ANSI C29.1-1988 for electrical power insulators test methods _. (714) 261.1455 " " " COPYRIGHT American National Standards Institute Licensed by Information Handling Services (IW) 151-7179 ectrical Power Insulators Test Methods Secretariat National Electrical ManufacturersAssociation Approved August 23. I nc COPYRIGHT American National Standards Institute Licensed by Information Handling Services .1988 American National Standards Institute.ANSI @ C29.1-1982 American National Standard for El.1-1988 Revision o f ANSI C29. processes. The procedures of the American National Standards Institute require that action be takenperiodically to reaffirm. Purchasers of American National Standards mayreceive current information onall standards by calling or writing the American National Standards Institute. their existence does not in any respect preclude anyone. Published by American National Standards Institute 1430 Broadway. or using products. New York 10018 Copyright O 1989 by American National Standards Institute. No part of this publication may be reproduced in any form. The American National Standards Institute does notdevelop standards and will in no circumstances give a n interpretation of anyAmerican National Standard. or withdraw this standard.Inc AU rights reserved. Requests for interpretations should be addressedto the secretariat or sponsor whose name appearson the title page of this standard. in the judgment of the ANSI Board of Standards Review. The use of American National Standards is completely voluntary. New York. revise. and that a concerted effort be made toward theirresolution.but not necessarily unanimity. Moreover. or procedures not conforming to the standards.L 8 8 W 0724350 0027822 O Approval of an American National Standard requires verification byANSI that the re- American quirements for due process. Consensus requiresthat all views and objections be considered. consensus. and other criteria for approval have been nlet by National thestandards developer. purchasing. no person shall have the right or authority toissue an interpretationof an American National Standard in the nameof the American National Standards Institute. marketing. without the prior written permission of the publisher. whether he has approved the standards or not. Substantial agreement means much more than a simple majority. substantial agreement has been reached by directly and materially affected interests. Standard Consensus is established when. in an electIonic refrieval system or otherwise. Printed in the United Statesof America AlC189/12 COPYRIGHT American National Standards Institute Licensed by Information Handling Services .A N S I C27. from manufacturing. CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. ... ... U. S.. ... . Committee appfoval does not necessarily imply that all committee members voted for its approval.. N W . .. W. ...... . .. Weber Institute of Electricaland Electronics Engineers ............ . L. .. National Electrical Manufacturers Association. Baker R.Foreword (This Foreword isnot part of American NationalStandardC29.. . Attn: Secretary.... ...... A. . which is in charge of this work. the C29 Committee had the following members: J. but rather a test method tobe used in conjunction with insulator specifications. Washington... Bonneville Power Administration.. W.. Nicholls R.. Labbe T. . . F.. .. (RepresentationVacant) R. . L. Kingsbury (Alt) . Chairman C. . Suggestions for improvement of this standard will be welcome..... . C29... ... A.. . .. Nicholls... . Harap J. . Marchbank D...1-1972. . The presentrevision was prepared by Accredited Standards Committeeon Insulators for Electric Power Lines. J. E... Sakich (Alt) J. .. M.... ..) This standard comprises a manual of procedures to be followed in making tests todetermine the characteristics of insulators usedon electric power systems. Davidson Stone & Webster Engineering Corporation. . E... Harmon (Alt) A.. This standard was processed and approved for submittal to ANSI by Accredited Standards Committee C29... White. Soffrin (Alt) J.... Pinkham N. Electric Light and Power Group... ... .. .. Cater B......... with Vote) . Schwalm (Alt) H. Van Herk (Alt) R. Cook A... .. .... At the time it approved this standard. . . ..1-1988is a revision of American National Standard Test Methods for ElectricalPower Insulators...ANSI C29.. . .. Karcher E. Secretary of Representative Organization Name Represented Association of American Railroads. Brown G. .... Jagtiani J. L...S. E.. F. Spauldmg (Alt) National Electrical Manufacturers Association .. . C. . D... . ...ASC C-29... American National Standard C29.1-1988... .. ... . . 2101 L St. DC 20037. . This standardis not an insulatorspecification. . K. ... G...Bridewesson Salisbury Co. They shouldbe sent to The Manager of Engineering. . ....... Department of the Army (Liaison. ... Juno I COPYRIGHT American National Standards Institute Licensed by Information Handling Services ..A. . .. 14 ..... .... . .. . .. . . .... ..... .... . .. . .. .... .. .. .... . . . . .. 14 7. . .......... ... . ... ... .. . .. ... .. .9Radio-InfluenceVoltageTests . ... ..... . .. .. . ... . . . ... ..... ....... . ... .. .. . .. .....10 Visual Corona Test . . .... ... .. ... .. .. . . . . . .... ... ...... . .... . . .... . ..2 Line Insulators (Pin.. . . 14 5 -6 Pinhole-GagingTest . ... .. ... . . .. . . . .... .. .. . 4. .. . . .. . 2. . .. . .. .... . . . ...... ..... . .. .. .. ..5 Miscellaneous .... .8 ImpulseWithstandVoltageTests .... . 2.4 Strain Insulators 3. .. . ... ... . . .. ... . ....... . .1 UltimateMechanical-StrengthTests . . .. .... ..... .. .. .... .. .. .. ..Scope 3.. .. 3 . ... . ... ... ... .. .. ... . .. . ... . ..' . ... . ...... . ... . . ..... . .. . 4..... .1 General . . .. . Galvanizing Test Figures Figure 1 Low-Frequency Humidity Correction Factors . . ... . 14 7. . ..... .. .. . ..... . .. . . . ..5 Spool Insulators (Cap andPin.. ... . .... .. .. .... . .. . . .... . .. .. ... .. .. . .. .. ... .. . . . .. . .. . . .... .. . .. .... . .... ...... .. . . .. .... ... . .......... ... . .. 13 5..... .... . . 13 5. .. 11 COPYRIGHT American National Standards Institute Licensed by Information Handling Services .... . . .. . . ... . .. ... .... .... ... . . .. ..and Electrical-Strength Test (Suspension Insulators) . .. ...1 Suspension Insulators . . 3. . . ... .7 ImpulseFlashoverVoltageTests . . ... . . 4 . . .. . . .... . . .. ... .. .... .... .. ... . ... . . .. . ..... . 12 6 .. . . .. ... .. .... . . .. 1... . Electrical Tests . .. .. 13 5. .. .. .. .... .. . .. .. . . . .... ..... .. . 4. .. . ... . . ... ......... . . . .. ... ... ... 3.. . . . . 5 5 5 5 6 6 6 6 6 7 7 7 7 8 8 8 9 9 12) 10 10 10 11 11 12 . ... . ... .. . .. . . .. . 2. . .... . . Revision of American National Standards Referred to in This Document .... .. 4. ... .. ..... .... .... . ..1 1 Puncture Tests .. .. . ..... . .. . .. ... ......... ... .. :...... .. . ... ..... 4.. . . . .. ...... . .. . . .. . ... .. .. . .. Routine Tests . . ... . .. ....... .. . . . . . ..... ... . . : .. . .. . . . ..... .2 Low-Frequency Voltages .. ... .... . 4. . . .. . . . . . .. ... . .... . . .. .... . .. .. ...... . .. . .. . . . .... . . . 2 .. . . .. . ...... . .. ... . .2 Mechanical Tests . . . .. . . . ... . . . . . ..Contents SECTION PAGE . .. .. .... .... .. ... . .. 9 Figure 2 Impulse Humidity Correction Factors. . .. .... .. .4 Low-Frequency Dry Withstand Voltage Tests . 2... .3 Impulse Voltages ..... . . . .. . .. . . ... ... . ..... .6 Low-Frequency Dew Withstand Voltage Tests . . ....... . . 4.. . .. . .... . 2. . . . .. . .. . . . .. ... . ....... . . ... . .... . .. .. . .. Post) .3ApparatusInsulators 3... .. .... . .... .. ... .. .... 15 Table 1 Rate of Increase of Load ... . .. ... .... . . . . 4. . Definitions . .. . . . .. ... ..... .... ... .. ....Post) .... . .... 4.. ..... 14 7. .. . .. .2 Low-Frequency Dry Flashover Voltage Tests .... . .... . ... .. . . . . . . . .. .......... .. 5 Mechanical Tests .. . . ... . . .5 Low-Frequency Wet WithstandVoltageTests . ..... 12 5.. . . .... . . .. .. ....... . . . Test-Specimen Mounting for Electrical Tests ..... . 12 5. .....3 Low-Frequency Wet Flashover Voltage Tests ... . .. .. .. .. . . ... ..2 Combined Mechanical. ..... . .. ... . . .. .......5 ThermalTest .. .. . . .. .. .. ..4PorosityTest . ... .. ....... . ... . . .... .. . .. 4...4 Mechanical Strength . . ...... .. .. . . ...... . .. . ........ . .... . ..1InsulatorsandParts .. . .1 ElectricalTests .3 Time-Load-WithstandStrengthTest ... . ... 14 8. . . . .... . ...... . ... . . . . . . ... . . .. 4. . .. causes a sustained disruptive discharge through the surrounding medium.4 Post Insulator. An apparatus-insulator unit is an assembly of one or more shells with attached metal parts.L 88 0 7 2 q 3 5 0 0027825 b W American National Standard for Electrical Power Insulators Test Methods 1.1.1. A wire holder is an insulator of generally cylindrical or pear shape. Low frequency. 2.1 Unit. A lowfrequency flashover voltage ofan insulator is the rootmean-square value of the low-frequency voltage that.1 Dry flashover voltage tests are tests as described in 4.8. .1.7.1.1.2. 2.5 Cap and Pin Insulator. the function of which is to support rigidly a conductor.1. intended to form a part of an insulator or an insulator assembly. A post insulator is an insulator of generally columnar shape.13 Suspension Insulator. means any frequency between15 and 100 hertz. A suspension-insulator string is an assembly of two or more suspension insulators in tandem.9 Strain Insulator.1. ANSI/IEEE 100-1988. A pin insulator is an insulator having means for rigid mounting on a separable pin.2 Wet flaskover voltage tests are tests as described in 4.2 Low-Frequency Flashover Voltage. with two transverse holes or slots.7. having means for direct and rigid mounting.A line insulator.7 Apparatus Insulator (Cap and Pm.8. An apparatus-insulator stack is a rigid assembly of two or more apparatus-insulator units.1.Post). as defined herein. having a hole for securing the conductor and screw a or bolt for mounting. 2. 2. 2. and pin. A cap and pin insulator is an assembly of one or moreshells with metallic cap.2.1. 2.1 Unit.2. 2.2 Stack. having means for nonrigid coupling to other units or terminal hardware. An insulator comprises one or more insulating parts to which connecting devices (metal fittings) are often permanently attached. 2. having means for semirigidly supporting lineconductors. An apparatus insulator is an assembly of one or more apparatus-insulator units.1. 2. or other conducting elements on a structure or base member.2. as used in this standard.1 Insulators and Parts 2. 2.2. having a skirt or skirts without cement or other connecting devices.1 Low Frequency.1. bus. assembly of a shell and hardware. A suspension insulator is an insulator with attached metal parts having means for nonrigidly supporting electric conductors. Scope This standard comprises a manual of test methods to be followed in making tests to determine the characteristics of electrical power insulators. Individual tests shall be made only when specified. An insulator is a device intended to give flexible or rigid support to electric conductors or equipment and to insulate these conductors or equipment from ground or from other conductors or equipment. having means for rigidly supporting electric equipment. 2.2. Post).1 Insulator. For additional definitions see American National Standard Dictionaryof Electrical and Electronics Terms.10 Spool Insulator.6 Line Insulator (Pin. A lowfrequency withstand voltage of an insulator is the root- 5 COPYRIGHT American National Standards Institute Licensed by Information Handling Services . Astrain insulatoris an insulator generally of elongated shape.11 Wire Holder. A suspension-insulator unit is an . 2.3 Low-Frequency Withstand Voltage.1. 2. 2.2.2. 2. 2. A shell is a single insulating member. A spool insulator is an insulator of generally cylindrical formhaving an axial mounting hole and a circumferentialgroove or grooves for the attachment of a conductor.3 Pin Insulator.2 String. under specified conditions. 2. 2.A N S I C 2 7 .3.having means for direct and rigid mounting.2 Shell.1. 2. 2.is an assembly of one or moreshells.1. Definitions NOTE: Definitions as given herein apply specificallyto the subject treated in this standard.2 Low-Frequency Voltages 2. 2. 8.2.3 Critical Impulse Flashover Voltage. The energized or bottom electrode or conductorshall be a straight.2.) 2. canbe continuously applied withoutmechanical or electrical failure.4.1-1988 mean-square value of the low-frequency voltage that. It shall be coupled to the lower integral fitting of the test specimen so that the distance from the lowest edge of the insulator shellto the upper surfaceof the electrode . along the insulating surfaces between the conductive 2.and electrical-strength test is a test as described in 5.2 Wet withstand voltage tests are tests as described in 4. 2.4 Impulse Withstand Voltage. The ultimate mechanical strength of an insulator is the load which at any part of the insulator fails to perform its function of providing a mechanical support without regard to electrical failure. An impulse flashparts. when voltage and mechanical stress are applied simultaneously.4.2. -on 50% of the applications. Ultimate mechanical-strength tests are testsas described in 511. Test-Specimen Mounting for Electrical Tests 3. impulse wave isaunidirec2.4 Low-Frequency Puncture Voltage. 6 COPYRIGHT American National Standards Institute Licensed by Information Handling Services 3.2 Energized Electrode. canbe applied without causing flashover orpuncture. as arranged for dry flashover test. under specified conditions. under specified conditions.5.7.1 1.3. A time-load withstand test is a test as described in 5.5. A test specimen is an insulator which is representative of the productbeing tested. The dry-arcing distance cal impulse flashover voltage of an insulator is the crest of an insulatoris the shortest distance through the survalue of the h p u l s e wave that.9.1. smooth rod or tube having an outside diameter not less than 314 inch (19 mm) nor more than 1-1/2 inches(38 mm). whichever is the shorter.2 Combined Mechanical and Electrical Strength (Suspension Insulator). A mechanical-impact strength testis a test as described in 5.3 Dry-Arcing Distance.5. plied impulse voltage that. A combined mechanical. or the tions.3. The combined mechanical and electrical strength of a suspension insulator is the mechanical load at whichthe insulator fails to perform its function either electrically or mechanically.2 Leakage Distance.1 Impulse Wave. 2.3 Dew withstand voltage tests are tests as described in 4.2. under specified condirounding medium between terminal electrodes. Puncture tests are testsas described in 4.A N S I C27. The impulse withvoltage of an insulatoris the radio-frequency voltage stand voltage of an insulatoris the crest value of an apmeasured under specified conditions. (Surfaces over voltage of an insulatoris the crest value of the coated with semiconducting glaze shall be considered ' impulse wave that. 2. in 4. puncture.3.1. under specified conditions. in 4.1 Suspension Insulators 3.3 88 0724350 0027826 8 W AMERICAN NATIONAL STANDARD C29. 2.4 Radio-Influence Voltage.3.1 Test Specimen.3 Time-Load Withstand Strength.4 MechanicalStrength 2.4. under specified conditions. 2.1 Dry withstand voltage tests are tests as described in 4. it is a specimen that is undamaged in any way which 2.2. 2. The leakage distance of an tional surge generated by therelease of electrical energy insulator is the sum of the shortest distances measured into an impedance network. The mechanicalimpact strength of an insulator is the impact which. the testspecimen (unit or string) shallbe suspended vertically at the endof a grounded conductorso that the vertical distance from the uppermost point of the insulator hardware to the supporting structure shallbe not less than 3 fee€ (9 14 mm). 2. A lowfrequency puncture voltage of an insulator is the rootmean-square value of the low-frequencyvoltage that. The time-load withstand strength of an insulator is the mechanical load that. causes as effective leakage surfaces. with the insu€ator mounted Impulse flashover voltage testsare tests as described for dry flashover test. Unless otherwise specified.2.1.4.4 Mechanical-Impact Strength.5.3. Radio-influence voltage tests are tests as described does not cause a flashover. - .3.3.5 Miscellaneous 2. underspecified conditions. Impulse withstand voltage tests are tests as described in 4.3 Impulse Voltages would influence the resultof the test.6. causes flashover throughthe surrounding medium sum of the distances between intermediate electrodes.4. and leakage distance over flashover through the surrounding medium. 2.or disruptive discharge on the test specimen. 2. 3. the insulator can withstand without damage. súch surfaces shall be included in the leakage distance.3.5. causes disruptive discharge through any part of the insulator. The criti2.1 Ultimate Mechanical Strength.2. The radio-influence 2. 2. under specified conditions.1 Mounting Arrangement. 2.2 Impulse Flashover Voltage. The other ends of 7 COPYRIGHT American National Standards Institute Licensed by Information Handling Services . the conductor shall be secured bymeans of at least two turns of wire not smaller than No. and with its horizontal axis in the same vertical plane as the vertical axis of the test specimen. with the channel flanges projecting down. The supporting channel shallbe of such length that flashöverwill not be initiated at its ends.4. the majoraxis shall beat right angles to the spray direction.3-19861. A rod of suitable diameter shall pass through the axial hole of the test specimen and one end of each of the straps. other than parts of the test assembly.3.5 Spool Insulators 3. The conductor shall be placed in the top conductorgroove of the test specimen.2.4. and its top surfaceshall be not less than 3 feet (914 mm) above the ground. Mechanical tension sufficient to avoid appreciablesag in the setup shall be applied to thetest specimen.2 Line Insulators (Pin. 3.2 Proximity of Other Objects. Unless otherwise specified. and in contact with two smoothmetallic straps 1-1/2 inches(38 mm) wide and of any suitable thickness. with a minimum allowable distance of 3 feet (914 mm). 3.3. The test specimen shall be mounted horizontally or vertically [as specified in Fig.5 and 0.When there is no top conductor groove. other than parts of the test assembly. The pin shallbe coaxial with the test specimen. 3.2. the conductor shall be placed in the other means provided for the conductor support. 3. 3. metallic tube or structural member having a horizontal width notless than 3 inches (76 mm) nor more than 6 inches (152 mm).T A N S I C 2 9 . Post) 3. shallbe nearer the test specimen or energized electrodes than 1-1/2 times the test-specimen dry-arcing distance. shallbe nearer the test specimen or energized electrodes than 1-1/2times the test-specimen dry-arcing distance. shall be nearer the test specimen or energized electrodes than 1-112 times the test-specimen dry-arcing distance. No objects. shall It be mounted directly in contact with the top integral fitting of the test specimen. with a minimum allowable distance of 1 foot (305 mm). 3. When a separable pin is required.1 Mounting Arrangement (Crossarm). the test specimen shallbe mounted vertically upright on a horizontal. the ends being closely wrapped around the conductor on each side of the insulator. The energized or top electrode or conductorshall be a horizontal round rod or tube placed at right angles to the supporting crossarm. Unless otherwise specified. with a minimum allowable distance of3 feet (914 mm).2 Mounfing Pin (If Required). and of-a diameter notless than 1!2 inch (13 mm).4 Strain Insulators 3. The lower conductor shall be grounded. straight.1 Mounting Arrangement. 3.4 Proximity of Other Objects. andthe axis of the upper conductor hole or slotshall be horizontal).3 Proximity of Other Objects.ANSI C29. the supporting crossarm shall be a horizontal. The conductor shall be of such length that flashoverwill not be initiated at the electrode ends. with a minimum allowable distance of3 feet (914 mm).2.3 Apparatus Insulators (Cap and Pin. No objects. The conductorsshall be clamped withguy clamps.1-1988 shall be between 0. 8 AWG (American Wire Gage). Insulators having integrally assembled means for mounting on a crossarm shall be mounted vertically and directly on th’e test crossam. shallbe nearer the test specimen or energized electrodes than 1-1/2 timesthe dry-arcing distance of the test specimen. the test specimen shall be mountedvertically on a l-inch (25-mm) diameter metal pin of such length that the shortest dry-arcing distance from the upper electrode and connected metallic partsto the supporting crossarm shallbe 25% greater than thesimilar distance to the pin.3 Energized Electrode. and of a diameter approximately 5% of the test-specimen dry-arcing distance within the limitsof 4-1/2 inches (1 14 mm) maximum and 1/2 inch (13 mm) minimum.1 Mounting Arrangement. It shall be of such length that flashoverwill not be initiated at its ends. smooth. 3. other than parts of the testassembIy. 3.3. The conductor shall be horizontal and at right angles to the axis of the test specimen.L B B W 0 7 2 ~ 5 0o 0 2 ~ 7 m AMERICAN NATIONAL STANDARD C29.7 of the diameter of the lowest insulator. It shall be of such lengththat flashover will not be initiated at its ends. No objects. other than parts of the test assembly. The length of the conductorshall be such that flashover will not be initiated at its ends. Post) 3.1 Mounting Arrangement. 1 through5 of American National Standard for Wet-Process Porcelain Insulators (Spool Type). spaced from the test specimen at a distance not less than the test-specimen length. using flexible metal conductors of approximately 50% of the hole diameter. the test specimen shall be mounted in a position with its majoraxis at 45 degrees from the vertical (for wet flashover test. grounded. 3. If a tie wire is to be used. No objects.1. The energized or top electrode or conductorshall be a horizontal round rod or tube atright angles to the supporting channel.2 Energized Electrode. The straps shall extend horizontally in one direction from the rod and remain parallelto each other for a distance from the test specimen of not less than the heightof the test specimen. grounded lO-inch (254-mm) channel.5. A subbase shallbe used if the insulator characteristics are predicated on its use.2.3 Proximity of Other Objects. Unless otherwise specified. 3. Values obtained by tests conductedin different laboratories may vary by f 8%. K d . a variation of * 5% from the probable true average dry flashover voltage valuemay occur in tests conducted in one laboratory. in degrees Celsius . of saturated aqueous vapor at temperature i" b = barometric pressure. or with the sling psychrometer. Dry flashover voltage values shall be corrected in accordance with American National Standard Techniques forHigh-Voltage Testing. 3.5.1 Standard Conditions.3. calculated in one of thefollowing ways: For U.2 Humidity. of saturated aqueous vapor at temperature r' b = barometric pressure.3 Dry Flashover Voltage Value. customary units: P K d = 17.086 X IO4 pascals) 77°F (25OC) 0.95 (460 t T ) where P = barometric pressureip inches of mercury T = air temperature in degrees Fahrenheit .) The vapor pressure shall be determined by the following procedure: Humidity shall be measured with wet. 8 COPYRIGHT American National Standards Institute Licensed by Information Handling Services Humidity and relative air density corrections shall be calculated in accordance with4. in inches of mercury. The initial applied voltage may be quickly raised to approximately 75% of the expected average dry flashover voltage value. The measurements shall be reduced to vapor pressure with the assistance of the Smithsonian Meteorological Tablesor bythe followingformulas: .001 1 st') where Ph = vapor pressure.2..2. For U. other than parts of the test assembly.3 Air Density. customary units: where Ph = vapor pressure. divide the measured voltage value by therelative air density correction factor. inpascals r = temperature of air. Elecfrical Tests 4. in inches of mercury P. The period between consecutive flashovers shall be not less than 15 seconds nor more than 5 minutes.2 Low-Frequency Dry Flashover Voltage Tests 4.0876b(t. 4.t')(l t 0.S.1 Mounting Arrangement. No objects. 4.2.84 feet). . The energized electrode shall consist of one turn of No. = pressure.2 and 4. and other uncontrollable conditions..4.ANSI CZ7-L 88 = 0724150 0027828 1.2. in degrees Celsius 4.' The dry flashover voltage value of a test specimenshall be the arithmetical mean of not less than five individual flashovers taken consecutively. The dry flashover voltage value shall be corrected to standard humidity conditions in accordance with the curves in Fig.051 X lo3 pascals) * Probable variation: Due to inaccuracies of correction methods. 4. 3.6085 inch of mercury (2.2 Energized Electrode. Test specimens used for the tests in this section shall have clean insulating surfaces. 1.2.0.2 Voltage Application. in inches of mercury r = temperature of air. This conductor shall be carried away from the test specimen parallel to and in a direction opposite to the supporting straps. = pressure. 4. 8 AWG conductor placed around the wire groove andserved back on itself. 4. in degrees Fahrenheit For SI units: Ph =P.2.2.2. shall be nearer to the test specimen or energized electrodes than 1 foot (305 mm).4.4 Corrections 4. the air being circulated past the thermometers at a velocity of 3 meters (9. r' = wet-bulb temperature of air.4. P. To doso.1-1988 the straps shall be suitably connected to a grounded support. 4. (Humidity correction curves are not available for spool and strain insulators.92 inches of mercury (10. The test-specimen mounting for dry flashover voltage tests shall be in accordance with Section 3. The continued rate of voltage increase shall be suchthat the time to flashover will be not less than 5 seconds nor more than 30 seconds after 75%of the flashover value is reached.4. per second.S.1 General.2. difficulties of precise calibrations. in pascals. or more. except the following standard conditionsshall apply: Barometric pressure: Temperature: Vapor pressure: 29. ANSIlIEEE 4-1978.4.and dry-bulb thermometers. The dry flashover voltage value shall be corrected to standard atmospheric temperature and pressure conditions. AMERICAN NATIONAL STANDARD C29.3 Proximity of Other Objects. in pascals .5.in degrees Fahrenheit r' = wet-bulb temperature ofair. in kilovolts 6 = relative air density H = humidity correction factorapplicable for the particular test specimen O 0.3. The continued rateof voltage increase shall be such that the time to flashover will be not less than 5 seconds nor more than 30 seconds after 75% of the wet flashover voltage value is reached.2 The wet flashover voltage value of a test specimenshall be the arithmetical mean of not less than five individual flashovers taken consecutively.4.3.3.002955 .4 Low-Frequency Dry WithstandVoltageTests .2.4 0. 4. which is the rated dry withstand voltage with appropriate atmospheric corrections applied.shall be held on the test specimen for 1 minute. difficulties of precise calibrations.3. inaccuracies of correction methods. applied to test specimen V. At not less than 1 minute after the final adjustment of the spray.1 Mounting Arrangement.2 of ANSIlIEEE 4-1978.3 Test Voltage and Time. the applied voltage may be raised quickly to approximately 75% of the expected average wet flashover voltage value. The testvoltage applicable to existing atmospheric conditions is obtained from the rated withstand voltage.4.7 0.4 Corrections.1 Fig.6 Corrections. P (273 + 7) where P = barometric pressure inpascals T = air temperature in degreesCelsius or Kd = 0.6 0.3.2 and Table 1. The test voltage. 4.1 0. in kilovolts.1 Mounting Arrangement. and other uncontrollable conditions.4.1 8 8 = 0724350 0029827 3 AMERICAN NATIONAL STANDARD C29.2 (Practice in USA) of ANSI/IEEE 4-1978.3 0. H where V = test voltage. 4.2 0. a variationof C 8% from the probable true average wet flashover voltage valuemay be expected in tests conducted in one laboratory.4.9 1. 4.5 0.0 VAPOR PRESSURE.5 Wet Flashover Voltage Value. 4. 4.3. by use of the following equation: 6 V = V. The preparation of the testspecimen shall be in accordance with subsection 1.392 P (273 t 7) where P = barometric pressure in millimeters of mercury T = air temperature in degrees Celsius 4.2. Corrections shall be made in accordance with 4.2 'Probable variation: Due to variations in water spray. 4. The test-specimen mounting for dry withstandvoltage tests shall be in accordance with Section 3.8 0. except that no correction for. 4.4. The precipitation shall be applied in accordance with subsection1.2 Precipitation.2 Voltage Application. 9 COPYRIGHT American National Standards Institute Licensed by Information Handling Services . 4.3.3. 4. Values obtained by tests conducted in different laboratories may vary by f 12%. 75%of the rated dry withstand voltage may be applied in one stepand gradually raised to the required value in not less than 5 nor more than 30 seconds. Corrections shall be made in accordance with 4. 1 Low-Frequency Humidity Correction Factors 1. .A N S I C27.X .3 Low-Frequency Wet Flashover Voltage Tests 4. The test specimen mounting for wetflashover voltage tests shall be in accordance with Section 3.3. humidity shall be made. = rated withstand voltage. INCHES OF MERCURY 1. The period between consecutive flashovers shall be not less than 15 seconds nor more than 5 minutes.1-4988 For SI units: Kd = 0.3 Preparation of Test Specimen.3.4 Voltage Application.4. as given for standard atmospheric conditions. 5 Test Voltage and Time.4.6. The time to raise the voltage shall be not more than 20 seconds.) 4.b B A AMERICAN NATIONAL STANDARD C29. This may be obtained by pass.1 General.6. whilethe test specimen is completely covered with dew.2. 4. The test voltage.1 Critical Impulse Flashover Voltage. except that the curves in Fig.6 Corrections .2 Mounting Arrangement.5. the correction shall be reduced in the direct ratio that the timeto flashover bears to the time at thecritical flashover.7. The humidity correction shall be made as follows: (1) When the critical flashover voltage value occurs at more than 10 microseconds. = rated withstand voltage. applied to test specimen V. The preparation of the testspecimen shall be in accordancewith subsection 1.6 Corrections. The test speci- .4 Test Voltage and Time. The full air-density corrections shall be applicable.7.5.ing live steam at atmosphericpressure into the chamber. 4. 4.8.8.2 Mounting Arrangement. The test specimen shall be mounted in accordance with Section3 in a test chamber having a temperature of approximately 77°F (25°C). The test-specimen 4.2 of ANSIlIEEE 4-1978. full corrections shall be applied to all values with time lags of 10 microseconds or more.4.3 Voltage Application. 4. 10 COPYRIGHT American National Standards Institute Licensed by Information Handling Services 4.2 (Practice in USA) of ANSI/IEEE 4-1978. as given for standard atmospheric conditions. ~~~ Probable variation: Due toinaccuracies o f correction methods.6. shallbe held on the test specimen for 10 seconds.2 and Table 1. The test-specimen mounting for impulse withstand voltage tests shall be in accordance with Section3.5. 75% of the rated wet withstand voltage may be applied in one stepand gradually raised to the required value in not less than 5 nor more than 30 seconds. The relative humidity in the test chambershall be approximately 100%. with appropriate atmospheric corrections applied. Corrections shall be made in accordance with 4. Impulse withstand voltage tests are made t o determine that the testspecimen is capable of withsfanding a specified impulsevoltage.2 Precipitation.5 Low-Frequency Wet Withstand Voltage Tests 4. difficulties of precise calibrations.3 Corrections.5.x 6 where V = test voltage. 2 shall be used.5 Volt-Time Flashover The volt-time flashover curves shall be determined in accordance with ANSI/IEEE 4-1978.6.3 The critical impulse flashover voltage shall be determined in accordance with ANSI/IEEE 4-1978.4. 4. 4. The test voltage. except that no correction shall be made for humidity.7 Impulse Flashover Voltage Tests 4. 2 shall be used. 4.5. which is the rated dew withstand voltage with appropriate atmospheric corrections applied.4 Voltage Application. Corrections shall be in accordance with 4.2 Mounting Arrangement. (Cooling may take 10 to 12 hours.3 Preparation of Test Specimen.6. In volt-time curves. (2) When the critical flashover voltage value occurs at less than 10 microseconds.4 Critical Impulse Flashover Voltage Value.5.3 Impulse Voltage Wave.7.shall be held on the test specimen for 10 seconds.3.7. Impulse flashover voltage tests are mounting for wet withstand voltage tests shall be in accordance with Section 3.6. 4.6. 4.6.7. v = v. 4. by use of the following equation: madeunder dry conditions only. men shall be placed in a chamber having a temperature of'from -10°C to -15°C (14°F to 5°F) until the specimen is thoroughly cooled. When flashover above critical voltage occurs at less than 10 microseconds. a variationof ? 5%from the probable true average impulse critical flashover voltagevalue maybe expected in tests conducted in one laboratory.8.A N S I C27. Values obtained by tests conducted in different laboratories may vary by f 8%.and other uncontrollable conditions.3. The testvoltage applicable to existing atmospheric conditionsis obtained from the rated withstand voltage.1-1988 4. . 4. 4.3. 4. except that thecurves in Fig.7.6 Low-Frequency Dew Withstand Voltage Tests 4. 4.2 X 50-microsecond wave. 4. All tests shall be made with a 1. similar variations are to be expected at points near the impulse critical flashover voltagevalue.2. with considerably larger variations involved as the time to breakdown decreases. the correction shall be reduced in the direct ratio that the time to flashover bears to 10 microseconds. . The critical impulse flashover voltage value shall be corrected to standard conditions in accordance with 4.3.2 Volt-Time Curves.5. Corrections shall bemade in accordance with 4. The voltage shall be raised rapidly to dew withstand test voltage.5 Corrections. The precipitationshall be applied in accordance with subsection 1.1 General. in accordance with ANSI/IEEE 4-1978. in kilovolts 6 = relative air density 4.1 Preparation of Test Specimen.4.8 Impulse Withstand Voltage Tests 4.7. which is the rated wet withstand voltage. 4. The test-specimen mounting for impulse flashover voltage tests shall be in accordance with Section3. in kilovolts.7. 4.1 Mounting Arrangement. 2 Impulse Humidify Correction Factors 4.A N S I C 2 7 . N. INCHES OF MERCURY Legend A Suspension insulators. negative wave Apparatus insulators. D.2 Equipment. it is recommended that barometricpressure and dry.1 Wave Shape. positive wave C Line insulators.. The following precautions shouldbe observed when making a radio-influence voltage teston a test specimen-: (1) The test specimen should be at approximately the same temperature as the room in which the test is made. . VAPOR PRESSURE. except that the clearance to objects. positive wave Suspension insulators. 4. Impulse withstand voltage tests shall be made withan impulse of that polaiity which produces thelower flashover voltage on the test specimen.and wet-bulb thermometer readingsbe recorded so that if suitable correction factors shouldbe determined.2.8.9. The wave shape of the applied voltage shall be a sine wave of acceptable commercial standards in accordance with ANSI/IEEE 4-1978. no correction factors are recommended for either at the presenttime. 2101 L Street.9.2. but itis recommended that tests be avoided when the vapor pressure exceeds 0.C. The equipmentused in making the radio-influence voltage tests shall be in accordance withNEMA 107-1964 (R1987). Since the effects of humidity and air density upon the radio-influence voltage are not definitely known.2 Supply-Voltage Frequency. In such cases it is permissible to stabilize conditions by preexciting the test specimen at normal operating voltage for a period not to exceed 5 minutes before proceeding with the tests. 4. The radio-influence characteristics are determined by plotting the test voltage against the correspondingradioinfluence voltage. other than parts of the test assembly.1-1988 4.4 Precautions in Making Radio-Influence Voltage Tests. It is considered hnpractical to read radio-influence test voltages that are less than 10 microvolts.9.5. Washington. negative wave Fig. 11 COPYRIGHT American National Standards Institute Licensed by Information Handling Services .10. and the radio-influence voltage shall be measured in microvolts at the specified radio frequency. The specified voltage shall be applied to the test specimen. Methods of Measuring Radio Noise: 4. 4. The test-specimen mounting shall be in accordance with Section 3.9. with appropriate atmospheric corrections.5. The frequency of the supply voltage shall be 60 hertz 5%. they couldbe applied to previous measurements.W.5 Methods of Making Tests 4.9.1 Mounting Arrangement. The crestvoltage of each shall be not less than the specified impulse withstand voltage.2 Radio-Influence Characteristics. 4. Three consecutive impulses shall be applied to the test specimen.3 Atmospheric Conditions. (3) In some cases it may be found that the radioinfluence voltage falls off rapidly after the 60-hertzvoltage has been applied for a short time. 4. 20037. negative wave Apparatus insulators.6 inch of mercury (2. positive wave B Line insulators.9.1 88 07241150 0029831 I AMERICAN NATIONALSTANDARD C29. 4.4 Voltage Application.9. shall in no case be less than 3 feet (914 mm) per 100 kilovolts of test voltage. To assist in locating a sourceof Available from National Electrical Manufacturers Association.9.1 General.1 Radio-Influence Voltage. Tests shall be conducted under atmospheric conditionsprevailing at the time and place of test.02 X IO3 pascals).1 O Visual Corona Test 4. However. * 4. (2) The test specimen should be clean. All hardware associated with the test circuit shall be relatively free of radio influence at a voltage 10% higher than the voltage at which the testsare to be performed.9 Radio-Influence Voltage Tests 4.9. The load shall be started at zero and smoothly brought up in a practically stepless variation to the failure point. + V. neglect the signs. electrodes shall be provided as follows: An electrode in the pinhole shall be provided by setting a metallic thimble. The observer’s eyes shall be thoroughly accustomed to the darkened room before making visual observations. . Let a = average variation.1 Ultimate Mechanical-Strength Tests 5.9. The loadmay be increased rapidly to approximately 75% of rated strength of the insulator. . Mechanical load shall be applied to the test specimen in the manner prescribed in 5. in kilovolts 51ftest-equipment limitationsare such that the test specimen cannot be punctured. Increase in Load per Minute in Percentage of Rated Strength Min 15 30 30 30 15 15 30 60 60 60 30 30 .l. 4. V.v.3.10. Y-v2 NOTE: Consider all these values of a as positive. Voltage shall be applied between the electrodes. .’ The percent average variation of the puncture voltage is determined as follows: Table 1 Rate of Increase of Load ~ Let V . The thimbleshall be provided with a close-fitting pin for attaching the conductor. . . The point of disappearance shall be the coronavoltage. The rate ofincrease of load from 75% of rating to failure is given in Table 1. + v. as described in 4. Mechanical Tests 5.2. -I. In the case of pin insulators having go conducting electrodes at oneor both terminals. The initial applied voltage may be raised quickly to the rated dry flashover voltage of lhe test.A N S I C 2 9 .. specimen. A voltage well above the corona point shall be applied and slowly lowered untilall discharges disappear from the test specimen. in kilovolts A = percent average variafion then a= + . = v.3 Percent Average Variation of Puncture Voltage.+a. The testshall be made in a thoroughly darkened room.2. 4.1 I . . = individual puncture voltage values.1 through 5. the puncture value shall be considered to be the maximum available applied test voltage.. a corona test may be performed.1.Y1 a3 = A. Puncture tests shall . The voltage shall then be raised a t the rate of approximately 10 O00 volts every 15 seconds to the value at which puncture occurs.1. 4.1-1988 radio-influence voltage. provided this value exceeds 150%of the puncture rating. 12 COPYRIGHT American National Standards Institute Licensed by Information Handling Services Class of Insulator Type of Max Test Suspension Line Apparatus Apparatus Apparatus Apparatus Tensile Cantilever Cantilever Torsion Tensile Compression ..L 8 8 W 0724350 0 0 2 7 8 3 2 3 W AMERICAN NATIONAL STANDARD C29. -I-v.1. .2 Voltage Application. The top of the test specimen shall be coated with conducting material toa diameter of approximately 1 inch (25 mm) larger than the test-specimen head.) (a1 t a 2 t a 3 n A = -1O& V 5.1. The oil shall be at least 6 inches (152 mm) deep over all parts of the test specimen.1 General.1 1. .1 1. Mechanical-tensile load shall be applied between terminal fittings in line with the axis of the test specimen. in kilovolts V = average puncture voltage.) n Let a1 = a2 = v . The test-specimen mounfing shall be in accordance with 4.3 Procedure. then V= ( V .2 Suspension Insulators 5. be performed on fully assembled insulators only.1. such as cement or alloy.1 1 Puncture Tests 4. V. . 4. that is. with suitable conducting material.1 Tensile Strength.1 1. 4. The test specimen shall be inverted and immersed in insulating oil having a sufficient dielectric strengthto prevent external flashover of the specimen. V3. Voltage shall be applied between the integrally assembled electrode (cap and pin)on all units having these parts.2 Mounting Arrangement. 5. .1 Mounting Arrangement.10.v3 v . 1. stranded.1. The test-specimen mounting shall be in accordance with the pertinent provisions in 5.having clean surfaces ex13 COPYRIGHT American National Standards Institute Licensed by Information Handling Services .1. The test specimen shall receive an impact of thespecified severity by releasing the pendulum when its shaft is opposite the corresponding mark on the indicating scale.2 Combined Mechanical. mountingbases. 5.1. Mechanical load shall be applied inline with theside groove of the test specimen and normal to the axis of the pinhole. Insulators whose design incorporates selfcontained metal caps.passing through the center of the wire groove.2 Mechanical-Impact Strength. The load shall be applied normal to the axis of the test specimen at the specified point of application.3 Tensile Strength.ANSI C29.7.4.1.1.2 Loading. with theinside edge of the nearest clamp placed9 inches (229 mm) from the end of the insulator.4. 5. - 5. using the flexible loop arrangement described in 5. Post) 5. The loop shall be clamped. The test specimen shall be mounted between close-fitting parallel straps. connecting hardware. Tensile-strength tests shall be made with the testspecimen adequately secured to the testing machine.4. The load shall be applied in line withtheaxis of the test specimen. 5.1 Mounting Arrangement. stranded. The test specimen shall be mounted in the specified test machine in the specified manner under a tensile load of approximately 2000 pounds-force (8896 N). The pendulum shall be released with no imparted acceleration. Torsional-strength tests shall be made with the test specimen adequately secured to the testing machine. the test specimen shall be checked for electrical soundness by being subjectedto momentary flashover.2 Cantilever Strength.1 Preparation of Test Specimens. or conductor clamps. The mounting screw or bolt shall be held rigidly in such a manner that the mounting base of the test specimenseats squarely against the face of the plate.1-1988 .and Electrical-Strength Test (Suspension.3 Time-Load-WithstandStrengthTest 5. without undue vibration or shock. 5.1. steel cable. 5.1. 5. The diameter of the cable used should not exceed50% of the diameter of the hole in the test specimen. The equivalent lever arm may be obtained by bolting a bar or pipe of proper length and stiffness to the test specimen. l . Thetorsional load shall be applied to the test specimen through a torque member so constructed that the test specimenis not subjected to any cantilever stress. steelcable. The mounting pin. . the diameter of which shall not exceed the radius of the wire hole in the insulator.1. whenreleased. Cantilever-strength tests shall be made with the test specimen adequately secured to the testing machine. the copper nose will strike the outerrim of the shell squarely in a directionparallel to the axis of the unit and towards the cap.4 Porosity Test 5. In demonstrating stack ratings.3. one insulator unit may be used.using a suitable rigid support. 5.7 Wire Holders 5. Compressionstrength tests shall be made by applying load in compression in line with the axis of the test specimen.7. Test specimens having more than one shell shall have each shell checked individually for electrical soundness.3.1.2. 5. After receiving the specified impact. 5.L 88 m 0 7 2 4 1 5 0 0029833 5 AMERICAN NATIONAL STANDARD C29. shall be tested with this hardware. Load shall be applied as described in 5. The straps and connectinglinkage shall be such that no appreciable deflection will take place. 5.Insulators).1. the test specimen.6 Spool Insulators (Transverse Strength). and maintained for thespecified period. stranded.3 Line Insulators (Pin.4.1 and 5. Mechanical load shalI be applied in the plane of the external wire groove. The bearing point of the pendulum shall be so adjusted that. using a loop of flexible.1.1 Tensile Strength. The specified loadshall be applied smoothly. the test specimen shall be tested for soundness by momentary flashover. Load shall be applied in a plane parallel to the mounting surface.2 Torsional Strength. Each cable loop shall be secured with clampsso positioned that the distance between the edge of the nearest clamp and the end of the test specimen is the same as the length of the test specimen. and linkages between the test specimen and the testing machine shall be such thatno appreciable deflection takes place at values up to thefailure point of the test specimen. Freshly broken fragments of the insulator.2. pins. The diameter of the cable shall not exceed the radius of the wire grooves. using a through bolt ofthe same diameter as that for which thetest specimen is designed.1. Mechanical loadshallbeappliedin line with the mainaxisof . using flexible.7.1. The load at the tie-wire groove may be applied by means of a loop of flexible stranded cable or the equivalent. The load shall be applied by means of a loop of flexible. 5. a lowfrequency voltage of notless than 75% of the rated dry flashover voltage shall be applied to the test specimen. The mountingscrew or bolt shall be installed in such a manner that the mounting surface of the test specimen does not touch the support.1 Cantilever Strength.1. steelcable. Simultaneously.1. After the load has been removed.1.4. 5.5 Strain Insulators (Tensile Strength).4 Compression Strength.4 Apparatus Insulators (Cap and Pin. Post) (Cantilever Strength). 5. Load shall be applied in line with the axisof the mounting screw or bolt. as indicated by the plunger and scale on the gage. Penetration into small fissures formed in preparing the test specimens shall be disregarded.1. and the number of revolutions of the gage required to release it from the pinholeshall be counted. applied in line with the axis of the insulator. 5.1 General. Each bath shall have a weight of water at least 10 times the weight of the test specimen immersed. 5.6 Pinhole-Gaging Test 5.6. The shells or insulators shall be subjected to a high-frequency discharge from a . The recorded temperature shall be measured at least 4 inches (102 mm) from the heating or cooling elements. transformer adjusted to a no-loadvoltage of not less than 115% of the low-frequency dry flashover of the shells or insulators. applied in line with the axis of the insulator. 14 COPYRIGHT American National Standards Institute Licensed by Information Handling Services 5. this test to be continued for a period of from 3 to 5 seconds.1.2 Testing qrrangement. cedure in 7.5. the assembled suspension insulators shall be given a tensile-strength test 3 seconds in duration. 6 .4 Interpretation of Results.6. at the specified value. For this test. The gage shall be screwed into the test specimen until the gage is tight.A N S I C 2 7 * L 88 W 0724150 0029834 7 - o AMERICAN NATIONAL STANDARD C29. The distance from the bottom of thepinhole to the point where the gage stops. 5. or an optional test at minimum 10 O00 pounds-force per square inch(68 900 kN/m*) for not less than 2 hours may be used. Prior to or simulta- neous with the final electrical test. Prior to or simultaneous with the final electrical test. ASTM B 499-75 (1987). The test specimens shall be completely immersed in the testing solution within a pressure chamber.5. After thespecified number of hot and cold cycles. The test specimen shall first be immersedin a hot water bath for 10 minutes. The shells or insulators shall be subjected to a damped high-frequency voltage sufficient to cause flashover for from 3 to 5 seconds. When the threaded pinholes of pin insulators are gaged.5 Thermal Test 5.1.Thickness by the Magnetic Method: Nonmagnetic Coatingsof Magnetic Base Metals. Not more than 5 seconds shall elapse in transferring the test specimen from one bath to another. The voltage control shall be such that a continual flashover occurs and divides uniformly over the shells orinsulators under test. The gage shall be removed from the test specimen. 5.1 or in 7. at thespecified value.4. .1.. a solution consisting of 1 gram of basic fuchsine dye dissolved in 1 liter of 50% alcohol shall be used. It shall then be withdrawn andimmersed in a cold water bath for 10 minutes.2. the test specimenshall be tested for electrical soundness by momentary flashover.4 Method of Making Test. the walls of the tank. 7.1-1988 posed.1 Suspension Insulators. shall be read. The frequency shall be approximately 200 kilohertz in damped trains.2 Test Procedure. Flashover tests on shells or insulators may be made in accordance with either the pro-.1 General. 7.2. If a denatured alcoholis used. 7.2 Testing Solution.4.5. The frequency superimposed upon the low-frequency voltage shall be higher than 100 kilohertz.1 Electrical Tests. Either natural or force6 circulation maybe used to maintain the temperature of all parts of the bath within fi 4°F (2OC) of the Specified value. the assembled apparatus insulators shall be given a tensile-strength test 3 seconds in duration. 5.4. shall be used for this test.1 High-FrequencyTest 7.2 Method 2. one should be selected which does not react with the dye to causefading of the color. The thermal test shall consist of alter- nate immersions of the test specimen in hot and cold water.1. 5. 7.1. Routine Tests 7.3 Equipment.2 Low-Frequency Test. At the conclusion of the pressure application. the specified pinhole gage shall be used.1.2 Mechanical Tests 7.3 Procedure. 5.1. Test specimens shall be at least 2 inches (5 1 mm) from .5. The test specimens shall be arranged so that they are not in contact with each other and so that air shall not be entrapped during immersion. The shells or insulators shall be subjected to vigorous dry flashover for from 3 to 5 minutes. 5. At least 75% of the surface area shall be free from glaze or other treatment. A minimum pressure of 4000 poundsforce per square inch (27 600 kN/mZ) shall be applied for not less than 5 hours. the test specimensshall be thoroughly dried and broken for examination.2. Free circulation of water shall be provided. Galvanizing Test Test for thickness of coating shall be in accordance with Standard Measurement of Coating. Fragments approximately 1/4 inch (6 mm) in the smallest dimension up to 3/4 inch (19 mm) in the largest dimension are recommended.1 Method 1. 7. 7. Porosity is indicated by penetration of the dye into thetest specimen to an extent visible to the unaided eye.2 Apparatus Insulators. Techniques forHigh-Voltage Testh3 ANSIlIEEE 100-1988.3-1986. Wet-Process Porcelain Insulators (Spool Type) ANSI/IEEE 4-1978.Dictionary of Electrical and Electronics Terms 15 COPYRIGHT American National Standards Institute Licensed by Information Handling Services .1-1988 8.d AMERICAN NATIONAL STANDARD C29. the revision shall apply: ANSI C29. Inc. Revision of American National Standards Referred to in This Document When the following American National Standards referred to inthis documentaresupersededby a revision approved by the American National Standards Institute. state.Some 1000 companies are affiliated with the Institute as company members.The completed standardsareused widely by industry and commerce andoften by municipal. of manufacturers. The Standards Institute provides the machinery for creating voluntary standards.seller. The American National Standards Institute is the United States member of the International Organization for Standardization (ISO) and the International Electrotechnical Commission (IECh Through these channels U.andgovernmentalagencies. AmericanNational Standards. under whose auspices this work is being done. American National Standards Institute. nationally acceptedstandardsunderthe designation "American National Standards. technical. distribution. It is a federation of trade associations. and scientific. reflect a national consensus .professionalgroups. Inc 1430 Broadway New York.eliminate duplication of standards activities and to weld conflicting standards into single. The standard in this booklet is one of 8000 standards approved to date by theAmericanNationalStandards Institute. standards interests make their positions felt on the international level. N. technical societies. It serves to . American National Standards are on file inthe libraries of the national standards bodies of more than60 countries.S. and consumption of goodsandservices. by reason ofInstitute procedures.andconsumerorganizations. The Standards Institute. Thus thecompletedstandards cut across the whole fabric of production. 10018 COPYRIGHT American National Standards Institute Licensed by Information Handling Services . is the United States clearinghouse and coordinating body for voluntary standards activity on the national level.anduser groups as to the best current practice with regard to some specific problem.Y." Eachstandardrepresentsgeneralagreementamongmaker. and professional organizations. and federal governments. consumers.American National Standards .