ASTM C1785-13
(Test Method)Standard Test Method for Concentration of Pinhole Detections in Moisture Barriers on Metal Jacketing
Standard Test Method for Concentration of Pinhole Detections in Moisture Barriers on Metal Jacketing
SIGNIFICANCE AND USE
5.1 Corrosion on the interior surface of metal jacketing can be caused by the formation of a galvanic cell between the dissimilar metals of the pipe and jacket or by crevice or pitting corrosion.
5.2 The application of a moisture barrier to the interior surface of the metal jacketing inhibits this corrosion by interfering with the galvanic cell formation or by preventing water from contacting the interior metal surface.
5.3 Holes in the moisture barrier decrease its effectiveness in preventing corrosion. Large holes, scratches, or tears in the moisture barrier visible to the naked eye are easily discerned and are cause for rejection of the metal jacketing.
5.4 Small holes called pinholes or holidays that are not visible to the naked eye but are large enough to allow corrosion are a significant concern and should be avoided to the extent possible.
5.5 This test method is used to quantify the concentration of pinhole detections present in a moisture barrier for the purpose of quality control on metal jacketing with an applied moisture barrier.
5.6 Examples of standards which have specific requirements for the maximum allowable concentration of pinhole detections in the moisture barrier are Specifications C1729 and C1767.
SCOPE
1.1 This test method covers the determination of the concentration of pinhole detections in a moisture barrier film or coating that is applied to the interior surface of metal jacketing.
1.2 Since this method relies on the completion through the metal jacketing of an electrical circuit, this method is only applicable to jacketing that is electrically conductive and has a moisture barrier applied which is not electrically conductive.
1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered 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.
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Standards Content (Sample)
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Designation: C1785 − 13
StandardTest Method for
Concentration of Pinhole Detections in Moisture Barriers on
Metal Jacketing
This standard is issued under the fixed designation C1785; 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 formation of a galvanic cell between the dissimilar metals of
the pipe and jacket or by preventing crevice or pitting
1.1 This test method covers the determination of the con-
corrosion.
centration of pinhole detections in a moisture barrier film or
coating that is applied to the interior surface of metal jacketing.
3.2.2 pinhole—a hole completely through a moisture barrier
typically too small to be seen by the eye.
1.2 Since this method relies on the completion through the
metal jacketing of an electrical circuit, this method is only
3.2.3 pinhole detection—a single sounding of the audible
applicable to jacketing that is electrically conductive and has a
test equipment alarm while the test is being conducted.
moisture barrier applied which is not electrically conductive.
3.2.3.1 Discussion—Because pinholes are very small and
1.3 The values stated in inch-pound units are to be regarded
the dampened cellulose sponge contacts the moisture barrier in
as standard. The values given in parentheses are mathematical
an area larger than a single pinhole (see 6.4), it is theoretically
conversions to SI units that are provided for information only
possible that multiple pinholes in close proximity to each other
and are not considered standard.
would register as a single detection. For this reason, this test
methodmeasurestheconcentrationofpinholedetectionsrather
1.4 This standard does not purport to address all of the
than pinholes.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
3.2.4 holiday—synonymous with pinhole.
priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
4. Summary of Test Method
2. Referenced Documents
4.1 A voltage is applied across the nonconductive moisture
barrier on metal jacketing using an electrode consisting of a
2.1 ASTM Standards:
cellulose sponge dampened with an electrically conductive
C168 Terminology Relating to Thermal Insulation
liquid such as tap water. Holes in the moisture barrier lead to
C1729 Specification for Aluminum Jacketing for Insulation
completion of an electrical circuit which triggers an audible
C1767 Specification for Stainless Steel Jacketing for Insula-
alarm in the test equipment. The number of pinhole detections
tion
collectively in ten specified test areas is determined and
3. Terminology reported.
3.1 Definitions—Definitions in Terminology C168 apply to
5. Significance and Use
terms used in this specification.
5.1 Corrosion on the interior surface of metal jacketing can
3.2 Definitions of Terms Specific to This Standard:
be caused by the formation of a galvanic cell between the
3.2.1 moisture barrier (moisture retarder)—a layer of plas-
dissimilar metals of the pipe and jacket or by crevice or pitting
tic film or other material applied to the inner side of metal
corrosion.
jacketing to inhibit jacket corrosion by interfering with the
5.2 The application of a moisture barrier to the interior
surface of the metal jacketing inhibits this corrosion by
This test method is under the jurisdiction ofASTM Committee C16 on Thermal
Insulation and is the direct responsibility of Subcommittee C16.33 on Insulation interfering with the galvanic cell formation or by preventing
Finishes and Moisture.
water from contacting the interior metal surface.
Current edition approved Nov. 1, 2013. Published December 2013. DOI:
10.1520/C1785-13.
5.3 Holes in the moisture barrier decrease its effectiveness
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
in preventing corrosion. Large holes, scratches, or tears in the
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
moisture barrier visible to the naked eye are easily discerned
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. and are cause for rejection of the metal jacketing.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
C1785 − 13
5.4 Small holes called pinholes or holidays that are not sections of the test specimen. This yields 10 approximately
visible to the naked eye but are large enough to allow corrosion evenly spaced and evenly sized test areas.
are a significant concern and should be avoided to the extent 8.2.2 For sheet jacketing, select one or more 4.8 to 5.2
2 2
possible. ft (0.45 to 0.48 m ) sections per sheet. Test enough sheets to
yield 10 approximately evenly spaced and evenly sized test
5.5 This test method is used to quantify the concentration of
areas.
pinhole detections present in a moisture barrier for the purpose
of quality control on metal jacketing with an applied moisture 8.3 Testing:
barrier. 8.3.1 Wet a test area with an electrolyte such as tap water
without allowing a wet connection to form between the wetted
5.6 Examplesofstandardswhichhavespecificrequirements
areasandanybaremetaledgeofthejacketing.Donotfloodthe
forthemaximumallowableconcentrationofpinholedetections
moisture barrier s
...
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