ASTM E1002-2005 Standard Test Method for Leaks Using Ultrasonics《用超声波检漏的标准试验方法》.pdf

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1、Designation: E 1002 05Standard Test Method forLeaks Using Ultrasonics1This standard is issued under the fixed designation E 1002; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in parentheses in

2、dicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 Test Method A, PressurizationThis test method coversprocedures for calibration of ultrasonic instruments, location,and estimated measurements of gas leakage t

3、o atmosphere bythe airborne ultrasonic technique.21.2 In general practice this should be limited to leaksdetected by two classifications of instruments, Class I andClass II. Class I instruments should have a minimum detectableleak rate of 6.7 3 107mol/s (1.5 3 102std. cm3/s at 0C) ormore for the pre

4、ssure method of gas leakage to atmosphere.Class II instruments should have a minimal detectable leak rateof 6.7 3 106mol/s (1.5 3 101std. cm3/s at 0C) or more forthe pressure method of gas leakage to atmosphere. Refer toGuide E 432 for additional information.1.3 Test Method B, Ultrasonic Transmitter

5、For objectunder test not capable of being pressurized but capable ofhaving ultrasonic tone placed/injected into the test area to actas an ultrasonic leak trace source.1.3.1 This test method is limited to leaks producing leakageof 6.7 3 106mol/s (1.5 3 101std. cm3/s at 0C) or greater.1.4 The values s

6、tated in SI units are to be regarded as thestandard.1.5 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 consult andestablish appropriate safety and health practices and deter-mine the applic

7、ability of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:3E 432 Guide for Selection of a Leak Testing MethodE 543 Practice for Agencies Performing NondestructiveTestingE 1316 Terminology for Nondestructive Testing2.2 Other Documents:SNT-TC-1A Recommended Practice for

8、Personnel Qualifi-cation and Certification in Nondestructive Testing4ANSI/ASNT CP-189 ASNT Standard for Qualification andCertification of Nondestructive Testing Personnel4NAS-410 Certification and Qualification of NondestructivePersonnel53. Terminology3.1 DefinitionsFor definitions of terms used in

9、this testmethod, see Terminology E 1316, Section E.4. Summary of Test Method4.1 Test Method AThis test method sets minimum require-ments for an ultrasonic detector (Classifications I and II). Itprovides for sensitivity validation of the detector and givesprocedures for pressurizing the test object,

10、locating leaks, andestimating the leakage rates.4.2 Test Method BThis test method sets minimum require-ments for an ultrasonic detector used in conjunction with anultrasonic transmitter. It gives procedures for locating leaksusing an electronically generated ultrasonic leak tracer source.5. Basis of

11、 Application5.1 The following items are subject to contractual agree-ment between parties using or referencing this test method.5.2 Personnel Qualification5.2.1 If specified in the contractual agreement, personnelperforming examinations to this test method shall be qualifiedin accordance with a nati

12、onal or internationally recognizedNDT personnel qualification practice or standard such asANSI/ASNT-CP-189, SNT-TC-1A, NAS-410, or a similardocument and certified by the employer or certifying agency,as applicable. The practice or standard used and its applicable1This test method is under the jurisd

13、iction of ASTM Committee E07 onNondestructive Testing and is the direct responsibility of Subcommittee E07.08 onLeak Testing Method.Current edition approved April 1, 2005. Published May 2005. Originallyapproved in 1986. Last previous edition approved in 1996 as E 1002 - 96.2This technique is sometim

14、es called “ultrasonic translation.”3For 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.4Available from TheAmerica

15、n Society for Nondestructive Testing (ASNT), P.O.Box 28518, 1711 Arlingate Lane, Columbus, OH 43228-0518.5Available from Aerospace Industries Association of America, Inc. (AIA), 1250Eye St., NW, Washington, DC 20005.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken

16、, PA 19428-2959, United States.revision shall be identified in the contractual agreement be-tween the using parties.5.3 Qualification of Nondestructive AgenciesIf specifiedin the contractual agreement, NDT agencies shall be qualifiedand evaluated as described in Practice E 543. The applicablerevisio

17、n of Practice E 543 shall be in the contractual agree-ment.6. Significance and Use6.1 Test Method AThis test method is useful for locatingand estimating the size of pressurized gas leaks, either as aquality control test or as a field inspection procedure. It is alsovaluable as a pretest before other

18、 more time consuming andmore sensitive leak tests are employed. It should not be usedexclusively to locate highly toxic or explosive gas leaks.6.2 Test Method BThis test method is useful for locatingleaks in systems that are not under pressure or vacuum as eithera quality control or a field inspecti

19、on procedure. It is not usefulfor estimating the size of a leak. It is also valuable as a pretestbefore leak tests using pressurized gas methods and moresensitive leak tests are employed.7. Interferences7.1 The areas to be tested must be free of oil, grease, paint,and other contaminants that might m

20、ask a leak.7.2 Under certain conditions background noise detected bythe instrument can prevent the detection of relevant leakage.This background noise can result from equipment vibration andair movement due, for example, to wind, or air-cooled motors,aircraft engines, pneumatic systems, etc.7.3 Use

21、of earphones is required in areas where the back-ground noise might interfere with hearing the audible output ofa speaker.8. Apparatus8.1 Ultrasonic Leak Detection System:8.1.1 The system shall consist of an instrument, probes,focusing probe accessory and earphones. (A speaker may ormay not be utili

22、zed.)8.1.2 The system shall provide for detection of acousticenergy in the ultrasonic range from 20 000 to 100 000 Hz andshall translate this energy into an audible signal that can beheard by use of earphones or speaker, or both.8.1.3 The detected energy shall be indicated on a signallevel indicator

23、.8.2 Minimum Instrument RequirementsThe instrumentshall meet the following requirements:8.2.1 The detected ultrasonic energy shall be indicated on asignal level indicator with a change above normal backgroundfluctuations.8.2.2 The audible response shall consist of the down-converted heterodyned ultr

24、asonic signal. This audio signal willbe representative of the amplitude or frequency characteristics,or both, of the original ultrasonic signal. Heterodyned signalscould allow the operator to discriminate audible backgroundinterference as in 7.2.8.2.3 The instrument shall be equipped with a sensitiv

25、itycontrol or gain adjustment, or both, to achieve the conditions of9.3.3.8.2.4 The internal power supply shall be regulated toprovide repeatability of the sensitivity set point to within 65%of full scale over the full range of battery condition.8.2.5 The instrument may include additional features w

26、hichcould enhance leak detection such as frequency controls ormeter/display response selection, or both.8.3 Other ApparatusPressure gages, valves, and piping asrequired.8.4 Ultrasonic Transmission8.4.1 The system shall consist of an apparatus described in8.1-8.3 with the addition of an ultrasonic tr

27、ansmitter.8.4.2 The transmitter shall produce an ultrasound peakedbetween the frequencies of 38 to 42 kHz.8.4.3 The output of the transmitter transducer shall be inexcess of 100 dB at 1 ft.8.4.4 The intensity of the output may be adjustable.8.4.5 The heterodyned signal received by the ultrasonic lea

28、kdetection system from the ultrasonic transmitter must be easilyidentified and recognized as the ultrasonic tracer source.8.4.6 The internal power supply shall be regulated and besufficient to produce the required output (see 8.4.3).8.4.7 The transmitter may include additional features thatcould enh

29、ance the leak detection process such as a warble tonetransmission and amplitude adjustments.9. Calibration9.1 Calibration/Sensitivity ValidationThe ultrasonic in-strument should be calibrated or have the sensitivity validatedbefore each initial use.9.2 Calibration/Sensitivity Validation EquipmentUse

30、 thefollowing equipment for calibration of the test system:NOTE 1This equipment serves a dual function; either to calibrate theultrasonic instrument for leakage rate approximation as in 11.3,ortoverify the sensitivity for detection and location as in 11.1.9.2.1 Leak Standard, with a preset flow rate

31、 of 6.7 3 105mol/s (1.5 std. cm3/s at 0C) 65 % for both Class I and ClassII instruments. The orifice size shall be approximately 0.2 mm0.008 in.9.2.2 Regulator, for the nitrogen supply with output pres-sure and flow gages. The tank pressure gage is optional.9.3 Air Probe Sensitivity Validation:9.3.1

32、 For Class I instruments, locate the detection probe adistance of 10.0 m (60.1 m) from the calibrated leak standardspecified in 9.2.1. For Class II instruments, place the detectionprobe a distance of 5.0 m (60.1 m) from the calibrated leakspecified in 9.2.1.9.3.2 Check to see that the detector probe

33、 and leak sourceare aligned to obtain the peak response (see Fig. 1).9.3.3 A signal level indication above normal backgroundfluctuations should be observed.9.3.4 Place a sound absorbing barrier in front of the micro-phone, blocking out the calibrated leak source; the meterreading should zero with a

34、corresponding absence of an audiblesignal.9.4 Recalibration:E10020529.4.1 Recheck or validate the sensitivity of the equipment atthe beginning of each shift or designated work period interval.This test must be performed at the same sensing frequency asthe initial test.9.4.2 Recheck the equipment whe

35、n abnormalities are ob-served in its operation.9.5 Ultrasonic Transmitter Sensitivity Validation, shouldhave the generated amplitude validated before each initial use.This could be done by placing the ultrasonic transmitter a fixeddistance from the detection instrument to obtain a reading or bytakin

36、g a NIST-traceable reading with a sound pressure leveldetector. Another method would be to place the ultrasonictransmitter in a container with a known leak that is equivalentto the leaks that are to be detected. To eliminate vessel orcontainer vibrations from influencing the readings, the interiorsh

37、ould be lined with closed cell foam, or rubber, or both. Theorifice size shall be equivalent to the leaks that are to bedetected.10. General Considerations10.1 Openings:10.1.1 Seal all openings using plugs, covers or other suit-able materials that can be readily and completely removed afterthe compl

38、etion of the test.10.1.2 Provide a gas inlet by attaching a valve to one of thetest covers on all items to be pressurized.10.2 Check of Test Parts:10.2.1 Examine the part and test equipment before pressureis applied to ensure that it is tight and all appurtenances thatshould not be subjected to the

39、test pressure have been discon-nected or isolated by valves or other suitable means.10.2.2 Check safe pressure rating to be sure it will not beexceeded during test.10.3 Temperature of Vessel and Testing Medium:10.3.1 The temperature of the pressurizing gas must not beat a level that would be injurio

40、us to the part or its components.10.3.2 The test gas is dry nitrogen. (Compressed air cancontain oil or water droplets which can seal leaks.)10.4 Pressure:10.4.1 Unless otherwise specified the gage pressure shall beat least 70 kPa 10 psig. Normal safety precautions should beobserved when pressurizin

41、g the part under test with the gas toavoid test part ruptures.10.4.2 Gradually increase the pressure in the part to finaltest pressure.10.5 Ultrasonic Transmitter MethodInspect test object tobe sure it is free of debris and liquids at the test sites.11. Detection and Location of Pressurized Gas Leak

42、s11.1 Detection:11.1.1 Set the sensitivity at maximum.11.1.2 Begin to scan by pointing the probe towards the testarea. The procedure is to go from “high sensitivity” to “lowsensitivity,” reducing the sensitivity as the leak is approached.11.1.3 Note the fluctuations in meter readings and thevolume f

43、rom the earphones or speaker.11.1.4 If there is too much ultrasound in the area, reduce thesensitivity and continue to scan.11.1.5 If it is difficult to isolate the leak due to competingultrasound, place the focusing probe accessory over the scan-ning probe. This increases the directional response c

44、haracter-istics of the probe.FIG. 1 Calibrated Leak Standard/Sensitivity Validation EquipmentE100205311.1.6 Listen for a “rushing” sound while observing themeter.11.1.7 Follow the ultrasound to the loudest point. The meterwill show a higher reading as the leak is approached.11.2 Ultrasonic Transmitt

45、er MethodProvide for access oftransmitter placement in the test object or provide an inlet pipeconduit fitting to couple with the transmitter allowing it toadequately saturate the test object with ultrasound in such away as to shield stray ultrasonic leakage into the ultrasonic leakdetection side.11

46、.2.1 All potential interferences shall be cleared away fromthe test areas either by cleaning or by blowing the areas drywith compressed gas.11.2.2 Transmitter PlacementThe transmitters shall beplaced to adequately cover the test object with a uniformultrasound.11.2.3 Listen for the distinct heterody

47、ned ultrasound pro-duced by the ultrasonic transmitter. This may be a whistle orwarbling tone.11.3 Location:11.3.1 In order to focus on the leak, keep reducing thesensitivity until a leak is located.11.3.2 To Confirm a LeakPosition the scanning probewith or without the rubber focusing extension clos

48、e to thesuspect leak site and move it, slightly back and forth, up anddown. If the leak is at this location, the sound and meterreadings will both increase and decrease in intensity. Thissource discrimination technique will eliminate false leak iden-tification due to reflected leak signals from othe

49、r sites near thesuspect leak site.11.4 Leakage Rate ApproximationFor Class I leaks, theleakage rate may be estimated by moving the probe away fromthe leak to maximum detection distance at the calibratedsensitivity (leakage just indicated by a slight increase in meterindication and sound level over normal background, with theprobe pointed to maximize the leak signal intensity). The leakrate can be approximated as follows:LR 5 6.7 3 1026mol/s 3 DDMorLR 5 1.5 3 1022std. cm3/s at 0C 3 DDMwhere:LR = leakage rate, andDDM = detection distance meters.12. Rep