ASTM E427-95(2006)
(Practice)Standard Practice for Testing for Leaks Using the Halogen Leak Detector(Alkali-Ion Diode) (Withdrawn 2013)
Standard Practice for Testing for Leaks Using the Halogen Leak Detector(Alkali-Ion Diode) (Withdrawn 2013)
SIGNIFICANCE AND USE
Halogen leak testing can be used to indicate the presence, location and magnitude of leaks in a closed vessel. This test method is normally used for production examination. Its use with halogenated refrigerant gases has been declining because of concerns about the effect of these gases on the ozone layer.
SCOPE
1.1 This practice covers procedures for testing and locating the sources of gas leaking at the rate of 2.2 10 14 mol/s (5 1010 Std cm3/s). The test may be conducted on any device or component across which a pressure differential of halogen tracer gas may be created, and on which the effluent side of the area to be leak tested is accessible for probing with the halogen leak detector.
1.2 Five methods are described:
1.2.1 Method A - Direct probing with no significant halogen contamination in the atmosphere.
1.2.2 Method B - Direct probing with significant halogen contamination in the atmosphere.
1.2.3 Method C - Shroud test.
1.2.4 Method D - Air-curtain shroud test.
1.2.5 Method E Accumulation test.
1.3 The values stated in inch-pound units are to be regarded as the standard. The metric equivalents of inch-pound units may be approximate.
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.
WITHDRAWN RATIONALE
This practice covered procedures for testing and locating the sources of gas leaking at the rate of 2.2 × 10−14 mol/s (5 × 10−10 Std cm3/s). The test may have been conducted on any device or component across which a pressure differential of halogen tracer gas may have been created, and on which the effluent side of the area to be leak tested was accessible for probing with the halogen leak detector.
Formerly under the jurisdiction of Committee E07 on Nondestructive Testing, this practice was withdrawn in June 2013 in accordance with section 10.6.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.
General Information
Relations
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: E427 − 95(Reapproved 2006)
Standard Practice for
Testing for Leaks Using the Halogen Leak Detector
(Alkali-Ion Diode)
This standard is issued under the fixed designation E427; 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 2.2 Other Documents:
ASNT “Leak Testing Handbook” Volume One of “Nonde-
1.1 This practice covers procedures for testing and locating
structive Testing Handbook”
−14
the sources of gas leaking at the rate of 2.2 ×10 mol/s
−10
SNT-TC-1ARecommended Practice for Personnel Qualifi-
3 2
(5×10 Stdcm /s). Thetestmaybeconductedonanydevice
cation and Certification in Nondestructive Testing
or component across which a pressure differential of halogen
ANSI/ASNT CP-189 ASNT Standard for Qualification and
tracergasmaybecreated,andonwhichtheeffluentsideofthe
Certification of Nondestructive Testing Personnel
areatobeleaktestedisaccessibleforprobingwiththehalogen
leak detector.
3. Terminology
1.2 Five methods are described:
3.1 Definitions—For definitions of terms used in this
1.2.1 Method A—Directprobingwithnosignificanthalogen
standard, see Terminology E1316, Section E.
contamination in the atmosphere.
1.2.2 Method B—Direct probing with significant halogen
4. Summary of Practice
contamination in the atmosphere.
4.1 Section1.8ofNASA’s Leakage Testing Handbook will
1.2.3 Method C—Shroud test.
be of value to some users in determining which leak test
1.2.4 Method D—Air-curtain shroud test.
method to use. Section 11 of the ASNT Testing Handbook may
1.2.5 Method E—Accumulation test.
also be of value.
1.3 Thevaluesstatedininch-poundunitsaretoberegarded
4.2 These methods require halogen leak detection equip-
−13
as the standard. The metric equivalents of inch-pound units
ment with a full-scale readout of at least 1.3×10 mol/s
−10 3 2
may be approximate.
(3×10 Stdcm /s) onthemostsensitiverange,amaximum
1mindriftof0andsensitivitydriftof 615percentoffullscale
1.4 This standard does not purport to address all of the
on this range, and 65 percent or less on others (see 8.1.5).
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro- 4.3 MethodA(Fig.1)isthesimplesttest,requiringonlythat
priate safety and health practices and determine the applica- a halogen tracer-gas pressure be created across the area to be
bility of regulatory limitations prior to use. tested, and the searching of the atmospheric side of the area
with the detector probe. This method detects leakage and
2. Referenced Documents locatesitssourceorsources,whenusedinatestareafreefrom
significant halogen contamination in the atmosphere (see 7.1).
2.1 ASTM Standards:
−10
Experience has shown that leak detection down to 4.5×10
E1316Terminology for Nondestructive Examinations
−5 3 2
mol/s (1×10 Std cm /s) in factory environments will
usually be satisfactory if reasonable precautions are taken
against releasing halogens in the building. If a test booth is
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
constructedsoastobepurgedwithcleanoutdoorair,thislevel
structive Testing and is the direct responsibility of Subcommittee E07.08 on Leak −12 −7 3 2
may be reduced to 4.5×10 mol/s (1×10 Std cm /s).
Testing Method.
−13 −9 3 2
Testing down to 4.5×10 mol/s (1×10 Std cm /s) will
Current edition approved Dec. 1, 2006. Published January 2007. Originally
approvedin1971.Lastpreviouseditionapprovedin2000asE427-95(2000).DOI:
10.1520/E0427-95R06.
The gas temperature is referenced to 0°C. To convert to another gas reference
temperature, T , multiply the leak rate by (T +273)/273. AvailablefromAmericanSocietyforNondestructiveTesting(ASNT),P.O.Box
ref ref
For referenced ASTM standards, visit the ASTM website, www.astm.org, or 28518, 1711 Arlingate Ln., Columbus, OH 43228-0518, http://www.asnt.org.
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Marr, J. William, Leakage Testing Handbook, prepared for Liquid Propulsion
Standards volume information, refer to the standard’s Document Summary page on Section,JetPropulsionLaboratory,NationalAeronauticsandSpaceAdministration,
the ASTM website. Pasadena, CA, Contract NAS 7-396, June 1967.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E427 − 95 (2006)
4.6 Method D (Fig. 5) is useful for high-production testing
of small items such as transistors which have been previously
subjected to a halogen gas pressure above atmospheric
(bombed), or testing the sealed-off end of a fill tube, and the
like. In this method, the end of the shroud is always open, and
the detector always draws a sample from the lower end.
Atmospheric halogens are prevented from entering by a
laminar-flow pure-air curtain. When any leaking object is
inserted below the flow division level, the leakage is then
picked up by the detector. This method is useful for detecting
−12 −7 3 2
leaks down to 4.5×10 mol/s (1×10 Std cm /s) in size.
4.7 MethodE(Fig.6)issimilartoMethodC(Fig.3),except
it provides for testing parts up to several cubic meters in
volume. This is accomplished by allowing the leakage to
accumulate in the chamber for a fixed period, while keeping it
FIG. 1 Halogen Leak Detector, Method A
wellmixedwithafan,andthentestingtheinternalatmosphere
for an increase in halogen content. The practical sensitivity
attainable with this method depends primarily on two things.
First, on the volume between the shroud and the object; and
require additional halogen removal. This can be accomplished
second, on the amount of halogen outgassing produced by the
by passing the test-booth purge air through a bed of activated
object.Thus,apartcontainingrubber,plastics,blindcavitiesor
charcoal.
threads cannot be tested with the sensitivity obtainable with a
smoothmetallicpart.Thesensitivityofthetestandnetvolume
4.4 Method B (Fig. 2) is essentially the same as MethodA,
of the system are related as follows:
except that the amount of air drawn by the probe from the test
area is reduced, and the required sample flow is made up with
A 5 LF/V (1)
s
pure(thatis,zero-halogen)air.Thisreducedsampleintakehas
where:
the disadvantage of reducing the vacuum-cleaner effect of the
A = rate of halogen increase in the volume, mol/s,
larger flow and thus requires closer and more careful probing.
s
L = leak rate into the volume, mol/s,
However, the tolerance to atmospheric halogen can be in-
F = flow rate in the detector probe, mol/s, and
creased up to 100 times.Also, large leaks beyond the range of
V = net volume of the system, cm .
Method A can be accurately located (but not measured) by
For practical operating considerations, the minimum value
Method B.
−16 −11
of A that should be used is about 8.9×10 mol/s (2×10
s
4.5 Method C (Fig. 3 and Fig. 4) is suited for leak testing
3 2 −11
Stdcm /s). (Thiswillgiveadetectorreadoutof100×10 or
itemswhichhaveanapproximatecross-sectiondimensionof2
−13 −9 3 2
4.5×10 mol/s (1×10 Std cm /s) after a 50-s accumu-
in.(50mm),butmaybeaslongas30ft(10m).Inthismethod,
−14
lation period.) Thus, (based on F=mol/s) a 2.2×10 mol/s
air, either atmospheric or purified, is passed over the halogen-
−10 3 2 2 3
(5×10 Std cm /s) may be detected in a system of 10 cm
pressurized part, which is inside a close-fitting container. The
−9 −5 3 2
net volume, or a 2.2×10 mol/s (5×10 Std cm /s) leak
discharge air from the container is sampled by the halogen
7 3
ina10 -cm system. Where variables, time, volume, and leak
detector, and any additional halogen content indicated. The
−12
rate permit, values of readout should be set in the 4.5×10
shroud principle may be applied in a manner as simple as Fig.
−13 −7 −8 3 2
or 4.5×10 mol/s (10 or 10 Std cm /s) range for less
4, wherein a piece of tape is applied around a flanged joint to
critical operation. Methods C, D, and E are well adapted for
be tested, or as complete as in Fig. 3. The latter provides
automation of valving and material handling.
isolation of the detector from atmospheric halogens, a pure-air
reference supply, and a convenient calibration means. This
5. Personnel Qualification
−12
enables detection of leaks as small as 4.5×10 mol/s
5.1 It is recommended that personnel performing leak test-
−7 3 2
(1×10 Std cm /s).
ing attend a dedicated training course on the subject and pass
a written examination.The training course should be appropri-
ate for NDT level II qualification according to Recommended
Practice No. SNT-TC-1A of theAmerican Society for Nonde-
structive Testing, or ANSI/ASNT Standard CP-189.
6. Significance and Use
6.1 Halogen leak testing can be used to indicate the
presence, location and magnitude of leaks in a closed vessel.
This test method is normally used for production examination.
Its use with halogenated refrigerant gases has been declining
because of concerns about the effect of these gases on the
FIG. 2 Proportioning Probe, Halogen Leak Detector, Method B ozone layer.
E427 − 95 (2006)
FIG. 3 Shroud Leak Test, Method C
FIG. 4 Simple Shroud Leak Test, Method C
FIG. 6 Accumulation Leak Test, Method E
smallest leak to be detected. For reliable testing, atmospheric
halogen must be kept well below this level.
7.2 Halogens Outgassed from Absorbent Materials—When
FIG. 5 Air-Curtain-Shroud Leak Test, Method D
leak testing is done in enclosures which prevent atmospheric
contamination from interfering with the test (Methods A, B,
and C), halogen absorbed in various nonmetallic materials
7. Interferences (suchasrubberorplastics)maybereleasedintheenclosure.If
the amount released starts to approach the amount from the
7.1 Atmospheric Halogens—When direct probing (Methods
leak in the same period of time, then a reliable leak test
A and B) is used to locate leaks, the leak detector probe is
becomes more difficult. The amount of such materials in the
drawing in air from the atmosphere. If the atmosphere is
enclosure,ortheirexposuretohalogenmustthenbereducedto
contaminated with halogen to a degree that produces a notice-
obtain a meaningful test.
able indication on the detector, the detection of halogen from
leaks becomes much more difficult. Significant atmospheric 7.3 Pressurizing with Test Gas—Inordertoevaluateleakage
contamination with halogen is defined as the level where the accurately, the test gas in all parts of the device must contain
detectorresponse,whentheprobeismovedfromzero-halogen substantially the same amount of tracer gas. When the device
air to test-area atmosphere, exceeds that expected from the contains air prior to the introduction of test gas, or when an
E427 − 95 (2006)
NOTE 1—When a vessel is not evacuated prior to adding test gas, the
inert gas and a tracer gas are added separately, this may not be
latter is automatically diluted by 1 atm of air.
true.Devicesinwhichtheeffectivediameterandlengtharenot
greatly different (such as tanks) may be tested satisfactorily by
9.1.2 Producing Premixed Test Gas—If the volume of the
simply adding tracer gas. However, when long or restricted deviceorthequantitytobetestedissmall,premixedgasescan
systems are to be tested, more uniform tracer distribution will
be conveniently obtained in cylinders. The user can also mix
be obtained by first evacuating to a few torr, and then filling gases by batch in the same way. Continuous mixing using
withthetestgas.Thelattermustbepremixedifnot100percent calibrated orifices is another simple and convenient method
tracer. when the test pressure does not exceed 50 percent of the tracer
gas pressure available (Note 2).Another method is to pass the
8. Apparatus nonhalogen gas through the liquid tracer. This produces test
gas containing the maximum amount of tracer gas.
8.1 Halogen Leak Detector—Toperformleaktestsasspeci-
fied in this standard, the leak detector should meet the
NOTE 2—Caution: The liquid tracer gas supply should not be heated
above ambient temperature.
following minimum requirements:
8.1.1 Sensor—Alkali-ion diode or electron capture.
9.2 Pure Air, Air from Which Halogens Have Been Removed
8.1.2 Readout—Panel instrument or digital readout.
to a Level of Less Than 1 ppb (or Other Suitable Nonhalogen
−11 −14
8.1.3 Range (Linear)—4.5×10 to 1.3×10 mol/s
Gas, Such as Nitrogen).
−6 −9 3 2
(1×10 to1×10 Std cm /s) full scale.
9.2.1 Requirements:
8.1.4 Response Time—3 s or less.
9.2.1.1 Less than 1 ppb of halogen.
8.1.5 Stability of Zero and Sensitivity— A maximum varia-
9.2.1.2 Less than 10 ppm of gases reactive with oxygen,
tion of 615 percent of full scale on most sensitive range while
such as petroleum-base solvent vapors.
probeisinpureair;amaximumvariationof 65percentoffull
9.2.1.3 Dew point 18°F (10°C) or more below ambient
scale on other ranges, for a period of 1 min.
temperature.
8.1.6 Controls:
9.2.1.4 Shall be reasonably free from rust, dirt, oil, etc.
8.1.6.1 Range—Preferablyinscalestepsofabout3timesor
9.2.2 Production of Pure Air, or Other Gas—Air or gas of
10 times.
suitable purity, may be produced by first passing it through a
8.1.6.2 Zero—Automatic zeroing option is desirable.
conventional filter-drier (if necessary) and then through acti-
vated charcoal.
8.2 Halogen Leak Standard—Toperformleaktestsasspeci-
fied in this standard, the leak standard should meet the
following minimum requirements: 10. Calibration
−10 −14 −5
8.2.1 Ranges—4.5×10 to 4.5 × 10 mol/s (10
10.1 The leak detectors used in making leak tests by these
−9 3 2
to×10 Std cm /s) full scale.
methods are not calibrated in the sense that they are taken to
8.2.2 Adjustability—Adjustable leak standards are a
the standards laboratory, calibrated, and then returned to the
convenience, but are not mandatory.
job. Rather, the leak detector is used as a comparator between
8.2.3 Accuracy—625 percent of full-scale value or better.
a leak standard (set to the specified leak size) which is part of
8.2.4 Temperature Coeffıcient—Shall be stated by manufac-
the instrumentation, and the unknown leak. However, the
turer.
sensitivity of the leak detector is checked and adjusted on the
job so that a leak of specified size will give a readily
8.3 Other Apparatus—Fixtures or other equipment specific
observable, but not off-scale reading. More specific details are
to one test method are listed under that method.
giveninSection11underthetestmethodbeingused.Toverify
detection,referencetotheleakstandardshouldbemadebefore
9. Material
and after a prolonged test. When rapid repetitive testing of
9.1 Test Gas:
many
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.