1、Designation: E1603/E1603M 11Standard Practice forLeakage Measurement Using the Mass Spectrometer LeakDetector or Residual Gas Analyzer in the Hood Mode1This standard is issued under the fixed designation E1603/E1603M; the number immediately following the designation indicates the yearof original ado
2、ption 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 covers procedures for testing the sourcesof gas leaking
3、at the rate of 1 3 108Pa m3/s (1 3 109standard-cm3/s at 0C) or greater. These test methods may beconducted on any object that can be evacuated and to the otherside of which helium or other tracer gas may be applied. Theobject must be structurally capable of being evacuated topressures of 0.1 Pa (app
4、roximately 103torr).1.2 Three test methods are described;1.2.1 Test Method AFor the object under test capable ofbeing evacuated, but having no inherent pumping capability.1.2.2 Test Method BFor the object under test with integralpumping capability.1.2.3 Test Method CFor the object under test as in T
5、estMethod B, in which the vacuum pumps of the object under testreplace those normally used in the leak detector (LD).1.3 UnitsThe values stated in either SI or std-cc/sec unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents: therefore, eachsyst
6、em shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 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
7、 appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E1316 Terminology for Nondestructive Examinations2.2 ASNT Standards:3SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certificat
8、ion in Nondestructive TestingANSI/ASNT-CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel2.3 Military Standard:MIL-STD-410 Nondestructive Testing Personnel Qualifica-tion and Certification42.4 AIA Standard:NAS-410 Certification and Qualification of Nondestructiv
9、eTest Personnel53. Terminology3.1 DefinitionsFor definitions of terms used in this prac-tice, see Terminology E1316.4. Summary of Practice4.1 These test methods covered in this practice require ahelium LD that can provide a system sensitivity of 10 % or lessof the intended leakage rate to be measure
10、d.4.2 Test Method AThis test method is used to helium leaktest objects that are capable of being evacuated to a reasonabletest pressure by the LD pumps during an acceptable length oftime (see Fig. 1). This requires that the object be clean and dry.Auxiliary vacuum pumps having greater capacity than
11、those inthe LD may be used in conjunction with them. The leak testsensitivity will be reduced under these conditions.4.3 Test Method BThis test method is used to leak testequipment that can provide its own vacuum (that is, equipmentthat has a built-in pumping system) at least to a level of a fewhund
12、red pascals (a few torr) or lower. Refer to Fig. 2.4.4 Test Method CWhen a vacuum system is capable ofproducing internal pressures of less than 2 3 102Pa(2 3 104torr) in the presence of leaks, these leaks may belocated and evaluated by the use of either a residual gasanalyzer (RGA) or by using the s
13、pectrometer tube and controlsfrom a conventional MSLD, provided that the leakage is withinthe sensitivity range of the RGAor MSLD under the conditionsexisting in the vacuum system. Refer to Fig. 3.1This practice is under the jurisdiction of ASTM Committee E07 on Nonde-structive Testing and is the di
14、rect responsibility of Subcommittee E07.08 on LeakTesting Method.Current edition approved July 1, 2011. Published July 2011. Originally approvedin 1994. Last previous edition approved in 2006 as E1603 - 99(2006). DOI:10.1520/E1603_E1603M-11.2For referenced ASTM standards, visit the ASTM website, www
15、.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 NondestructiveTesting (ASNT), P.O. Box28518, 1711 Arlingate Ln., Columbus, OH 43228-
16、0518, http:/www.asnt.org.4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http:/dodssp.daps.dla.mil.5Available from Aerospace Industries Association of America, Inc. (AIA), 1000Wilson Blvd., Suite 1700,Arlington, VA22209-
17、3928, http:/www.aia-aerospace.org.1*A Summary of Changes section appears at the end of this standard.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5. Significance and Use5.1 Test Method AThis test method is the most frequentlyused i
18、n leak testing components. Testing of components iscorrelated to a standard leak, and the actual leak rate ismeasured. Acceptance is based on the maximum systemallowable leakage. For most production needs, acceptance isbased on acceptance of parts leaking less than an establishedleakage rate, which
19、will ensure safe performance over theprojected life of the component. Care must be exercised toensure that large systems are calibrated with the standard leaklocated at a representative place on the test volume. As thevolume tends to be large (1 m3) and there are often lowconductance paths involved,
20、 a check of the response time aswell as system sensitivity should be made.5.2 Test Method BThis test method is used for testingvacuum systems either as a step in the final test of a newsystem or as a maintenance practice on equipment used formanufacturing, environmental test, or conditioning parts.
21、Aswith Test MethodA, the response time and a system sensitivitycheck may be required for large volumes.5.3 Test Method CThis test method is to be used onlywhen there is no convenient method of connecting the LD tothe outlet of the high-vacuum pump. If a helium LD is used andthe high-vacuum pump is a
22、n ion pump or cryopump, leaktesting is best accomplished during the roughing cycle, as thesepumps leave a relatively high percentage of helium in thehigh-vacuum chamber. This will limit the maximum sensitivitythat can be obtained.6. Basis of Application6.1 Personnel QualificationIf specified in the
23、contractualagreement, personnel performing examinations to these testmethods shall be qualified in accordance with a nationallyrecognized NDT personnel qualification practice or standard,such as ANSI/ASNT-CP-189, SNT-TC-1A, MIL-STD-410,NAS-410, or a similar document and certified by the employeror c
24、ertifying agency, as applicable. The practice or standardused and its applicable revision shall be identified in thecontractual agreement between the using parties.7. Interferences7.1 Series leaks with an unpumped volume between thempresent a difficult if not impossible problem in helium leaktesting
25、. Although the trace gas enters the first leak readilyenough since the pressure difference of helium across the firstleak is approximately one atmosphere, it may take many hoursto build up the partial pressure of helium in the volumebetween the two leaks so that enough helium enters the vacuumsystem
26、 to be detected by the LD. This type of leak occursfrequently under the following conditions:7.1.1 Double-welded joints and lap welds,7.1.2 Double O-rings,7.1.3 Threaded joints,7.1.4 Ferrule and flange-type tubing fittings,7.1.5 Casting with internal voids,7.1.6 Flat polymer gaskets, and7.1.7 Unvent
27、ed O-ring grooves.7.2 In general, the solution is proper design to eliminatethese conditions; however, when double seals must be used, anaccess port between them should be provided for attachment tothe LD. Leaks may then be located from each side of the seal.The access port can be sealed or pumped c
28、ontinuously afterrepair by a holding pump (large vacuum system).7.3 Temporarily plugged leaks often occur because of poormanufacturing techniques. Water, cleaning solvent, plating,flux, grease, paint, etc. are common problems. These problemscan be eliminated to a large extent by proper preparation o
29、f theparts before leak testing. Proper degreasing, vacuum baking,and testing before plating or painting are desirable.7.4 The time constant for evacuation and for the rise of thehelium signal is inversely proportional to the pumping speedand directly proportional to the volume being evacuated.t5V/S
30、(1)FIG. 1 Test Method AFIG. 2 Test Method BFIG. 3 Test Method CE1603/E1603M 112Low-conductance tubing, or any other flow impedance, canreduce the pumping speed of the system very significantly, thusextending the system response time constant. If such animpedance connects two volumes under test, a LD
31、 connectionto each volume should be provided.7.5 When unusually long pumping times are necessary, allof the connections not being tested should be protected fromcontinuous exposure to the helium. This will reduce undesiredhigh-helium background levels due to permeation of heliumthrough the O-rings.
32、This can be effected by double-seals (withevacuation of the space between), or sometimes by moreinformal shielding approaches.TEST METHOD AHELIUM LEAK TESTING OFCOMPONENTS/SYSTEMS USING THE LD8. Apparatus8.1 Leak Detector, having a minimum detectable leak rateas required by the test sensitivity.8.2
33、Auxiliary Pumps, capable of evacuating the object to betested to a low enough pressure that the LD may be connected.8.3 Suitable Connector and Valves, to connect to the LD testport. Compression fitting and metal tubing should be used inpreference to a vacuum hose.8.4 Standard Leaks of Both Capsule T
34、ype (Containing ItsOwn Helium Supply) and Capillary Type, an actual leak that isused to simulate the reaction of the test system to a heliumleak. The leak rate of the standard leak used for the systemcalibration shall be equal to or less than the acceptance level(maximum permissible leakage rate). T
35、emperature correctionof the permeation capsule-type standard leaks should beperformed when the ambient temperature has a difference of3C 5F from the calibration temperature of the standardleak. The leakage rate error may become significant (12 %)without temperature correction.8.5 Vacuum Gauge, to re
36、ad the pressure before the LD isconnected when using an auxiliary roughing pump.8.6 Helium Tank and Regulator, with attached helium probehose and jet for locating leaks.8.7 Test Component/System Enclosure (Hood)Either arigid structure or heavy plastic cover to contain and surroundthe test part total
37、ly in helium tracer gas.9. Instrument Calibration9.1 Attach the capsule leak to the LD and tune the LD toachieve the desired sensitivity scale in accordance with themanufacturers instructions. Allow sufficient time for the flowrate from the capsule leak to equilibrate. The permeation-typecapsule lea
38、k should be stored with the shutoff valve (if present)open, and the leak should be allowed to equilibrate to ambienttemperature for several hours.9.2 Adjust the LD readout to correspond to the temperature-corrected standard leak value in accordance with the manufac-turers instructions.NOTE 1Valve cl
39、osures may be accomplished automatically on someLDs, and some counterflow-type MSLDs require continued use of theroughing pump during testing. Refer to the manufacturers operatingmanual.9.3 Disconnect the capsule standard leak from the LD andconnect the test system to the LD.9.4 Instrument calibrati
40、on shall be performed prior to andupon completion of each test. Any change in sensitivity shallbe evaluated to determine if the test results are valid.10. System Calibration and Test Procedure10.1 For small-volume tests (a few litres and less) or whenthe standard leak cannot be attached directly to
41、the testcomponent, the instrument calibration shall be used for thesystem calibration. The correction factor (CF) used to multiplythe instrument calibration value for the system leak rate is one.10.2 For large-volume systems, attach one of the standardleaks to the test system at a location that prov
42、ides the lowestconductance path to the LD.NOTE 2If using a capsule leak, open the calibrated leak (CL) andpump isolation valves, and close the calibration valve. Turn on the CLvacuum pump. Refer to Fig. 4.10.3 Evacuate the device to be tested until near equilibriumpressure is reached on the rough va
43、cuum gauge. Open thevalve to the LD and check the background helium concentra-tion. When the helium background is equal to or less than oneFIG. 4 Calibration SetupsE1603/E1603M 113half the acceptance level (maximum permissible leakage rate)and stable, close the valve(s) to the roughing pumps.10.4 Sy
44、stem Calibration or Procedure Qualification:10.4.1 Record the helium background level.10.4.2 Open the valve of the system standard leak (calibra-tion valve) attached to the test component/system (Fig. 4).NOTE 3If using a capillary leak, apply helium of one atmosphere tothe standard leak. For the cap
45、sule standard leaks, close the pump isolationvalve immediately prior to opening the calibration valve.10.4.3 Graph the LD response as a function of time until asteady-state condition is reached. Refer to Fig. 5.10.4.4 Close the standard leak valve, and reduce the heliumbackground of the test compone
46、nt/system to the same level asthat obtained before system calibration. It may be necessary toopen roughing pump valves and use the roughing pumps toexpedite the reduction of the helium background.10.4.5 Calculate the LD CF for adjusting the instrumentcalibration reading to a system calibration readi
47、ng. For tests onlarge-volume systems, the amplitude response of a leak in thesystem is less than the amplitude response from the instrumentcalibration standard leak.10.4.5.1 This CF should be calculated at either the time atwhich a steady-state response (SS) is reached or at the time atwhich the LD
48、response is 63 % of the change. This shall be theminimum test period. The formula for the CF at this test timeis as follows:CF 5CLcLR 2 BR(2)where:CLc= temperature-corrected standard leak rate,LR = indicated LD reading (0.63 SS or SS) at the end ofthe test period (t or 5t respectively), andBR = back
49、ground reading (initial reading).10.5 Set the LD on the appropriate range.10.6 Close the valves to the roughing pump(s) if they wereopened to expedite the reduction of the helium background.10.7 Fill the test component/system enclosure with heliumor place the test part in the enclosure. Large enclosures shouldbe purged sufficiently to remove the trapped air. For anyconcentration other than 100 % helium atmosphere, the systemacceptance level shall be adjusted for the reduced sensitivity bythe following formula:LRACC5 LRS3 %C/100! (3)where:LRACC = sys
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