Guidelines for Acoustic Induced Vibration (AIV), Flow Induced Vibration (FIV) Analysis

Guidelines for Acoustic Induced Vibration (AIV), Flow Induced Vibration...1 of 8 http://www.piping-engineering.com/acoustic-induced-vibration-aiv-flow-... Home Valve Piping Components Piping layout Pipe fittings Forum Guidelines for Acoustic Induced Vibration (AIV), Flow Induced Vibration (FIV) Analysis By A JAD Introduction The scope of this topic is to define the design criteria and guidelines to be used for Design & Supporting for lines prone to Acoustic Induced Vibration (AIV) & Flow Induced Vibration (FIV), especially with regard to small bore connections, in line with EI (Energy Institute) Guide lines. This topic does not address lines subjected to other types of vibrations, such as vibrations due to pulsation, mechanical excitation, wind, earth quake etc. High Frequency Acoustic Excitation more commonly referred to as Acoustic Induced Vibration (AIV). Flow Induced Turbulence more commonly referred to as Flow Induced Vibration (FIV). Abbreviations AIV Acoustic Induced Vibration DLF Dynamic Load Factor EI Energy Institute FIV Flow Induced Vibration LOF Likelihood of Failure NPS Nominal Pipe Size IFC Issued for construction SIF Stress Intensification Factor SBC Small Bore Connections TPI Third party Inspection References Energy Institute (EI) Guide lines: Guide Lines for the Avoidance of Vibration Induced Fatigue Failure in Process Pipe Work. 6/24/2014 6:06 AM ASME B31. The study recommendations shall be incorporated in the design of Piping Systems. Piping downstream of Pressure reducing devices as below is prone to Acoustic Induced Vibration AIV. Decks etc.. (E. SBC tappings (2” & below) shall be braced back to header by 2-plane bracing. Generally after Acoustic Induced Vibration AIV study. Small bore connections shall not be braced from a local structure such as steel work..3 regarding use of Tee fittings or complete encirclement types of reinforcement for branch stub-in connection. Compressor recycle Valve.. c) Mitigation of Acoustic Induced Vibration – AIV Detailed Acoustic Induced Vibration – AIV study shall be carried out by AIV Consultant based on the Multidiscipline responsibility Matrix as per Appendix-1. Choke Valve. thermal transients and vibration. A separate Pipe Class may be used for Flare system. Flow Induced Vibration. particularly in low wall thick lines. Any mass at the free end of a cantilever shall be supported in both directions to the axis of the small bore. The amplitude of this energy is governed primarily by the Flow rate & Pressure drop. the Consultant comes up with typical recommendations such as increase of Pipe wall thickness particularly. at early stage of the Project. D/T (Diameter/Thickness) ratios of pipes shall be reviewed & D/T<= 72 is recommended along with use of Sweepolets in place of weldolets. Pressure reducing Valves. In order to minimize the modifications due to Acoustic Induced Vibration AIV Consultant’s recommendations. Relief Valves.g. 6/24/2014 6:06 AM . For Small bore standout connections. Control valve or Orifice plate. 2 of 8 http://www.3.) Pipe wall thickness for flare systems shall be agreed with Consultant at early stage of Project.3: Process Piping Description of Activities 4.piping-engineering. the following guidelines shall be followed during initial design of lines prone to AIV. Type of Branch fittings for Acoustic Induced Vibration AIV prone lines shall be agreed with Consultant at early stage of Project. Excitation due to this can lead to fatigue failure of welded downstream connections. Any possibility of reducing mass at the free end of cantilever also to be considered.1 Acoustic Induced Vibration a) Acoustic Induced Vibration – AIV Definition Acoustic Induced Vibration (AIV) is generally applicable to lines in gas service. In header pipe sufficient spool shall be provided to accommodate this bracing support.5 (b) of ASME B31. the branch fitting and overall unsupported length shall be as short as feasible. for low wall thick Flare lines. Blow Down valves & Restriction Orifices. As this will have impact on material procurement & design. in low wall thick piping. thus ensuring that the small bore connection moves with the main pipe during start up.com/acoustic-induced-vibration-aiv-flow-. However.Guidelines for Acoustic Induced Vibration (AIV). consideration shall be given to Clause 304. For high energy level PSVs like Slug Catcher/ Export Line PSVs. b) Impact of Acoustic Induced Vibration – AIV Acoustic Induced Vibration can lead to Fatigue failure at Small Bore branches. forged lateral/ 90 Deg Tee in place of stub –in lateral/ 45 Degree connections. In a Gas System. In case of reinforced Stub-in connection. Full encirclement pad for supports at PSV outlets etc.. Process to identify Acoustic Induced Vibration AIV Prone lines in Line list. using mono block / slim line valves instead of 2 separate block and bleed valve arrangement. high levels of high frequency acoustic energy can be generated by a pressure reducing device such as a Relief valve. this needs to be reviewed during initial Piping bulk procurement stage in consultation with Acoustic Induced Vibration AIV Consultant & Project Management. the study shall be expedited & provision for incorporation of such recommendations shall be kept to the extent possible in preliminary piping design itself. Sweepolet branch fitting in place of weldolet. Generally the study recommendations will be available at a later stage of the Project. Bracing supports shall be from the main pipe. . Avoid Spool between PSV inlet/outlet Flange & reducers at upstream & downstream of relief valves.FIV Definition Turbulence due to flow depends on flow regime. as mentioned in Pipe Support Standard. Blow down valves. Low noise trim.Guidelines for Acoustic Induced Vibration (AIV). Periodic inspection at field shall be recommended to ensure that no loosening occurs during years of operation. b) Impact of Flow Induced Vibration .FIV Flow Induced Vibration can lead to Fatigue failure at Small Bore branches. The main sources of turbulence are flow discontinuities in the system. For lines where Acoustic Insulation is recommended. Provide Hold Down support & Guides for Flare lines. In such cases.FIV 6/24/2014 6:06 AM . Dressing of welds by grinding shall be recommended and discussed with Construction & QC. Support span for flare lines for offshore platforms especially running on bridge to be determined at early stage of design to finalize bridge structural drawings. Support selection shall be as per support codes suitable for Acoustic Insulation. as clamped shoes. 3 of 8 http://www. confirmation for use of welded shoes shall be taken from Acoustic Induced Vibration AIV Consultant. Provide Axial Stop support very close to relief valve at PSV outlet lines. This leads to excitation of low frequency vibration modes of the pipe work causing vibrations of piping and in some cases pipe supports. This in turn generates high levels of broad band Kinetic Energy which can propagate through the Piping system. especially in higher sizes 24” & above are to be avoided. In certain cases use of clamped Pipe shoes will be recommended by Acoustic Induced Vibration AIV Consultant for flare system. specific confirmation shall be taken from Consultant for the locations where this is mandatory & at other locations confirmation for use of welded shoes shall be taken.piping-engineering. In Flare lines from outlet of Flare Knock out Drum to Flare Stack. which is generally referred to as Flow Induced Vibration FIV. c) Mitigation of Flow Induced Vibration . Flow Induced Vibration.2 Flow Induced Vibration a) Flow Induced Vibration . 4.. Any fastenings used shall be designed to be effective under vibration such as providing lock nuts etc..com/acoustic-induced-vibration-aiv-flow-. with full encirclement pad. if used by Instrumentation. the same shall be informed to Acoustic Induced Vibration AIV Consultant to include in Acoustic Induced Vibration AIV calculations which will help to reduce Acoustic Energy levels in the system.. Minimize use of Trunion supports. Clamp type supports rely on bolted arrangements. Particular care shall be taken when adopting small bore supports that are welded to the connection and its main pipe as these welds provide additional sites for fatigue failure. It shall be ensured that Guides & Axial stops in these lines are active for all Load cases. Also provide adequate Hold down supports (types FCG. provide axial stops on main line at all changes of direction as per feasibility. Any fastenings used shall be designed to be effective under vibration such as providing lock nuts etc. thus ensuring that the small bore connection moves with the main pipe during start up. Generally the study recommendations will be available at a later stage of the Project. Brace supports for SBCs etc. The recommended support configuration for Control valve is Rest+Guide on one side & Rest+Guide+Axial Stop+Hold Down on the other side. provide spool on upstream & downstream piping to accommodate Anchor Support on one side & Guide support on the other side. Process to Identify Flow Induced Vibration FIV prone lines at the beginning of the project. the study shall be expedited & provision for incorporation of such recommendations shall be kept in piping deign. As this will have impact on material procurement. Clamp type supports rely on bolted arrangements. Particular care shall be taken when adopting small bore supports that are welded to the connection and its main pipe.. Provide Axial Stop support very close to Control valves.The study recommendations shall be incorporated in the design of Piping Systems. Provide adequate Hold down supports & Guides for FIV lines. Generally after Flow Induced Vibration FIV study.. the branch fitting & overall unsupported length shall be as short as feasible. Bracing supports shall be from the main pipe. SG2 etc. the Consultant comes up with typical recommendations such as Sweepolet branch fitting in place of weldolet. 4 of 8 http://www.. For 2 Phase & Slug Flow lines. thermal transients and vibration. Any mass at the free end of a cantilever shall be supported in both directions perpendicular to the axis of the small bore. In order to minimize the modifications due to Flow Induced Vibration FIV requirements the following guidelines shall be followed during initial design of lines prone to Flow Induced Vibration FIV. Periodic inspection shall be recommended to ensure that no loosening occurs during years of operation. For High Delta P valves. Detailed Flow Induced Vibration FIV study shall be carried out by the Consultant based on the multi discipline responsibility Matrix as per Appendix-1. Decks etc..com/acoustic-induced-vibration-aiv-flow-. Type of Branch fittings for Flow Induced Vibration FIV prone lines shall be agreed with Consultant at early stage of Project. Small bore connections shall not be braced from a local structure such as steel work. Appendix.1(Work Process Steps and the Responsibility Matrix for AIV /FIV study) 6/24/2014 6:06 AM . Minimize use of Trunion supports. Dressing of welds by grinding shall be recommended and discussed with Construction.piping-engineering.Guidelines for Acoustic Induced Vibration (AIV). Flow Induced Vibration. as per Support Standard) for main line & braced support for Small bore stand-alone connections. For Small bore standout connections. as these welds provide additional sites for fatigue failure. subject to feasibility as per line geometry & Stress analysis. .com/acoustic-induced-vibration-aiv-flow-..Guidelines for Acoustic Induced Vibration (AIV).... Flow Induced Vibration..0 Introduction to Stress Analysis Stress Analysis is a subject. Selection of Pipe Supports: Parameters Considered The basic parameters considered during the selection of supports are . Introduction The Piping Profile in general can . Related Posts: Stress Analysis: Steps for Stress Analysis 1.0 Introduction to Cooling Tower: Cooling Tower is the most common equipment/ . which is . 5 of 8 http://www.. Send Leave a Reply 6/24/2014 6:06 AM . Induced Stresses in Pipe.....piping-engineering...Hoop. Longitudinal and Radial… Topic covered Introduction Circumferential or Hoop Stresses Longitudinal Stresses Radial Stress Introduction to Induced Stresses: When . Purpose of Pipe Supports Purpose of Pipe Supports: 1.. Cooling Tower: Heat Transfer Equipment in Process Industry 1. com Subscribe Updates. 6 of 8 http://www.. Add a comment... Facebook social plugin Or reach me on aj@piping-engineering. Flow Induced Vibration.piping-engineering.... It's Free! Your email: 6/24/2014 6:06 AM .com/acoustic-induced-vibration-aiv-flow-. Facebook social plugin Find us on Facebook Piping-engineering Like 486 people like Piping-engineering.Guidelines for Acoustic Induced Vibration (AIV). How PDMS is organized 3.Guidelines for Acoustic Induced Vibration (AIV). Different Modules In PDMS Plant design management system (PDMS) and it’s related application Read More » Crude Oil Processing on Offshore Facilities 6/24/2014 6:06 AM . A solenoid valve is an electromechanically operated valve used for controlling Read More » Plant Design And Management System PDMS – An Overview 4:55 pm By Piping engineering Table of contents: 1. Features Of PDMS 2. 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Privacy Policy | About Me 6/24/2014 6:06 AM .3 Methods 3. DESCRIPTION 4.4 Application and extent of winterization 3.5 General Read More » Copyright © 2014 Piping engineering All Rights Reserved. Flow Induced Vibration.1 Application of Winterization 3. PURPOSE 2.Guidelines for Acoustic Induced Vibration (AIV). 8 of 8 http://www.