1、Designation: E 1603 99 (Reapproved 2006)Standard Test Methods forLeakage Measurement Using the Mass Spectrometer LeakDetector or Residual Gas Analyzer in the Hood Mode1This standard is issued under the fixed designation E 1603; the number immediately following the designation indicates the year ofor
2、iginal adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover procedures for testing thesources o
3、f gas leaking at the rate of 4.4 3 1014moles/s(1 3 109standard-cm3/s at 0C) or greater. These test meth-ods may be conducted on any object that can be evacuated andto the other side of which helium or other tracer gas may beapplied. The object must be structurally capable of beingevacuated to pressu
4、res of 0.1 Pa (approximately 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
5、under test as in TestMethod B, in which the vacuum pumps of the object under testreplace those normally used in the leak detector (LD).1.3 The values stated in SI units are to be regarded asstandard. The values given in brackets are for information only.1.4 This standard does not purport to address
6、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:2E 1316 Terminology
7、 for Nondestructive Testing2.2 ASNT Standards:3SNT-TC-1A Recommended Practice for Personnel Qualifi-cation and Certification in Nondestructive TestingANSI/ASNT-CP-189 Standard for Qualification and Certi-fication of Nondestructive Testing Personnel2.3 Military Standard:MIL-STD-410 Nondestructive Tes
8、ting Personnel Qualifica-tion and Certification42.4 AIA Standard:NAS-410 Certification and Qualification of NondestructiveTest Personnel53. Terminology3.1 DefinitionsFor definitions of terms used in these testmethods, see Terminology E 1316.4. Summary of Test Methods4.1 These test methods require a
9、helium LD that can providea system sensitivity of 10 % or less of the intended leakage rateto be measured.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.
10、 1). This requires that the object be clean and dry.Auxiliary vacuum pumps having greater capacity than 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 provid
11、e its own vacuum (that is, equipmentthat has a built-in pumping system) at least to a level of a fewhundred 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, the
12、se leaks may belocated and evaluated by the use of either a residual gasanalyzer (RGA) or by using the spectrometer 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
13、.5. Significance and Use5.1 Test Method AThis test method is the most frequentlyused in leak testing components. Testing of components is1These test methods are under the jurisdiction of ASTM Committee E07 onNondestructive Testing and are the direct responsibility of Subcommittee E07.08 onLeak Testi
14、ng Method.Current edition approved Feb. 1, 2006. Published February 2006. Originallyapproved in 1994. Last previous edition approved in 1999 as E 1603 - 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of AST
15、MStandards 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 43228-0518.4Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,Section D,
16、 700 Robbins Ave., Philadelphia, PA 19111-5098.5Available 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, PA 19428-2959, United States.correlated to a standard le
17、ak, 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 will ensure safe performance over theprojected life of the component. Care mus
18、t 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, a check of the response time aswell as system sensitivity should be made.5.2
19、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. Aswith Test MethodA, the response time and a system sensitivitycheck may be re
20、quired 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 an ion pump or cryopump, leaktesting is best accomplished during the roughing c
21、ycle, 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 contractualagreement, personnel performing examinations to these testmethods s
22、hall 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 certifying agency, as applicable. The practice or standardused and its applicab
23、le 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. Although the trace gas enters the first leak readilyenough since the pressur
24、e 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 to be detected by the LD. This type of leak occursfrequently under the follow
25、ing 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 Unvented O-ring grooves.7.2 In general, the solution is proper design to eliminateth
26、ese 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 continuously afterrepair by a holding pump (large vacuum system).7.3 Temporaril
27、y 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 of theparts before leak testing. Proper degreasing, vacuum baking,and testing b
28、efore 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 (1)Low-conductance tubing, or any other flow impedance, canreduce the pumping
29、speed of the system very significantly, thusFIG. 1 Test Method AFIG. 2 Test Method BFIG. 3 Test Method CE 1603 99 (2006)2extending the system response time constant. If such animpedance connects two volumes under test, a LD connectionto each volume should be provided.7.5 When unusually long pumping
30、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. This can be effected by double-seals (withevacuation of the space between), o
31、r 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 Auxiliary Pumps, capable of evacuating the object to betested to a low enough
32、 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 Type (Containing ItsOwn Helium Supply) and Capillary Type, an actual leak that
33、 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 one half of theacceptance level (maximum permissible leakage rate). Tem-perature correction of the permeation capsule-type standardlea
34、ks should be performed when the ambient temperature hasa difference of 3C 5F from the calibration temperature ofthe standard leak. The leakage rate error may become signifi-cant (12 %) without temperature correction.8.5 Vacuum Gauge, to read the pressure before the LD isconnected.8.6 Helium Tank and
35、 Regulator, with attached helium probehose and jet.8.7 Test Component/System Enclosure (Hood)Either arigid structure or heavy plastic cover to contain and surroundthe test part totally in helium tracer gas.9. Instrument Calibration9.1 Attach the capsule leak to the LD and tune the LD toachieve the d
36、esired sensitivity scale in accordance with themanufacturers instructions. Allow sufficient time for the flowrate from the capsule leak to equilibrate. The permeation-typecapsule leak should be stored with the shutoff valve (if present)open, and the leak should be allowed to equilibrate to ambientte
37、mperature for several hours. Capillary-type capsule leaksshould be stored with the shutoff valve closed to preventunwanted decay of the reservoir pressure.9.2 Adjust the LD readout to correspond to the temperature-corrected standard leak value in accordance with the manufac-turers instructions.NOTE
38、1Valve closures 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.10. System Cali
39、bration and Test Procedure10.1 For small-volume tests (a few litres and less) or whenthe standard leak cannot be attached directly to the testcomponent, the instrument calibration shall be used for thesystem calibration. The correction factor (CF) used to multiplythe instrument calibration value for
40、 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 provides 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
41、 on the CLvacuum pump. Refer to Fig. 4.10.3 Evacuate the device to be tested until near equilibriumpressure is reached on the rough vacuum gauge. Open thevalve to the LD and check the background helium concentra-tion. When the helium background is equal to or less than onehalf the acceptance level (
42、maximum permissible leakage rate),close the valve(s) to the roughing pumps.10.4 System Calibration or Procedure Qualification:FIG. 4 Calibration SetupsE 1603 99 (2006)310.4.1 Record the helium background level.10.4.2 Open the valve of the system standard leak (calibra-tion valve) attached to the tes
43、t component/system (Fig. 4).NOTE 3If using a capillary leak, apply helium of one atmosphere tothe standard leak. For the capsule 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 con
44、dition is reached. Refer to Fig. 5.10.4.4 Close the standard leak valve, and reduce the heliumbackground of the test component/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 th
45、e helium background.10.4.5 Calculate the LD CF for adjusting the instrumentcalibration reading to a system calibration reading. 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 Th
46、is CF should be calculated at either the time atwhich a steady-state response (SS) is reached or at the time atwhich the LD 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 st
47、andard leak rate,LR = indicated LD reading (0.63 SS or SS) at the end ofthe test period (t or 5t respectively), andBR = background 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 heli
48、um 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 should be adjusted for the redu
49、ced sensitivity.10.8 Keep the test component/system in the test enclosurefor the test period established in accordance with 10.4.5 andrecord the LD reading at the end of the period.NOTE 4The system time response may be longer than the instrumentresponse time.10.9 Calculate the system leakage by multiplying the LDreading by the CF to obtain the corrected system leakage. Fortests in which a system calibration was not performed (that is,test volumes less than a few litres), use a CF of one.10.10 Write a test report, or otherwise indicate the testresults as
