraft damper. watts. When this possibility exists. is to make a velocity pressure measurement traverse in the longest available duct run of each branch. velocity pressure measurements would be made in a single plane. 4. it is essential that the static pressure in the region of the discharging air be measured. If a 58 Pitot-static tube is used. In order to determine the air flow rates it is necessary to measure the area of each traverse point. including volts (NPV) and full load amps (FLA). The static pressure at the outlet of the backdraft damper is zero gauge pressure. 5. This fan. These measurements are used in determining densities at the planes of interest. located in a duct common to all branches. volts. referred to the same atmospheric pressure as used in all other pressure measurements. Ps1. 3. td2 is assumed to be equal to td1. and if possible. it should be positioned well within the inlet collar in which Plane 1 is located. In situations such as this example. In this example. does not include the backdraft damper. If the motor power output is to be . as indicated in the diagram.4.AMCA 203-90 (R2007) EXAMPLE 3A: CENTRIFUGAL FAN IN AN EXHAUST SYSTEM AIR INTAKE VENTS BACKDRAFT DAMPER SEF 1 3a 3c 2 3b 1 STATIC PRESSURE TAPS PLAN VIEW COMMENTS 1. Determine pb for the general vicinity of the fan. Measure the dry-bulb and wet-bulb temperatures at each velocity traverse plane and the dry-bulb temperature at Plane 1. These static pressure values are used in determining the densities at the traverse planes. wg = 800 rpm = 16. Refer to Annex K.0731)0. wg = 0. SEF 1 is due to the effect of there being no duct at the fan outlet. Hg 72°F 62°F 77°F 67°F 65°F 56°F 70°F 62°F -1. and the blast area of the fan. 458. 32 FLA GENERAL Fan connected to motor through belt drive. it is necessary to convert the results to the specified conditions.1 in Annex N.0 ft2 Blast Area = 11. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point.0750)0.8 in. no appreciable error will occur by using the barometric pressure instead of the absolute pressure at each plane in the determination of the densities.Ps1 . The use of the multiplier is indicated because the damper is mounted directly to the fan outlet. Pv3a Pv3b Pv3c N A1 A2 A3a A3b = 0.765 in.765/0. and 3c are very small.5 = 1096 (0.5 = 3754 fpm 59 . it is not necessary to measure motor watts.86 in. 8. it is necessary to measure the outlet area of the fan.8 ft2 = 13. 3b.88 in. which was measured as zero. CALCULATIONS DENSITIES Since the static pressure values at Planes 1.80 in. however.88/0.040 in.45 in. and the backdraft damper pressure loss.Pv1 + SEF 1 Where: Pv1 = (Q1/1096 A1)2 ρ1 Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) + Q3c (ρ3c/ρ1) Ps2 is the sum of the static pressure in the region of the damper outlet. Determine the backdraft damper pressure loss by using the performance ratings supplied by the manufacturer and the pressure loss multiplier data in Figure 8.5 = 1096 (0. 3 phase. wg -0. 3a. OBSERVATIONS SITE MEASUREMENTS pb td1 tw1 td3a tw3a td3b tw3b td3c tw3c Ps1 Ps3a Ps3b Ps3c = = = = = = = = = = = = = 29.4 ft2 = A3c = 3. The basis for the calculations is described in Section 14.0741 lbm/ft3 lbm/ft3 lbm/ft3 lbm/ft3 FLOW RATES V3a = 1096 (Pv3a/ρ3a)0.0750 0. wg -0. 27.0 ft2 MEASURED MOTOR Volts = = Amps = = NLA = 460. A2.00 in.7 ρ1 ρ3a ρ3b ρ3c = = = = 0.7 of AMCA Publication 201-90. wg = 0. To calculate the Fan Static Pressure: MOTOR NAMEPLATE DATA Ps = Ps2 .AMCA 203-90 (R2007) estimated by using the phase current method described in Annex K. 462 460 av 28. wg -0.8 ft2 = 5. 6. In order to calculate the value of SEF 1.0739 0.075 lbm/ft3 density. Pressure loss data supplied by manufacturer of backdraft damper. 60 hertz 460 volts.0731 0.5 = 3546 fpm V3b = 1096 (Pv3b/ρ3b)0. 1760 rpm. 7. The densities at these planes are obtained by using Figure N. wg 25 hp. 26 27 av 14. In order to compare the test results to the quoted fan curve drawn for operation at 810 rpm and 0. 9. 0739      = 41603 cfm SYSTEM EFFECT FACTOR AMCA Publication 201-90. wg Ps2 is equal to the static pressure at the outlet of the damper.5 = 3734 fpm Q3a = V3aA3a = 3546 × 5.0. Backdraft damper loss = ∆Ps × 1.8)]2 0.45 = 0.80 For a blast area ratio of 0.0741  = 19148   + 11262  0.075) = 0.0739   0.075) = 0. Figures 7.0) .048 × 19. Figure 7.1 shows SEF 1 = 0.27 (0.0739  + 11202  0. wg BACKDRAFT DAMPER LOSS MULTIPLIER The data supplied by the manufacturer of the damper indicate that the pressure loss for the damper.8 = 0.(-1. which is zero.52 hp 60 .75 0.8.45 .1 and 8. Figure 8.0 = 11202 cfm Q = Q1 = Q3a ( ρ3a / ρ1 ) + Q3 b ( ρ3 b / ρ1 ) + Q3c ( ρ3c / ρ1 )  0.0731   0.0/13.5 = 1096 (0.0750   0.3 indicate the following calculations: Q2 = Q1 = 41603 cfm It is assumed that ρ2 = ρ1. is 0.0.75 . V2 = (Q2/A2) = (41603/13.8 hp Hmo = (21.7 indicates a ∆Ps multiplier of 1. wg at 0.84 = 84% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 25 hp motor operating at 84% FLA.0739 = 0.4 = 19148 cfm Q3b = V3bA3b = 3754 × 3.0739/0.1 in Annex L indicates estimated belt drive loss of 4.75 in.0739/0. wg FAN STATIC PRESSURE Pv1 = (Q1/1096 A1)2 ρ1 = [41603/(1096 × 16.4 × 1.64 in.93 = 18. For 3015 fpm velocity and curve T-U. At 0.8 and no duct. wg at the flow rate of 41603 cfm at 0.38 + 0.9 (0.Pv1 + SEF 1 0.0 = 11262 cfm Q3c = V3cA3c = 3734 × 3.3 shows System Effect Curve T-U applies.27 1. plus the damper loss.75 in.9 × (ρ2/0.9 for a damper which is mounted directly to the outlet of a fan which has a blast area ratio of 0. wg FAN POWER INPUT Measured amps/FLA = (27/32) = 0.8) = 3015 fpm Blast area ratio = Blast area/A2 = 11.45 hp Figure L.38 in.0741)0.7)] (460/460) = 17.075 lbm/ft3 density. Eqn A = 25 (27/32) (460/460) = 21.1 + 17. HL = 0.HL = 19. AMCA Publication 201-90.075 lbm/ft3 density.93 hp H = Hmo .Ps1 .7)/(32 .27 in.8)/2 = 19.14.8%.0739 lbm/ft3: SEF 1 = 0.14.048 Hmo = 0.075) = 0. Ps2 = = = Ps = = = 0 + damper loss 0 + 0. Figure 8.27 in. ∆Ps.86/0.AMCA 203-90 (R2007) V3c = 1096 (Pv3c/ρ3c)0.4 in.1 hp Eqn B = 25 [(27 . wg Ps2 . 51 hp 61 .52 (810/800)3 (0.075/0.075/0.71 in.AMCA 203-90 (R2007) CONVERSION TO SPECIFIED CONDITIONS Qc = 41603 (810/800) = 42123 cfm Psc = 1.64 (810/800)2 (0.0739) = 1.0739) = 19. wg Hc = 18. 3. L1 and L2. 2. Record all pertinent motor nameplate data. volts.4. Determine Ps5 by averaging the pressure measurements at each of four static pressure taps located near the end of the duct connection at the fan outlet. A1 and A2. Measure the area of the traverse plane. it should not project into the upstream elbow but be located well within the length of the duct connection. Ps3 is used in determining the density at the traverse plane. located near the end of a straight run of duct.AMCA 203-90 (R2007) EXAMPLE 3B: AXIAL FAN IN AN EXHAUST SYSTEM 3 2-PIECE ELBOW SEF 1 L1 1 STATIC PRESSURE TAPS GUIDE VANES INNER CYLINDER 2 L2 SEF 2 5 PLAN VIEW COMMENTS 1. and if possible. Procedures for traverses are described in Section 9. A3. it is not necessary to measure motor watts. SEF 1 is due to the effect of insufficient length of duct between the fan inlet and the elbow upstream of the fan. td1 is assumed to be equal to td3. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. In order to calculate the values of the SEFs. These measurements are used in determining densities at the planes of interest.Pv1 + SEF 1 + SEF 2 Where: Pv1 = Pv3 Since: A1 = A3 And: . SEF 2 is due to the effect of insufficient length of duct between the fan outlet and the elbow downstream of the fan. Determine pb for the general vicinity of the fan. and full 62 load amps (FLA). it is necessary to measure the inlet area and the outlet area of the fan. Determine Ps1 by using a Pitot-static tube or static pressure taps in the duct connection at the fan inlet. including volts (NPV). To calculate the Fan Static Pressure: Ps = Ps2 . Measure the fan speed and the motors amps. Measure td5. If a Pitot-static tube is used. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. If the motor power output is to be estimated by using the phase current method described in Annex K. Refer to Annex K. as shown in the diagram. Determine Ps3 by averaging the static pressure measurements made in the same traverse. which is located at the tip of the Pitot-static tube. 6.Ps1 . 5. 4. watts. and the lengths of the inlet and outlet duct connections. Measure td3 and tw3 in the traverse plane. however. 92 in. 228 228 av 12.0719 lbm/ft3. all conditions which exist at Plane 5 are assumed to exist at Plane 2. wg 0.02 + 13.0719    533  13. 60 hertz 230 volts. 14.20   532  = 0.3.0719/0. 229. wg -1.64 ft2 1. The basis for the calculations is described in Section 14.AMCA 203-90 (R2007) ρ1 = ρ3 Due to the close proximity of Planes 2 and 5 and the fact that there is no change in area between the two planes.0721) 6366 cfm 63 MEASURED MOTOR DATA Volts = = Amps = = NLA = 227. Hg Use Figure N. In order to compare the test results to the quoted fan curve drawn for operation at 1730 rpm and 0. 3 phase.64 = 6384 cfm Q = = = = Q2 = = = = Q1 Q3 (ρ3/ρ1) 6384 (0.06    = 0.20 + (-1.6 p3   t d1 + 460   −2.10 + 13.02 in. 12.0719)0.6 pb   t d3 + 460  = ρ3  s5    13.6 × 29.0719) 6384 cfm Q5 Q3 (ρ3/ρ5) 6384 (0.5 = 1096 (0.06 in.5 = 2418 fpm Q3 = V3A3 = 2418 × 2.6 × 29. Assume that td1 = td3.0719    532  13.0 FLA GENERAL Fan connected to motor through belt drive.2. it is necessary to convert the results to the specified conditions. length of inlet duct 2.20   532  = 0.06    = 0.  P + 13. 1760 rpm.6) = 29. .10 in.6 pb   t d3 + 460  ρ1 = ρ3  s1    13.6 × 29. Therefore: Ps2 = Ps5 7.25 ft.1 in Annex N to obtain ρ3 = 0.6 p3   t d5 + 460   0.92/13.6 × 29. wg 0. 12.20 in.3 av 7 MOTOR NAMEPLATE DATA 5 hp.0721 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.0719 lbm/ft 3 Assume that td2 = td5 and Ps2 = Ps5. ρ 2 = ρ5  P + 13.35 in.0719/0.5 ft. wg 1710 rpm A2 = A3 = A5 2.4 12.6) = 29.35/0. Hg 72°F 66°F 73°F -2. length of the outlet duct DENSITIES CALCULATIONS For Plane 3 conditions of: td3 = 72°F tw3 = 66°F p3 = pb + (Ps3/13.075 lbm/ft3 density. OBSERVATIONS SITE MEASUREMENTS = = = = = = = = = = = L1 = L2 = pb td3 tw3 td5 Ps1 Ps3 Pv3 Ps5 N A1 29. wg For SEF 2.HL = 4. for a vaneaxial fan with a 49% effective duct length between its discharge and a two piece elbow.24 (0.075) = 0.4 indicate the following calculations: V2 = (Q2/A2) = (6366/2.23 in.58) 100 = (2. Figure 9.5 = (4 × 2.0. Figures 7.1 shows that for velocities of 2500 fpm or less.3/14) (228/230) = 4.063 × 4.1 in Annex L indicates estimated belt drive loss of 6. wg Figure L. From Figure 7. SEF 2 is less than 0.83 ft Figure 8.26 hp H = Hmo . Calculate the length of duct between the elbow and the fan inlet in terms of the fan inlet diameter: = (L1/D1) = (1.35 + 3.5 = (4 × 2.35 hp Eqn B = 5 [(12. wg at 0.05 .5/1.00 in.5 = 1.075 lbm/ft3 density. calculate the velocity at the fan inlet: V1 = (Q1/A1) = (6384/2.24 in. indicates that for a vaneaxial fan with a two piece elbow with a length of duct between the elbow and the fan inlet equal to 0.58) 100 = 49% From Figure 8. Figure 7.00 = 2. and is considered negligible.(-2.64) = 2411 fpm The diameter of the fan outlet: D2 = (4A2/π)0.79 hp SYSTEM EFFECT FACTORS To determine the value of SEF 1.3 .23 + 0.0719 lbm/ft3: SEF 1 = 0.1 shows SEF 1 = 0. and 8.26 = 3. System Effect Curve R-S (estimated) applies.10 .0719/0.Pv1 + SEF 1 + SEF 2 = 0.25/4.7)] (228/230) = 3.7)/(14 .82 AMCA Publication 201-90.64) = 2418 fpm .8 diameters.2.1.58 ft The length of the outlet duct in % effective duct length: = (L2/4.3%. HL = 0.0) = 0.83 = 4.83 ft.AMCA 203-90 (R2007) FAN POWER INPUT Measured amps/FLA = (12. SEF 2 = 0.1.05 = 0.Ps1 .063 Hmo = 0.64/π)0. System Effect Curve W applies.88 = 88% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 5 hp motor operating at 88% FLA.5 diameters: = 2.0.02) .1.64/π)0. At 0. For 2418 fpm velocity and curve 64 Since: A 1 = A3 ρ1 = ρ3 Pv1 = Pv3 Ps = Ps2 . for 2411 fpm velocity and curve W.3/14. 8. AMCA Publication 201-90.1 in. the 100% effective duct length is 2.5 × 1. wg.83) = 0.05 hp R-S.75)/2 = 4.35 + 0. Eqn A = 5 (12.00 Calculate the diameter of the fan inlet: FAN STATIC PRESSURE D1 = (4A1/π)0.75 hp Hmo = (4.5 = 1.4. wg Hc = 3.0719) = 2.14 in.09 hp 65 .AMCA 203-90 (R2007) CONVERSION TO SPECIFIED CONDITIONS Qc = 6384 (1730/1710) = 6459 cfm Psc = 2.075/0.00 (1730/1710)2 (0.075/0.0719) = 4.79 (1730/1710)3 (0. 3. is zero. Determine pb for the general vicinity of the fan. Due to the close proximity of Planes 1 and 3. 2. In locating Plane 3 downstream of the scrubber. In order to calculate the value of SEF 1. These measurements are used in determining densities at the planes of interest. including volts (NPV). Measure td3 and tw3 in the traverse plane. and the fact that there is no change in area between the two planes.AMCA 203-90 (R2007) EXAMPLE 3C: CENTRIFUGAL FAN IN A SCRUBBER SYSTEM 3 1 WET CELL SCRUBBER 2 SEF 1 PLAN VIEW SIDE VIEW COMMENTS 1. however. . Record all pertinent motor nameplate data. Ps3 is used in determining the density at the traverse plane. as shown in the diagram. and full load 66 amps (FLA). it is necessary to convert the results to the specified conditions.071 lbm/ft3 density. If the motor power output is to be estimated by using the phase current method described in Annex K. it is necessary to measure the outlet area of the fan. the static pressure at the fan outlet. Measure the area of the traverse plane. In order to compare the test results to the quoted fan curve drawn for operation at 1700 rpm and 0. changes in the composition of the air as a result of the action of the scrubber are properly taken into account in the determination of fan air flow rate. which is located at the tip of the Pitot-static tube. A2.Ps1 . and if possible. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. Procedures for traverses are described in Section 9. volts. To calculate the Fan Static Pressure: Ps = Ps2 . Determine Ps3 by averaging the static pressure measurements made in the same traverse. watts.Pv1 + SEF 1 Where: Pv1 = Pv3 Ps1 = Ps3 Ps2 = 0 7. Measure td2. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. located in the duct connection at the fan inlet. Measure the fan speed and the motor amps. Refer to Annex K. The basis for the calculations is described in Section 14. SEF 1 is due to the effect of there being no duct at the fan outlet.4. A3. the conditions which exist at Plane 3 are assumed to exist at Plane 1. 5. and the blast area of the fan. it is not necessary to measure motor watts. 4. 6. Ps2. 6 = 34.80   525  = 0. 1780 rpm.5/49) (457/460) = 36. It is assumed that: td1 = td3 Ps1 = Ps3 ρ1 = ρ3 Q2 = Q3 (ρ3/ρ2) = 16605 (0.1 in Annex N to obtain ρ3 = 0.06 ft2 A2 = 5.5 hp SYSTEM EFFECT FACTOR AMCA Publication 201-90.AMCA 203-90 (R2007) OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 td2 Ps3 Pv3 N A1 = 29. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 65°F tw3 = 64°F p3 = pb + (Ps3/13.6 p3   t d2 + 460   0 + 13.5 av  P + 13. 458.6 × 29.0732     13.5/49) = 0.0732)0.6 × 29.1 .15 ft2 Blast Area = 3.6) = 29. 45. indicate the following calculations: 67 .21 in.0/13. wg = 1672 rpm = A3 = 7. 3 phase. Hg Use Figure N. 44.5 44.045 Hmo = 0.1 in Annex L indicates estimate belt drive loss of 4. Hmo = 40 (44. wg = 0.1 = 1.045 × 36.5%. HL = 0.67 ft2 MEASURED MOTOR DATA Volts = = Amps = = 450.0740 lbm/ft 3 FLOW RATES V3 = 1096 (Pv3/ρ3)0.91 = 91% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 40 hp motor operating at 91% FLA.337/0.5 = 2352 fpm Q3 = V3A3 = 2353 × 7.0732/0.1.3.80 + (-8.337 in.0732) 16605 cfm MOTOR NAMEPLATE DATA 40 hp.0732/0.0732 lbm/ft3. Figures 7. Hg = 65°F = 64°F = 70°F = -8.1 and 8.6 pb   t d3 + 460  ρ2 = ρ3  s2    13. 60 hertz 460 volts.0 in.80 in. 462 457 av 44.6 hp H = Hmo .1 hp Figure L.6) = 29.21   530  = 0.0740) = 16425 cfm FAN POWER INPUT Measured amps/FLA = (44. 49 FLA GENERAL Fan connected to motor through belt drive.5 = 1096 (0.06 = 16605 cfm Q = = = = Q1 Q3 (ρ3/ρ1) 16605 (0.HL = 36. 337 in.071/0.071/0.71 For a blast area ratio of 0.15 in.49 = 8. At 0.15) = 3189 fpm Blast area ratio = Blast area/A2 = 3.5 in.AMCA 203-90 (R2007) V2 = (Q2/A2) = (16425/5.15 (1700/1672)2 (0.17 in.3 shows System Effect Curve S applies.(-8.0.Ps1 . Figure 7.1 shows SEF 1 = 0.0740 lbm/ft3: SEF 1 = 0.075) = 0.15 = 0.2 hp 68 .0732) = 35.67/5.0732) = 8. wg at 0.075 lbm/ft3 density.Pv1 + SEF 1 = 0 .7 and no duct.49 in. wg Hc = 34.5 (0. Figure 8. wg FAN STATIC PRESSURE Pv1 = Pv3 = 0. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 16605 (1700/1672) = 16883 cfm Psc = 8. For 3189 fpm velocity and curve S.0) .337 + 0.074/0.5 (1700/1672)3 (0. wg Ps = Ps2 . otherwise uneven velocity distribution will occur at the inlet to the ventilator. If a Pitot-static tube is used. Ps2 was measured as zero. is to make a velocity pressure measurement traverse in each branch.4. referred to the same atmospheric pressure as used in all other pressure measurements. In order to determine the air flow rates. td1 and td4 are assumed to be equal to td3a. Ps4 may be determined by averaging the static pressure measurements at each of four static pressure taps or by averaging the static pressure measurements made in a Pitot-static tube traverse of Plane 4. is zero gauge pressure. In this example. 3. 69 . Normally. Procedures for traverses are described in Section 9. a measurement plane which provides a satisfactory velocity profile cannot be located within the short length of duct between the point of connection of the branch ducts and the ventilator inlet. it is essential that the static pressure in the region of the discharging air be measured. and not project into the upstream elbows. A4 = A1. The alternative. Measure the area of Plane 1 for use in calculating Pv1. it is necessary to measure the area of each traverse plane. The static pressure at each traverse plane is determined by averaging the static pressure measurements made in the same traverse. 2. This centrifugal roof ventilator. located in a duct common to all branches. In this case. These measurements are used in determining densities at the planes of interest. Ps2. The velocity pressure for each branch is determined by using the root mean square of the velocity pressure measurements made in the traverse. In this example. the static pressure at the outlet of the ventilator.AMCA 203-90 (R2007) EXAMPLE 3D: CENTRIFUGAL ROOF VENTILATOR WITH DUCTED INLET 2 1 BACKDRAFT DAMPER 4 STATIC PRESSURE TAPS 3a SIDE VIEW 3b COMMENTS 1. In situations such as this example. it should be positioned well within the duct in which Plane 4 is located. Determine pb for the general vicinity of the fan. does not include the backdraft damper. the air may be discharging from the ventilator into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred. When this possibility exists. velocity pressure measurements would be made in a single plane. as indicated in the diagram. as supplied and rated by the manufacturer. These static pressure values are used in determining the densities at the traverse planes. 4. Measure the dry-bulb and wet-bulb temperatures at each velocity traverse plane. referred to the atmospheric pressure in the region of the ventilator outlet. In this example. It is essential that the backdraft damper blades be fixed in their full open positions. adversely affecting its performance. If the motor power output is to be estimated by using the phase current method described in Annex K.075 lbm/ft3 density. 5. Refer to Annex K. 3 phase.14 in. Use Figure N. 460 455 av 5. it is not necessary to measure motor watts.1 in Annex N to obtain: ρ3a = ρ3b = 0.5 = 1096 (0. 455.85/13.95 FLA GENERAL Fan connected to motor through belt drive.0721)0.20 + (-0.9 5.9 ft2 A3a = 3.85 in. and 4 are very small. wg Pv3a = 0.4 ft2 A3b = 3. 60 hertz 460 volts.7. no appreciable error will occur by assuming: ρ1 = ρ4 = ρ3a = ρ3b FLOW RATES V3a = 1096 (Pv3a/ρ3a)0. OBSERVATIONS SITE MEASUREMENTS pb = 29. watts. 5. wg Ps3a = Ps3b = -0.27 in. 6.AMCA 203-90 (R2007) 5. wg N = 625 rpm A1 = A4 = 7. Measure the fan speed and the motor amps.27/0. To calculate the Fan Static Pressure: Ps = Ps2 .275 in. volts. Hg MEASURED MOTOR DATA Volts = = Amps = = 450. it is necessary to convert the results to the specified conditions. wg Pv3b = 0. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. 5.5 = 2121 fpm 70 .Ps1 .backdraft damper pressure loss Ps2 = 0 8. 1780 rpm. however.88 in. Pressure loss data supplied by manufacturer of backdraft damper. The basis for the calculations is described in Section 14. Determine the backdraft damper pressure loss by using the performance ratings supplied by the manufacturer. Record all pertinent motor nameplate data.3 ft2 For Planes 3a and 3b conditions of: td3a = = tw3a = = p3a = = = = td3b 72°F tw3b 66°F p3b pb + (Ps3a/13. including volts (NPV) and full load amps (FLA).82 av MOTOR NAMEPLATE DATA 5 hp. 7. wg Ps4 = -0.0721 lbm/ft3 It is assumed that: td1 = td4 = td3a = td3b Since the differences in the static pressures at Planes 1. and if possible. Hg td3a = td3b = 72°F tw3a = tw3b = 66°F Ps2 = 0 in. In order to compare the test results to the quoted fan curve drawn for operation at 620 rpm and 0. 3a.85.20 in.Pv1 CALCULATIONS Where: DENSITIES Pv1 = (Q1/1096 A1)2 ρ1 Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) Ps1 = Ps4 .6) 29.6) 29. 3 = 7062 cfm Q = = = = Q1 Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) 7211 (0.075/0.0.0.89 in.56 hp 71 .damper loss = -0.20 = 0. wg Hc = 4.84 .95) = 0. Backdraft damper loss = ∆Ps (ρ4/0.075) = 0. wg FAN STATIC PRESSURE Pv1 = (Q1/1096 A1)2 ρ1 = [14273/(1096 × 7.0721) = 4. HL = 0.5 = 1096 (0.82/5.21 = -1.275/0.1 in Annex L indicates estimated belt drive loss of 5.22 (0.075 lbm/ft3 density.4 = 7211 cfm Q3b = V3bA3b = 2140 × 3.075) = 0.HL = 4. Hmo = 5 (5.058 × 4.0721) = 0.84 hp Figure L.98 = 98% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 5 hp motor operating at 98% FLA.22 in.0721/0.(-1.Pv1 = 0 .5 = 2140 fpm Q3a = V3aA3a = 2121 × 3.88 . ∆Ps.0721 = 0. wg at the flow rate of 14273 cfm at 0.0.0721)0.0721/0.91 in.95) (455/460) = 4.8%. wg Ps1 = Ps4 .84 = 0.89 (620/625)2 (0.21 in.AMCA 203-90 (R2007) V3b = 1096 (Pv3b/ρ3b)0. is 0.075/0.9)]2 0. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 14273 (620/625) = 14159 cfm Psc = 0.Ps1 .0721) 14273 cfm BACKDRAFT DAMPER LOSS The data supplied by the manufacturer of the damper indicate that the pressure loss for the damper.82/5.28 = 4.0721/0.56 (620/625)3 (0.09) .28 hp H = Hmo .63 hp FAN POWER INPUT Measured amps/FLA = (5.20 in.058 Hmo = 0. wg Ps = Ps2 .09 in.0721) + 7062 (0. . the temperatures of the heating coils must be kept constant throughout the test period. The fan performance ratings are based on operation with the fan outlet ducted. Also. The velocity pressure for each branch 72 is determined by using the root mean square of the velocity pressure measurements made in the traverse. velocity pressure measurements would be made in a single plane.4. located in a duct common to all branches. mixing box. 3b. Therefore. multizone. Measure the dry-bulb and wet-bulb temperatures at Plane 4 and the dry-bulb temperatures at Planes 3a. These static pressure values are used in determining the densities at the traverse planes. Before proceeding with the test. it is essential that all dampers--outside air. or otherwise modify automatic control devices in order to prevent the positions of the dampers and temperatures of the coils from changing during the test. and 5. which is rated by the manufacturer as free-standing. 4. it is necessary to measure the area of each traverse plane. Determine Ps4 by averaging the static pressure measurements made in a traverse of Plane 4. as indicated in the diagram. disconnect.AMCA 203-90 (R2007) EXAMPLE 4A: CENTRIFUGAL FAN IN A BUILT-UP AIR CONDITIONING UNIT 2 4 SEF 1 L 5 RETURN AIR PLAN VIEW SEF 2 3a FAN SECTION SPRAY SECTION + + + + + + OUTSIDE AIR + + + + PREHEAT COILS FILTER SECTION SIDE VIEW DIFFUSER PLATE REHEAT COIL 3b COMMENTS 1. Refer to Section 17. face and bypass or volume control--be fixed in the positions agreed upon by all interested parties as being applicable for the installation. The alternative. 2. It may be necessary to lock out. Measure the area of Plane 4 for use in calculating Pv4. Procedures for traverses are described in Section 9. 3. In order to determine the air flow rates. The subject of the test is the fan. it is assumed that Ps2 = Ps5. a measurement plane which provides a satisfactory velocity profile cannot be located upstream of the fan or between the point of connection of the branch ducts and the fan outlet. the static pressure at each traverse plane is determined by averaging the static pressure measurements made in the same traverse.3 for additional considerations affecting the test procedure for fans in this type of installation.4. unencumbered by the cabinet in which it has been installed. Pitot-static tube traverses are used in determining these static pressures because the installation of suitable pressure taps is usually prevented by the insulating material encountered in this type of equipment. This is an air conditioning unit which has been assembled at the installation site. Determine Ps5 in a similar manner. Normally. Due to the abrupt expansion in area from Plane 2 to Plane 5. is to make a velocity pressure measurement traverse in each branch. These measurements are used in determining densities at the planes of interest. return air. In this example. it is assumed that there is no conversion of velocity pressure at Plane 2 to static pressure at Plane 5. Determine pb for the general vicinity of the air conditioning unit. The effect created by this fitting is considered to be equivalent to the effect created by having no duct at the fan outlet. and the outlet area and blast area of the fan.77 in. Hg td3a = 59°F td3b = 90°F td4 = 56°F td5 = 58°F Ps4 = -1. 7. 6. wg Ps5 = 3. fan inlet diameter L = 2.9 ft2 A3a = 7. wg Pv3b = 0.3 ft2 D1 = 3. In order to compare the test results to the quoted fan curve drawn for operation at 1170 rpm and 0.75/13.Ps1 . SEF 2 is attributed to the high degree of divergence of the transition fitting at the fan outlet. 3 phase. watts. the distance between a fan inlet and a side wall of the fan cabinet.83 ft MEASURED MOTOR DATA Volts = = Amps = = 462.075 lbm/ft3 density.72 in. 60 hertz 460 volts.3 FLA GENERAL Fan connected to motor through belt drive. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. 465 464 av 82. 81.92 ft. volts.(Ps1 + Pv1) + SEF 1 + SEF 2 Where: Ps2 = Ps5 Ps1 + Pv1 = Ps4 + Pv4 Pv4 = (Q4/1096 A4)2 ρ4 Q4 = Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) The calculation of Pv4 is often ignored in instances similar to this example on the basis that the calculated value of Pv4 is relatively small and its omission does not affect the test results significantly. 8. CALCULATIONS DENSITIES For Plane 4 conditions of: td4 = 56°F tw4 = 54°F p4 = pb + (Ps4/13.59 in.2 ft2 A3b = 9. wg N = 1160 rpm A2 = 18. SEF 1 is due to the effect of insufficient distance between the fan inlets and the side walls of the fan cabinet. Record all pertinent motor nameplate data. Measure the fan speed and motor amps. The basis for the calculations is described in Section 14. 1780 rpm.45 in. 465. wg Ps3a = 3.65 in.6) = 28.72 + (-1.AMCA 203-90 (R2007) 5. it is not necessary to measure motor watts. Hg 73 . including volts (NPV). To calculate the Fan Static Pressure: Ps = Ps2 . it is necessary to measure the diameter of an inlet of the fan. In order to determine the values of the SEFs.47 in.2 ft2 Blast Area = 13. 90. OBSERVATIONS SITE MEASUREMENTS pb = 28. If the motor power output is to be estimated by using the phase current method described in Annex K. wg Pv3a = 0.Pv1 + SEF 1 + SEF 2 = Ps2 .60 in. however. Refer to Annex K.75 in. it is necessary to convert the results to the specified conditions. wg Ps3b = 3. and if possible.7 ft2 A4 = 93. 83 82 av MOTOR NAMEPLATE DATA 75 hp. and full load amps (FLA).6) = 28. 075 lbm/ft3 density.77 + 13.1 in Annex N to obtain ρ4 = 0.72 = 72% Of the fan inlet diameter.59    = 0. The distance is 2.0695 lbm/ft 3 FLOW RATES V3a = 1096 (Pv3a/ρ3a = 1096 (0.043 × 68.72   516  = 0.59    = 0.11A. It is assumed that ρ1 = ρ4.7 = 27645 cfm Q = Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) = 22514 (0. At 0.45 + 13.6 × 28.6 p4   t d5 + 460   3.1) = 2032 fpm AMCA Publication 201-90.5 = 2850 fpm Q3a = V3aA3a = 3127 × 7.91 = 91% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 75 hp motor operating at 91% FLA.0731   550  13.5 V3b = 1096 (Pv3b/ρ3b)0.0731   518  13.0695/0.0731 lbm/ft3. Figures 7.06 (0.2 = 22514 cfm Q3b = V3bA3b = 2850 × 9.5 = 3127 fpm )0.0731 lbm/ft3: SEF 1 = 0.59    = 0. Hmo = 75 (82/90.HL = 68.72   516  = 0.6 × 28. wg For SEF 2.7 = 2. Figure 7.0731/0.075) = 0.95 hp H = Hmo .3%.0739) = 48452 cfm (2.  P + 13.1 shows SEF 1 = 0.6 × 28.6 × 28.72   516  = 0.6 × 28. The area of the fan inlets: A1 = 2 (π D12/4) = 2 (π × 3.1 in Annex L indicates estimated belt drive loss of 4.83/3.92) = 0.83 ft.043 Hmo = 0.5 = 1096 (0.47/0.6 p4   t d3b + 460   3.60/0.6 p4   t d3a + 460   3. AMCA Publication 201-90. For 2032 fpm inlet velocity and curve V. or: 74 .0737)0.75 hp SYSTEM EFFECT FACTORS SEF 1 is due to the effect of insufficient distance between the fan inlets and the side walls of the fan plenum.7 .3) = 0.0731) + 27645 (0.3.06 in.0695)0.0731) = 48982 cfm Q2 = Q1 (ρ1/ρ2) = 48982 (0.2. wg at 0.95 = 68. indicate the following calculations: FAN POWER INPUT Measured amps/FLA = (82/90.3) (464/460) = 68. indicates that for a plenum wall spacing of 72% of the fan inlet diameter System Effect Curve V applies. HL = 0.0737/0.1 and 8.6 × 28.AMCA 203-90 (R2007) Use Figure N.6 pb   t d4 + 460  ρ5 = ρ 4  s5    13.0731   519  13.06 in.7 hp Figure L.65 + 13.1 ft2 The fan inlet velocity: V1 = (Q1/A1) = (48982/24. Figure 9.0737 lbm/ft 3  P + 13.0739 lbm/ft 3  P + 13.6 pb   t d4 + 460  ρ3b = ρ 4  s3b    13.0731/0.6 pb   t d4 + 460  ρ3a = ρ 4  s3a    13.922/4) = 24. 0739/0.(Ps1 + Pv1) + SEF 1 + SEF 2 3.9 = 0. For 2564 fpm velocity and curve S.22 hp ρ4 = ρ1 Q4 = Q1 Pv4 = (48982/1096 × 93.75 + 0.(-1. wg Ps1 + Pv1 = Ps4 + Pv4 = -1. Figure 8. wg Ps = = = = Ps2 .7 and no duct.075) = 0.73 in. Figure 7. wg 75 .0731 = 0.06 + 0.33 in.1 shows SEF 2 = 0.0739 lbm/ft3: SEF 2 = 0.3 shows System Effect Curve S applies. wg Hc = 65.02 in.33 5.15 in. wg at 0. At 0.02 = -1.33 in.075 lbm/ft3 density.70 For a blast area ratio of 0.89 in.AMCA 203-90 (R2007) V2 = (Q2/A2) = (48452/18.3/18.0731) = 69.Ps1 .075/0.Pv1 + SEF 1 + SEF 2 Ps2 .73) + 0.33 (0. wg FAN STATIC PRESSURE Pv4 = (Q4/1096 A4)2 ρ4 Since: CONVERSION TO SPECIFIED CONDITIONS Qc = 48982 (1170/1160) = 49404 cfm Psc = 5.75 (1170/1160)3 (0.0731) = 6.075/0.77 .9) = 2564 fpm Blast area ratio = Blast Area/A2 = 13.89 (1170/1160)2 (0.2)2 0. In order to determine the air flow rate.4. return air. or otherwise modify automatic control devices in order to prevent the positions of the dampers and temperatures of the coils from changing during the test. draw-through central station unit. volts. as shown in the diagram. their use is preferred in the region of the fan outlet. It may be necessary to lock out. disconnect. it is necessary to measure the area of the traverse plane. Determine pb for the general vicinity of the air conditioning unit. 2.AMCA 203-90 (R2007) EXAMPLE 4B: CENTRAL STATION AIR CONDITIONING UNIT. Also. Refer to Section 17. If the motor power output is to be estimated by using the phase current method described in Annex K. The subject of the test is the fan section. 4. As a draw-through unit. multizone. This static pressure value is used to determine the density at the traverse plane. located near the end of a straight run of duct. the conditions which exist at Plane 5 are assumed to exist at Plane 2. 5. it is not necessary to measure . Ps5 may be determined in a similar manner or by averaging the pressure measurements at each of four static pressure taps. it is essential that all dampers--outside air. and full load amps (FLA). Procedures for traverses are described in 76 Section 9. 3. or volume control--be fixed in the positions agreed upon by all interested parties as being applicable for the installation. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. including volts (NPV). This is a factory assembled. If it is possible to install suitable pressure taps. These measurements are used to determine densities at the planes of interest. the temperatures of heating and cooling coils must be kept constant throughout the test period. and the fact that there is no change in area between the two planes. FACTORY ASSEMBLED DRAWTHROUGH TYPE 1 RETURN AIR PLAN VIEW 3 STATIC PRESSURE TAPS L SEF 1 OUTSIDE AIR + + 5 2 + + FAN SECTION SIDE VIEW FILTER SECTION COIL SECTION COMMENTS 1. the performance ratings for the fan section are based on operation with the fan outlet ducted. Determine Ps3 by averaging the static pressure measurements made in the same traverse. which is rated by the manufacturer as an assembly of the fan and the cabinet in which the fan has been installed. Measure the area of Plane 1 for use in calculating Pv1. Measure the dry-bulb and wet-bulb temperatures at Plane 3 and the dry-bulb temperatures at Planes 1 and 5.2 for additional considerations affecting the test procedure in this type of installation. Determine Ps1 by averaging the static pressure measurements made in a traverse of Plane 1. mixing box. watts. Record all pertinent motor nameplate data. due to the close proximity of Planes 2 and 5. face and bypass. Measure the fan speed and the motor amps.4. Before proceeding with the test. and if possible. 3°F tw3 = 47.37    = 0. 48. 7.7 FLA GENERAL Fan connected to motor through belt drive. 49.294/0.27 + (1.6 p3   t d1 + 460   −0. SEF 1 is due to the effect of insufficient length of duct between the fan outlet and the elbow downstream of the fan.AMCA 203-90 (R2007) motor watts.39 + 13. FLOW RATES V3 = 1096 (Pv3/ρ3)0.3°F = 47.31/13.Pv1 + SEF 1 Where: Ps2 = Ps5 Pv1 = (Q1/1096A1)2 ρ1 The calculation of Pv1 is often ignored in instances similar to this example on the basis that the calculated value of Pv1 is relatively small. wg = 1. 8. and it omission does not affect the test results significantly.5 = 2153 fpm MEASURED MOTOR DATA Volts = = Amps = = 440.39 in.3°F p3 = pb + (Ps3/13. it is necessary to convert the results to the specified conditions.4 ft2 L = 2.0763 lbm/ft 3 It is assumed ρ2 = ρ5.6 pb   t d3 + 460  ρ5 = ρ3  s5    13.0762 lbm/ft3.847 + 13.  P + 13. 60 hertz 440 volts. The basis for the calculations is described in Section 14.4.0762    507.0762)0.5°F = 49.27 in.5 = 1096 (0.3°F = 49°F = -0. In order to compare the test results to the quoted fan section curve drawn for operation at 1430 rpm and 0.6 pb   t d3 + 460  ρ1 = ρ3  s1    13. however.847 in. and the blast area of the fan.27   509. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point.294 in.3  = 0.6 p3   t d5 + 460   1.7. 3 phase. 442 442 av 47.0 47. Refer to Annex K. Hg Use Figure N. wg = 1.0760 lbm/ft t3  P + 13.5  13.27   509.6) = 29.0762    509  13.42 ft2 Blast Area = 9. 444. To calculate the Fan Section Static Pressure: Ps = Ps2 . A2. wg = 0. length of outlet duct pb td1 td3 tw3 td5 Ps1 Ps3 Pv3 Ps5 N A1 A2 DENSITIES For Plane 3 conditions of: td3 = 49. 47. CALCULATIONS 77 .075 lbm/ft3 density.1 in Annex N to obtain ρ3 = 0. Hg = 47.31 in.Ps1 .6 × 29. OBSERVATIONS SITE MEASUREMENTS = 29. L. 1770 rpm. the length of the outlet duct. wg = 1402 rpm = 147. In order to determine the value of SEF 1.3  = 0.37 in.6 × 29.6) = 29.2 ft2 = A3 = A5 = 15.7 av MOTOR NAMEPLATE DATA 40 hp.0 ft. it is necessary to measure the outlet area of the fan.6 × 29.6 × 29.37    = 0. 6. AMCA 203-90 (R2007) Q3 = V3A3 = 2153 × 15.42 = 33199 cfm Q = = = = Q2 = = = = Q1 Q3 (ρ3/ρ1) 33199 (0.0762/0.0760) 33286 cfm Q5 Q3 (ρ3/ρ5) 33199 (0.0762/0.0763) 33155 cfm For velocities of 2500 fpm or less, the 100% effective outlet duct length is 2.5 duct diameters: = 2.5 × 4.43 = 11.1 ft The length of the outlet duct in % effective duct length: = (L/11.1) 100 = (2.0/11.1) 100 = 18% Blast area ratio = Blast Area/A2 = 9.4/15.42 = 0.61 For a blast area ratio of 0.6, 18% effective duct length and elbow position A, Figure 8.5 shows System Effect Curve R applies. For 2150 fpm velocity and curve R, Figure 7.1 shows SEF 1 = 0.34 in. wg at 0.075 lbm/ft3 density. At 0.0762 lbm/ft3: SEF 1 = 0.34 (0.0762/0.075) = 0.35 in. wg FAN SECTION STATIC PRESSURE Pv1 = (Q1/1096 A1)2 ρ1 = (33286/1096 × 147.2)2 0.0760 = 0.003 in. wg It is assumed that Ps2 = Ps5 Ps = Ps2 - Ps1 - Pv1 + SEF 1 = 1.39 - (-0.847) - 0.003 + 0.35 = 2.58 in. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 33286 (1430/1402) = 33951 cfm Psc = 2.58 (1430/1402)2 (0.075/0.0760) = 2.65 in. wg Hc = 36.86 (1430/1402)3 (0.075/0.0760) = 38.60 hp FAN POWER INPUT Measured amps/FLA = (47.7/49.7) = 0.96 = 96% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 40 hp motor operating at 96% FLA. Hmo = 40 (47.7/49.7) (442/440) = 38.6 hp Figure L.1 in Annex L indicates estimated belt drive loss of 4.5%. HL = 0.045 Hmo = 0.045 × 38.6 = 1.74 hp H = Hmo - HL = 38.6 - 1.74 = 36.86 hp SYSTEM EFFECT FACTOR To determine SEF 1, AMCA Publication 201-90, Figures 7.1 and 8.5, indicate the following calculations: V2 = (Q2/A2) = (33155/15.42) = 2150 fpm Duct diameter equivalent to the fan outlet area: De2 = (4 A2/π)0.5 = (4 × 15.42/π)0.5 = 4.43 ft 78 AMCA 203-90 (R2007) EXAMPLE 4C: PACKAGED AIR-CONDITIONING UNIT 3 2 L SEF 1 4 1 INLET PLENUM FILTERS + PLAN VIEW FANS 5 + COOLING COIL SIDE VIEW COMMENTS 1. The subject of the test in this example is the air conditioning unit assembly. This assembly does not include the inlet plenum. The performance ratings for the unit assembly are based on operation with the outlets of the fans ducted. Before proceeding with the test, it is essential that all system dampers be fixed in the positions agreed upon by all interested parties as being applicable for the installation. Also, the temperature of the cooling coil must be kept constant throughout the test period. It may be necessary to lock out, disconnect or otherwise modify automatic control devices in order to prevent the positions of the dampers and the temperature of the coil from changing during the test. Refer to Section 17.4.1 for additional considerations affecting the test procedure in this type of installation. 2. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3, located near the end of a straight run of duct, as shown in the diagram. Determine Ps3 by averaging the static pressure measurements made in the same traverse. This static pressure value is used to determine the density at the traverse plane. Procedures for traverses are described in Section 9.4. in order to determine the air flow rate, it is necessary to measure the area of the traverse plane. 3. Ps4 may be determined by averaging the pressure measurements at each of four static pressure taps or by averaging the static pressure measurements made in a Pitot-static tube traverse of Plane 4. Ps5 is determined in a similar manner. However, if it is possible to install suitable static pressure taps, their use is preferred in the regions of the outlets of the fans. Due to the close proximity of Planes 1 and 4 and the fact that there is no change in area between the two planes, the conditions which exist at Plane 4 are assumed to exist at Plane 1. Although Plane 5 is greater in area that Plane 2, the degree of divergence is relatively small. Therefore, Ps2 will be calculated based on Ps5 and the assumption that there is no change in total pressure from Plane 2 to Plane 5. 4. Measure the dry-bulb and wet-bulb temperatures at Plane 4 and the dry-bulb temperatures at Planes 3 and 5. In this example, the cooling medium, normally circulated in the coil was shut off in order to maintain constant air temperatures during the test. In order to account for water vapor which may have been added to the air as a result of evaporation of moisture previously condensed on the coil, the wet-bulb temperature at Plane 3 was measured. Determine pb for the general vicinity of the air conditioning unit. These measurements are used in determining densities at the planes of interest. 79 AMCA 203-90 (R2007) 5. Measure the fan speed and the motor amps, volts, and if possible, watts. Record all pertinent motor nameplate data including volts (NPV), and full load amps (FLA). If the motor power output is to be estimated by using the phase current method described in Annex K, it is not necessary to measure motor watts; however, it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. Refer to Annex K. 6. Although an elbow is located shortly downstream of the fans, SEF 1 is judged to be more closely characterized as the effect due to insufficient lengths of duct on the outlets of the fans. In order to determine the value of SEF 1, it is necessary to measure the outlet area and the blast area of one of the fans and the length, L, of its outlet duct. 7. To calculate the static pressure for the unit assembly: Ps = Ps2 - Ps1 - Pv1 + SEF 1 Fans connected to motor through belt drive. Where: CALCULATIONS Ps1 = Ps4 Pv1 = (Q1/1096A1)2 ρ1 Ps2 = Ps5 + Pv5 - Pv2 Pv2 and Pv5 are calculated in manners similar to the calculation of Pv1. 8. In order to compare the test results to the quoted unit assembly curve drawn for operation at 1050 rpm and 0.075 lbm/ft3 density, it is necessary to convert the results to the specified conditions. The basis for the calculations is described in Section 14. OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 td4 tw4 td5 Ps3 Pv3 Ps4 Ps5 N 80 = = = = = = = = = = = 29.65 in. Hg 75.0°F 59.5°F 72.5°F 58.5°F 74.5°F 2.02 in. wg 0.35 in. wg -0.32 in. wg 2.11 in. wg 1025 rpm DENSITIES For Plane 3 conditions of: td3 = 75.0°F tw3 = 59.5°F p3 = pb + (Ps3/13.6) = 29.65 + (2.03/13.6) = 29.80 in. Hg Use Figure N.1 in Annex N to obtain ρ3 = 0.0736 lbm/ft3. For Plane 4 conditions of: td4 = 72.5°F tw4 = 58.5°F p4 = pb + (Ps4/13.5) = 29.65 + (-0.32/13.6) = 29.63 in. Hg Use Figure N.1 in Annex N to obtain ρ4 = 0.0735 lbm/ft3. It is assumed that ρ1 = ρ4. A 1 = A4 = 31.7 ft2 A2 = 11.5 ft2 A3 = 16.4 ft2 A5 = 14.3 ft2 Blast Area = 4.0 ft2 per fan L = 2.0 ft, length of outlet duct MEASURED MOTOR DATA Volts = = Amps = = 460, 455, 465 460 av 38.2, 38, 37.9 38.0 av MOTOR NAMEPLATE DATA 25 hp, 3 phase, 60 hertz 460 volts, 1760 rpm, 39.5 FLA GENERAL 5/2π)0.4 = 39196 cfm Q2 = = = = Q = = = = Q5 Q3 (ρ3/ρ5) 39196 (0.0/39.0/39.11 + 13.AMCA 203-90 (R2007)  P + 13.5  13.5 = 0.5) (460/460) = 24.0737 lbm/ft3: SEF 1 = 0. wg Pv2 = (Q2/1096 A2)2 ρ2 = (39143/1096 × 11. Figures 7. Figure 7. AMCA Publication 201-90.8%.2 hp H = Hmo .65   535  = 0.22 ft L in % effective duct length: = (L/9.71 in.6 pb   t d3 + 460  ρ5 = ρ3  s5    13.13 (0.9 hp 81 .0737 = 0.1 in Annex L indicates estimated belt drive loss of 4. indicate the following calculations: V2 = (Q2/A2) = (39143/11.048 × 24.5 = 2390 fpm Q3 = V3A3 = 2390 × 16.22) 100 = (2. FLOW RATES V3 = 1096 (Pv3/ρ3)0. wg FAN POWER INPUT Measured amps/FLA = (38.13 in.2 = 22. For 3404 fpm velocity and curve W.0737/0.35/0.1 and 8.5 = 1096 (0.80    = 0.7.1 . wg STATIC PRESSURE OF UNIT Pv5 = (Q5/1096 A5)2 ρ5 = (39143/1096 × 14.5 = 2. 100% effective duct length is one diameter for every 1000 fpm: = De2 (V2/1000) = 2. HL = 0.0736/0.0/9.3 shows that for velocities over 2500 fpm.5) = 3404 fpm Duct diameter equivalent to the outlet area of one fan: De2 = (4A2/2π)0.048 Hmo = 0.0736    534.3.3 shows System Effect Curve W applies.0)/11. At 0. Hmo = 25 (38.71 (3404/1000) = 9.71 ft Figure 8.0735) 39249 cfm SYSTEM EFFECT FACTOR To determine SEF 1.6 × 29.0736/0.0736)0.22) 100 = 22% Blast area ratio = Blast area/A2 = (2 × 4.075) = 0.70 For a blast area ratio of 0. and 22% effective duct length Figure 8.1.46 in.0737 lbm/ft 3 It is assumed ρ2 = ρ5.6 × 29.1 shows SEF 1 = 0.6 p3   t d5 + 460   2.5 = (4 × 11.3)2 0.HL = 24.5)2 0.5) = 0.0737 = 0.1 hp Figure L.075 lbm/ft3 density. wg at 0.96 = 96% Annex K indicates that Equation A will provide a reasonably accurate estimate of motor power output for a 25 hp motor operating at 96% FLA.13 in.1 = 1.0737) 39143 cfm Q1 = Q4 Q3 (ρ3/ρ4) 39196 (0. 86 in.Ps1 .32) .1 hp 82 . wg Hc = 22.AMCA 203-90 (R2007) Ps2 + Pv2 = Ps5 + Pv5 Ps2 = Ps5 + Pv5 .Pv2 = 2.075/0.075/0.22 in.86 .0.09 in.7)2 0.13 = 2. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 39249 (1050/1025) = 40206 cfm Psc = 2.Pv1 + SEF 1 = 1.0735) = 2.11 + 0. wg Pv1 = (Q1/1096 A1)2 ρ1 = (39249/1096 × 31.38 in.9 (1050/1025)3 (0.0735) = 25.71 = 1.0735 = 0.09 + 0. wg Ps = Ps2 .(-0.46 .0.22 (1050/1025)2 (0. In this example. a measurement plane which provides a satisfactory velocity profile cannot be located upstream of the fans or between the point of connection of the branch ducts and the outlets of the fans. is to make a velocity pressure measurement traverse in each of two branches. the temperature of the heating coil must be kept constant throughout the test period. and 5. In order to determine the air flow rates. Refer to Section 17. it is important to be certain that all pressure measurements are referred to the same atmospheric pressure. based on their close proximity and the fact that there is no change in area between the two planes. including the static pressure. The velocity pressure for each branch is determined by using the root mean square of the velocity pressure measurements made in the traverse. The static pressure at each traverse plane is determined by using the root mean square of the velocity measurement traverse in each of two branches. The conditions which exist at Plane 5. 2. Also. are assumed to exist at Plane 2. Determine Ps5 by averaging the pressure measurements at each of four static pressure taps located in the duct fitting at the outlets of the fans.1 for additional considerations affecting the test procedure in this type of installation. The alternative. 4.5. Measure the dry-bulb and wet-bulb temperatures at Plane 1 and the dry-bulb temperatures at Planes 3a. it is essential that all system dampers be fixed in the positions agreed upon by all interested parties as being applicable for the installation. Normally. Procedures for traverses are described in Section 9. In situations such as this example. disconnect or otherwise modify automatic control devices in order to prevent the positions of the dampers and the temperature of the coil from changing during the test. Determine pb for the general vicinity of 83 . as indicated in the diagram. This assembly includes the filter section and the inlet louver. These static pressure values are used in determining the densities at the traverse planes. velocity pressure measurements would be made in a single plane. The performance ratings for the unit assembly are based on operation with the outlets of the fans ducted. the velocity pressure for reach branch is determined by using the root mean square of the velocity pressure measurements made in the traverse. The subject of the test in this example is the air conditioning unit assembly.4. The static pressure at each traverse plane is determined by averaging the static pressure measurements made in the same traverse. 3. Before proceeding with the test. 3b.AMCA 203-90 (R2007) EXAMPLE 4D: PACKAGED AIR-CONDITIONING UNIT 3a 3b PLAN VIEW STATIC PRESSURE TAPS 2 SEF 1 + + L 5 FILTER SECTION 1 HEATING COIL SIDE VIEW INLET LOUVER COMMENTS 1. located in a duct common to all branches. It may be necessary to lock out. it is necessary to measure the area of each traverse plane. 6.075 lbm/ft3 density.Ps1 . it is not necessary to measure motor watts.AMCA 203-90 (R2007) the air conditioning unit. charges to the unit losses incurred in accelerating the air into its inlet and eliminates the inaccuracies which arise in any attempt to measure the velocity pressure and static pressure at the inlet.5°F = 83°F = 1. it is necessary to convert the results to the specified conditions.25 in. at a point sufficiently distant from the inlet as to be in still air.15 in.Pv1 + SEF 1 = Ps2 . Ps1 + Pv1 = Psx + Pvx = 0 This consideration. 13. and velocity pressure. In order to determine the value of SEF 1.5% at 1/2 load 84. and velocity pressure.96 ft. watts. wg = 1710 rpm = A5 = 5. Pvx. If the motor power output is to be estimated by using the phase current method described in Annex K.0. which is the same as that used in the methods for testing this type of unit for performance rating purposes. it is necessary to measure the outlet area and the blast area of one of the fans and the length of the duct. 60 hertz 460 volts. Psx. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. The following motor performance data was supplied by the motor manufacturer: Motor Efficiency: 82. volts. These measurements are used to determine densities at the planes of interest. between the fan and the elbow.64 ft2 A3a = 3. 1750 rpm. length of outlet duct MEASURED MOTOR DATA Volts = = Amps = = 460. Pv1. 462 460 av 10. Hg = 72°F = 61°F = 85°F = 82. The basis for the calculations is described in Section 14. To calculate the static pressure for the unit assembly: Ps = Ps2 . including volts (NPV). wg = 1. Record all pertinent motor nameplate data. Motor performance data. and if possible. are used in the determination of motor power output in this example. The sum of the static pressure. Ps1.(Ps1 + Pv1) + SEF 1 Since: Ps1 + Pv1 = 0 Ps = Ps2 + SEF 1 Where: Ps2 = Ps5 8. 7.60 in. the static pressure is zero.1 ft2 A3b = 2. At this point. wg = 0. 458.8 9.22 in.5 FLA GENERAL Fans connected to motor through belt drive. however. wg = 1.85 84 . 10. and full load amps (FLA).9 av pb td1 tw1 td5 td3a td3b Ps5 Ps3a Ps3b Pv3a Pv3b N A2 MOTOR NAMEPLATE DATA 10 hp. and the velocity pressure in still air is zero. L. 3 phase. at the inlet to the unit assembly is considered to be equal to the sum of the static pressure. SEF 1 is due to the effect of insufficient length of duct between the outlets of the fans and the elbow downstream of the fans.65 in.5 ft2 per fan L = 0.5% at 3/4 load 84. 5. 9. In order to compare the test results to the quoted performance curve for the packaged unit drawn for operation at 1720 rpm and 0. OBSERVATIONS SITE MEASUREMENTS = 29. wg = 0. Measure the fan speed and the motor amps.2 ft2 Blast Area = 2.0. supplied by the motor manufacturer.5% at full load Power Factor = 0.56 in. 6 × 29.0723/0.2.43 hp H = Hmo .6 × 29.1.5 = 3159 fpm Q3a = V3aA3a = 3050 × 3.65    = 0.6 × 29.6 pb   t d1 + 460  ρ3a = ρ1  s3a    13.1 in Annex N to obtain ρ1 = 0.0720) 16464 cfm FAN POWER INPUT Measured amps/FLA = (9.0723)0.16 hp SYSTEM EFFECT FACTOR SEF 1 is due to the effect of insufficient lengths of duct between the outlets of the fans and the elbow downstream of the fans.65 in.59 .6 × 29.0735    542.65   532  = 0.6 × 29.89 ft Figure 8.65   532  = 0.73 = 73% The data supplied by the motor manufacturer indicate power factor of 0.43 = 7.1 in Annex L indicates estimated belt drive loss of 5.5 = 1096 (0.5% for the motor operating at 73% FLA.5 = (4 × 5.65    = 0.0735/0.5 = 3050 fpm V3b = 1096 (Pv3b/ρ3b)0.6 pb   t d1 + 460  ρ5 = ρ1  s5    13.5 = 1096 (0.65    = 0.0722/0.1.6 p1   t d5 + 460   1.6 × 29.0722 lbm/ft 3 FLOW RATES V3a = 1096 (Pv3a/ρ3a)0.0735 lbm/ft3.22 + 13.9 × 460 × 0.59 hp Figure L.0723 lbm/ft 3  P + 13.1 shows that for velocities over 2500 fpm 100% effective duct length is one diameter for every 1000 fpm: 85 .9/13.5 = 1.85 × 0.0735) + 6950 (0.0735) 16128 cfm Q5 Q1 (ρ1/ρ5) 16128 (0.056 Hmo = 0.60/0.15 + 13.5 indicate the following calculations: V2 = (Q2/A2) = (16464/5. Hg Use Figure N.056 × 7.6 p1   t d3a + 460   1.0735    543  13.2 = 6950 cfm Q = = = = Q2 = = = = Q1 Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) 9455 (0.6%.0722)0.5  13.56/0.845/746 = 7.65   532  = 0.6 p1   t d3b + 460   1.0720 lbm/ft 3 It is assumed that ρ2 = ρ5  P + 13.5) = 0.5 × 9.59 = 0.0. Figures 7. AMCA Publication 201-90.0735    545  13.1 = 9455 cfm Q3b = V3bA3b = 3159 × 2.64/2π)0.64) = 2919 fpm Duct diameter equivalent to the outlet area of one fan: De2 = (4A2/2π)0.2: Hmo = (3)0.HL = 7.6 pb   t d1 + 460  ρ3b = ρ1  s3b    13.25 + 13. and 8.  P + 13.AMCA 203-90 (R2007) DENSITIES For Plane 1 conditions of: td1 = 72°F tw1 = 61°F p1 = pb = 29. 8.85 and motor efficiency of 84. HL = 0. Using the appropriate equation in Section 10. 52) 100 = (0.66 (1720/1710)2 (0.44 hp 86 . wg Ps2 = Ps5 = 1.43 in.075 lbm/ft3 density.075) = 0. Figure 8.0735) = 7.25 + 0.64 = 0. wg Hc = 7.25 in.96/5.5)/5. wg at 0.1 shows SEF 1 = 0.0720 lbm/ft3: SEF 1 = 0. For 2919 fpm velocity and curve S.0720/0. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 16128 (1720/1710) = 16222 cfm Psc = 1.075/0. Figure 7.16 (1720/1710)3 (0. in % effective duct length: = (L/5. At 0.71 in. 17% effective duct length and elbow position C.075/0. wg Ps = Ps2 + SEF 1 = 1.41 in.0735) = 1.AMCA 203-90 (R2007) STATIC PRESSURE OF UNIT = De2 (V2/1000) = 1.5 shows System Effect Curve S applies.43 (0.89 (2919/1000) = 17% L.89.52) 100 = 17% Blast area ratio = Blast Area/A2 = (2 × 2.66 in.41 = 1.89 For a blast area ratio of 0. In this example. multizone.AMCA 203-90 (R2007) EXAMPLE 4E: CENTRAL STATION AIR CONDITIONING UNIT. return air. These static pressure values are used in determining the densities at the traverse plane. FACTORY ASSEMBLED BLOWTHROUGH TYPE 1 2 5 STATIC PRESSURE TAPS PLAN VIEW RETURN AIR 3b HEATING COIL + 3a SPRAY SECTION + + + OUTSIDE AIR + + + + FILTER SECTION FAN SECTION SIDE VIEW COOLING COIL COMMENTS 1. 3. Ps5 may be determined in a similar manner or by averaging the pressure measurements at each of four static pressure taps. In instances in which a cooling coil is located between a velocity pressure traverse plane and the fan. It may be necessary to lock out. Before proceeding with the test. as indicated in the diagram. blow-through central station unit. the temperatures of heating and cooling coils must be kept constant throughout the test period.5.2 for additional considerations affecting the test procedure in this type of installation. The static pressure at each traverse plane is determined by averaging the static pressure measurements made in the same traverse. face and bypass. Also. 2. their use is preferred in the regions of the fan outlet. disconnect. Normally. Therefore. As a blow-through unit. the flow of the cooling medium should be stopped or its temperature raised to a level sufficient to prevent condensation on the cooling coil. located in a duct common to all branches. The velocity pressure for each branch is determined by using the root mean square of the velocity pressure measurements made in the traverse.4. or volume control) be fixed in the positions agreed upon by all interested parties as being applicable for the installation. it is assumed that there is no conversion of velocity pressure at Plane 2 to static pressure at Plane 5. The subject of the test is the fan section. Determine Ps1 by averaging the static pressure measurements made in a traverse of Plane 1. otherwise the moisture condensed will not be properly taken into account in the determination of fan air flow rate. Procedures for traverses are described in Section 9. In order to determine the air flow rates it is necessary to measure the area of each traverse plane. is to make a velocity pressure measurement traverse in each branch. This is a factory assembled. The alternative. a measurement plane which provides a satisfactory velocity profile cannot be located upstream of the fan or between the point of connection of the branch ducts and the fan outlet. as in this example. Due to the abrupt expansion in area from Plane 2 to Plane 5. Refer to Section 17. or otherwise modify automatic control devices in order to prevent the positions of the dampers and temperatures of the coils from changing during the test. mixing box. the performance ratings for the fan section are based on operation without the fan outlet ducted. it is essential that all dampers (outside air. it is assumed 87 . If it is possible to install suitable pressure taps. velocity pressure measurements would be made in a single plane. which is rated by the manufacturer as an assembly of the fan and the cabinet in which the fan has been installed. 53 in. Determine pb for the general vicinity of the air conditioning unit.37 ft2 6. it may be necessary to disconnect the drive and measure the no load amps (NLA) if the motor is not operating at or near its full load point. To calculate the Fan Section Static Pressure: Ps = Ps2 . wg 6. These measurements are used to determine densities at the planes of interest.67 in. 60 hertz 575 volts. wg 0. and its omission does not affect the test results significantly. 81 81.6) = 29. Measure the area of Plane 1 for use in calculating Pv1.85 + (-2. 3a. volts. 3 phase.Pv1 Where: Ps2 = Ps5 Pv1 = (Q1/1096 A1)2 ρ1 Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) The calculation of Pv1 is often ignored in instances similar to this example on the basis that the calculated value of Pv1 is relatively small. 565 570 av 81. and full load amps (FLA). 8.35 in. wg 5.7 19 MOTOR NAMEPLATE DATA 100 hp. OBSERVATIONS SITE MEASUREMENTS pb td1 tw1 td3a 88 = = = = 28. 1790 rpm. 6.6) = 28.43 in.5. it is necessary to convert the results to the specified conditions. however. 7.6) = 28.0720 lbm/ft3.1 in.Ps1 . wg 0. CALCULATIONS . wg 1695 rpm 68. 575.5°F 60°F 58°F -2. 5. Measure the fan speed and the motor amps. If the motor power output is to be estimated by using the phase current method described in Annex K.85 in. Since the performance ratings for the fan section are based on operation without the fan outlet ducted. including volts (NPV).9 ft2 5.24 in. Hg 65°F 60°F 100°F td3a = 100°F tw3a = 71.35/13. Record all pertinent motor nameplate data.43/13.85 + (5. watts. 95 FLA GENERAL Fan connected to motor through belt drive.5°F p3a = pb + (Ps3a/13. it is not necessary to measure motor watts.075 lbm/ft3 density. wg 5.78 ft2 MEASURED MOTOR DATA Volts = = Amps = = NLA = 570. an SEF does not apply for the unducted position. The basis for the calculations is described in Section 14.AMCA 203-90 (R2007) that Ps2 = Ps5. Refer to Annex K. Hg DENSITIES For Plane 1 conditions of: td1 = 65°F tw1 = 60°F p1 = pb + (Ps1/13. and if possible.6) = 28.60 in. 82. 4.55 in. Hg Use Figure N.1 in Annex N to obtain ρ1 = 0. The measurements of additional wet-bulb temperatures were made in this example in order to provide data which may be used to determine whether the moisture content of the air changed between Plane 1 and Planes 3a and 3b.5. In order to compare the test results to the quoted fan section curve drawn for operation at 1650 rpm and 0. and 3b. Measure the dry-bulb and wet-bulb temperatures at Planes 1. For Plane 3a conditions of: tw3a = td3b = tw3b = Ps1 = Ps5 = Ps3a = Ps3b = Pv3a = Pv3b = N = A1 = A3a = A3b = 71. 7/95) (570/575) = 85. wg Hc = 80.075/0.0720) = 37405 cfm FAN POWER INPUT Measured amps/FLA = (81.86 = 86% Annex K indicates that the average of the results of Equation A and Equation B will provide a reasonably accurate estimate of motor power output for a 100 hp motor operating at 86% of FLA.8 hp Hmo = (85.60/0. A = 100 (81. HL = 0.23 in.0720 lbm/ft3.6 .6 = 3.0720) = 8.9)2 0.5 = 80.Ps1 .0.5 = 1096 (0.0741/0.1 in Annex L indicates estimated belt drive loss of 4.85 + (5.0720 = 0.96 (1650/1695)2 (0.19)] (570/575) = 81.042 Hmo = 0.6) = 28.02 in.AMCA 203-90 (R2007) Use Figure N.84 in.7 .3 + 81.2%.53/0. For Plane 3b conditions of: td3b = 60°F tw3b = 58°F p3b = pb + (Ps3b/13.5 = 3035 fpm V3b = 1096 (Pv3b/ρ3b = 1096 (0.1 in Annex N to obtain ρ3b = 0.37 = 16298 fpm Q3b = V3bA3b = 3119 × 6.0720) + 21147 (0.HL = 83.042 × 83.0691/0. wg CONVERSION TO SPECIFIED CONDITIONS Qc = 37405 (1650/1695) = 36412 cfm Psc = 8.0 hp 89 .5 Q3a = V3aA3a = 3035 × 5.96 in.7/95) = 0.43) .0691)0. Eqn.1/13.0720) = 77. B = 100 [(81.5 hp H = Hmo .02 = 8.1 hp FAN SECTION STATIC PRESSURE Pv1 = (Q1/1096 A1)2 ρ1 = (37405/1096 × 68. FLOW RATES V3a = 1096 (Pv3a/ρ3a)0.1 in Annex N to obtain ρ1 = 0.075/0.3.6 hp Reference to Figure L.8)/2 = 83.1 (1650/1695)3 90.3 hp Eqn.Pv1 = 6.0741 lbm/ft3.6) = 29.(-2. wg It is assumed that Ps2 = Ps5 Ps = Ps2 .55 . Hg Use Figure N.78 = 21147 cfm Q = Q1 = Q3a (ρ3a/ρ1) + Q3b (ρ3b/ρ1) = 16298 (0.5 = 3119 fpm )0.0741)0.19)/(95 . In this example.Ps1 . Before proceeding with the test. referred to the same atmospheric pressure as used in all other pressure measurements.(Ps1 + Pv1) . 6. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. the air may 90 be discharging from the ventilator into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred. referred to the same atmospheric pressure as in the static pressure measurements made at Plane 3. Measure the dry-bulb and wet-bulb temperatures at the velocity traverse plane. Determine pb for the general vicinity of the ventilator. The duct. These measurements are used to determine densities at the planes of interest. To calculate the Fan Static Pressure: Ps = Ps2 . Measure the fan speed and the motor amps and volts.AMCA 203-90 (R2007) EXAMPLE 5A: FREE INLET. which is located at the tip of the Pitot-static tube. For the horsepower rating of the motor in this example. obtained from the motor manufacturer. located in the duct which has been installed on the inlet side of the ventilator. In situations such as this example. referred to the atmospheric pressure in the region of the ventilator outlet. 2. The subject of the test in this example is the roof ventilator assembly. Procedures for traverses are described in Section 9. is square in cross-section.Pv1 = Ps2 . 3. Ps2 was measured. The length of the duct is twice its equivalent diameter and the entrance to the duct is flared in oder to reduce inlet losses. 5. A3. Record all pertinent motor nameplate data. FREE OUTLET ROOF VENTILATOR 2 1 3 TEMPORARY DUCT WITH SQUARE CROSS-SECTION. the static pressure at the outlet of the ventilator. it is essential that the static pressure in the region of the discharging air be measured. The installation of a duct of this size and cross-sectional configuration is judged as creating no significant effect on the performance of the ventilator in this example. it is recommended that the fan power input be determined by using the measured watts input to the motor and motor performance data. De = EQUIVALENT DIAMETER OF DUCT 2 De 1.4. Determine Ps3 by averaging the static pressure measurements made in the same traverse. 4. When this possibility exists. Its cross-sectional dimensions were selected as the maximum permissible for its installation into the opening in the ventilator mounting curb.4 for considerations affecting the test procedure in this type of installation.5 De COMMENTS 1. temporarily installed for purposes of the test. Measure the area of the traverse plane. refer to Section 17. is zero gauge pressure. Ps2. 047 in. Hg 73. wg CONVERSION TO SPECIFIED CONDITIONS MEASURED MOTOR DATA Volts = 235.077 = -0. and: H = Hmo = 0. wg -0. wg 0. 230.58 ft2 FLOW RATE V3 = 1096 (Pv3/ρ3)0. 3. In order to compare the test results to the quoted fan curve drawn for operation at 1180 rpm and 0.62 hp FAN STATIC PRESSURE Ps1 + Pv1 = Ps3 + Pv3 = -0. 60 hertz 230 volts.075/0.1°F 0.37 + (-0.045 in.(Ps1 + Pv1) = 0. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 73.037 in.008 in. it is necessary to convert the results to the specified conditions.6 FLA General Fan direct connected to motor.36 in. Hmo = (755 × 0.37 in. The basis for the calculations is described in Section 14.6) = 29. 3 phase. 230 = 232 av Watts = 755 MOTOR NAMEPLATE DATA 1 hp. wg Ps = Ps2 .0727) = 0.62 (1180/1177)3 (0.1 in Annex N to obtain ρ3 = 0. there is no drive loss.0727 lbm/ft3.085/13.64 hp 91 . wg Hc = 0. Motor efficiency data supplied by motor manufacturer. wg 1177 rpm 5.085 in.085 + 0.5 = 1096 (0.077 in.0727) = 0.075/0.6) = 29.1°F p3 = pb + (Ps3/13.075 lbm/ft3 density. Qc = 6294 (1180/1177) = 6310 cfm Psc = 0.58 6294 cfm FAN POWER INPUT At the measured power input value of 755 watts.62 hp Since the fan is direct connected to the motor.0727)0.5°F 58.61)/746 = 0.5 = 1128 fpm Q = = = = Q1 = Q3 V3A3 1128 × 5.045 (1180/1177)2 (0. the data supplied by the motor manufacturer indicate efficiency of 61% for the motor.077/0.AMCA 203-90 (R2007) Where: Ps1 + Pv1 = Ps3 + Pv3 7.008) = 0.037 . Hg Use Figure N.(-0. It is assumed that ρ1 = ρ3.5°F tw3 = 58. 1175 rpm. OBSERVATIONS SITE MEASUREMENTS pb td3 tw3 Ps2 Ps3 Pv3 N A3 = = = = = = = = 29. it is recommended that the fan power input be determined by using the measured watts input to the motor and motor performance data obtained from the motor manufacturer. Measure the dry-bulb and wet-bulb temperatures at the velocity traverse plane. is zero gauge pressure. De = EQUIVALENT DIAMETER OF DUCT COMMENTS 1.Ps1 . 6.5 De 2 D2 TEMPORARY DUCT WITH SQUARE CROSS-SECTION. Determine pb for the general vicinity of the fan. Ps2 was measured. Ps2. referred to the same atmospheric pressure as in the static pressure measurements made at Plane 3. is square in cross-section. Determine Pv3 by using the root mean square of the velocity pressure measurements made in a traverse of Plane 3. 5.AMCA 203-90 (R2007) EXAMPLE 5B: FREE INLET. For the horsepower rating of the motor in this example. The subject of the test in this example is the propeller fan assembly. the static pressure at the outlet of the fan. When this possibility exists. In situations 92 such as this example. which is located at the tip of the Pitot-static tube. Determine Ps3 by averaging the static pressure measurements made in the same traverse.4.Pv1 = Ps2 . The installation of the duct is judged as creating no significant effect on the performance of the fan in this example.(Ps1 + Pv1) . A3. it is essential that the static pressure in the region of the discharging air be measured. FREE OUTLET PROPELLER FAN 2 De 3 1. Measure the fan speed and the motor amps and volts. Measure the area of the traverse plane. 2. with side dimension of 1. the air may be discharging from the fan into a region in which the atmospheric pressure is somewhat different from that to which all other pressure measurements are referred. The duct.5 D2. Before proceeding with the test. referred to the same atmospheric pressure as used in all other pressure measurements.4 for considerations affecting the test procedure in this type of installation. refer to Section 17. In this example. These measurements are used to determine densities at the planes of interest. and the entrance to the duct is flared in order to reduce inlet losses. Procedures for traverses are described in Section 9. referred to the atmospheric pressure in the region of the fan outlet. located in the duct which has been installed on the inlet side of the fan. The shape and area of the duct cross-section were selected on the basis of minimizing the effect of the duct on the performance of the fan while providing velocity pressure readings of measurable magnitudes. Record all pertinent motor nameplate data. 4. To calculate the Fan Static Pressure: Ps = Ps2 . The length of the duct is twice its equivalent diameter. temporarily installed for purposes of the test. 3. The basis for the calculations is described in Section 14.56 hp FAN STATIC PRESSURE Ps1 + Pv1 = Ps3 + Pv3 = -0. OBSERVATIONS SITE MEASUREMENTS pb = td3 = tw3 = Ps2 = Ps3 = Pv3 = N = A3 = 29.65 + (-0.075 lbm/ft3 density. wg This small value is attributed to the loss at the duct inlet.(-0. 1760 rpm. wg Ps = Ps2 .65)/746 = 0. CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 85°F tw3 = 74°F p3 = pb + (Ps3/13.075/0.6) = 29.1 in Annex N to obtain ρ3 = 0.AMCA 203-90 (R2007) Where: Ps1 + Pv1 = Ps3 + Pv3 7. wg 1775 rpm 5.54 hp 93 . 230 = 228 av Watts = 637 MOTOR NAMEPLATE DATA 3/4 hp.025 in. 4. Hg 85°F 74°F 0 in.6) = 29.06 3279 cfm FAN POWER INPUT At the measured power input value of 637 watts.002 in.0715 lbm/ft3. It is assumed that ρ1 = ρ3 Qc = 3279 (1725/1775) = 3187 cfm Psc = 0 in. and: H = Hmo = 0. it is necessary to convert the results to the specified conditions.5 = 1096 (0. 60 hertz 230 volts.56 hp Since the fan is direct connected to the motor.025 = -0.027 + 0. and the fan is considered to be operating at free delivery (Ps = 0). Motor efficiency data supplied by motor manufacturer.06 ft2 FLOW RATES V3 = 1096 (Pv3/ρ3)0.0715) = 0.027/13. CONVERSION TO SPECIFIED CONDITIONS MEASURED MOTOR DATA Volts = 230.5 = 648 fpm Q = = = = Q1 = Q3 V 3 A3 648 × 5.65 in. wg -0.(Ps1 + Pv1) = 0 .8 FLA GENERAL Fan direct connected to motor. Hg Use Figure N. Hmo = (637 × 0. 3 phase.027 in. wg 0. In order to compare the test results to the quoted fan curve drawn for operation at 1725 rpm and 0.0715)0. the data supplied by the motor manufacturer indicate efficiency of 65% for the motor. 225. wg Hc = 0. there is no drive loss.002) = 0.002 in.56 (1725/1775)3 (0.025/0.65 in. but since this measurement is actually part of the differential pressure described in paragraph 2. which is the fan static pressure. Record all pertinent motor nameplate data. consider the fan static pressure (Ps) as the differential pressure. a temporary duct was not installed and the Pitot tube traverse could not be accomplished. Also. The fan airflow rate is then determined by entering this curve at the test values of fan static pressure and fan power input. between the pressure measured inside the room (Ps3) and the pressure measured outside the room in the vicinity of the ventilator outlet (Ps2). the correction is to the differential pressure. The subject of the test in this example is the roof ventilator assembly.AMCA 203-90 (R2007) EXAMPLE 5C: FREE INLET. In this method for testing a nonducted fan. OBSERVATIONS SITE MEASUREMENTS pb = 29.1 for considerations affecting the test procedure in this type of installation. wg N = 1735 rpm 94 . refer to Section 17.19 in. Ps3. These pressures are measured at a sufficient distance from the ventilator so as to be unaffected by the velocity of the entering or leaving air. as read on a manometer. it is necessary to make only one density correction.Ps3 = 0. the static pressure in the vicinity of the ventilator inlet. Measure the dry-bulb and wet-bulb temperatures in the region of the inside pressure measurement. would normally be determined by averaging the static pressure measurements made in a Pitot tube traverse. 6. it is recommended that the fan power input be determined by using the measured watts input to the motor and motor performance data obtained from the motor manufacturer. FREE OUTLET ROOF VENTILATOR 2 1 3 COMMENTS 1. Airflow rates are determined from the fan manufacturer’s certified performance ratings. 2. Ps2 is considered to be zero gauge pressure. 5. determine pb in the same vicinity. 4. Draw a fan performance curve from these ratings converted to operation at the test values of fan speed and entering air density. Hg td3 = 79°F tw3 = 63°F Ps2 . But in this example.13 in. Measure the fan speed and the motor amps and volts. 3. Before proceeding with the test. For the horsepower rating of the motor in this example. The basis for these calculations is described in Section 14. and: H = Hmo = 1.0715/0.0715/0. 60 hertz 230 volts.50 1. If.125 (1735/1750)2 (0.77)/746 = 1.Ps1)/13. these two points will coincide at the same cfm.45 (1735/1750)3 (0. it is only a reflection of test inaccuracies.13/13. wg It is assumed that Ps1 = Ps3 CONVERSION OF MANUFACTURER’S RATINGS TO OPERATING CONDITIONS Rating Point #1 Q1c = 8900 (1735/1750) = 8824 cfm Ps1c = 0 H1c = 1. Point 1) 2) 3) CFM 8900 8520 8060 Ps 0 1/8 1/4 HP 1. such as in this example.1 in Annex N to obtain ρ3 = 0.8 FLA GENERAL Fan direct connected to motor.25 (1735/1750)2 (0. FAN POWER INPUT At the measured power input value of 1395 watts.6 = 29. However.0715/0.6) = 29. there is no drive loss.2 in.0750) = 1. Motor efficiency data supplied by motor manufacturer.234 in. the system should be reanalyzed for SEFs that may have been overlooked.0750) = 0.AMCA 203-90 (R2007) MEASURED MOTOR DATA Volts = 229. 4.0750) = 0. Hmo = (1390 × 0. Enter the measured values for static pressure and horsepower on the appropriate curves.0750) = 1.0715 lbm/ft3.45 1. however. as supplied by fan manufacturer for 1750 rpm.0715/0. wg H2c = 1.50 (1735/1750)3 (0. Ps = Ps2 . usually they will not coincide and should be averaged to determine the fan airflow rate.19 + (0.35 hp Rating Point #2 Q2c = 8520 (1735/1750) = 8447 cfm Ps2c = 0. 232 = 230 av Watts = 1390 MOTOR NAMEPLATE DATA 1.5 hp. 229.0715/0. Fan performance. at standard air density.117 in.55 FAN STATIC PRESSURE The fan static pressure is considered to be the differential static pressure. or for procedural errors in the initial testing.13 in. If this difference is small.43 hp Since the fan is direct connected to the motor.Ps3 = 0. 1740 rpm. wg H3c = 1. 3 phase. It is assumed that ρ1 = ρ3.43 hp .55 (1735/1750)3 (0. Ideally. these differences exceed 10%.44 hp Draw a performance curve for these operating conditions. Hg Use Figure N. the data supplied by the motor manufacturer indicate efficiency of 77% for the motor.39 hp Rating Point #3 Q3c = 8060 (1735/1750) = 7991 cfm Ps3c = 0. 95 FAN CALCULATIONS DENSITIES For Plane 3 conditions of: td3 = 79°F tw3 = 63°F pb3 = pb + (Ps2 .0750) = 1. WG (Ps) .50 BHP (H) .0715 Air Density 96 .40 x x BHP x 1.00 .20 1.30 x STATIC PRESSURE IN.10 x SP 0 7000 x 8000 CFM(Q) 9000 Fan Performance at 0.25 1.AMCA 203-90 (R2007) Qa = 8070 cfm (based upon horsepower) Qb = 8400 cfm (based upon static pressure) Use: Q = 8235 cfm (average of above). . 343 0.147 0.468 0.371 0. diameter.109 0. In no case shall the stem diameter exceed 1/30 of the test duct diameter.0.420 0.496 0.449 0.796 1.163 0.176 0.875 1.336 0.314 0.231 0.921 V/D 0.1° SECTION A-A All dimensions shall be within ±2%.538 1.192 0.250 0.333 0.920 1.228 1.602 1. 8 holes .741 0.211 0.313 1.279 0.657 1.918 1.4D 3D Radius D Head shall be free from nicks and burrs.10 in. Pitot Static Tubes 16D 8D 0.388 0.237 0.487 0. not to exceed 0.436 0.04 in.AMCA 203-90 (R2007) Annex B.936 1.404 0.118 0.100 D X 0. 8D X/D 0.357 0. PITOT-STATIC TUBE WITH SPHERICAL HEAD All other dimensions are the same as for spherical head pitot-static tubes. The minimum Pitot tube stem diameter recognized under this standard shall be 0.494 0. or better. 90° ± 0. diameter equally spaced and free from burrs.000 0.8D 0. The static orifices may not exceed 0.858 1.500 0.730 1.442 1. Hole depth shall not be less than the hole diameter.04 in.323 X/D 1.134 1.266 0.295 0.13D.762 1.570 V/D 0.474 0..025 1.910 1. Static Pressure Total Pressure Note: Surface finish shall be 32 micro in.1 97 .830 1.477 0.131 0.888 1.900 1.622 0.390 1.2D Diameter V ALTERNATE PITOT-STATIC TUBE WITH ELLIPSOIDAL HEAD Figure B.506 1.698 1.5D Radius 0. 0. OD SECTION VIEW TOTAL PRESSURE = READING A CORRECTED FOR MANOMETER CALIBRATION FLEXIBLE TUBING READING A READ ING B Notes: 1. and type S tube. combined reverse tube. The double reverse tube must be calibrated and used in the same orientation as used in its calibration 3. VELOCITY PRESSURE = READING B CORRECTED FOR MANOMETER CALIBRATION AND CALIBRATION FACTOR FOR THE DOUBLE REVERSE TUBE.375 in.AMCA 203-90 (R2007) Annex C. For use in dirty or wet gas streams.Double Reverse Tube 98 . Also referred to as impact reverse tube. Double Reverse Tubes AIR FLOW TUBE ENDS MUST BE SMOOTH AND FREE FROM BURRS IMPACT TUBE REVERSE TUBE STAINLESS STEEL TUBING PREFERRED APPROX. 2. Figure C.1 . Pitot-Static Tube Holder 0. diameter tube slides inside 1. PIPE NIPPLE 12 in. which can be unscrewed and moved to another traverse location 4. OUTSIDE DIA. The gas sampling tube and thermocouple may be omitted if these data are obtained in other manners SPLIT BRASS BUSHING CUT-OFF AND REBRAZE AFTER ASSEMBLY Figure D.5 in. 1 in.AMCA 203-90 (R2007) Annex D.312 in. × 8 ft. THERMOCOUPLE PITOT-STATIC TUBE SPLIT BRASS BUSHING PRESS TO FIT INTO TUBING DUCT WALL 1½ in. pipe. LONG STAINLESS STEEL TUBING 1 in. DIA. PIPE HALF-COUPLING WELDED TO DUCT BRASS BUSHINGS 1½ in.1 .Pitot-Static Tube Holder (Typical) 99 . STAINLESS STEEL TUBING FOR GAS SAMPLING 1. For use in large ducts or high velocity gas streams 3. Apparatus for mounting Pitot-static tube on duct 2. LONG SLIP FIT IN BRASS BUSHINGS Notes: ¼ in. OUTSIDE DIA. 2 . USE THE AVERAGE OF THE MEASUREMENTS AS THE STATIC PRESSURE FOR THE PLANE Figure E.Static Pressure Tap MINIMUM OF FOUR TAPS. LOCATED 90° APART AND NEAR THE CENTER OF EACH WALL STATIC PRESSURE MEASUREMENT REQUIRED AT EACH TAP. MAY BE NECESSARY TO INCREASE TO 0.Locations of Static Pressure Taps 100 . PIPE HALF-COUPLING OR SIMILAR ARRANGEMENT DUCT WALL INSIDE SURFACE OF DUCT AND EDGE OF HOLE ARE TO BE SMOOTH AND FREE FROM BURRS Figure E.312 in.AMCA 203-90 (R2007) Annex E. DIAMETER FOR USE IN RELATIVELY CLEAN GASES. Static Pressure Tap MAXIMUM 0. DIAMETER FOR DIRTY OR WET GASES ½ in.1 .125 in. 3 .AMCA 203-90 (R2007) Annex F.Fan with Inlet Duct and Outlet Duct 101 .Pv1 + SEF 1 where Ps1 = Ps4 Pv1 = Pv3 Figure F.1 .Ps1 . Pitot-Static Tube Connections PLANE 2 PLANE 1 PLANE 4 PLANE 3 *SEF 1 Ps4 FAN STATIC PRESSURE Ps = .2 .Pv1 where Ps2 = Ps5 Ps1 = Ps4 Pv1 = Pv3 Ps4 Ps3 P v3 Figure F.Fan with Outlet Duct Only ALTERNATE PLANE 5 PLANE 3 PLANE 2 PLANE 1 PLANE 4 PLANE 3 Ps5 FAN STATIC PRESSURE Ps = Ps2 .Ps1 .Fan with Inlet Duct Only Ps2 = 0 PLANE 3 PLANE 5 Ps3 P v3 *SEF 1 is due to no duct at fan outlet PLANE 2 PLANE 1 Ps3 Ps5 P v3 FAN STATIC PRESSURE Ps = Ps2 where Ps2 = Ps5 Pt1 = 0 Figure F. 5 in. wg 1:1 SLOPE RATIO 2 in. wg 20:1 SLOPE RATIO 1 in.1 .Manometer Data 102 .AMCA 203-90 (R2007) Annex G. wg 5:1 SLOPE RATIO 0. Manometer Data 10 in. wg 10:1 SLOPE RATIO Figure G. 02 VELOCITY PRESSURE READING.04 .AMCA 203-90 (R2007) PERCENT UNCERTAINTY IN VELOCITY DETERMINATION USING PITOT-STATIC TUBE AND MANOMETER DUE TO MANOMETER SLOPE Based on an uncertainty equivalent to an indicating column length of 0.3 0.06 0.05 in.Uncertainty in Velocity Determination 103 .6 0. wg in a vertical manometer (1:1 slope ratio) .0 6.3 0.0 4.8 1 2 3 4 6 8 10 15 STANDARD AIR VELOCITY.8 0.0 . fpm (×1000) Figure G.4 0.0 1.0 0.4 0.5 2:1 R TE ME TIO NO RA MA OPE SL 1:1 0.6 0.1 0.01 10.2 .2 0. in. wg .0 % UNCERTAINTY IN VELOCITY DETERMINATION 3.6 1 2 3 4 6 8 10 2.0 5.0 8.4 5:1 :1 10 20 :1 0.2 0. 817 .886 . It is recommended that the number of traverse points increase with increasing duct size.918 .626 .979 12 .114 .082 .775 .945 .128 .010 . 60º X1 X2 X3 X4 D Xn Xa = D × Ka Where: D is the inside diameter of the duct Ka is the factor corresponding to the duct size and the traverse point location as indicated in the table below NUMBER OF TRAVERSE INSIDE DIAMETER POINTS IN K1 OF DUCT EACH OF 3 DIAMETERS LESS THAN 8 ft.AMCA 203-90 (R2007) Annex H.724 .655 . it is necessary to locate each traverse point accurately.391 .184 .055 .986 16 .990 Figure H.816 .021 .166 . are based on log-linear Pitot traverse method.883 .183 .276 . THROUGH 12 ft. Distribution of Traverse Points In order to obtain a representative average velocity in a duct.1 .834 .345 .117 .225 .075 . GREATER THAN 12 ft. The distributions of traverse points for circular ducts.925 .609 .241 .759 .014 . 8 K2 K3 K4 K5 K6 K7 K8 K9 K10 K11 K12 K13 K14 K15 K16 .Distribution of Traverse Points for Circular Ducts 104 .872 . as indicated below. 8 ft.374 . For cross-sectional areas greater than 24 square feet. For rectangular ducts with cross-sectional areas of 24 square feet and less. however.3.AMCA 203-90 (R2007) The recommended minimum number of traverse points for rectangular ducts is indicated below in Figure H. The points are to be located in the centers of equal areas with the areas as nearly square as practical (see Figure H. the recommended minimum number is 24.Distribution of Traverse Points for Rectangular Duct NUMBER OF TRAVERSE POINTS 100 90 80 70 60 50 40 30 25 20 15 10 10 15 20 25 30 40 50 60 70 80 100 150 200 250 300 DUCT CROSS-SECTIONAL AREA. the minimum number of points increases as indicated in Figure H. the accuracy of the determination of flow rate may be improved by using more than the recommended minimum number of points. Y Y 2 X 2 X Figure H. the maximum area covered per point should not exceed 3 square feet. If the flow conditions at the traverse plane are less than satisfactory.Recommended Minimum Number of Traverse Points for Rectangular Ducts 105 . ft2 Figure H. Fewer points may be used if the flow is very uniform.3 .2).2 .3. 3 0. Melting and boiling points of materials Remote-testing -100/1000 20/500 -50/2100 1500 upward Any range 1000/3600 125/900 All except extremely high temp 2 2 2 15 ” ” For intensity of narrow spectra band of high temp radiation (remote) For intensity of total high temp radiation (remote) Approx temp (within temp source) Approx temp (in surface) Standards 50 ±1% Extremely precise For laboratory use only Reprinted by permission from ASHRAE Handbook . accuracy affected by radiation ” ” ” Less than 0. Pressure-bulb thermometers Gas-filled bulb Vapor-filled bulb Liquid-filled bulb 8. especially suited for low temp For differential temp in same applications as in glass stem thermometer For approx temp Must be set for temp to be measured Time lag. Instrumentation Characteristics Table J. unreliable Caution must be exercised so that installation is correct ” ” 7. remote readings. Gas thermometer 3.1 to 10 ” ” ” Limitations In gases. Glass-stem thermometers Mercury-glass thermometer Alcohol-glass thermometer Pentane-glass thermometers Jena or quartz mercury nitrogen thermometers 2. Radiation pyrometers 10.01 Less than 0. requires expensive measuring device Less accurate than above Subject to oxidation Precision.Temperature Measurement No. Indicating crayons 12.018 1. usually much more Requires considerable skill to use High cost.AMCA 203-90 (R2007) Annex J. Beckman thermometers (metastatic) 6. Measurement Means 1. Bimetallic thermometers General testing of high temp.1 to 5 0.1 to 15 0. temp by contact ” Standard for thermocouples -320/1800 Nickel-resistance thermometer Thermistors 4. remote rapid readings by direct contact ” Same as above. also. Thermocouples Pt-Pt-Rh thermocouple -150/300 Up to 600 500/3000 Up to 2200 Up to 1500 Up to 700 9 diff 0/1000 Chromel-alumel thermocouple Iron-constantain thermocouple Copper-constantan thermocouple Chromel-constantan thermocouple 5.1 0.02 to 5 0. temp of fluids or solids by contact Remote readings.1 to 15 0. Optical pyrometers 9.1989 Fundamentals 106 .1 . Resistance thermometers Platinum-resistance thermometer Application Temp of gases and liquids by contact ” ” ” Primary standard Approximate Range F -38/575 -100/100 -200/70 -38/1000 -459/1000 Precision F Less than 0.1 to 15 0. accuracy affected by radiation in gases Accuracy affected by radiation in gases High cost. Seger cones (fusion pyrometers) 11. unsuitable for remote use. velocity distributions (a) Low air velocities.. easily damaged.005 to 0. at outlets. crystal. complex. Deflecting-vane anemometer 3. Medium to high press.05 in. steady state measurements only Requires accurate calibration at frequent intervals.000 up with manometer 120 to 10.05 to 5% 0. directional Moderate air velocities in ducts and rooms. 10. Heated thermocouple anemometer 7. Manometer 4. magnet Table J. H20 0 to 100 in.001 in. Pressure transducersstrain gauge. Impact tube and sidewall or other static tap High velocities. costly 1 to 1000 1 to 20% up to 60.Differential Pressure Measurement No. Micromanometer 2. Medium press diff. needs periodic calibration Accuracy falls off at low end of range 1. Pitot tube 180 to 10.000 with draft gauges. H20 0. etc. not easy to use with pulsating pressure Must be leveled carefully Where used with liquid must be compensated for liquid density Generally usable to atmospheric pressure only Subject to damage due to over press-shock or pulsation Requires electronic amplifier and readout device 1.000 1 to 20% Reprinted by permission from ASHRAE Handbook . Hot-wire anemometer Air velocities in ducts. Revolving-vane anemometer 4. H20 or Hg 0 to 0. Draft gauges 3.3 . Moderately low press. 10.05 in. H20 0 to 20 in.1989 Fundamentals 107 .000 with micromanometer. diff. somewhat directional Std instrument for measurement of duct velocities Range 5 to 50 30 to 24. highly directional Air velocities in rooms. capacity.05 to 50.AMCA 203-90 (R2007) Table J. Swinging-vane-type gauge 5. H20 Any 0. potentiometer. Bourdon-tube type 6.1 to 0. Moderately low press. 5% 0.000 100 to 3000 Precision 10 to 20% 5% 5 to 20% Limitations Awkward to use but valuable in tracing air movement Not well suited for duct readings. usually to atmosphere Remote reading.2 .Velocity Measurement No. H20 0 to 10 in. diff. small tubes and where air direction may be variable 1 to 5% Accuracy depends upon constancy of static pressure across stream section 6.005 to 0. needs periodic check calibration Extremely subject to error with variations in velocities with space or time. H20 0. diff.5 in. directional and nondirectional available (b) High air velocities (c) Transient velocity and turbulence 3 to 20% Accuracy of some types not good at lower end of range.000 psi Precision 0. Measurement Means Application Low air velocities in rooms. 600 to 10. Measurement Means Application Very low press.000 up with manometer 10 to 2000 1 to 5% 5.5% Limitations Not readily portable.000 with micromanometer 600 to 10. Smoke puff or airborne solid tracer 2.000 with draft gauges. diff. responds to rapid changes of pressure Range 0 to 6 in. Use the average of Equation A and Equation B to estimate the Hmo for all motors operating at less than 90% of FLA and for 3 horsepower and smaller motors operating above 90% of FLA. The actual ampsload characteristics for motors of the same horsepower rating can vary greatly from motor manufacturer to motor manufacturer. various motor design requirements result in different ampload characteristics even though the horsepower ratings of the motors are the same. 108 .AMCA 203-90 (R2007) Annex K. Where: NLA = average of the measured phase values of no load amps NPH = nameplate horsepower FLA = full load amps NPV = nameplate volts NLA can usually be obtained with the motor operating and the motor shaft coupling or belt drive disconnected. The chart is only intended to indicate the accuracy and suitability of using the above equations for estimating motor power output. An estimated Hmo less than 50% of NPH can contain 15% uncertainties or greater. it will be necessary to remove the impeller in order to obtain NLA measurements. Phase Current Method for Estimating the Power Output of Three Phase Fan Motors The power output of three phase motors can be estimated based on the relationship of motor current and motor power output. that your results approach the typical calibration curve. Many fractional horsepower and small integral horsepower motors do not have a significant change in current from no load to full load. The “dashed” lines between 0% NPH and 100% NPH for motor sizes shown represents Equation B. The solid lines between these same end points for the motor sizes shown represent the general shape of typical motor calibration amp/load curves. Two equations can be used in estimating the motor power output. These are some of the reasons that Figure K. No load amperage (NLA) varies significantly for the same size motor between manufacturers. In the case where the fan impeller is mounted directly on the motor shaft.NLA   Measured volts  Hmo = NPH    FLA . In addition. These curves indicate that if you average the results of Equation A and Equation B for a specific measured amp draw. It also points out that the uncertainties are low if just Equation A is used above 90% FLA. operating at 90% or more of FLA. The equations are as follows: Equation A:  Measured amps   Measured volts  Hmo = NPH    FLA NPV    Where: Hmo = motor power output NPH = nameplate horsepower FLA = full load amps NPV = nameplate volts measured volts = average of the measured phase volts measured amps = average of the measured phase amps Equation B:  Measured amps . Figure K. The uncertainties will be less than 5%. especially in the larger integral motor horsepowers.NLA NPV    Use Equation A to estimate the Hmo for motors of 5 horsepower and greater.1 cannot be used to determine the motor output directly.1 represents the relationship of motor current and motor power output. The solid line from 100% NPH and 100% FLA to 0% NPH and 0% FLA represents Equation A. AMCA 203-90 (R2007) GENERALIZED CURVES ILLUSTRATING THE RELATIONSHIP OF HORSEPOWER TO AMPS FOR THREE PHASE MOTORS Do not use for determining actual motor horsepower DOTTED LINES PER EQUATION B: Hmo ∝ MEASURED AMPS . 109 .NLA/FLA . IT CANNOT BE USED TO DETERMINE THE HORSEPOWER OUTPUT OF A MOTOR. USE THE EQUATIONS AS DIRECTED ON THE PREVIOUS PAGE.NLA 100 90 RATED HORSEPOWER 1 2 80 70 3 60 5 50 10 40 400 30 2500 20 10 0 0 10 20 30 40 50 60 70 80 90 100 % NAMEPLATE HORSEPOWER PER EQUATION A: Hmo ∝ MEASURED AMPS FLA CAUTION: THIS CHART IS REPRESENTATIVE ONLY! SINCE THE AMP-LOAD CHARACTERISTICS OF THE SAME SIZE MOTOR WILL VARY BETWEEN THE VARIOUS MOTOR MANUFACTURERS. AMCA 203-90 (R2007) Annex L. Estimated Belt Drive Loss Drive loss is defined as follows: Percent drive loss equals power to driving sheave minus power from driven sheaves times 100, divided by power to driving sheave. There are several things which can affect belt drive efficiencies. Some of these are: 1) Over-designed drives. This was considered good practice at one time because the drive would last longer. It will still last longer but it is more inefficient. 2) Multiple belts on subminimum diameter sheaves are less efficient than fewer belts on larger diameter sheaves. Both the National Electric Motor Association and the Rubber Manufacturer’s Association publish data dealing with minimum recommended sheave diameters. As these minimum sheave diameters are approached, the drive loss becomes greater. 3) A larger belt section than required will increase the drive loss. 4) A badly undertensioned drive will increase the drive loss. 5) Misaligned drives will increase the drive loss. Drive loss is manifested as heat in belt drives. Under ambient conditions of less than 100°F, well designed drives that operate efficiently will be warm to the touch immediately after being shut down. If the drive is uncomfortable to the touch (approximately 140°F or more), then the drive loss is high. Obviously poorly tensioned and misaligned drives should be corrected before estimating brake horsepowers and drive losses. 110 AMCA 203-90 (R2007) 100 80 60 40 30 20 15 10 8 6 4 3 2 1.5 1 0.3 0.4 0.6 0.8 1 RANGE OF DRIVE LOSSES FOR STANDARD BELTS DRIVE LOSS, % MOTOR POWER OUTPUT* 2 3 4 6 8 10 20 30 40 60 80 100 200 300 400 600 MOTOR POWER OUTPUT, hp HIGHER BELT SPEEDS TEND TO HAVE HIGHER LOSSES THAN LOWER BELT SPEEDS AT THE SAME HORSEPOWER *Drive losses are based on the conventional V-belt, which has been the “work horse” of the drive industry for several decades. EXAMPLE • Motor power output, Hmo, is determined to be 13.3 hp • The belts are the standard type and just warm to the touch immediately after shutdown • From chart, drive loss = 5.1% • Drive loss, HL = 0.051 × 13.3 = 0.7 hp • Fan power input, H = 13.3 - 0.7 = 12.6 hp Figure L.1 - Estimated Belt Drive Loss 111 AMCA 203-90 (R2007) Annex M. Density Determinations M.1 General p 1 = pb = 28.60 in. Hg The wet-bulb depression is: This annex contains examples illlustrating the procedures for determining densities. Determinations of densities are shown for air and for gases other than air. td1 - tw1 = 78 - 62 = 16°F For wet-bulb depression of 16°F, dry-bulb temperature of 78°F and absolute pressure of 28.60 in. Hg, obtain ρ1 = 0.0701 lbm/ft3 by using the Psychrometric Density Chart in Figure N.1 in Annex N. EXAMPLE M2.2 The conditions at a fan inlet, located at an elevation of 1000 ft above sea level are: Ps1 = -3.45 in. wg td1 = 85°F tw1 = 75°F Barometric pressure, obtained from a nearby airport, is 29.82 in. Hg at sea level. Using the data in Figure N.3 in Annex N, the barometric pressure at 1000 ft above sea level is: pb = 29.82 × 0.964 = 28.75 in. Hg The absolute pressure at the fan inlet is: p1 = pb + (Ps1/13.6) = 28.75 + (-3.45/13.6) = 28.50 in. Hg The wet-bulb depression is: td1 - tw1 = 85 - 75 = 10°F For dry-bulb temperature of 85°F, absolute pressure of 28.50 in. Hg and wet-bulb depression of 10°F, use the Psychrometric Density Table in Figures N.5 in Annex N to obtain: M.2 Determination of the density of air, general case Determine air density by using the Psychrometric Density Chart, shown in Figure N.1 in Annex N, the Psychrometric Density Table, shown in Annex N, or a calculation procedure which makes use of perfect gas relationships and the modified Apjohn equation for partial vapor pressure. Examples of the use of these procedures are included in this section. Each of the procedures requires knowledge of the pressure, dry-bulb temperature and wet-bulb temperature of the air. The Psychrometric Density Chart and the Psychrometric Density Table are limited to the temperatures and pressures normally encountered in fan applications. Limit the use of the calculation procedure that is based on perfect gas relationships and illustrated in Example M2.3, to instances in which the dry-bulb temperature is 180°F or less. Accurate wet-bulb temperature measurements are difficult to obtain when the dry-bulb temperature exceeds 180°F. When the dry-bulb temperature exceeds 180°F, it may be necessary to rely on site personnel for the water vapor content of the air. Alternately, commercially available instrumentation for dew point determination may be used. For the procedure required to determine density based on the data provided in either of the above cases, refer to Psychrometric Tables and Charts by Zimmerman and Lavine.1 EXAMPLE M2.1 The conditions that exist at the inlet of a fan that is not ducted on the inlet side are: td1 = 78°F tw1 = 62°F Since: Ps1 = 0 ρ1 = 0.06829 + 10 × 0.000041 = 0.0687 lbm/ft3 Example M2.3 The conditions at a fan inlet are: Ps1 = -8.75 in. wg td1 = 146°F tw1 = 93°F 112 1. O. T. Zimmerman and I. Lavine, Psychrometric Tables and Charts, 2nd ed. (Dover, N.H.: Industrial Research Service Inc., 1964) 947 = 28. measured for the atmosphere to which Ps1 is referred.075 lbm/ft3. located at an elevation of 1000 ft above sea level.2 in Annex N to obtain saturated vapor pressure.964 = 28.92) [530/(95 + 460)] = 0. pp.3257 ( p1 − 0. Knowledge that the air is either dry or saturated eliminates the usual requirement of the wet-bulb temperature determination.3 Determination of the density of air. obtained from a nearby airport.3 in Annex N.27.2 Saturated air is enterting a fan inlet.75 in.562 .3 in Annex N.51 (146 .4 in Annex N to obtain saturated air density of 0. The pressure and temperature at the inlet are: Ps1 = -15 in. is 28. Hg at sea level. is 29.6) = 28.92 in.AMCA 203-90 (R2007) The barometric pressure.075 (27. is 29.6) = 27.09 in. Hg.6) = 28. Consider the density of air to be directly proportional to absolute pressure and inversely proportional to absolute temperature.2 are valid for dry air.6) = 28.15 + (-8.51 in.022 in.24 × 0.59 in. Hg for the wet-bulb temperature of 93°F. pb. it should be noted that an incorrect assumption of either of these conditions can result in a significant uncertainty in the density determination.6) = 27. This section contains alternate procedures for cases in which it is known that the air is either dry or saturated.0593 lbm/ft 3 M. Hg at sea level.19 + (-15/13. wg td1 = 95°F .75/13.p1 (td1 . pe.66 in.562 in. located at an elevation of 1500 ft above sea level.15 in.0648 lbm/ft3 EXAMPLE M3. The pressure and temperature at the inlet are: Ps1 = . the barometric pressure at 1500 ft above sea level is: pb = 29.93)/2700 = 1.06868 at 103°F and 29.6.09 + (-6. Assuming the density of saturated air to be directly proportional to absolute pressure. Hg Barometric pressure. Using the data in Figure N.19 in.75/13.09/29. Using the data in Figure N. Use the modified Apjohn equation for partial vapor pressure.378 pp ) ρ1 = ( td1 + 460 ) ρ1 = 0.51 − 0. EXAMPLE M3.92) [(70 + 460)/(td1 + 460)] = 0. Hg Dry air at 29.92 in. The absolute pressure at the fan inlet is: p1 = pb + (Ps1 /13. of 1.378 × 1.66 × 0.075 (p1/29. wg td1 = 103°F Barometric pressure.09 in. however. special cases The procedures for the determination of the density of air that are described in Section M. the density at the fan inlet is calculated as follows: 113 = 1.3257 ( 27. air that is saturated with water vapor and air that is partially saturated with water vapor.6) = 27. the barometric pressure at 1000 ft above seal level is: pb = 29. Hg The absolute pressure at the fan inlet is: p1 = pb + (Ps1/13. Hg and 70°F has a density of 0. Hg Use Figure N.24 in. to obtain: pp = pe . obtained from a nearby airport. The density of the air at the fan inlet is calculated as follows: ρ1 is calculated by using perfect gas relationships: 1.1 Dry air is entering a fan inlet. Hg.022 ) (146 + 460 ) = 0.tw1)/2700 = 1. Hg Refer to Figure N. Hg The absolute pressure at the fan inlet is: p1 = pb + (Ps1/13. The uncertainty in the density determination as a result of this approximation increases with increasing temperature and increases with increasing variation between the actual absolute pressure and 29.7 386. it is suggested that the company chemist be consulted for the gas analysis.AMCA 203-90 (R2007) Barometric pressure. is illustrated in Example M4. is 29.92 × 0.21 in. Hg Consider the density of the gas to be directly proportional to absolute pressure and inversely proportional to absolute temperature.3. 1% H2.1 A gas is entering a fan inlet located at an elevation of 2000 ft above sea level. The first two examples in this section illustrate gas density determinations based on analyses that provide the relative amounts of the gas constituents.70 29.0756 (26.15 0. as found in certain industrial processes.055 0. The pressure and temperature at the inlet are: Ps1 = .06868 (27. .92) = 0. the barometric pressure at 2000 ft above sea level is: pb = 29. consideration should be given to substituting air for the test.92 in.92 in.0756 (p1/29.59/29.0756 lbm/ft 3 Using the data in Figure N.92 in. and in these cases. which is the stated pressure for the data in Figure N. Hg is calculated as follows: Apparent molecular weight 29. 1% CO. which is provided in Figure N. The barometric pressure. If the gas is a complex mixture of various consitutuents. Since the actual density may be significantly different from the density determined by using typical data. Particular care should be used if the gas is toxic.92) = 0.01 0. Hg • At 180°F and at an absolute pressure within 4% of 29. The uncertainty will be approximately 1% or less under the following conditions: • At 120°F and at an absolute pressure within 20% of 29.92 in.21/29.28 4.3 in Annex N.02 21.92 in. EXAMPLE M4.5% CO2.00) = 29.6) = 27. The composition of the gas is 5. wg and td1 = 240°F.6) = 26. Hg • At 150°F and at an absolute pressure within 10% of 29.22 The density of the gas at 70°F and 29. The apparent molecular weight of the gas is determined as follows: Volume Molecular Component Fraction × Weight = lb/mole CO2 CO O2 H2 N2 0.92 in.83 + (-22/13.930 = 27.5% N2.42 0. Typical flue gas density data.06868 (p1/29.22 ρ1 = 0.92)[(70 + 460)/(td1 + 460)] = 0. by volume. corrosive or explosive. Hg The absolute pressure at the fan inlet is: p1 = pb + (Ps1/13.92) [530/(230 + 460)] = 0.4.83 in.0633 lbm/ft3 Assuming the density of saturated air to be directly proportional to absolute pressure is an approximation. wg td1 = 230°F 114 Apparent molecular weight = (29. obtained from a nearby airport.0509 lbm/ft3 EXAMPLE M4. an expert should be consulted for the proper use of the equipment. Hg M.22 = 386.22/1.6 in Annex N.2 The conditions that exist at the inlet of a fan are Ps1 = -19.01 0.4 DETERMINATION OF THE DENSITY OF A GAS OTHER THAN AIR The determination of the density of a gas other than air may require the use of complex equipment.775 1. The density of the gas at the fan inlet is calculated as follows: ρ1 = 0. 15% O2. Hg at sea level. Unless specifically qualified.22 in.80 0. and 77.5 in. Hg.7 = 0.00 44 28 32 2 28 2. it is recommended that the typical data be used only in the even that more specific information is not available. 92 in. Hg Consider the density of the gas to be directly proportional to absolute pressure and inversely proportional to absolute temperature. The density of the gas at the fan inlet is calculated as follows: 44 28 32 2 28 0.00125 0. Consider the density of the flue gas to be directly proportional to absolute pressure and inversely proportional to absolute temperature.7 = 0.00036 0.0725 (29. 1% CO.6) = 28.35 + (-19.92) [530/(240 + 460)] = 0.005 0. Hg Refer to Figure N. Hg is calculated as follows: Apparent molecular weight 25.0662 (27.0725 lbm/ft3 at 70°F and 29.00 Apparent molecular weight = 1/0.01 0.27/29. pb.85 in.5% N2 by weight.AMCA 203-90 (R2007) pb.055 0.27 in.6) = 29. The density of the gas at Plane 3 is calculated as follows: ρ1 = 0. measured for the atmosphere to which Ps3 is referred is 28.0330 lbm/ft3 ρ1 = 0.92 in.0662 lbm/ft 3 The absolute pressure at the fan inlet is: p1 = pb + (Ps1/13.85 + (5.92)[(70 + 460)/(td1 + 460)] = 0.92/29.7 386.6 = 386.74 in.15 0.35 in.6) = 27. 15% O2.6 in Annex N to obtain typical flue gas density when natural gas is used as the fuel of 0.6 The density of the gas at 70°F and 29.0047 0. the Pitot traverse measurement plane.0390 = 25. wg td3 = 680°F The barometric pressure. The conditions that exsit at Plane 3 are: Ps3 = 5. and 77.92) [530/(680 + 460)] = 0.5% CO2.74/13. 1% H2. The composition of the gas is 5. The flue gas is the result of using natural gas as the fuel.0662 (p1/29.5/13.775 1.6) = 29.0390 EXAMPLE M4. Hg.92)[(70 + 460)/(td3 + 460)] = 0. Hg.0468 lbm/ft3 115 .3 Flue gas is flowing at Plane 3.92 in. Hg.0725 (p3/29.0277 0.01 0. The absolute pressure at Plane 3 is: p3 = pb + (Ps3/13. The apparent molecular weight of the gas is determined as follows: Volume Molecular Component Fraction × Weight = lb/mole CO2 CO O2 H2 N2 0. measured for the atmospheric to which Ps1 is referred is 29. AMCA 203-90 (R2007) 116 . 254 1.4859 .2576 .5036 80 81 82 83 84 85 86 87 88 89 .50 12.Thermodynamic Properties of Water at Absolute Vapor Pressures.313 2.08 13.2204 .9359 .033 1.64 14.8468 .833 2.647 3.13 11.4359 .451 3.423 1. Inches of Mercury 117 118 .714 1.689 6.437 9.214 1.3764 .1805 . Hg 30 31 32 33 34 .69 14.5603 .515 1.2384 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 1.7397 .915 2.994 9.2783 .9053 .767 1.103 1.1 . Hg tw °F 120 121 122 123 124 pe in.889 6.263 3.069 4.450 5.8757 .038 5.562 1.4203 55 56 57 58 59 .4687 .580 7.359 6.79 13.599 2.AMCA 203-90 (R2007) AMCA 203-90 (R2007) Annex N.067 1.043 6.246 2.999 3.1879 .21 12.548 3.960 4.Psychrometric Density Charts 35 36 37 38 39 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 .1989 Fandamentals Figure N.310 5.3626 .898 10.908 5.2678 .213 9.6445 .853 tw °F 150 151 152 153 154 pe in.531 4.176 1.6906 .212 7.779 8.1724 .117 2.180 4.31 Adapted from ASHRAE Handbook .675 2.5219 .821 1.611 pe in.3241 .740 5.139 1.356 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 3.412 4.7917 .9673 .38 10.38 13. Hg 7.379 .1956 pe in.14 10.569 8.753 2.381 2.525 2.294 1.5804 .6011 90 91 92 93 94 1.662 1.9997 1.654 4. Density Charts and Tables tw °F tw °F 60 61 62 63 64 .32 14. Hg tw °F pe in.2036 .7653 .5408 .522 6.054 2.2 .3365 .1646 .180 2.3494 .40 11.779 4.935 1.7148 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 .394 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 8.963 8.3004 .173 3.2292 .468 1.877 1. Hg 3.3905 .173 5.63 10.94 12.00 14.085 3.770 7.2478 .8188 .4052 .336 1.6667 .4520 .034 7.295 4.593 5.2892 .452 2.199 6.88 11.2118 .66 11.3121 .665 9.161 8.6225 .860 7.94 15.362 Fold out for Figure N.994 2.749 3. 065 0.067 0.2 28.8 29.8 30.072 0.AMCA 203-90 (R2007) 40 0.1 .080 DRY-BULB TEMPERATURE. Proceed horizontally to the appropriate dry-bulb temperature. 20 WET-BULB DEPRESSION. Hg.070 0. 0. °F 16 14 12 10 8 6 4 2 90 88 86 84 82 80 78 98 96 94 92 0 Figure N.075 0. 0.9 in.074 0.ρ = 0.063 0.061 0.064 38 36 34 32 30 URE 26 in. H 28 g Wet-bulb depression = 4°F.079 76 74 72 70 68 66 64 62 60 58 56 54 52 50 48 46 44 42 0.4 28. Enter chart at the left.0 29. 4.060 0.6 29.068 0.062 1.0 PRE SS 24 . read horizontally to the density -.076 0.9 in. 2.077 0. tw = 50°F. proceed horizontally to 54°F dry-bulb temperature. lbm/ft3 18 ABS OLU 22 TE 28. Example • • Solution: Given: td = 54°F. Calculate wet-bulb depression. pb = 29.6 28.4 29. Hg Then read horizontally to the density.069 0. read vertically to 29. 3.Psychrometric Density Chart AIR DENSITY.073 0. °F Read vertically to the absolute pressure.066 0.0 28.0769 lbm/ft3.078 0.071 0.2 29. 42 26.98 23.27 25.82 27.13 28.84 25.21 27.920 0.86 28.46 25. Fan Engineering.02 27.33 28.65 25.75 11.89 13.65 28..54 28.729 0.832 0.807 0.460 0.42 27.60 29.44 28.89 7.235 0.877 0.03 25.982 0.989 0.820 0.92 29.801 0. 7th ed.00 Figure N.701 0.890 0.857 0. Hg 26.70 29.34 24.297 0.17 29.916 0.62 27.04 5.814 0.906 0.937 0. ed.72 27.909 0.52 27.16 23. 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200 5400 5600 5800 6000 6500 7000 7500 8000 8500 9000 9500 10000 15000 20000 25000 30000 35000 40000 SPECIFIC GRAVITY 0.743 0.899 PRESSURE in.71 24. Hg 29.930 0.22 21.975 0.92 27. Hg = 1.986 0.92 in.23 28.98 20.AMCA 203-90 (R2007) ALTITUDE ft.772 0.371 0.715 0.996 0.950 0.82 26.947 0.75 28.786 0.968 0.926 0.Reprinted by Permission 119 .96 28.757 0.49 29. Robert Jorgensen.54 Note: Specific gravity of standard air at sea level and 29.90 24.954 0.39 20.01 26.957 0.3 . Buffalo Forge Co..845 0.28 29.933 0.903 0.864 0.11 27.851 0.838 0.80 21.07 28.913 0.62 26.65 22. 0 100 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 2500 2600 2700 2800 2900 SPECIFIC GRAVITY 1.896 0.38 29.961 0.964 0.993 0. 1970) p.58 16.564 0.688 0.32 27.Relative Specific Gravity of Air at Various Altitudes1 1.870 0.09 22.8 .08 24.833 0.923 0.185 PRESSURE in.91 ALTITUDE ft.00 0.23 26.971 0.10 8.944 0.940 0.81 29.979 0. NY.52 24. (Buffalo.53 23.826 0. 07544 .07887 .000632 .08264 .001532 .AMCA 203-90 (R2007) PROPERTIES OF SATURATED AIR2 Temp °F WEIGHT IN A CUBIC FOOT OF MIXTURE VOLUME ft3/lb WEIGHT OF THE VAPOR Temp °F WEIGHT IN A CUBIC FOOT OF MIXTURE VOLUME ft3/lb WEIGHT OF THE VAPOR OF TOTAL lb/lb lb/lb DRY AIR VAPOR WEIGHT DRY AIR OF OF lb lb lb DRY AIR MIXTURE .00376 .07933 .08083 .00980 .00792 .00602 .12 13.000829 .07506 .000193 .01052 .07687 .00035 .07803 .00913 .01417 .00272 .00409 .29 13.001115 .00234 .07166 .08156 .07458 .08006 .85 11.87 12.01185 .00943 .23 12.09025 .84 .01662 .00027 .07880 .07897 .000886 .000409 .00750 .92 in.54 12.08247 . Jorgensen.91 13.37 12.01468 .07409 .07702 .21 11.00877 .000749 .32 12.00516 .08025 .07670 .00130 .01368 .15 13.53 13.08159 .00327 .07657 .07969 .07441 .02079 .71 13.07408 .000364 .08230 .07600 .00579 .000202 .07310 .00213 .01520 . and Saturated Mixture of Air and Water Vapor at Different Temperatures and 29.02036 .01841 .00392 .00458 .000425 .001080 .08213 .07604 .00168 .000339 .07952 .00035 .000651 .01016 .07104 .35 13.08022 .12 12.00425 .07425 .00020 .08194 .00480 .07557 .00314 .08925 .00626 OF TOTAL lb/lb lb/lb DRY AIR VAPOR WEIGHT DRY AIR OF OF lb lb lb DRY AIR MIXTURE .0223 .000723 .00583 .07350 .07860 .07936 .01876 .00786 .000380 .00541 .07694 .02174 -25 -20 -15 -10 -5 0 5 10 15 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 Figure N.07916 .000353 .78 12.22 13.00700 .99 12.49 13.01630 .00260 .000264 .00499 .00225 .000916 .001395 .00102 .00756 .01780 .25 13.07393 .07188 .08124 .00378 .00444 . Water Vapor.01717 .01026 .00313 .07562 .01257 .99 14.08210 .07277 .95 13.96 12.08723 .07921 .00285 .57 13.00558 .00361 .07 11.00284 .07491 .09134 .00102 .83 13.00952 .07250 .000041 .07572 .000775 .07360 .000857 .001310 .00299 .07843 .57 12.08063 .01214 .08354 .01349 .07676 .93 12.000213 .51 12.08136 .08109 .000087 .87 13.08055 .08820 .08434 .07622 .03 14.07970 .08445 .29 12.07293 .00561 .01063 . pp 15-17 Reprinted by Permission 120 .00246 .00496 .00734 .09136 .000491 .01691 .07524 .00989 .08625 .07714 .000176 .01904 .00245 .000303 .00728 .08529 .000587 .00680 .07468 .72 12.4 .07343 .15 12.00921 .07852 .01748 .000527 .08072 .000327 .34 11.00168 .95 11.00271 .07506 .00854 .07369 .00762 .00259 .07902 .60 13.02150 .07785 .01320 .00819 .32 13.07788 .07524 .000031 .75 12.08248 .09027 .07737 .66 12.000222 .00300 .01229 .07989 .02008 .46 13.00345 . cit.07837 10.000024 .07637 .00651 .07377 .00046 .08141 .000185 .07825 .001439 .01447 .08824 .00080 .00884 .63 12.00460 .001268 .000290 .64 13.39 13.69 12.00606 .001485 .00442 .08922 .00630 .07637 .000277 .000947 .00130 .26 12.07654 .07589 .90 12.02106 .01143 .08099 .00061 .07620 .07539 .00027 .07805 .001579 .08038 .08538 .07144 .01397 .01091 .01551 .07330 .49 12.79 13.000700 .07486 .34 12.08229 .Weights of Air.07871 .00823 .000440 .000456 .07390 .000545 .99 13.08728 .60 12.001045 .01941 .000675 .43 12.00408 .000254 .68 13.00213 .08173 .07290 .08090 .09 13.001229 .01968 .07124 .00426 .07819 .07987 .46 11.07447 .01497 .00519 .000608 .00344 .01171 .07328 . Hg 2.001189 .01103 .08043 .08117 .000018 .07753 .00845 .00224 .001352 .000979 .06 13.07720 .001152 .46 12.00235 .08193 .00362 .00020 .000243 .00046 .72 11.07582 .08 .42 13.59 11.75 13.07229 .07310 .00061 .00478 .00675 .01576 .01273 .07954 .000509 .18 12.08632 .01812 .02 13.000068 .000140 .00080 .000315 .01604 .08340 .07731 .08004 .20 12.07270 .07473 .81 12.07771 .07262 12.07429 .01130 ..08178 .000567 .00705 .19 13.07768 .07208 .00328 .001012 .000394 .40 12.000801 .000233 .00655 .000473 .000053 .00538 .01303 .000110 .00393 . op. 02462 .017926 .02826 .06532 .06667 .06486 OF TOTAL lb/lb lb/lb DRY AIR VAPOR WEIGHT DRY AIR OF OF lb lb lb DRY AIR MIXTURE .002620 .05319 .05934 .60240 .69660 .02482 .58 16.06132 .06452 .07059 .06931 . .58 14.003872 .06957 .69 26.08677 .18 15.05212 .04806 .06798 .07109 ..44 15.029730 .35660 .11523 .03543 .03730 16.03109 .02651 .02813 .002404 .07958 .493 Inf.07042 .03757 .06885 .06092 .29810 .10 18.014436 .03422 .02915 .001840 .04890 .03993 .50 15.02631 .035942 .07126 .06832 .03398 .06704 .04443 .68 16.001629 .06711 .00 16.0 ____ .04662 .004548 .12 15.06216 .08121 .11 127.04523 .04475 .49 18.05960 .06991 .002072 .93700 1.07193 .04159 . Jorgensen.12 14.009162 .06904 .24 16.06016 .26285 .001785 .34530 .06973 .85 15.06855 .06902 .001898 .52270 .016118 . cit.85 56.06609 .08428 .93 16.07015 .012937 .08376 .04667 .79 19.03 24.003568 .78 44.02380 .04270 .22962 .004085 .83410 1.67 23.03035 .002937 .03428 .77 16.07094 .78 15.05734 .02301 .48 14.03002 .30150 .04385 .94 37.50 16.01297 .03836 .05100 .024393 .06832 .04340 .06477 .07084 .003019 .06111 .005049 .05379 .9 431.06993 .01779 .06513 .20 77.05927 .07511 .03111 .07 15.08194 .03734 .25038 .4 .003193 .06634 .04300 .06678 .002692 .02736 .15230 .006355 .003470 .001733 .63 14.004669 .06778 .07869 .52750 .90 14.03870 .20022 .05524 .02645 .06278 .002853 .003766 . op.0948 1.21178 .07142 .004921 .07160 .65580 .019905 .07211 .31 15.06686 .26 14.002201 .71 15.04025 .07177 .06849 .03642 .07729 .004199 .06809 .09204 .003106 .07007 .06947 .0000 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 130 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 212 Figure N.03314 .08925 .03211 .00232 .79 14.06530 . and Saturated Mixture of Air and Water Vapor at Different Temperatures and 29.002770 .06629 .06722 .06247 .03904 .77 29.002474 .02723 .06970 .05895 .05556 .05422 .05917 .08 .05892 .06583 .1838 15.026957 .05492 .007195 .06785 .005183 .AMCA 203-90 (R2007) PROPERTIES OF SATURATED AIR2 Temp °F WEIGHT IN A CUBIC FOOT OF MIXTURE VOLUME ft3/lb WEIGHT OF THE VAPOR Temp °F WEIGHT IN A CUBIC FOOT OF MIXTURE VOLUME ft3/lb WEIGHT OF THE VAPOR OF TOTAL lb/lb lb/lb DRY AIR VAPOR WEIGHT DRY AIR OF OF lb lb lb DRY AIR MIXTURE .32 16.43168 .69 14.002139 .17478 .96 17.03015 .02545 .06660 .06306 .87 16.05346 .06244 .06647 14.01 15. pp 15-17 Reprinted by Permission 121 .03660 .02566 .37 15.05191 .16 16.05634 .34 14.06027 .55 21.07058 .39525 .80500 .00782 .06688 .02249 .06610 .08646 .003375 .06060 .07227 .002267 .037298 .Weights of Air.05264 .06814 .39 14.001954 .04953 .13026 .011547 .95 15.003283 .64 15.07244 .03212 .005598 .07390 .06935 .06492 .07038 .16 14.04255 .06925 .45425 . Hg 2. Water Vapor.06394 .53 14.06868 .04737 .06349 .06919 .5153 2.10010 .06124 .06336 .07157 .05587 .05767 .57 15.04048 .06451 .44 14.008128 .03780 .03318 .003666 .07081 .07625 .2923 4.15280 .06591 .07296 .06760 .06571 .06154 .001680 .06299 .03531 .022062 .004311 .05048 .002334 .04586 .010303 .06473 .05036 .41 16.004427 .73 14.02908 .06761 .21 14.09502 .02325 .06736 .17966 .005456 .002014 .06882 .11125 .06723 .04851 .06741 .05995 .032715 .06186 .60 20.92 in.06421 .07075 .02228 .06552 .13255 .06308 .05760 .05713 .06364 .04124 .005319 .06507 .06880 .04064 .30 14.002546 .00000 .04865 .06504 .07025 .003978 .84 14.05105 .43 32.02403 .004794 .04612 .06557 .06110 .25 15. 00027 .07772 .00026 .07240 .000027 .07839 .07625 .00027 .00026 .07673 .000019 .07790 .07445 .07890 .0 .07336 .08175 .000025 .07855 .1 in.08363 .08093 .Psychrometric Density Table (I-P) 122 .07919 .000027 .07640 .00026 .07828 .07350 .07913 .07896 .07734 .08041 .07756 .000025 .07605 . Hg 29.08345 .07956 .07641 .07544 .07528 .08021 .07674 .08075 .08222 .07512 .07287 .07271 .00026 .000019 .08187 .07576 .00026 .07940 .07208 .07998 .00026 .07856 .07161 29.07724 .000020 .07922 .07302 .08310 .07609 .08123 .07701 .07621 .07986 .000024 .00026 .08004 .08118 .07811 .000022 .07823 .07964 .00026 .07939 .07352 .07822 .00026 .00026 .08089 .000017 .08193 .07593 .00027 .07822 .000018 .000019 .07889 .5 .07477 .08205 .07541 .000018 .000023 .00027 .000021 .07525 .07654 .09705 .07607 .07924 .07414 30.07706 .07684 .07642 .07957 .000017 .000020 .000019 .000018 .000020 .07794 Approximate average increase in Increase in density per density per °F wet-bulb 0.07557 .07399 .08015 .07479 .08380 .08058 .07495 .5 .lbm/ft3 Dry-Bulb Temp.07845 .07431 .07383 .08170 .07429 .000024 .07885 .07689 .07784 .07868 . pressure depression .07447 .07805 .08032 .07397 .07413 . °F 28.00026 .000023 .07970 .00026 .07879 .07657 .07304 .07873 .07479 .07947 .08072 .07288 Barometric Pressure in.08239 .07512 .000020 .08110 .07367 .07656 .07541 30.07981 .07415 .07447 .07801 .000021 .08141 .08292 .07703 .07852 .07807 .00026 .08135 .07806 .07691 .08055 .07255 .00027 .08228 .07430 .1°F rise in dry-bulb temperature equals .08038 .07334 .07739 .07723 .07177 .07789 .07718 .000026 .00027 .07658 .07589 .07509 .000025 .00027 .07193 .07576 .07751 .000023 .08024 .07707 .07838 .08210 .AMCA 203-90 (R2007) Density of Saturated Air for Various Barometric Conditions .00027 .07496 .08158 .07840 .07320 .07740 .07463 .00026 .07590 .07772 .000021 .07788 .00027 .07574 .07706 .08066 .07722 .00026 .07930 .07768 .5 .000026 .07381 .07818 .07739 .00027 .000017 .07464 .07671 .07953 .07668 31.07974 .00026 .07623 .07990 .07973 .5 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 .000022 .08245 .07806 .08274 .07560 .00026 .07835 .00026 .07318 .08049 .07528 .07544 .07862 .08327 .07773 .07638 .00026 .07690 .00027 .08084 .07592 .07755 .07366 .08106 .07757 .07872 .0 .07224 .00026 .07493 .00026 .07936 .08153 .000018 .07674 .0 .07902 .07560 .000022 .07573 .000020 .00026 .000017 lbm/ft3.000028 Note: Approximate average decrease in density per 0. Figure N.07557 .07461 .08257 .00026 .07907 .07625 .07609 .08101 .07687 .00026 . 00024 .07310 .06904 .07114 .06829 .07301 .06835 .07574 .06731 .06715 .06937 30.06940 .000031 .07263 .06768 .000034 .07247 .07625 .00025 .07385 .00025 .06870 .07280 .06950 .000030 .07092 .07073 .07236 .07420 .000036 .06818 .07041 .00024 .000028 .07108 .00025 .000054 .5 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 .07000 .07437 .000043 .06917 .06989 .07618 .07224 .07523 .07285 .000031 .07551 .00024 .07138 .07299 .000041 .07727 .07693 .07472 .1°F rise in dry-bulb temperature equals .07020 .07227 .00024 .06700 Barometric Pressure in. °F 28.07316 .00025 .00025 .07634 .07211 .06901 .000017 lbm/ft3.00026 . Hg 29.07268 .000049 . Figure N.07501 .5 .06972 .000043 .07177 .07281 .07410 .07492 .000039 .07006 .07333 .00024 .07178 .07203 .07187 .07676 .000034 .000050 .07220 .07333 .06988 .07191 .06877 .00024 .07075 .06861 .07651 .07517 .06938 .07744 .07525 .07333 .00025 .07351 .07568 .000038 .06665 .000048 .00024 .00024 .000053 .07256 .07591 .06921 .000046 .06956 .07244 .000035 .07317 .07194 .00025 .000051 .06785 .06780 .07398 .000037 .07383 .06845 .000039 .07417 .06925 .07426 .5 .000029 .07642 .07534 .07195 .07176 .06648 .07208 .000042 .07403 .07442 .00024 .07083 .07459 .000055 Note: Approximate average decrease in density per 0.07584 .06972 .07096 .07126 .000033 .07032 .000036 .07058 .07475 .07368 .000052 .07489 .07192 .07467 .07601 .000045 .07760 .06764 .06934 .00024 .07245 .07366 .06581 29.AMCA 203-90 (R2007) Psychrometric Density Table (I-P) Density of Saturated Air for Various Barometric Conditions .07261 .07393 .07112 . pressure depression .06717 .000029 .lbm/ft3 Dry-Bulb Temp.07240 .06801 .00024 .000040 .07350 .00024 .00026 .06887 .07015 .07004 .00026 .07213 .07039 .5 .00024 .07294 .06852 .Psychrometric Density Table (I-P) 123 .07143 .07161 .07143 .07171 .000030 .07434 .06734 .07067 .01091 .07055 31.07130 .06598 .00026 .06967 .0 .00026 .07659 .07557 .07349 .07252 .07316 .07264 .06972 .06868 .07540 .07484 .07343 .07298 .07105 .000047 .00024 .07230 .06983 .07035 .06885 .07144 .06989 .07072 .07024 .07770 .07155 .07022 .07160 .07128 .00024 .07051 .06698 .06893 .07080 .00024 .07454 .07122 .07272 .06751 .06796 .000032 .07209 .06632 .00025 .00024 .06748 .06954 .07098 .00024 .07508 .07160 .07377 .07126 .00025 .07145 .07451 .07327 .07089 .07048 .00024 .07400 .07227 .06955 .06835 .06909 .07710 .07277 .06682 .06818 30.1 in.07056 .06853 .06812 .06615 .07109 .07382 .07360 .07603 .00025 .07174 Approximate average increase in Increase in density per density per °F wet-bulb 0.00025 .07366 .07064 .000044 .0 .07506 .0 .00026 .000033 .07005 . 92 in.076 0.6 . Hg are based on average fuel analyses and moisture contents Figure N.Typical Densities for Various Flue Gases 124 .075 0.070 The above densities at 70°F and 29.AMCA 203-90 (R2007) FUEL COAL OIL NATURAL GAS BAGASSE BLAST FURNACE GAS LIGNITE WOOD FLUE GAS DENSITY lbm/ft3 0.070 0.073 0.078 0.0725 0. Add 1 duct diameter for each additional 1000 fpm. Diffusion at Fan Outlets BLAST AREA DISCHARGE DUCT CUTOFF OUTLET AREA 25% 50% 75% CENTRIFUGAL FAN 100% EFFECTIVE DUCT LENGTH AXIAL FAN To calculate 100% effective duct length.AMCA 203-90 (R2007) Annex P.Controlled Diffusion and Establishment of a Uniform Velocity Profile in a Straight Length of Outlet Duct 125 . with side dimensions equal to a and b.1 .5 Figure P. the equivalent duct diameter is equal to (4ab/π)0. Example: 5000 fpm = 5 equivalent duct diameters If the duct is rectangular. assume a minimum of 2½ duct diameters for 2500 fpm or less. Terminology for Fans and Air Handling Units CASING BACKPLATE RIM HUB INLET MOTOR GUIDE VANE BLADE IMPELLER INLET BELL Tubular Centrifugal Fan .Direct Drive CASING BLADE DIFFUSER HUB MOTOR IMPELLER CASING BEARING CASING BELT TUBE BLADE Tubeaxial Fan-Direct Drive (Impeller Downstream) HUB GUIDE VANE IMPELLER Vaneaxial Fan-Belt Drive MECHANISM FOR CONTROLLING BLADE ANGLE INLET BOX BEARINGS FAN CASING GUIDE VANES INNER CYLINDER IMPELLER DIFFUSER Vaneaxial Mechanical Draft Fan Figure R.Common Terminology for Axial and Tubular Centrifugal Fans 126 .AMCA 203-90 (R2007) Annex R.1 . 2 .AMCA 203-90 (R2007) HOUSING DIVERTER CU TO FF CENTER PLATE BLAST AREA DISCHARGE OUTLET AREA SIDE SHEET BACKPLATE BLADE INLET CU TO FF SCROLL IMPELLER FRAME RIM BEARING SUPPORT INLET COLLAR Figure R.Common Terminology for Centrifugal Fan 127 . 3 .AMCA 203-90 (R2007) Figure R.Common Terminology for Centrifugal Fan Appurtenances 128 . 4 .AMCA 203-90 (R2007) HEATING AND VENTILATING DRAW-THROUGH UNIT FS FB MB BELT GUARD FS CS EXT F & BP INT F & BP HC + FB MB AS + HEATING AND VENTILATING BLOW-THROUGH UNIT ZONE DAMPERS BYPASS COLD DECK HOT DECK + + + FS HC + FB MB AIR-CONDITIONING DRAW-THROUGH UNIT AS FS CC + + + DRIP TRAY + HC SS + + + + FB MB ELIM AIR-CONDITIONING BLOW-THROUGH UNIT ZONE DAMPERS HC HOT DECK COLD DECK CC DIFFUSER PLATE FS HC + CC + FB MB + + FLEXIBLE CONNECTION AS CS CC HC ACCESS SECTION COIL SECTION COOLING COIL HEATING COIL EXT F & BP INT F & BP ELIM EXTERNAL FACE AND BYPASS DAMPER INTERNAL FACE AND BYPASS DAMPER ELIMINATORS FS FB MB SS FAN SECTION FILTER BOX MIXING BOX SPRAY SECTION Figure R.Common Terminology for Central Station Air-Handling Units 129 + + + + . . .. Typical Format for Field Test Data Sheet FIELD TEST DATA SHEET JOB DESCRIPTION: Location. . Ident.. MOTOR DESCRIPTION: Mfgr. . .. . .1 . . Performance Data Reference. . . Size. . User. . . . .. Contractor. FAN DESCRIPTION: Mfgr. .AMCA 203-90 (R2007) Annex S. . Size. Nameplate Data (Ident. No. MOTOR DATA: volts... DRIVE DESCRIPTION: Type.. . rpm. .) Figure S. Measurement Plane Locations. . . . Type. FAN SPEED GAS DENSITY DATA: GAS TEMPERATURES AT MEASUREMENT PLANES: READING Ps1 or Ps4 Ps2 or Ps5 Ps3 Pv3 Pv3 1 2 3 4 5 • • • • n TOTAL AVERAGE CALCULATIONS: (Refer to the various sections of this publication for the appropriate calculation procedures. . volts. . . . REFERENCE DRAWINGS OR SKETCHES OF INSTALLATION: System Configuration with Dimensions. . . . No. Wet-Bulb Temp. . Ident. . FLA. . watts. No. . . MEASUREMENTS AMBIENT DATA: Barometric Pressure. Engineer. . . amps. ). Mfgr. . . hp. Dry-Bulb Temp.Typical Format for Field Test Data Sheet 130 . therefore. This analysis deals.1 Introduction In an attempt to determine the range of uncertainties likely to be encountered in field testing of fans. of course.3 Symbols In the analysis that follows. and fan power input. This publication specifies uncertainties in percent. therefore. 131 . an uncertainty range will be defined with minimum and maximum values. T. the actual deviations in results will be less than the calculated deviations 95% of the time.. These are. b. Maximum and minimum uncertainties were assigned to each quantity to be measured based on the degree of difficulty in measuring the quantity.AMCA 203-90 (R2007) Annex T. with the probable uncertainty in the results obtained from a single set of observations. Symbol ex ∆X R Subscript A b d f g h H N P Q w x ρ Quantity Per Unit Uncertainty in X Absolute Uncertainty in X Gas Constant (ft-lb/lbm —°R) Description area Barometric Pressure Dry-bulb Temperature Velocity Pressure Static Pressure Power Input Fan Power Input Fan Speed Fan Static Pressure Fan Flow Rate Wet-bulb Depression Generalized Quantity (A.. The considerations that led to their adoption include difficulties in field testing generally not encountered in laboratory testing. The accuracies specified in this publication are based upon two standard deviations. multiplied by 100. For Type B and Type C tests. To do this. These individual maximum and minimum uncertainties were then combined statistically to arrive at the probable range of overall uncertainties for the fan flow rate. it may be necessary to calculate the uncertainties. certain symbols and notations are used in addition to those shown in Annex Q. Only one set of observations is specified in this publication. each measured quantity is assigned an estimated uncertainty by agreement of the parties involved and the overall uncertainty is calculated as outlined in this annex. Field test conditions range from near ideal to near impossible. Uncertainty Analysis T. are equal to the per unit uncertainty multiplied by the measured or calculated quantity. Test results will be considered to be the fan static pressure versus flow rate and fan power input versus flow rate. it may be sufficient to accept the results of any field test without consideration of the probable uncertainties in the results. This range of possible uncertainty is necessary to cover the varying degrees of difficulty encountered in performing tests in field installations. Absolute uncertainties which bear the units of the quantity being measured or calculated. It would be unlikely. per unit uncertainties.. The uncertainty in results will be expressed in terms of fan flow rate. The most probable performance would. a statistical uncertainty analysis was undertaken. In Type A tests. Systematic uncertainties should be eliminated by the use of properly calibrated test instruments. Since the tolerance on measured values is specified on the basis of 95% confidence limits. This means that there should be a 95% probability that the actual uncertainties will be less than the specified value. For the purposes of a field test. be the mean results based on repeated observations at each point of operation. . Therefore. This analysis considers only the uncertainties inherent in testing. fan static pressure. T.2 General This analysis is based on the assumption that fan perfomance can be treated as a statistical quantity and that the performances derived from repeated tests would have a normal distribution. fan static pressure. an agreement by the parties as to acceptable measurement tolerances for a given installation should be established prior to testing. ρ) Density T. however. The results of a fan field performance test for a single point of operation are a combination of variables which are normally presented graphically.4 Measurement uncertainties The various measurement uncertainty ranges used in this publication are listed below. This applies only to random uncertainties. and fan power input. the previously specified accuracies of instruments and the conditions expected to be encountered in field testing. that any particular field installation would have all minimum or all maximum uncertainties occurring simultaneously. 0% minimum to 5.0033 + [0.5% minimum to 7.5 = 0.5 = 0.5 = {0.5% minimum to 10.Ps1)]2}0.007 (max) Barometric pressure is generally obtained by portable aneroid barometer.02)2 + (0. A combined uncertainty can be written as: ef (min) = [(0.01)2 + (0.01)2 + (0.0% minimum and 7. In addition.0% maximum.Ps1)]2}0.5% minimum and 1.AMCA 203-90 (R2007) T.5 .02)2 + (0.1136 T.7 Flow measurement area.4. ew = 5/(td . T.4.03 (min) to 0. The estimated uncertainty in measuring wet-bulb depression is between 5°F minimum and 10°F maximum. In addition.005 (min) to 0.010 (min) to 0.5 = {0. The estimated uncertainty in measuring dry-bulb temperature is between 0. an allowance of 0.5% of absolute temperature minimum and 2.4.Ps1)]2}0.5 Power input. 132 ec = 0.0% minimum to 2. accessibility.005)2 + [0. eN = 0. and turbulence. T. broad range of duct sizes.10)2]0.4. T.075 (max) The uncertainty range in the Pitot traverse is estimated on the basis of traverse location.7% maximum.003 (min) to 0. The uncertainty range above is estimated based on the use of portable or on-site instrumentation and applicable corrections.0229 ef (max) = [(0.5 eg (max) = {(0.8 Velocity pressure. and the rigidity of ducts under pressure. and the broad horsepower range encountered in the field.0% maximum of the reading is estimated for calibrated manometer uncertainty and relocation of the instrument after . The estimated uncertainty in measuring power input is betwen 3.4 Fan speed. eb = 0.9 Static pressure.01)2 + (0.0% minimum to 2.07 (max) The estimated uncertainty range is based on the various measurement methods and their respective accuracies. estimated drive losses. The estimated uncertainty in the flow measurement area is between 1.4.015 (min) to 0. An allowance of 1.4. An allowance of 2.tw) (max) The estimated uncertainty range is based on a broad temperature range with the associated difficulties in determining wet-bulb readings at high or low temperatures and the likelihood of stratification.0% maximum of the fan velocity pressure should cover the influence of Pitot-static tube yaw or velocity influence on static pressure taps and other possible effects.0% of absolute temperature maximum.0% maximum of the reading is estimated for instrument precision. T. eA = 0.020 (max) The estimated uncertainty is based on a broad range of duct sizes.0% maximum of the reading is estimated for the mental averaging performed on a fluctuating reading.0% maximum of the reading is estimated for calibrated manometer uncertainty and relocation of the instrument after calibration. The estimated uncertainty in measuring fan speed is between 0. An allowance of 1.2 Pv/(Ps2 .0% maximum.02 (max) The estimated uncertainty range is based on a broad temeprature range and the likelihood of stratification.0% maximum of the reading is estimated for the mental averaging performed on a fluctuating reading.01 (max) The uncertainty range in fan speed is estimated on the basis of portable instrumentation accuracy and an allowance for fluctuation in fan speed.3 Web-bulb depression.5% maximum.2 Dry-bulb temperature. An allowance of 1. T.02)2 + (0.005 (min) to 0.000225 + [0.1 Pv/(Ps2 .2 Pv/(Ps2 .3% minimum and 0. A combined uncertainty can be written as: eg (min) = {(0.4. a tolerance of 10% minimum to 20.Ps1)]2}0.05)2 + (0.0% maximum.1 Barometric pressure.0% minimum to 2. ed = 0. No allowance is included for yaw on the assumption that the Pitot-static tube is aligned within 10 degrees of streamlines.6 Pitot traverse.tw) (min) to 10/(td . The estimated uncertainty in measuring barometric pressure is between 0.0% minimum to 5. eh = 0.05)2 + (0. nonuniform velocity profiles.4. T. T.1 Pv/(Ps2 .02)2 + [0. A properly performed field traverse is estimated to have an accuracy of 1.4. on-site barometer (mercury or aneroid) or by use of data obtained from a nearby airport.005)2]0. 015 0.003 0.5 T.0. Air density involves the various psychrometric measurements and the approximate formula: ρ= 70.2 Pv/(Ps2 . Uncertainties in density will produce a first-power uncertainty in fan static pressure while uncertainties in fan speed will produce a second-power uncertainty in fan static pressure when making fan law conversions.AMCA 203-90 (R2007) Where the denominator in the final term in each equation will involve Ps2 or Ps5 and Ps1 or Ps4.[(td .010 0.000225 + [0.378 {(pe/pb) .5 T.5 * These uncertainties do not account for the effect of swirl at the fan inlet.1 Measurement eb ed** eW eN eh ec eA ef eg Minimum 0. Combining: ep = [eg2 + eρ2 + (2eN)2]0.tw)/2700]} For random and independant uncertainties in products.010 0.030 0.5 Table T.005 0.0033 + [0.020 10/(td .00000725 tw .1 Pv/(Ps2 .5 It can be shown that: ev2 = [(0.1 Density. the combined uncertainty is determined as follows: ∆ρ/ρ = {(∆70. T.5 Combined uncertainties The uncertainties in the test performance are the result of using various values.tw)]2 Where: ∆(td .Ps1)]2}0. Uncertainties in fan speed will produce a first-power uncertainty in flow rate when making the fan law conversions.0229 {0.5.020 0.tw) 0. lack of ideal measurement locations. the square root of the pressure measurement for flow. Fan static pressure directly involves static pressure measurements.73)2 + (∆pb/pb)2 + (∆V/V)2 + (∆R/R)2 + [∆td/(td + 460)]2}0. Assuming ∆70. Fan flow rate directly involves the area at the flow measuring station.2 Fan flow rate.Ps1)]2}0.tw) = Absolute uncertainty in wet-bulb depression. This situation must be corrected in order to produce acceptable fan-system performance (see Section 5). turbulence.075 0.3 Fan static pressure. The estimated uncertainty range is based on an allowance for fluctuation in the fan-system operation.0.1136 {0.73 and ∆R are both zero: eρ = (eb2 + ev2 + ed2)0.5.tw) 0. whichever are measured.0 .5 Maximum 0. Other methods for determining density are assumed to have equal accuracy. and the relocation of instrumentation after calibration. Combining: eQ = [ec2 + eA2 (ef/2)2 + (eρ/2)2 + eN2]0.007 0.070 0. ** Based on absolute temperature 133 .73/70. and the square root of the density. the Pitot traverse. T.73 pbV R ( t d + 460 ) Where: V = 1.5.005 5/(td .0000542) ∆(td . each of which contains a probable uncertainty. The combined uncertainty for each of the fan performance variables is given below. 4.7 Examples Two examples of the calculation of uncertainties and the method of comparison with the quoted fan curve are included in this section.1) were defined earlier in Section T. when making fan law conversions. T. See the examples in Section T.5 The uncertainty calculations lead to absolute uncertainties in fan flow rate. eP is applied directly to Psc. Uncertainty calculations for Example 2B utilize all minimum uncertainty tolerances. the above equation was developed on the basis of tests in which static pressure measurements are made at a single plane.AMCA 203-90 (R2007) In order to simplify the application of this uncertainty analysis to the results of field tests. Combining: eH = [eh2 + eρ2 + (3eN)2]0. fan static pressure. Uncertainty calculations for Example 2C utilize all maximum uncertainty tolerances. and fan power input that can be applied directly to the corresponding test results. However. which may include System Effect Factors. 134 . in addition. as would be the case in which a fan is ducted on one side only. Although in most cases the determination of fan static pressure involves Pv1.1. T.5.6 Summary The minimum and maximum measurement uncertainties (See Table T. the per unit uncertainties are as shown in Table T. Agreement of the parties as to acceptable measurement tolerances for a given installation should be established prior to testing.4 Fan power input. Intersection of the rectangles with the quoted fan performance within the limitations of a field test. It would be unlikely that any field installation would lend itself to all minimum or all maximum measurement tolerances. density has a first-power effect and speed has a third-power effect on fan power input. T. For purposes of this publication. Uncertainty calculations and comparisons have been developed for Examples 2B and 2C of Annex A.7. the uncertainty in determining Pv1 is not included in the above equation on the basis that it normally has a very small effect on the overall uncertainty in fan static pressure. Fan power input directly involves the power measurement. Summarizing. the equation is reasonably accurate for all other fan-system configurations. The uncertainty results can then be plotted as rectangles around the test point. 0222 × 7114 = 158 cfm Qc + ∆Q = 7114 + 158 = 7272 cfm Qc .005 5/(td2 .0233 × 11.64 = 18.020112 + 0.0000542) ∆(td .006261 eP = [eg2 + eρ2 + (2eN)2]0.003 0.5 = 0.006261/2)2 + 0.0062612 + (2 × 0.54)/(0.0052]0.27 = 11.69 in.42 = 0. wg ∆Q = eQQc = 0.0052)0.0229 {0.57/1.5 = (0.5 = [0.5 = 0.0233 eQ = [ec2 + eA2 + (ef/2)2 + (eρ/2)2 + eN2]0.0705/0.3°F 70.0.64 hp Hc + ∆H = 18.90 = 0.1 in.0341 ∆P = ePPsc = 0.0.90 + 0.57 ft2 0.1 Pv/(Ps2 .0.0714) 1.000225 + [0.54 hp Hc . wg Hc = 18.∆P = 11.∆Q = 7114 .Ps1)]2}0.5 CALCULATIONS Pv = = = = Pv2 Pv3 (A3/A2)2 (ρ3/ρ2) 1.000225 + [0.40 ft2 1.54 in. wg Psc .158 = 6956 cfm ∆H = eHHc = 0.0714 lbm/ft3 0.42 .AMCA 203-90 (R2007) EXAMPLE 1: CALCULATION OF UNCERTAINTIES IN TEST RESULTS BASED ON MINIMUM MEASUREMENT UNCERTAINTY TEST VALUES Reference: Example 2B in Annex A SITE MEASUREMENTS td2 = tw2 = Ps1 = Ps2 = Pv3 = A2 = A3 = ρ2 = ρ3 = 91.0.4)]2}0.6 eb ed ew eN eh ec eA ef eg = = = = = = = = = 0.0229/2)2 + (0.0152 + 0. wg 0.0102 + (0.005 0.00000725 × 70.∆H = 18.5 = 0.27 in.4 in.42 in. wg eg = {0.0341 × 18.90 .42 + 0.0705 lbm/ft3 ev2 = [(0.1 + 11.0000542) 5]2 = 0.1 × 1.40)2 (0.4 .26 hp CONVERTED RESULTS Qc = 7114 cfm Psc = 11.15 in.24 (1.tw2) 0.5 = 0.5 = [0.02011 135 .4°F -11.24 in.1 Pv/(Ps2 .030 0.0222 eH = [eh2 + eρ2 + (3eN)2]0.005)2]0.90 hp MEASUREMENT UNCERTAINTIES Reference: Minimum values per Section T.0302 + 0.00000520 eρ = [eb2 + ev2 + ed2)0.tw)]2 = [(0.000225 + [(0. wg 1.010 0. wg 1.5 = 0.0032 + 0.5 = {0.005)2]0.Ps1)]2}0.64 = 19.27 = 11.5 = [0.00000520 + 0. wg Psc + ∆P = 11.00000725 tw .0062612 + (3 × 0.015 0. ∆P TEST POINT MINIMUM UNCERTAINTY RANGE Qc = 7114 cfm ∆Q = 158 cfm Psc = 11.42 in. FAN POWER INPUT Hc Hc .AMCA 203-90 (R2007) GRAPHICAL PRESENTATION Psc Ps.1 136 .∆H Qc .∆Q Qc + ∆Q Qc Q. FAN FLOW RATE Qc + ∆Q QUOTED FAN PERFORMANCE CURVES Hc + ∆H H.90 hp ∆H = 0. FAN STATIC PRESSURE Psc + ∆P Psc . FAN FLOW RATE Figure T. wg ∆P = 0.64 hp Qc . wg Hc = 18.27 in.∆Q Qc Q. 36 = 18.02176 eP = [eg2 + eρ2 + (2eN)2]0.54 = 0.0792 × 17.010)2]0.0780 eQ = [ec2 + eA2 + (ef/2)2 + (eρ/2)2 + eN2]0.1136/2)2 + (0.5 = 0.00000725 tw .tw3) 0.36 hp Hc + ∆H = 17.007 0.34 in.0000542) ∆(td .5 = [0.75 hp 137 .0792 ∆P = eP Psc = 0.072192 + 0.5 = 0.20 = 2.∆Q = 25964 .0.Ps4)]2}0.6 eb ed eW eN eh ec eA ef eg = = = = = = = = = 0.075 0.Ps4)]2}0.0202 + (0.010)2]0.0102]0.AMCA 203-90 (R2007) EXAMPLE 2: CALCULATION OF UNCERTAINTIES IN TEST RESULTS BASED ON MAXIMUM MEASUREMENT UNCERTAINTIES TEST VALUES Reference: Example 2C in Annex A SITE MEASUREMENTS td3 = 86.0702 + 0.0033 + [0.1136 {0.36 = 15.74 in.07219 ev2 = [(0.0033 + [(0.0000243 + 0.0000542) 10]2 = 0.2 Pv/(Ps5 .5 = {0.070 0.5 = 0.021762 + (2 × 0. wg ∆Q = eQQc = 0.2 Pv/(Ps5 . wg Ps5 = 1.2526 = 23438 cfm ∆H = eHHc = 0.57 in.tw)]2 = [(0. wg Psc .57)]2}0.11 = 1.0000243 eρ = (eb2 + ev2 + ed2)0.1.0. wg CONVERTED RESULTS Qc = 25964 cfm Psc = 2. wg Hc = 17.0. wg Psc + ∆P = 2.∆P = 2.00000725 × 75.11 + 1.0033 + [0.22 + 1.61 in.54 .021762 + (3 × 0.11 .5 = 0.∆H = 17.5 = [0.0973 × 25964 = 2526 cfm Qc + ∆Q = 25964 + 2526 = 28490 cfm Qc .20 in.5 = (0.020 10/(td3 .0780 × 2.11 hp MEASUREMENT UNCERTAINTIES Reference: Maximum values per Section T.0752 + 0.0072 + 0.47 hp Hc .54 in.5 = [0.5 CALCULATIONS eg = {0.020 0.54 + 0.5 = 0.5 .2 × 0.61)/(1.02176/2)2 + 0.20 = 2.010 0.0202)0.5°F tw3 = 75.22 in. wg Pv2 = 0.0973 eH = [eh2 + eρ2 + (3eN)2]0.5°F Ps4 = -1. wg ∆P = 0.20 in. wg Hc = 17.∆P Psc = 2. FAN STATIC PRESSURE Psc .36 hp Qc .∆Q Qc + ∆Q Qsc Q.2 138 .11 hp ∆H = 1. FAN FLOW RATE QUOTED FAN PERFORMANCE CURVES H.∆Q Qsc Q.AMCA 203-90 (R2007) GRAPHICAL PRESENTATION TEST POINT MAXIMUM UNCERTAINTY RANGE Qc = 25964 cfm ∆Q = 2526 cfm Psc + ∆P Psc Ps. FAN POWER INPUT Hc + ∆H Hc Hc . FAN FLOW RATE Qc + ∆Q Figure T.∆H Qc .54 in. S.A. IL 60004-1893 U. dampers.amca.AIR MOVEMENT AND CONTROL ASSOCIATION INTERNATIONAL. . airflow measurement stations. 30 West University Drive Arlington Heights. Inc. louvers.org Fax: (847) 253-0088 Web: www. Tel: (847) 394-0150 E-Mail : info@amca. is a not-for-profit international association of the world’s manufacturers of related air system equipment primarily. but limited to: fans. INC. acoustic attenuators.org The Air Movement and control Association International. commercial and residential markets. and other air system components for the industrial. air curtains. 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