ASTM E498/E498M-11(2022)

Standard Practice for Leaks Using the Mass Spectrometer Leak Detector or Residual Gas Analyzer in the Tracer Probe Mode

SIGNIFICANCE AND USE
6.1 Test Method A is the most frequently used in leak testing components which are structurally capable of being evacuated to pressures of 0.1 Pa (approximately 10−3 torr). Testing of small components can be correlated to calibrated leaks, and the actual leak rate can be measured or acceptance can be based on a maximum allowable leak. For most production needs acceptance is based on acceptance of parts leaking less than an established standard which will ensure safe performance over the projected life of the component. Care must be exercised to ensure that large systems are calibrated with reference leak at a representative place on the test volume. Leak rates are determined by calculating the net gain or loss through a leak in the test part that would cause failure during the expected life of the device.  
6.2 Test Method B 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 for conditioning parts. As the volume tends to be large, a check of the response time as well as system sensitivity should be made. Volume of the system in liters divided by the speed of the vacuum pump in L/s will give the response time to reach 63 % of the total signal. Response times in excess of a few seconds makes leak detection difficult.  
6.3 Test Method C is to be used only when there is no convenient method of connecting the leak detector to the outlet of the high vacuum pump. If a helium leak detector 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 obscure all but large leaks, and the trace gas will quickly saturate the pumps.
SCOPE
1.1 This practice covers procedures for testing and locating the sources of gas leaking at the rate of 1 × 10 −8 Pa m3/s (1 × 10−9  Std cm 3/s)3 or greater. The test may be conducted on any object to be tested that can be evacuated and to the other side of which helium or other tracer gas may be applied.  
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.  
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, health, and environmental 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: Published
• Publication Date: 31-May-2022
• ICS: 19.100 - Non-destructive testing
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.08 - Leak Testing Method

Relations

• Refers: ASTM E1316-24 - Standard Terminology for <?Pub Dtl?>Nondestructive Examinations
• Effective Date: 01-Feb-2024
• Refers: ASTM E1316-19b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2019
• Refers: ASTM E1316-19 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Mar-2019
• Refers: ASTM E1316-18 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jan-2018
• Refers: ASTM E1316-17a - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2017
• Refers: ASTM E1316-17 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2017
• Refers: ASTM E1316-16a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Aug-2016
• Refers: ASTM E1316-16 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Feb-2016
• Refers: ASTM E1316-15a - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2015
• Refers: ASTM E1316-15 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Sep-2015
• Refers: ASTM E1316-14e1 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-14 - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2014
• Refers: ASTM E1316-13d - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Dec-2013
• Refers: ASTM E1316-13c - Standard Terminology for Nondestructive Examinations
• Effective Date: 15-Jun-2013
• Refers: ASTM E1316-13b - Standard Terminology for Nondestructive Examinations
• Effective Date: 01-Jun-2013

Overview

ASTM E498/E498M-11(2022) - Standard Practice for Leaks Using the Mass Spectrometer Leak Detector or Residual Gas Analyzer in the Tracer Probe Mode outlines standardized procedures for detecting and locating gas leaks in components and systems using mass spectrometer leak detectors (MSLD) or residual gas analyzers (RGA) with tracer gases, typically helium. This practice is widely recognized in nondestructive testing and is applicable to any object that can be evacuated and tested with a tracer gas such as helium.

This standard helps ensure the safety, reliability, and integrity of products and systems by setting clear guidelines for acceptable leak rates and systematic testing methods. The procedures are particularly vital for critical components where undetected leaks could compromise functionality or operational lifespan.

Key Topics

• Scope of Application

  • Procedures for gas leak testing at or above a rate of 1×10⁻⁸ Pa m³/s (1×10⁻⁹ std cm³/s).
  • Applies to any object that can be evacuated and exposed to helium or another tracer gas.

• Three Test Methods

  • Test Method A: For objects that can be evacuated but lack their own pumping system.
  • Test Method B: For objects with built-in vacuum systems, allowing for direct leak detection.
  • Test Method C: For testing when direct connection to the leak detector outlet is not feasible, using the vacuum pumps of the object itself.

• Calibration and Sensitivity

  • Procedures for calibrating mass spectrometer leak detectors and ensuring test sensitivity.
  • Emphasis on the importance of response time based on system volume and vacuum pump capacity.

• Personnel Qualification

  • Recommends personnel be trained and qualified to Nondestructive Testing (NDT) Level II per industry standards.

• Interferences and Challenges

  • Discusses typical issues encountered, such as series leaks, temporary leaks, and limitations related to system design or materials.

Applications

• Quality Assurance and Production Acceptance

  • Ensures that production parts and components meet established leak rate criteria, preventing failures over the expected service life.
  • Leak rate testing is routinely used in manufacturing to validate product integrity and avoid costly product recalls.

• Maintenance and System Reliability

  • Used for maintenance in vacuum systems, manufacturing equipment, and environmental testing chambers to prevent undetected leaks that could affect performance or safety.
  • Supports predictive maintenance by identifying leaks during scheduled inspections.

• Vacuum Systems and Sealed Devices

  • Essential for industries including aerospace, automotive, electronics, and pharmaceuticals, where component leak-tightness is critical.
  • Ensures the reliability of components such as sensors, valves, assemblies, and complex vacuum systems.

• Research and Development

  • Assists in the development and validation of new products requiring hermetic sealing or ultra-high vacuum conditions.

Related Standards

• ASTM E1316 - Terminology for Nondestructive Examinations, for definitions and context relating to leak testing.
• SNT-TC-1A - Recommended Practice for Personnel Qualification and Certification in Nondestructive Testing.
• ANSI/ASNT CP-189 - ASNT Standard for Qualification and Certification of Nondestructive Testing Personnel.

Practical Value

Adhering to ASTM E498/E498M ensures:

• Accurate detection and quantification of gas leaks.
• Enhanced product safety and longevity.
• Compliance with customer and regulatory requirements.
• Consistency and repeatability in leak testing procedures.

This standard is a vital reference across industries where leak integrity is essential to product performance and safety, providing a robust methodology for both new production and maintenance environments.

Standards Content (Sample)

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.
Designation: E498/E498M − 11 (Reapproved 2022)
Standard Practice for
Leaks Using the Mass Spectrometer Leak Detector or
1,2
Residual Gas Analyzer in the Tracer Probe Mode
This standard is issued under the fixed designation E498/E498M; the number immediately following the designation indicates the year
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.
This standard has been approved for use by agencies of the U.S. Department of Defense.
1. Scope* 2. Referenced Documents
1.1 This practice covers procedures for testing and locating 2.1 ASTM Standards:
−8 3
the sources of gas leaking at the rate of 1×10 Pa m /s E1316Terminology for Nondestructive Examinations
−9
3 3
(1×10 Std cm /s) or greater. The test may be conducted on
2.2 Other Documents:
any object to be tested that can be evacuated and to the other
SNT-TC-1A Recommended Practice for Personnel Qualifi-
side of which helium or other tracer gas may be applied.
cation and Certification in Nondestructive Testing
ANSI/ASNT CP-189ASNT Standard for Qualification and
1.2 Three test methods are described:
Certification of Nondestructive Testing Personnel
1.2.1 Test Method A—For the object under test capable of
being evacuated, but having no inherent pumping capability.
3. Terminology
1.2.2 Test Method B—Fortheobjectundertestwithintegral
pumping capability. 3.1 Definitions—For definitions of terms used in this
1.2.3 Test Method C—For the object under test as in Test practice, see Terminology E1316, Section E.
MethodB,inwhichthevacuumpumpsoftheobjectundertest
4. Summary of Practice
replace those normally used in the leak detector.
4.1 The tests in this practice require a helium leak detector
1.3 Units—The values stated in either SI or std-cc/sec units
−9 3
that is capable of detecting a leak of 1×10 Pa m /s
are to be regarded separately as standard. The values stated in
−10
3 3
(1×10 Stdcm /s).
each system may not be exact equivalents: therefore, each
system shall be used independently of the other. Combining
4.2 Test Method A—This test method is used to helium leak
values from the two systems may result in non-conformance
test objects that are capable of being evacuated to a reasonable
with the standard.
testpressurebytheleakdetectorpumpsinanacceptablelength
1.4 This standard does not purport to address all of the of time. This requires that the object be clean and dry.Also to
cope with larger volumes or relatively “dirty” devices, auxil-
safety concerns, if any, associated with its use. It is the
iary vacuum pumps having greater capacity than those in the
responsibility of the user of this standard to establish appro-
mass spectrometer leak detector (MSLD) may be used in
priate safety, health, and environmental practices and deter-
conjunction with the MSLD. The leak test sensitivity will be
mine the applicability of regulatory limitations prior to use.
reduced under these conditions.
1.5 This international standard was developed in accor-
dance with internationally recognized principles on standard-
4.3 Test Method B—This test method is used to leak test
ization established in the Decision on Principles for the
equipmentthatcanprovideitsownvacuum(thatis,equipment
Development of International Standards, Guides and Recom-
that has a built-in pumping system) at least to a level of a few
mendations issued by the World Trade Organization Technical
hundred pascals (a few torr) or lower.
Barriers to Trade (TBT) Committee.
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
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
torr) in the presence of leaks, these leaks may be located and
structive Testing and is the direct responsibility of Subcommittee E07.08 on Leak
Testing Method.
CurrenteditionapprovedJune1,2022.PublishedJuly2022.Originallyapproved
in 1973. Last previous edition approved in 2017 as E498/E498M–11(2017). DOI: For referenced ASTM standards, visit the ASTM website, www.astm.org, or
10.1520/E0498_E0498M-11R22. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
(Atmospheric pressure external, vacuum internal). This document covers the Standards volume information, refer to the standard’s Document Summary page on
Tracer Probe Mode described in Terminology E1316. the ASTM website.
The gas temperature is referenced to 0°C. To convert to another gas reference AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
temperature, T , multiply the leak rate by (T +273) ⁄273. 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
ref ref
*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
E498/E498M − 11 (2022)
evaluatedbytheuseofeitheraresidualgasanalyzer(RGA)or 7.1.2 Double O-rings.
by using the spectrometer tube and controls from a conven-
7.1.3 Threaded joints.
tional MSLD, provided, of course, that the leakage is within
7.1.4 Ferrule and flange-type tubing fittings.
thesensitivityrangeoftheRGAorMSLDundertheconditions
7.1.5 Casings with internal voids.
existing in the vacuum system.
7.1.6 Flat polymer gaskets.
7.1.7 Unvented O-ring grooves.
5. Personnel Qualification
5.1 It is recommended that personnel performing leak test- 7.2 In general, the solution is in proper design to eliminate
theseconditions;however,whendoublesealsmustbeused,an
ing attend a dedicated training course on the subject and pass
a written examination.The training course should be appropri- accessportbetweenthemshouldbeprovidedforattachmentto
the MSLD. Leaks may then be located from each side of the
ate for NDT level II qualification according to Recommended
Practice No. SNT-TC-1A of theAmerican Society for Nonde- seal and after repair, the access port can be sealed or pumped
continuously by a “holding” pump (large vacuum systems).
structive Testing or ANSI/ASNT Standard CP-189.
7.3 Temporarily plugged leaks often occur because of poor
6. Significance and Use
manufacturing techniques. Water, cleaning solvent, plating,
6.1 TestMethodAisthemostfrequentlyusedinleaktesting
flux, grease, paint, etc., are common problems. To a large
components which are structurally capable of being evacuated
extent,theseproblemscanbeeliminatedbyproperpreparation
−3
to pressures of 0.1 Pa (approximately 10 torr). Testing of
of the parts before leak testing. Proper degreasing, vacuum
smallcomponentscanbecorrelatedtocalibratedleaks,andthe
baking, and testing before plating or painting are desirable.
actualleakratecanbemeasuredoracceptancecanbebasedon
7.4 In a device being tested, capillary tubing located be-
a maximum allowable leak. For most production needs accep-
tween the leak and the leak detector can make leak testing
tance is based on acceptance of parts leaking less than an
extremely difficult as test sensitivity is drastically reduced and
established standard which will ensure safe performance over
responsetimeincreased.Ifthereisavolumeateachendofthe
the projected life of the component. Care must be exercised to
capillary, each such volume should be attached to the leak
ensure that large systems are calibrated with reference leak at
detector during testing. If this is impossible, the device should
a representative place on the test volume. Leak rates are
be surrounded with a helium atmosphere while attached to the
determinedbycalculatingthenetgainorlossthroughaleakin
leak detector for a long time to assure leak tightness. When
thetestpartthatwouldcausefailureduringtheexpectedlifeof
unusually long pumping times are necessary, the connections
the device.
to the leak detector (and all other auxiliary connections) that
6.2 TestMethodBisusedfortestingvacuumsystemseither
are exposed to the helium should be double-sealed and the
as a step in the final test of a new system or as a maintenance
space between the seals evacuated constantly by a small
practice on equipment used for manufacturing, environmental
auxiliary roughing pump to avoid allowing helium to enter the
test or for conditioning parts.As the volume tends to be large,
system through seals that are not a part of the device to be
a check of the response time as well as system sensitivity
tested.
should be made. Volume of the system in liters divided by the
speed of the vacuum pump in L/s will give the response time
TEST METHOD A—HELIUM LEAK TESTING OF
to reach 63% of the total signal. Response times in excess of
SMALL DEVICES USING THE MSLD
a few seconds makes leak detection difficult.
8. Apparatus
6.3 Test Method C is to be used only when there is no
convenientmethodofconnectingtheleakdetectortotheoutlet
8.1 Helium Mass Spectrometer Leak Detector, having a
ofthehighvacuumpump.Ifaheliumleakdetectorisusedand
minimumdetectableleakrateasrequiredbythetestsensitivity.
the high vacuum pump is an ion pump or cryopump, leak
8.2 Auxiliary Pumps, capable of evacuating the object to be
testingisbestaccomplishedduringtheroughingcycleasthese
tested to a low enough pressure so that the MSLD may be
pumps leave a relatively high percentage of helium in the high
connected.
vacuum chamber.This will obscure all but large leaks, and the
trace gas will quickly saturate the pumps.
NOTE 1—If the object under test is small and clean and the MSLD has
a built-in roughing pump, the auxiliary pumps are not required.
7. Interferences
8.3 Suitable Connectors and Valves, to connect to the
7.1 Series leaks with an unpumped volume between them
MSLD test port. Compression fittings and metal tubing should
present a difficult if not impossible problem in helium leak
be used in preference to vacuum hose.
testing. Although the trace gas enters the first leak readily
enough since the pressure difference of helium across the first 8.4 Standard Leaks of Both Capsule Type (Containing its
leak is approximately one atmosphere, it may take many hours own Helium Supply) and Capillary Type (an Actual Leak which
to build up the partial pressure of helium in the volume is Used to Simulate the Reaction of the Test System to Helium
betweenthetwoleakssothatenoughheliumentersthevacuum Spray)—The leak rate from the capsule-type leak should be
system to be detected by the MSLD. This type of leak occurs adequate to demonstrate the minimum allowable sensitivity of
frequently under the following conditions: the MSLD. The capillary type should be slightly smaller than
7.1.1 Double-welded joints and lap welds. the test requirement.
E498/E498M − 11 (2022)
8.5 Vacuum Gage, to read the pressure before the MSLD is valve and partially closing the MSLD inlet valve or by
connected. reducing the sensitivit
...