ASTM E1603/E1603M-11(2017)

Standard Practice for Leakage Measurement Using the Mass Spectrometer Leak Detector or Residual Gas Analyzer in the Hood Mode

SIGNIFICANCE AND USE
5.1 Test Method A—This test method is the most frequently used in leak testing components. Testing of components is correlated to a standard leak, and the actual leak rate is measured. Acceptance is based on the maximum system allowable leakage. For most production needs, acceptance is based on acceptance of parts leaking less than an established leakage rate, which will ensure safe performance over the projected life of the component. Care must be exercised to ensure that large systems are calibrated with the standard leak located at a representative place on the test volume. As the volume tends to be large (>1 m3) and there are often low conductance paths involved, a check of the response time as well as system sensitivity should be made.  
5.2 Test Method B—This test method is used for testing vacuum systems either as a step in the final test of a new system or as a maintenance practice on equipment used for manufacturing, environmental test, or conditioning parts. As with Test Method A, the response time and a system sensitivity check may be required for large volumes.  
5.3 Test Method C—This test method is to be used only when there is no convenient method of connecting the LD to the outlet of the high-vacuum pump. If a helium LD is used and the high-vacuum pump is an ion pump or cryopump, leak testing is best accomplished during the roughing cycle, as these pumps leave a relatively high percentage of helium in the high-vacuum chamber. This will limit the maximum sensitivity that can be obtained.
SCOPE
1.1 This practice covers procedures for testing the sources of gas leaking at the rate of 1 × 10 −8 Pa m3/s (1 × 10−9  standard-cm3/s at 0°C) or greater. These test methods may be conducted on any object that can be evacuated and to the other side of which helium or other tracer gas may be applied. The object must be structurally capable of being evacuated to pressures of 0.1 Pa (approximately 10−3 torr).  
1.2 Three test methods are described;  
1.2.1 Test Method A—For the object under test capable of being evacuated, but having no inherent pumping capability.  
1.2.2 Test Method B—For the object under test with integral pumping capability.  
1.2.3 Test Method C—For the object under test as in Test Method B, in which the vacuum pumps of the object under test replace those normally used in the leak detector (LD).  
1.3 Units—The values stated in either SI or std-cc/sec units are to be regarded separately as standard. The values stated in each system may not be exact equivalents: therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard.  
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.  
1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Historical
• Publication Date: 31-May-2017
• ICS: 23.040.99 - Other pipeline components
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.08 - Leak Testing Method

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1603/E1603M − 11 (Reapproved 2017)
Standard Practice for
Leakage Measurement Using the Mass Spectrometer Leak
Detector or Residual Gas Analyzer in the Hood Mode
ThisstandardisissuedunderthefixeddesignationE1603/E1603M;thenumberimmediatelyfollowingthedesignationindicatestheyear
of original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
2.1 ASTM Standards:
1.1 This practice covers procedures for testing the sources
−8 3 −9
E1316Terminology for Nondestructive Examinations
of gas leaking at the rate of 1×10 Pa m /s (1×10
standard-cm /s at 0°C) or greater. These test methods may be
2.2 ASNT Standards:
conducted on any object that can be evacuated and to the other
SNT-TC-1ARecommended Practice for Personnel Qualifi-
side of which helium or other tracer gas may be applied. The
cation and Certification in Nondestructive Testing
object must be structurally capable of being evacuated to
ANSI/ASNT-CP-189Standard for Qualification and Certifi-
−3
pressures of 0.1 Pa (approximately 10 torr).
cation of Nondestructive Testing Personnel
2.3 Military Standard:
1.2 Three test methods are described;
MIL-STD-410 Nondestructive Testing Personnel Qualifica-
1.2.1 Test Method A—For the object under test capable of
tion and Certification
being evacuated, but having no inherent pumping capability.
2.4 AIA Standard:
1.2.2 Test Method B—Fortheobjectundertestwithintegral
NAS-410Certification and Qualification of Nondestructive
pumping capability.
Test Personnel
1.2.3 Test Method C—For the object under test as in Test
MethodB,inwhichthevacuumpumpsoftheobjectundertest
3. Terminology
replace those normally used in the leak detector (LD).
3.1 Definitions—For definitions of terms used in this
1.3 Units—The values stated in either SI or std-cc/sec units
practice, see Terminology E1316.
are to be regarded separately as standard. The values stated in
each system may not be exact equivalents: therefore, each
4. Summary of Practice
system shall be used independently of the other. Combining
4.1 These test methods covered in this practice require a
values from the two systems may result in non-conformance
heliumLDthatcanprovideasystemsensitivityof10%orless
with the standard.
of the intended leakage rate to be measured.
1.4 This standard does not purport to address all of the
4.2 Test Method A—This test method is used to helium leak
safety concerns, if any, associated with its use. It is the
test objects that are capable of being evacuated to a reasonable
responsibility of the user of this standard to establish appro-
test pressure by the LD pumps during an acceptable length of
priate safety and health practices and determine the applica-
time(seeFig.1).Thisrequiresthattheobjectbecleananddry.
bility of regulatory limitations prior to use.
Auxiliary vacuum pumps having greater capacity than those in
1.5 This international standard was developed in accor-
the LD may be used in conjunction with them. The leak test
dance with internationally recognized principles on standard-
sensitivity will be reduced under these conditions.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Barriers to Trade (TBT) Committee.
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
This practice is under the jurisdiction of ASTM Committee E07 on Nonde- 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
structive Testing and is the direct responsibility of Subcommittee E07.08 on Leak Available from Standardization Documents Order Desk, DODSSP, Bldg. 4,
Testing Method. Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://
CurrenteditionapprovedJune1,2017.PublishedJuly2017.Originallyapproved dodssp.daps.dla.mil.
in1994.Lastpreviouseditionapprovedin2011asE1603-11.DOI:10.1520/E1603 Available fromAerospace IndustriesAssociation ofAmerica, Inc. (AIA), 1000
_E1603M-11R17. WilsonBlvd.,Suite1700,Arlington,VA22209-3928,http://www.aia-aerospace.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E1603/E1603M − 11 (2017)
FIG. 1 Test Method A
4.3 Test Method B—This test method is used to leak test
equipmentthatcanprovideitsownvacuum(thatis,equipment
that has a built-in pumping system) at least to a level of a few
hundred pascals (a few torr) or lower. Refer to Fig. 2.
FIG. 3 Test Method C
4.4 Test Method C—When a vacuum system is capable of
−2 −4
producing internal pressures of less than 2×10 Pa (2×10
torr) in the presence of leaks, these leaks may be located and
withTestMethodA,theresponsetimeandasystemsensitivity
evaluatedbytheuseofeitheraresidualgasanalyzer(RGA)or
check may be required for large volumes.
by using the spectrometer tube and controls from a conven-
tionalMSLD,providedthattheleakageiswithinthesensitivity
5.3 Test Method C—This test method is to be used only
rangeoftheRGAorMSLDundertheconditionsexistinginthe
when there is no convenient method of connecting the LD to
vacuum system. Refer to Fig. 3.
theoutletofthehigh-vacuumpump.IfaheliumLDisusedand
the high-vacuum pump is an ion pump or cryopump, leak
5. Significance and Use
testingisbestaccomplishedduringtheroughingcycle,asthese
5.1 Test Method A—This test method is the most frequently pumps leave a relatively high percentage of helium in the
used in leak testing components. Testing of components is high-vacuumchamber.Thiswilllimitthemaximumsensitivity
correlated to a standard leak, and the actual leak rate is that can be obtained.
measured. Acceptance is based on the maximum system
6. Basis of Application
allowable leakage. For most production needs, acceptance is
based on acceptance of parts leaking less than an established
6.1 Personnel Qualification—If specified in the contractual
leakage rate, which will ensure safe performance over the
agreement, personnel performing examinations to these test
projected life of the component. Care must be exercised to
methods shall be qualified in accordance with a nationally
ensure that large systems are calibrated with the standard leak
recognized NDT personnel qualification practice or standard,
located at a representative place on the test volume. As the
such as ANSI/ASNT-CP-189, SNT-TC-1A, MIL-STD-410,
volume tends to be large (>1 m ) and there are often low
NAS-410, or a similar document and certified by the employer
conductance paths involved, a check of the response time as
or certifying agency, as applicable. The practice or standard
well as system sensitivity should be made.
used and its applicable revision shall be identified in the
contractual agreement between the using parties.
5.2 Test Method B—This test method is used for testing
vacuum systems either as a step in the final test of a new
7. Interferences
system or as a maintenance practice on equipment used for
manufacturing, environmental test, or conditioning parts. As 7.1 Series leaks with an unpumped volume between them
present a difficult if not impossible problem in helium leak
testing. Although the trace gas enters the first leak readily
enough since the pressure difference of helium across the first
leak is approximately one atmosphere, it may take many hours
to build up the partial pressure of helium in the volume
betweenthetwoleakssothatenoughheliumentersthevacuum
system to be detected by the LD. This type of leak occurs
frequently 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, and
FIG. 2 Test Method B 7.1.7 Unvented O-ring grooves.
E1603/E1603M − 11 (2017)
7.2 In general, the solution is proper design to eliminate 8.7 Test Component/System Enclosure (Hood)—Either a
theseconditions;however,whendoublesealsmustbeused,an rigid structure or heavy plastic cover to contain and surround
accessportbetweenthemshouldbeprovidedforattachmentto the test part totally in helium tracer gas.
the LD. Leaks may then be located from each side of the seal.
The access port can be sealed or pumped continuously after
9. Instrument Calibration
repair by a holding pump (large vacuum system).
9.1 Attach the capsule leak to the LD and tune the LD to
7.3 Temporarily plugged leaks often occur because of poor
achieve the desired sensitivity scale in accordance with the
manufacturing techniques. Water, cleaning solvent, plating,
manufacturer’s instructions.Allow sufficient time for the flow
flux, grease, paint, etc. are common problems.These problems
rate from the capsule leak to equilibrate. The permeation-type
canbeeliminatedtoalargeextentbyproperpreparationofthe
capsuleleakshouldbestoredwiththeshutoffvalve(ifpresent)
parts before leak testing. Proper degreasing, vacuum baking,
open, and the leak should be allowed to equilibrate to ambient
and testing before plating or painting are desirable.
temperature for several hours.
7.4 The time constant for evacuation and for the rise of the
9.2 AdjusttheLDreadouttocorrespondtothetemperature-
helium signal is inversely proportional to the pumping speed
corrected standard leak value in accordance with the manufac-
and directly proportional to the volume being evacuated.
turers’ instructions.
τ 5 V/S (1)
NOTE 1—Valve closures may be accomplished automatically on some
LDs, and some counterflow-type MSLDs require continued use of the
Low-conductance tubing, or any other flow impedance, can
roughing pump during testing. Refer to the manufacturer’s operating
reducethepumpingspeedofthesystemverysignificantly,thus
manual.
extending the system response time constant. If such an
9.3 Disconnect the capsule standard leak from the LD and
impedance connects two volumes under test, a LD connection
connec
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1603/E1603M − 11 E1603/E1603M − 11 (Reapproved 2017)
Standard Practice for
Leakage Measurement Using the Mass Spectrometer Leak
Detector or Residual Gas Analyzer in the Hood Mode
This standard is issued under the fixed designation E1603/E1603M; the number immediately following the designation indicates the year
of 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*Scope
−8 3 −9 3
1.1 This practice covers procedures for testing the sources of gas leaking at the rate of 1 × 10 Pa m /s (1 × 10 standard-cm /s
at 0°C) or greater. These test methods may be conducted on any object that can be evacuated and to the other side of which helium
or other tracer gas may be applied. The object must be structurally capable of being evacuated to pressures of 0.1 Pa (approximately
−3
10 torr).
1.2 Three test methods are described;
1.2.1 Test Method A—For the object under test capable of being evacuated, but having no inherent pumping capability.
1.2.2 Test Method B—For the object under test with integral pumping capability.
1.2.3 Test Method C—For the object under test as in Test Method B, in which the vacuum pumps of the object under test replace
those normally used in the leak detector (LD).
1.3 Units—The values stated in either SI or std-cc/sec units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents: therefore, each system shall be used independently of the other. Combining values from the
two systems may result in non-conformance with the standard.
1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
1.5 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
E1316 Terminology for Nondestructive Examinations
2.2 ASNT Standards:
SNT-TC-1A Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing
ANSI/ASNT-CP-189 Standard for Qualification and Certification of Nondestructive Testing Personnel
2.3 Military Standard:
MIL-STD-410 Nondestructive Testing Personnel Qualification and Certification
2.4 AIA Standard:
NAS-410 Certification and Qualification of Nondestructive Test Personnel
3. Terminology
3.1 Definitions—For definitions of terms used in this practice, see Terminology E1316.
This practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.08 on Leak Testing
Method.
Current edition approved July 1, 2011June 1, 2017. Published July 2011July 2017. Originally approved in 1994. Last previous edition approved in 20062011 as
E1603 - 99E1603 - 11.(2006). DOI: 10.1520/E1603_E1603M-11.10.1520/E1603_E1603M-11R17.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from American Society for Nondestructive Testing (ASNT), P.O. Box 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
Available from Standardization Documents Order Desk, DODSSP, Bldg. 4, Section D, 700 Robbins Ave., Philadelphia, PA 19111-5098, http://dodssp.daps.dla.mil.
Available from Aerospace Industries Association of America, Inc. (AIA), 1000 Wilson Blvd., Suite 1700, Arlington, VA 22209-3928, http://www.aia-aerospace.org.
*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
E1603/E1603M − 11 (2017)
4. Summary of Practice
4.1 These test methods covered in this practice require a helium LD that can provide a system sensitivity of 10 % or less of the
intended leakage rate to be measured.
4.2 Test Method A—This test method is used to helium leak test objects that are capable of being evacuated to a reasonable test
pressure by the LD pumps during an acceptable length of time (see Fig. 1). This requires that the object be clean and dry. Auxiliary
vacuum pumps having greater capacity than those in the LD may be used in conjunction with them. The leak test sensitivity will
be reduced under these conditions.
4.3 Test Method B—This test method is used to leak test equipment that can provide its own vacuum (that is, equipment that
has a built-in pumping system) at least to a level of a few hundred pascals (a few torr) or lower. Refer to Fig. 2.
−2 −4
4.4 Test Method C—When a vacuum system is capable of producing internal pressures of less than 2 × 10 Pa (2 × 10 torr)
in the presence of leaks, these leaks may be located and evaluated by the use of either a residual gas analyzer (RGA) or by using
the spectrometer tube and controls from a conventional MSLD, provided that the leakage is within the sensitivity range of the RGA
or MSLD under the conditions existing in the vacuum system. Refer to Fig. 3.
5. Significance and Use
5.1 Test Method A—This test method is the most frequently used in leak testing components. Testing of components is correlated
to a standard leak, and the actual leak rate is measured. Acceptance is based on the maximum system allowable leakage. For most
production needs, acceptance is based on acceptance of parts leaking less than an established leakage rate, which will ensure safe
performance over the projected life of the component. Care must be exercised to ensure that large systems are calibrated with the
standard leak located at a representative place on the test volume. As the volume tends to be large (>1 m ) and there are often low
conductance paths involved, a check of the response time as well as system sensitivity should be made.
5.2 Test Method B—This test method is used for testing vacuum systems either as a step in the final test of a new system or as
a maintenance practice on equipment used for manufacturing, environmental test, or conditioning parts. As with Test Method A,
the response time and a system sensitivity check may be required for large volumes.
5.3 Test Method C—This test method is to be used only when there is no convenient method of connecting the LD to the outlet
of the high-vacuum pump. If a helium LD is used and the high-vacuum pump is an ion pump or cryopump, leak testing is best
accomplished during the roughing cycle, as these pumps leave a relatively high percentage of helium in the high-vacuum chamber.
This will limit the maximum sensitivity that can be obtained.
6. Basis of Application
6.1 Personnel Qualification—If specified in the contractual agreement, personnel performing examinations to these test methods
shall be qualified in accordance with a nationally recognized 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 employer or certifying
agency, as applicable. The practice or standard used and its applicable revision shall be identified in the contractual agreement
between the using parties.
7. Interferences
7.1 Series leaks with an unpumped volume between them present a difficult if not impossible problem in helium leak testing.
Although the trace gas enters the first leak readily enough since the pressure difference of helium across the first leak is
approximately one atmosphere, it may take many hours to build up the partial pressure of helium in the volume between the two
leaks so that enough helium enters the vacuum system to be detected by the LD. This type of leak occurs frequently under the
following conditions:
7.1.1 Double-welded joints and lap welds,
7.1.2 Double O-rings,
FIG. 1 Test Method A
E1603/E1603M − 11 (2017)
FIG. 2 Test Method B
FIG. 3 Test Method C
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, and
7.1.7 Unvented O-ring grooves.
7.2 In general, the solution is proper design to eliminate these conditions; however, when double seals must be used, an access
port between them should be provided for attachment to the LD. Leaks may then be located from each side of the seal. The access
port can be sealed or pumped continuously after repair by a holding pump (large vacuum system).
7.3 Temporarily plugged leaks often occur because of poor manufacturing techniques. Water, cleaning solvent, plating, flux,
grease, paint, etc. are common problems. These problems can be eliminated to a large extent by proper preparation of the parts
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 the helium signal is inversely proportional to the pumping speed and
directly proportional to the volume being evacuated.
τ 5 V/S (1)
Low-conductance tubing, or any other flow impedance, can reduce the pumping speed of the system very significantly, thus
extending the system response time constant. If such an impedance connects two volumes under test, a LD connection to each
volume should be provided.
7.5 When unusually long pumping times are necessary, all of the connections not being tested should be protected from
continuous exposure to the helium. This will reduce undesired high-helium background levels due to permeation of helium through
the O-rings. This can be effected by double-seals (with evacuation of the space between), or sometimes by more informal shielding
approaches.
E1603/E1603M − 11 (2017)
TEST METHOD A—HELIUM LEAK TESTING OF COMPONENTS/SYSTEMS USING THE LD
8. Apparatus
8.1 Leak Detector, having a minimum detectable leak rate as required by the test sensitivity.
8.2 Auxiliary Pumps, capable of evacuating the object to be tested to a low enough pressure that the LD may be connected.
8.3 Suitable Connector and Valves, to connect to the LD test port. Compression fitting and metal tubing should be used in
preference to a vacuum hose.
8.4 Standard Leaks of Both Capsule Type (Containing Its Own Helium Supply) and Capillary Type, an actual leak that is used
to simulate the reaction of the test system to a helium leak. The leak rate of the standard leak used for the system calibration shall
be equal to or less than the acceptance level (maximum permissible leakage rate). Temperature correction of the permeation
capsule-type standard leaks should be performed when the ambient temperature has a difference of 3°C [5°F] from the calibration
temperature of the standard leak. The leakage rate error may become significant (>12 %) without temperature correction.
8.5 Vacuum Gauge, to read the pressure before the LD is connected when using an auxiliary roughing pump.
8.6 Helium Tank and Regulator, with attached helium probe hose and jet for locating leaks.
8.7 Test Component/System Enclosure (Hood)—Either a rigid structure or heavy plastic cover to contain and surround the test
part totally in helium tracer gas.
9. Instrument Calibration
9.1 Attach the capsule leak to the LD and tune the LD to achieve the desired sensitivity scale in accordance with the
manufacturer’s instructions. Allow sufficient time for the flow rate from the capsule leak to equilibrate. The permeation-type
capsule leak should be stored with the shutoff valve (if present) open, and the leak should be allowed to equilibrate to ambient
temperature for several hours.
9.2 Adjust the LD readout to correspond to the temperature-corrected standard leak value in accordance with the manufacturers’
instructions.
NOTE 1—Valve closures may be accomplished automatically on some LDs, and some counterflow-type MSLDs require continued use of the roughing
pump during testing. Refer to the manufacturer’s operating manual.
9.3 Disconnect the capsule standard leak from the LD and connect the test system to the LD.
9.4 Instrument calibration shall be performed prior to and upon completion of each test. Any change in sensitivity shall be
evaluated to determine if the test results are valid.
10. System Calibration and Test Procedure
10.1 For small-volume tests (a few litres and less) or when the standard leak cannot be attached directly to the test component,
the instrument calibration shall be used for the system calibration. The correction factor (CF) used to multiply the instrument
calibration value for the system leak rate is one.
10.2 For large-volume systems, attach one of the standard leaks to the test system at a location that provides the lowest
conductance path to the LD.
NOTE 2—If using a capsule leak, open the calibrated leak (CL) and pump isolation valves, and close the calibration valve. Turn on the CL vacuum
pump. Refer to Fig. 4.
10.3 Evacuate the device to be tested until near equilibrium pressure is reached on the rough vacuum gauge. Open the valve
to the LD and check the background helium concentration. When the helium background is equal to or less than one half the
acceptance level (maximum permissible leakage rate) and stable, close the valve(s) to the roughing pumps.
10.4 System Calibration or Procedure Qualification:
10.4.1 Record the helium background level.
10.4.2 Open the valve of the system standard leak (calibration valve) attached to the test component/system (Fig. 4).
NOTE 3—If using a capillary leak, apply helium of one atmosphere to the standard leak. For the capsule standard leaks, close the pump isolation valve
immediately prior to opening the calibration valve.
10.4.3 Graph the LD response as a function of time until a steady-state condition is reached. Refer to Fig. 5.
10.4.4 Close the standard leak valve, and reduce the helium background of the test component/system to the same level as that
obtained before system calibration. It may be necessary to open roughing pump valves and use the roughing pumps to expedite
...