ASTM F2391-22

Standard Test Method for Measuring Package and Seal Integrity Using Helium as the Tracer Gas

SIGNIFICANCE AND USE
5.1 The vacuum, bubble test method, as described in Test Method D3078, and various other leak detection methods described elsewhere (Test Method D4991, Guide E432, Test Method E493, Test Method E498, Test Method E499, and Test Method E1603) have been successfully used widely in various industries and applications to determine that a given package is or is not a “leaker.” The sensitivity of any selected leak test method has to be considered to determine its applicability to a specific situation.  
5.2 The procedures presented in this test method allow the user to carry out package and seal integrity testing with sufficient sensitivity to quantify seals in the previously defined moderate to fine seal ranges.  
5.3 By employing seal-isolating leak testing fixtures, packages constructed of various materials can be tested in the full range of seal performance requirements. Design of these fixtures is beyond the scope of this method.  
5.4 These seal/package integrity test procedures can be utilized as:  
5.4.1 A design tool,  
5.4.2 For tooling qualification,  
5.4.3 Process setup,  
5.4.4 Process validation tool,  
5.4.5 Quality assurance monitoring, or  
5.4.6 Research and development.
SCOPE
1.1 This test method includes several procedures that can be used for the measurement of overall package and seal barrier performance of a variety of package types and package forms, as well as seal/closure types. The basic elements of this method include:  
1.1.1 Helium (employed as tracer gas),  
1.1.2 Helium leak detector (mass spectrometer), and  
1.1.3 Package/product-specific test fixtures.  
1.1.4 Most applications of helium leak detection are destructive, in that helium needs to be injected into the package after the package has been sealed. The injection site then needs to be sealed/patched externally, which often destroys its saleability. Alternatively, if helium can be incorporated into the headspace before sealing, the method can be non-destructive because all that needs to be accomplished is to simply detect for helium escaping the sealed package.  
1.2 Two procedures are described; however the supporting data in Section 14 only reflects Procedure B (Vacuum Mode). The alternative, Sniffer Mode, has proven to be a valuable procedure for many applications, but may have more variability due to exactly the manner that the operator conducts the test such as whether the package is squeezed, effect of multiple small leaks compared to fewer large leaks, background helium concentration, package permeability and speed at which the scan is conducted. Further testing to quantify this procedure’s variability is anticipated, but not included in this version.  
1.2.1 Procedure A: Sniffer Mode—the package is scanned externally for helium escaping into the atmosphere or fixture.  
1.2.2 Procedure B: Vacuum Mode—the helium containing package is placed in a closed fixture. After drawing a vacuum, helium escaping into the closed fixture (capture volume) is detected. Typically, the fixtures are custom made for the specific package under test.  
1.3 The sensitivity of the method can range from the detection of:  
1.3.1 Large leaks—10-2 Pa·m 3/s to 10-5 Pa·m3/s (10–1 cc/sec/atm to 10-4 cc/sec/atm).  
1.3.2 Moderate leaks—10-5 Pa·m 3/s to 10-7 Pa·m3/s (10-4 cc/sec/atm to 10-6 cc/sec/atm).  
1.3.3 Fine leaks—10-7 Pa·m 3/s to 10-9 Pa·m3/s (10-6 cc/sec/atm to 10-8 cc/sec/atm).  
1.3.4 Ultra-Fine leak—10-9 Pa·m 3/s to 10-11 Pa·m3/s (10-8 cc/sec/atm to 10-10 cc/sec/atm).
Note 1: Conversion from cc/sec/atm to Pa·m3/s is achieved by multiplying by 0.1.  
1.4 The terms large, moderate, fine and ultra-fine are relative terms only and do not imply the acceptability of any leak rate. The individual application dictates the level of integrity needed. For many packaging applications, only “large leaks” are considered unacceptable and the ability to detect smaller leaks is immaterial. All leak rates referred...

General Information

• Status: Published
• Publication Date: 14-Nov-2022
• ICS: 55.040 - Packaging materials and accessories
• Technical Committee: F02 - Primary Barrier Packaging
• Drafting Committee: F02.40 - Package Integrity

Relations

• Refers: ASTM F17-20 - Standard Terminology Relating to Primary Barrier Packaging
• Effective Date: 01-May-2020
• Refers: ASTM F17-18a - Standard Terminology Relating to Primary Barrier Packaging
• Effective Date: 01-Oct-2018
• Refers: ASTM F17-18 - Standard Terminology Relating to Primary Barrier Packaging
• Effective Date: 15-Aug-2018
• Refers: ASTM F17-17 - Standard Terminology Relating to Primary Barrier Packaging
• Effective Date: 01-Jun-2017
• Refers: ASTM F17-13a - Standard Terminology Relating to Flexible Barrier Packaging
• Effective Date: 01-Aug-2013
• Refers: ASTM E691-13 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-May-2013
• Refers: ASTM F17-13 - Standard Terminology Relating to Flexible Barrier Packaging
• Effective Date: 15-Apr-2013
• Refers: ASTM F17-12 - Standard Terminology Relating to Flexible Barrier Packaging
• Effective Date: 01-Nov-2012
• Refers: ASTM E691-11 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Nov-2011
• Refers: ASTM E432-91(2011) - Standard Guide for Selection of a Leak Testing Method
• Effective Date: 01-Jul-2011
• Refers: ASTM D996-10a - Standard Terminology of Packaging and Distribution Environments
• Effective Date: 01-Dec-2010
• Refers: ASTM E691-08 - Standard Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
• Effective Date: 01-Oct-2008
• Refers: ASTM F17-08 - Standard Terminology Relating to Flexible Barrier Packaging
• Effective Date: 01-Aug-2008
• Refers: ASTM D3078-02(2008) - Standard Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission
• Effective Date: 01-Apr-2008
• Refers: ASTM D3078-02(2008)e1 - Standard Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission
• Effective Date: 01-Apr-2008

Overview

ASTM F2391-22 is the Standard Test Method for Measuring Package and Seal Integrity Using Helium as the Tracer Gas. Developed by ASTM International, this method is widely adopted for assessing package and seal barrier performance across a range of packaging types-including flexible, semi-rigid, and rigid formats. Helium is used as a tracer gas, with detection performed using a mass spectrometer-based helium leak detector. This method supports sensitive, reliable testing to identify and quantify leaks, enhancing packaging integrity in critical applications such as pharmaceuticals, food, medical devices, and high-value electronics.

Key Topics

• Test Procedures: Two main procedures are described in ASTM F2391-22:

  • Procedure A: Sniffer Mode - Scans the package externally to detect helium escaping into the atmosphere.
  • Procedure B: Vacuum Mode - The package is placed in a sealed chamber under vacuum, and helium escaping into the chamber is measured.

• Detection Ranges: The method is capable of detecting a wide range of leak rates, providing categorized sensitivity for:

  • Large leaks
  • Moderate leaks
  • Fine leaks
  • Ultra-fine leaks

• Package Types Supported:

  • Flexible, semi-rigid, and rigid packaging
  • Packages with permeable or impermeable components, such as blister packs, cartridges, vials, and syringes

• Destructive and Non-destructive Testing: Depending on whether helium is introduced before or after sealing, the test can be destructive or non-destructive.

• Industry Applications: Used for quality assurance, process validation, design qualification, tooling qualification, and research and development.

• Calibration Requirements: Emphasizes frequent calibration of equipment and use of certified reference leaks to ensure accuracy and repeatability.

Applications

The ASTM F2391-22 standard test method is especially valuable for industries that demand the highest levels of package integrity and seal reliability:

• Pharmaceutical and Medical Packaging: Ensures sterility and safety by validating the barrier performance of packaging for vials, syringes, pouches, and blister packs. This is crucial for compliance with regulatory requirements for container closure integrity testing (CCIT).

• Food Packaging: Protects products from contamination and spoilage by detecting leaks that could compromise shelf life and product quality.

• High-value Electronics: Verifies seal integrity in moisture-sensitive or vacuum-sealed products, where even ultra-fine leaks can affect product performance.

• Quality Assurance & Compliance: Provides a quantitative, highly sensitive means to establish pass/fail criteria during production, process validation, or R&D phases.

• Tooling and Process Development: Used as a design tool to optimize package configurations and sealing processes, ensuring robust and repeatable sealing performance.

Related Standards

For organizations implementing ASTM F2391-22, the following standards are often relevant for comprehensive package integrity and leak testing programs:

• ASTM D3078: Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission
• ASTM D4991: Test Method for Leakage Testing of Empty Rigid Containers by Vacuum Method
• ASTM E432: Guide for Selection of Leak Testing Method
• ASTM E493/E498/E499/E1603: Practices for Mass Spectrometer Leak Detection
• ASTM E691: Practice for Conducting Interlaboratory Studies to Determine Test Method Precision

Adhering to ASTM F2391-22 enables manufacturers to achieve rigorous package integrity standards, reduce contamination risks, and enhance customer confidence by ensuring the consistent performance of packaging and closure systems.

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: F2391 − 22
Standard Test Method for
Measuring Package and Seal Integrity Using Helium as the
Tracer Gas
This standard is issued under the fixed designation F2391; 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.
1. Scope 1.3 The sensitivity of the method can range from the
detection of:
1.1 Thistestmethodincludesseveralproceduresthatcanbe
-2 3 -5 3 –1
1.3.1 Large leaks—10 Pa·m /s to 10 Pa·m /s (10
used for the measurement of overall package and seal barrier
-4
cc/sec/atm to 10 cc/sec/atm).
performance of a variety of package types and package forms,
-5 3 -7 3 -4
1.3.2 Moderate leaks—10 Pa·m /s to 10 Pa·m /s (10
aswellasseal/closuretypes.Thebasicelementsofthismethod
-6
cc/sec/atm to 10 cc/sec/atm).
include:
-7 3 -9 3 -6
1.3.3 Fineleaks—10 Pa·m /sto10 Pa·m /s(10 cc/sec/
1.1.1 Helium (employed as tracer gas),
-8
atm to 10 cc/sec/atm).
1.1.2 Helium leak detector (mass spectrometer), and
-9 3 -11 3 -8
1.3.4 Ultra-Fine leak—10 Pa·m /s to 10 Pa·m /s (10
1.1.3 Package/product-specific test fixtures. -10
cc/sec/atm to 10 cc/sec/atm).
1.1.4 Most applications of helium leak detection are
NOTE 1—Conversion from cc/sec/atm to Pa·m /s is achieved by
destructive,inthatheliumneedstobeinjectedintothepackage
multiplying by 0.1.
afterthepackagehasbeensealed.Theinjectionsitethenneeds
1.4 The terms large, moderate, fine and ultra-fine are rela-
to be sealed/patched externally, which often destroys its
tive terms only and do not imply the acceptability of any leak
saleability.Alternatively,ifheliumcanbeincorporatedintothe
rate. The individual application dictates the level of integrity
headspace before sealing, the method can be non-destructive
needed. For many packaging applications, only “large leaks”
because all that needs to be accomplished is to simply detect
are considered unacceptable and the ability to detect smaller
for helium escaping the sealed package.
leaksisimmaterial.Allleakratesreferredtointhismethodare
1.2 Two procedures are described; however the supporting
based on conversion of actual conditions (based on partial
data in Section 14 only reflects Procedure B (Vacuum Mode).
pressureofhelium)tooneatmospherepressuredifferentialand
The alternative, Sniffer Mode, has proven to be a valuable
standard temperature conditions.
procedure for many applications, but may have more variabil-
1.5 Themethodmayhaveapplicabilitytoanypackagetype:
ityduetoexactlythemannerthattheoperatorconductsthetest
1.5.1 Flexible, semi-rigid, or rigid.
such as whether the package is squeezed, effect of multiple
1.5.2 Permeable or impermeable.
small leaks compared to fewer large leaks, background helium
concentration, package permeability and speed at which the 1.5.3 Packages comprised of both permeable and imperme-
able components, for example, formed aluminum blisters and
scan is conducted. Further testing to quantify this procedure’s
variability is anticipated, but not included in this version. other high barrier aluminum packaging, cartridges, and sy-
ringes.
1.2.1 Procedure A: Sniffer Mode—the package is scanned
externally for helium escaping into the atmosphere or fixture.
1.6 The sensitivities reported in the supporting data for this
1.2.2 Procedure B: Vacuum Mode—the helium containing
method pertain to the detectability of helium emanating from
package is placed in a closed fixture.After drawing a vacuum,
the sample and are not a function of the packaging form.
helium escaping into the closed fixture (capture volume) is
1.7 The method is not applicable to breathable or porous
detected. Typically, the fixtures are custom made for the
packaging.
specific package under test.
1.8 The results obtained can be qualitative, semi-
quantitative or quantitative depending on the procedure used.
1.9 Testfixturedesignisnotwithinthescopeofthismethod
ThistestmethodisunderthejurisdictionofASTMCommitteeF02onPrimary
Barrier Packaging and is the direct responsibility of Subcommittee F02.40 on
excepttonotethatdifferentdesignswillbeneededfordifferent
Package Integrity.
applications (which have different package types and package
Current edition approved Nov. 15, 2022. Published December 2022. Originally
integrity requirements). Furthermore, the fixture selection and
approved in 2005. Last previous edition approved in 2016 as F2391 – 05 (2016).
DOI: 10.1520/F2391-22. design will be based on where the testing is to be conducted
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2391 − 22
within the manufacturing process (in other words, quality 3.2.4 flexible packaging, n—packages (typically, pouches,
control versus research). sachets, and bags) constructed of materials that are readily
bendable. (See also Terminology Method F17)
1.10 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the 3.2.5 impermeable packaging, n—packages constructed of
responsibility of the user of this standard to establish appro- materials (typically metal or glass) that prevent gases/vapors
priate safety, health, and environmental practices and deter- from flowing into or out of the package.
mine the applicability of regulatory limitations prior to use.
3.2.6 large leaks, n—for the purpose of this test method,
-2 3
1.11 This international standard was developed in accor-
leaks that exhibit gas/vapor leak rates between 1×10 Pa·m /s
-5 3 –1 -4
dance with internationally recognized principles on standard-
to 1×10 Pa·m /s (1×10 cc/sec/atm to 1×10 cc/sec/
ization established in the Decision on Principles for the
atmosphere).
Development of International Standards, Guides and Recom-
3.2.7 measured helium leak rate (MHLR), n—helium signal
mendations issued by the World Trade Organization Technical
level obtained based on the actual helium concentration in the
Barriers to Trade (TBT) Committee.
package.
3.2.8 moderate leaks, n—for the purpose of this test method,
2. Referenced Documents
-5 3
leaks that exhibit gas/vapor leak rates between 1×10 Pa·m /s
2.1 ASTM Standards:
-7 3 -4 -6
to 10 Pa·m /s (1×10 cc/sec/atmosphere to 1×10 cc/sec/
D996Terminology of Packaging and Distribution Environ-
atmosphere).
ments
3.2.9 outgassing, v—the release of adsorbed, absorbed or
D3078Test Method for Determination of Leaks in Flexible
physically trapped gas from a surface of structure.
Packaging by Bubble Emission
D4991Test Method for Leakage Testing of Empty Rigid
3.2.10 pass/fail criterion, n—the predetermined AHLR
Containers by Vacuum Method above which the package being tested is considered defective
E432Guide for Selection of a Leak Testing Method
and, therefore, unacceptable.
E493Practice for Leaks Using the Mass Spectrometer Leak
3.2.11 permeable packaging, n—packages, in whole or in
Detector in the Inside-Out Testing Mode
part, that allow gases/vapors to flow into and out of a package
E498Practice for Leaks Using the Mass Spectrometer Leak
via diffusion controlled process.
Detector or Residual Gas Analyzer in the Tracer Probe
3.2.12 semi-rigid packaging, n—packages (typically,
Mode
thermo-formable, or cold-formable materials) that are formed
E499Practice for Leaks Using the Mass Spectrometer Leak
into blisters or trays, with associated lidding materials applied
Detector in the Detector Probe Mode
as the closure means.
E691Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method 3.2.13 ultra fine leaks, n—for the purpose of this test
-9
method, leaks that exhibit gas/vapor leak rates between 1×10
E1603Practice for Leakage Measurement Using the Mass
3 -11 3 -8
Spectrometer Leak Detector or Residual Gas Analyzer in Pa·m /s to 1×10 Pa·m /s (1×10 cc/sec/atmosphere to
-10
1×10 cc/sec/atmosphere).
the Hood Mode
F17Terminology Relating to Primary Barrier Packaging
3.2.14 virtual leak, n—a source of detectable tracer gas
other than from a defect of the seal or package. Such a virtual
3. Terminology
leak may be the result of membrane permeability, surface
desorption or release of trapped gas.
3.1 General Term Definitions—For definitions used in this
standard see Terminology D996 and Terminology F17.
4. Summary of Test Procedures
3.2 Specific Term Definitions:
4.1 Therearetwobasictestprocedurescontainedinthistest
3.2.1 actual helium leak rate (AHLR), n—measured helium
method:
leak rate (MHLR) signal level adjusted to a driving force of
4.1.1 Procedure A—Sniffer Mode.
100% concentration at 101 KPa (1.0 atmosphere), absolute.
4.1.2 Procedure B—Vacuum Mode.
3.2.2 breathable/porous packaging, n—packages, in whole
or in part, that intentionally allow gases/vapors to flow freely
4.2 Both of these test procedures require the package under
into and out of the package. test to have helium at some measurable level on the side of the
package opposite the leak detector sensor (typically, the inside
3.2.3 fine leaks, n—for the purpose of this test method,leaks
-7 3
of the package). If the package cannot, or should not be sealed
that exhibit gas/vapor leak rates between 1×10 Pa·m /s to
-9 3 -6 -8
with helium inside, the test fixture used for that particular test
10 Pa·m /s (1×10 cc/sec/atmosphere to 1×10 cc/sec/
needs to provide a means of helium introduction at the
atmosphere).
appropriate location and the appropriate time in the test cycle.
The one exception is a package with a gross leak for which a
variation of the helium pressurized “back-filling” or “soaking”
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
technique may be applicable. In all cases helium, at as high a
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
concentrationaspracticable,mustbepresentononesideofthe
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. package/seal barrier element.
F2391 − 22
4.3 To quantify the leak rate level of a given package, or 6.3 When attempting to detect very small leaks, care must
package seal, the partial pressure driving force of the helium be taken to eliminate, minimize, or compensate for false
must be known. Therefore, an important part of the process of readings from “virtual leak” sources, particularly trapped
conducting a leak rate test is the determination of the concen- helium in seal areas.
trationofheliumatoneatmosphere(absolutepressure)present
6.4 The permeation of the package by helium does not
during the test. Generally speaking, some type of head space
indicate a leak. Care must be taken to understand the level of
analyzerdevicecalibratedtoknownheliumconcentrationswill
permeation to prevent misinterpretation of results. Similarly,
be utilized for this to measure the helium concentration within
somematerialsmayabsorbheliumandyieldfalseresultswhen
packages.
tested. Outgassing of these materials may greatly increase test
4.4 The MHLR (measured helium leak rate) values will be time.
determinedbasedonacomparisontothecalibration,reference
6.5 These procedures, particularly when detecting moderate
standard employed. It is subsequently adjusted to an AHLR
to fine leaks, should be carried out using calibrated external
(actual helium leak rate), which is based on the actual package
leak standards.
helium partial pressure (see 4.5).
6.6 Physical/mechanical constraints are generally required
4.5 If appropriate, the AHLR value for the package under
for flexible and semi-rigid packages to avoid vacuum-induced
test can be compared to the pre-established Pass/Fail criterion
seal failures. Properly constrained packages can mean the
forthatspecificproduct/packagetoascertainacceptability(per
difference between success and failure in carrying out the test
established specification requirements).
procedure.
5. Significance and Use
7. Apparatus
5.1 The vacuum, bubble test method, as described in Test
7.1 Ahelium leak detector (mass spectrometer).An oil-free
Method D3078, and various other leak detection methods
vacuum system is recommended with hard vacuum test port
described elsewhere (Test Method D4991, Guide E432, Test
and sniffer probe attachment (as appropriate for a specific
Method E493,Test Method E498,Test Method E499, andTest
application)forthoseapplicationswherethetestingareaneeds
Method E1603) have been successfully used widely in various
to be maintained as a clean environment, or where the release
industriesandapplicationstodeterminethatagivenpackageis
of vacuum pump oil could lead to product contamination, or
or is not a “leaker.” The sensitivity of any selected leak test
both.
method has to be considered to determine its applicability to a
7.2 External calibrated leaks (certified within the last 12
specific situation.
months; 6 months is recommended). At least one external
5.2 The procedures presented in this test method allow the
helium leak standard should be used, typically near the
user to carry out package and seal integrity testing with
pass/failleaklimit.Alternatively,morecalibratedleaksmaybe
sufficient sensitivity to quantify seals in the previously defined
used.
moderate to fine seal ranges.
7.3 Avacuumchamber,withcustom-designconstraintsthat
5.3 By employing seal-isolating leak testing fixtures, pack-
are package-specific (sniffer mode testing may not require a
ages constructed of various materials can be tested in the full
vacuum chamber).
range of seal performance requirements. Design of these
7.4 A headspace analyzer device for measuring the partial
fixtures is beyond the scope of this method.
pressure of (helium concentration at 1 atm pressure) helium in
5.4 These seal/package integrity test procedures can be
samples.
utilized as:
7.5 The method to introduce helium into the package needs
5.4.1 A design tool,
to be developed specifically for the package under test.
5.4.2 For tooling qualification,
Techniques and devices that have been successfully employed
5.4.3 Process setup,
include:
5.4.4 Process validation tool,
7.5.1 Pre-filling of packages using an on-line flooding
5.4.5 Quality assurance monitoring, or
fixture (helium introduced to package headspace prior to
5.4.6 Research and development.
sealing).
7.5.2 Post-fillingofpackagesbyinjectionofheliumintothe
6. Interferences
sealedpackage.Afinegagesyringeneedleandflow-controlled
heliumgassupply,followedbysealingofthepuncturesitehas
6.1 The introduction of the helium tracer gas to the non-
been found to work well.
sensor side of the package (typically the inside) can be done
either before or after sealing. 7.6 Anenclosureforsniffermodetestingseals/packagesfor
moderate, fine, or ultra-fine leaks in a lowered helium back-
6.2 Some helium may be present in the testing environment
ground environment may be found necessary to reduce infer-
which may interfere with results. Care must be taken to
ence of background helium.
eliminate background helium with ventilation, location of
supply cylinders, proper sample isolation fixturing or other 7.7 A data acquisition and analysis (software application)
means. device is optional, but recommended, for recording, or
F2391 − 22
calculating, or both the measured helium leak rates (MHLR), 11.1.1 Start the helium leak detector unit and allow suffi-
heliumpartialpressureandtheactual(normalized)heliumleak cient warm-up time before sensor calibration (per manufactur-
rate (AHLR). er’s instructions).
11.1.2 Carry out the sensor (mass spectrometer) calibration
8. Instrument Calibration
(per manufacturer’s instructions).
11.1.3 Attach the sniffer probe to the leak detector and set
8.1 Sensor Calibration—Most contemporary helium leak
the detector for sniffer probe mode.
detector units have a built-in calibrated reference leak that is
11.1.4 For moderate, fine, or ultra-fine leaks, test the
used to calibrate the mass spectrometer sensor incorporated
packages/seals in an enclosure with a N atmosphere (to
into the leak detector. Generally, the accelerating voltage and
minimize interference from atmospheric helium).
emissioncurrentssettingsareautomaticallyadjustedasneeded
11.1.5 Bring the sniffer probe gas collection tip in close
tohavethesensoragreewiththecalibratedreferenceleak.This
1 1
proximity (approximately ⁄16 – ⁄8 in.) to the area (portion of a
calibration procedure should be carried out frequently, typi-
seal or portion of a package sidewall) to be leak checked.
cally once a day.
11.1.6 Scan (manually or automatically) over the package
8.2 Test Fixture Calibration:
with the sniffer probe at approximately ⁄8 in. of travel per
...

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: F2391 − 05 (Reapproved 2016) F2391 − 22
Standard Test Method for
Measuring Package and Seal Integrity Using Helium as the
Tracer Gas
This standard is issued under the fixed designation F2391; 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
1.1 This test method includes several procedures that can be used for the measurement of overall package and seal barrier
performance of a variety of package types and package forms, as well as seal/closure types. The basic elements of this method
include:
1.1.1 Helium (employed as tracer gas),
1.1.2 Helium leak detector (mass spectrometer), and
1.1.3 Package/product-specific test fixtures.
1.1.4 Most applications of helium leak detection are destructive, in that helium needs to be injected into the package after the
package has been sealed. The injection site then needs to be sealed/patched externally, which often destroys its saleability.
Alternatively, if helium can be incorporated into the headspace before sealing, the method can be non-destructive because all that
needs to be accomplished is to simply detect for helium escaping the sealed package.
1.2 Two procedures are described; however the supporting data in Section 14 only reflects Procedure B (Vacuum Mode). The
alternative, Sniffer Mode, has proven to be a valuable procedure for many applications, but may have more variability due to
exactly the manner that the operator conducts the test such as whether the package is squeezed, effect of multiple small leaks
compared to fewer large leaks, background helium concentration, package permeability and speed at which the scan is conducted.
Further testing to quantify this procedure’s variability is anticipated, but not included in this version.
1.2.1 Procedure A: Sniffer Mode—the package is scanned externally for helium escaping into the atmosphere or fixture.
1.2.2 Procedure B: Vacuum Mode—the helium containing package is placed in a closed fixture. After drawing a vacuum, helium
escaping into the closed fixture (capture volume) is detected. Typically, the fixtures are custom made for the specific package under
test.
1.3 The sensitivity of the method can range from the detection of:
-2 3 -5 3 –1 -4
1.3.1 Large leaks—10 Pa·m /s to 10 Pa·m /s (10 cc/sec/atm to 10 cc/sec/atm).
This test method is under the jurisdiction of ASTM Committee F02 on FlexiblePrimary Barrier Packaging and is the direct responsibility of Subcommittee F02.40 on
Package Integrity.
Current edition approved April 1, 2016Nov. 15, 2022. Published April 2016December 2022. Originally approved in 2005. Last previous edition approved in 20112016
as F2391 – 05(2011). 05 (2016). DOI: 10.1520/F2391-05R16.10.1520/F2391-22.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
F2391 − 22
-5 3 -7 3 -4 -6
1.3.2 Moderate leaks—10 Pa·m /s to 10 Pa·m /s (10 cc/sec/atm to 10 cc/sec/atm).
-7 3 -9 3 -6 -8
1.3.3 Fine leaks—10 Pa·m /s to 10 Pa·m /s (10 cc/sec/atm to 10 cc/sec/atm).
-9 3 -11 3 -8 -10
1.3.4 Ultra-Fine leak—10 Pa·m /s to 10 Pa·m /s (10 cc/sec/atm to 10 cc/sec/atm).
NOTE 1—Conversion from cc/sec/atm to Pa·m /s is achieved by multiplying by 0.1.
1.4 The terms large, moderate, fine and ultra-fine are relative terms only and do not imply the acceptability of any leak rate. The
individual application dictates the level of integrity needed. For many packaging applications, only “large leaks” are considered
unacceptable and the ability to detect smaller leaks is immaterial. All leak rates referred to in this method are based on conversion
of actual conditions (based on partial pressure of helium) to one atmosphere pressure differential and standard temperature
conditions.
1.5 The method may have applicability to any package type:
1.5.1 Flexible, semi-rigid, or rigid.
1.5.2 Semi-rigid,Permeable or impermeable.
1.5.3 Rigid.Packages comprised of both permeable and impermeable components, for example, formed aluminum blisters and
other high barrier aluminum packaging, cartridges, and syringes.
1.6 The sensitivities reported in the supporting data for this method pertain to the detectability of helium emanating from the
sample and are not a function of the packaging form.
1.7 The method is not applicable to breathable or porous packaging.
1.8 The results obtained can be qualitative, semi-quantitative or quantitative depending on the procedure used.
1.9 Test fixture design is not within the scope of this method except to note that different designs will be needed for different
applications (which have different package types and package integrity requirements). Furthermore, the fixture selection and design
will be based on where the testing is to be conducted within the manufacturing process (in other words, quality control versus
research).
1.10 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.11 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:
D996 Terminology of Packaging and Distribution Environments
D3078 Test Method for Determination of Leaks in Flexible Packaging by Bubble Emission
D4991 Test Method for Leakage Testing of Empty Rigid Containers by Vacuum Method
E432 Guide for Selection of a Leak Testing Method
E479 Guide for Preparation of a Leak Testing Specification (Withdrawn 2014)
E493 Practice for Leaks Using the Mass Spectrometer Leak Detector in the Inside-Out Testing Mode
E498 Practice for Leaks Using the Mass Spectrometer Leak Detector or Residual Gas Analyzer in the Tracer Probe Mode
E499 Practice for Leaks Using the Mass Spectrometer Leak Detector in the Detector Probe Mode
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.
F2391 − 22
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
E1603 Practice for Leakage Measurement Using the Mass Spectrometer Leak Detector or Residual Gas Analyzer in the Hood
Mode
F17 Terminology Relating to Primary Barrier Packaging
F1327 Terminology Relating to Barrier Materials for Medical Packaging (Withdrawn 2007)
2.2 Other Documents:
Principal author L. Kirsch, et al - (shown in reference Appendix X1 as literature references 1, 2, 3 and 5)
Principal author L. Nguyen, et al - (shown in reference appendix I at literature reference 4)
Co-authors include C. Moeckly, L. Nguyen, R. Gerth, W. Muangsiri, R. Scheire, D. M. Guazzo, L. Kirsch, G. Schmitt, A. Kirsch,
M. Koch, T. Wertli, M. Lehman and G. Schramm.
3. Terminology
3.1 General Term Definitions—For definitions used in this standard see Terminology D996, and Terminology F17 and
Terminology F1327.
3.2 Specific Term Definitions:
3.2.1 actual helium leak rate (AHLR)—(AHLR), n—Measuredmeasured helium leak rate (MHLR) signal level adjusted to a driving
force of 100 % concentration at 101 KPa (1.0 atmosphere), absolute.
3.2.2 breathable/porous packaging—packaging, n—Packages,packages, in whole or in part, that intentionally allow gases/vapors
to flow freely into and out of the package. (See also Terminology F1327)
-7 3
3.2.3 fine leaks—leaks, n—Forfor the purpose of this test method, leaks that exhibit gas/vapor leak rates between 1×10 Pa·m /s
-9 3 -6 -8
to 10 Pa·m /s (1×10 cc/sec/atmosphere to 1×10 cc/sec/atmosphere).
3.2.4 flexible packaging—packaging, n—Packagespackages (typically, pouches, sachets, and bags) constructed of materials that
are readily bendable. (See also Terminology Method F17)
3.2.5 impermeable packaging—packaging, n—Packagespackages constructed of materials (typically metal or glass) that prevent
gases/vapors from flowing into or out of the package.
-2 3
3.2.6 large leaks—leaks, n—Forfor the purpose of this test method, leaks that exhibit gas/vapor leak rates between 1×10 Pa·m /s
-5 3 –1 -4
to 1×10 Pa·m /s (1×10 cc/sec/atm to 1×10 cc/sec/atmosphere).
3.2.7 measured helium leak rate (MHLR)—(MHLR), n—Heliumhelium signal level obtained based on the actual helium
concentration in the package.
-5
3.2.8 moderate leaks—leaks, n—Forfor the purpose of this test method, leaks that exhibit gas/vapor leak rates between 1×10
3 -7 3 -4 -6
Pa·m /s to 10 Pa·m /s (1×10 cc/sec/atmosphere to 1×10 cc/sec/atmosphere).
3.2.9 outgassing—outgassing, v—Thethe release of adsorbed, absorbed or physically trapped gas from a surface of structure.
3.2.10 pass/fail criterion—criterion, n—Thethe predetermined AHLR above which the package being tested is considered
defective and, therefore, unacceptable.
3.2.11 permeable packaging—packaging, n—Packages,packages, in whole or in part, that allow gases/vapors to flow into and out
of a package via diffusion controlled process.
3.2.12 semi-rigid packaging—packaging, n—Packagespackages (typically, thermo-formable, or cold-formable materials) that are
formed into blisters or trays, with associated lidding materials applied as the closure means.
-9
3.2.13 ultra fine leaks—leaks, n—Forfor the purpose of this test method, leaks that exhibit gas/vapor leak rates between 1×10
3 -11 3 -8 -10
Pa·m /s to 1×10 Pa·m /s (1×10 cc/sec/atmosphere to 1×10 cc/sec/atmosphere).
F2391 − 22
3.2.14 virtual leak—leak, n—Aa source of detectable tracer gas other than from a defect of the seal or package. Such a virtual leak
may be the result of membrane permeability, surface desorption or release of trapped gas.
4. Summary of Test Procedures
4.1 There are two basic test procedures contained in this test method:
4.1.1 Procedure A—Sniffer Mode.
4.1.2 Procedure B—Vacuum Mode.
4.2 Both of these test procedures require the package under test to have helium at some measurable level on the side of the package
opposite the leak detector sensor (typically, the inside of the package). If the package cannot, or should not be sealed with helium
inside, the test fixture used for that particular test needs to provide a means of helium introduction at the appropriate location and
the appropriate time in the test cycle. The one exception is a package with a gross leak for which a variation of the helium
pressurized “back-filling” or “soaking” technique may be applicable. In all cases helium, at as high a concentration as practicable,
must be present on one side of the package/seal barrier element.
4.3 To quantify the leak rate level of a given package, or package seal, the partial pressure driving force of the helium must be
known. Therefore, an important part of the process of conducting a leak rate test is the determination of the concentration of helium
at one atmosphere (absolute pressure) present during the test. Generally speaking, some type of calibrated residual gas analyzer
(RGA) device will need to head space analyzer device calibrated to known helium concentrations will be utilized for this step.to
measure the helium concentration within packages.
4.4 The MHLR (measured helium leak rate) values will be determined based on a comparison to the calibration, reference standard
employed. It is subsequently adjusted to an AHLR (actual helium leak rate), which is based on the actual package helium partial
pressure (see 4.5).
4.5 If appropriate, the AHLR value for the package under test can be compared to the pre-established Pass/Fail criterion for that
specific product/package to ascertain acceptability (per established specification requirements).
5. Significance and Use
5.1 The vacuum, bubble test method, as described in Test Method D3078, and various other leak detection methods described
elsewhere (Test Method D4991, Guide E432, Guide E479, Test Method E493, Test Method E498, Test Method E499, and Test
Method E1603) have been successfully used widely in various industries and applications to determine that a given package is or
is not a “leaker.” The sensitivity of any selected leak test method has to be considered to determine its applicability to a specific
situation.
5.2 The procedures presented in this test method allow the user to carry out package and seal integrity testing with sufficient
sensitivity to quantify seals in the previously defined moderate to very fine seal ranges.
5.3 By employing seal-isolating leak testing fixtures, packages constructed of various materials can be tested in the full range of
seal performance requirements. Design of these fixtures is beyond the scope of this method.
5.4 These seal/package integrity test procedures can be utilized as:
5.4.1 A design tool,
5.4.2 For tooling qualification,
5.4.3 Process setup,
5.4.4 Process validation tool,
F2391 − 22
5.4.5 Quality assurance monitoring, or
5.4.6 Research and development.
6. Interferences
6.1 The introduction of the helium tracer gas to the non-sensor side of the package (typically the inside) can be done either before
or after sealing.
6.2 Some helium may be present in the testing environment which may interfere with results. Care must be taken to eliminate
background helium with ventilation, location of supply cylinders, proper sample isolation fixturing or other means.
6.3 When attempting to detect very small leaks, care must be taken to eliminate, minimize, or compensate for false readings from
“virtual leak” sources, particularly trapped helium in seal areas.
6.4 The permeation of the package by helium does not indicate a leak. Care must be taken to understand the level of permeation
to prevent misinterpretation of results. Similarly, some materials may absorb helium and yield false results when tested. Outgassing
of these materials may greatly increase test time.
6.5 These procedures, particularly when detecting moderate to very fine leaks, should be carried out using calibrated external leak
standards.
6.6 Physical/mechanical constraints are generally required for flexible and semi-rigid packages to avoid vacuum-induced seal
failures. Properly constrained packages can mean the difference between success and failure in carrying out the test procedure.
7. Apparatus
7.1 A helium leak detector (mass spectrometer). An oil-free vacuum system is recommended with hard vacuum test port and
sniffer probe attachment (as appropriate for a specific application) for those applications where the testing area needs to be
maintained as a clean environment, or where the release of vacuum pump oil could lead to product contamination, or both.
7.2 External calibrated leaks (calibrated(certified within the last 12 months; 6 months is recommended). At least three ranges
should be covered depending on the application; typically 1×10one external helium leak standard should be used, typically near
-7 -8
-6, 1×10 the and 1×10pass/fail leak cc/s/atm.limit. Alternatively, more calibrated leaks may be used.
7.3 A vacuum chamber, with custom-design constraints that are package-specific (sniffer mode testing may not require a vacuum
chamber).
7.4 A headspace analyzer device for measuring the partial pressure of (concentration (helium concentration at 1 atm pressure)
helium in samples.
7.5 The method to introduce helium into the package needs to be developed specifically for the package under test. Techniques
and devices that have been successfully employed include:
7.5.1 Pre-filling of packages using an on-line flooding fixture (helium introduced to package headspace prior to sealing).
7.5.2 Post-filling of packages by injection of helium into the sealed package. A fine gage syringe needle and flow-controlled
helium gas supply, followed by sealing of the puncture site has been found to work well.
7.6 An enclosure for sniffer mode testing seals/packages for moderate, fine, or ultra-fine leaks in a lowered helium background
environment may be found necessary to reduce inference of background helium.
7.7 A data acquisition and analysis (software application) device is optional, but recommended, for recording, or calculating, or
both the measured helium leak rates (MHLR), helium partial pressure and the actual (normalized) helium leak rate (AHLR).
F2391 − 22
8. Instrument Calibration
8.1 Sensor Calibration—Most contemporary helium leak detector units have a built-in calibrated reference leak that is used to
calibrate the mass spectrometer sensor incorporated into the leak detector. Generally, the accelerating voltage and emission currents
settings are automatically adjusted as needed to have the sensor agree with the calibrated reference leak. This calibration procedure
should be carried out frequently, typically once a day.
8.2 Test Fixture Calibration—Calibration:
8.2.1 For Procedure A (Sniffer Mode), external calibration leaks, with custom housing assemblies, can be used.
8.2.2 For Procedure B (Vacuum Mode), the sample chamber and headspace analyzer fixtures must be designed to optimize
sensitivity. Inclusion of calibration leaks or calibrated helium gas mixtures can be used.
8.3 Total System Calibration—For calibration of the full system (when operating in the vacuum mode), externally calibrated leaks
are sequentially mounted on the vacuum test port of the leak detector.
9. Reagents and Materials
9.1 Helium (nominally 100 %) Gas—supply cylinder and regulator. Flow meter is optional but recommended.
9.2 Nitrogen (nominally 100 %) Gas—supply cylinder and regulator. Flow meter is optional, but recommended.Used to vent
helium detector to help minimize helium background levels.
9.3 He/N calibrated gas mixtures; typically, 75 % helium & 50 % helium—supply cylinder and regulator (flow meter, optional,
but recommended).
9.4 Pressure-sensitive adhesive aluminum tape can be used effectively to seal t
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