ASTM_E_1211_-_E_1211M_-_12.pdf

Designation:E1211/E1211M12Standard Practice forLeak Detection and Location Using Surface-MountedAcoustic Emission Sensors1This standard is issued under the fixed designation E1211/E1211M;the number immediately following the designation indicates the yearof original adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.A superscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope*1.1 This practice describes a passive method for detectingand locating the steady state source of gas and liquid leakingout of a pressurized system.The method employs surface-mounted acoustic emission sensors(for non-contact sensorssee Test Method E1002),or sensors attached to the system viaacoustic waveguides(for additional information,see Terminol-ogy E1316),and may be used for continuous in-servicemonitoring and hydrotest monitoring of piping and pressurevessel systems.High sensitivities may be achieved,althoughthe values obtainable depend on sensor spacing,backgroundnoise level,system pressure,and type of leak.1.2 UnitsThe values stated in either SI units or inch-pound units are to be regarded as standard.The values stated ineach system may not be exact equivalents;therefore,eachsystem shall be used independently of the other.Combiningvalues from the two systems may result in non-conformancewith the standards.1.3 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2E543 Specification for Agencies Performing NondestructiveTestingE650 Guide for Mounting Piezoelectric Acoustic EmissionSensorsE750 Practice for Characterizing Acoustic Emission Instru-mentationE976 Guide for Determining the Reproducibility ofAcousticEmission Sensor ResponseE1002 Practice for Leaks Using UltrasonicsE1316 Terminology for Nondestructive ExaminationsE2374 Guide for Acoustic Emission System PerformanceVerification2.2 ASNT Documents:3SNT-TC-1A Recommended Practice for NondestructiveTesting Personnel Qualification and CertificationANSI/ASNT CP-189 Standard for Qualification and Certifi-cation of Nondestructive Testing Personnel2.3 AIA Document:NAS 410 Certification and Qualification of NondestructiveTesting Personnel43.Summary of Practice3.1 This practice requires the use of contact sensors,ampli-fier electronics,and equipment to measure their output signallevels.The sensors may be mounted before or during theexamination period and are normally left in place oncemounted rather than being moved from point to point.3.2 Detection of a steady-state leak is based on detection ofthe continuous,broadband signal generated by the leak flow.Signal detection is accomplished through measurement ofsome input signal level,such as its root-mean-square(RMS)amplitude or average signal level.3.3 The simplest leak test procedure involves only detectionof leaks,treating each sensor channel individually.A morecomplex examination requires processing the signal levelsfrom two or more sensors together to allow computation of theapproximate leak location,based on the principle that the leaksignal amplitude decreases as a function of distance from thesource.4.Significance and Use4.1 Leakage of gas or liquid from a pressurized system,whether through a crack,orifice,seal break,or other opening,1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the direct responsibility of Subcommittee E07.04 onAcoustic Emission Method.Current edition approved June 15,2012.Published August 2012.Originallyapproved in 1987.Last previous edition approved in 2007 as E1211-07.DOI:10.1520/E1211_E1211M-12.2For referenced ASTM standards,visit the ASTM website,www.astm.org,orcontact ASTM Customer Service at serviceastm.org.For Annual Book of ASTMStandards volume information,refer to the standards Document Summary page onthe ASTM website.3Available fromAmerican Society for Nondestructive Testing(ASNT),P.O.Box28518,1711 Arlingate Ln.,Columbus,OH 43228-0518,http:/www.asnt.org.4Available from Aerospace Industries Association of America,Inc.(AIA),1000Wilson Blvd.,Suite 1700,Arlington,VA22209-3928,http:/www.aia-aerospace.org.*A Summary of Changes section appears at the end of this standardCopyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 may involve turbulent or cavitational flow,which generatesacoustic energy in both the external atmosphere and the systempressure boundary.Acoustic energy transmitted through thepressure boundary can be detected at a distance by using asuitable acoustic emission sensor.4.2 With proper selection of frequency passband,sensitivityto leak signals can be maximized by eliminating backgroundnoise.At low frequencies,genera