ASTM G42-11
(Test Method)Standard Test Method for Cathodic Disbonding of Pipeline Coatings Subjected to Elevated Temperatures
Standard Test Method for Cathodic Disbonding of Pipeline Coatings Subjected to Elevated Temperatures
SIGNIFICANCE AND USE
Damage to pipe coating is almost unavoidable during transportation and construction. Breaks or holidays in pipe coatings may expose the pipe to possible corrosion since, after a pipe has been installed underground, the surrounding earth will be moisture-bearing and will constitute an effective electrolyte. Applied cathodic protection potentials may cause loosening of the coating, beginning at holiday edges. Spontaneous holidays may also be caused by such potentials. This test method provides accelerated conditions for cathodic disbondment to occur and provides a measure of resistance of coatings to this type of action.
The effects of the test are to be evaluated by physical examinations and monitoring the current drawn by the test specimen. Usually there is no correlation between the two methods of evaluation, but both methods are significant. Physical examination consists of assessing the effective contact of the coating with the metal surface in terms of observed differences in the relative adhesive bond. It is usually found that the cathodically disbonded area propagates from an area where adhesion is zero to an area where adhesion reaches the original level. An intermediate zone of decreased adhesion may also be present.
Assumptions associated with test results include:
Maximum adhesion, or bond, is found in the coating that was not immersed in the test liquid, and
Decreased adhesion in the immersed test area is the result of cathodic disbondment.
Ability to resist disbondment is a desired quality on a comparative basis, but disbondment in this test method is not necessarily an adverse indication of coating performance. The virtue of this test method is that all dielectric-type coatings now in common use will disbond to some degree, thus providing a means of comparing one coating to another.
The current density appearing in this test method is much greater than that usually required for cathodic protection in natural environments.
That any relative...
SCOPE
1.1 This test method describes an accelerated procedure for determining comparative characteristics of insulating coating systems applied to steel pipe exterior for the purpose of preventing or mitigating corrosion that may occur in underground service where the pipe will be exposed to high temperatures and is under cathodic protection. This test method is intended for use with samples of coated pipe taken from commercial production and is applicable to such samples when the coating is characterized by function as an electrical barrier.
1.2 This test method is intended for testing coatings submerged or immersed in the test solution at elevated temperature. When it is impractical to submerge or immerse the test specimen, Test Method G95 may be considered where the test cell is cemented to the surface of the coated pipe specimen. If room temperatures are required, see Test Methods G8. If a specific test method is required with no options, see Test Method G80.
1.3 The values stated in SI units to three significant decimals are to be regarded as the standard. The values given in parentheses are for information only.
1.4 WarningMercury has been designated by EPA and many state agencies as a hazardous material that can cause central nervous system, kidney, and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution should be taken when handling mercury and mercury-containing products. See the applicable product Material Safety Data Sheet (MSDS) for details and EPA’s website (http://www.epa.gov/mercury/faq.htm) for additional information. Users should be aware that selling mercury or mercury-containing products, or both, in your state may be prohibited by state law.
1.5 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 ...
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Designation: G42 − 11
Standard Test Method for
Cathodic Disbonding of Pipeline Coatings Subjected to
1
Elevated Temperatures
ThisstandardisissuedunderthefixeddesignationG42;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope priate safety and health practices and determine the applica-
bility of regulatory limitations prior to use.
1.1 This test method describes an accelerated procedure for
determining comparative characteristics of insulating coating
2. Referenced Documents
systems applied to steel pipe exterior for the purpose of
2
2.1 ASTM Standards:
preventing or mitigating corrosion that may occur in under-
G8Test Methods for Cathodic Disbonding of Pipeline Coat-
ground service where the pipe will be exposed to high
ings
temperaturesandisundercathodicprotection.Thistestmethod
G12Test Method for Nondestructive Measurement of Film
is intended for use with samples of coated pipe taken from
Thickness of Pipeline Coatings on Steel (Withdrawn
commercialproductionandisapplicabletosuchsampleswhen
3
2013)
the coating is characterized by function as an electrical barrier.
G80Test Method for Specific Cathodic Disbonding of Pipe-
1.2 This test method is intended for testing coatings sub- 3
line Coatings (Withdrawn 2013)
merged or immersed in the test solution at elevated tempera-
G95TestMethodforCathodicDisbondmentTestofPipeline
ture. When it is impractical to submerge or immerse the test
Coatings (Attached Cell Method)
specimen, Test Method G95 may be considered where the test
E1Specification for ASTM Liquid-in-Glass Thermometers
cell is cemented to the surface of the coated pipe specimen. If
E2251Specification for Liquid-in-Glass ASTM Thermom-
room temperatures are required, see Test Methods G8.Ifa
eters with Low-Hazard Precision Liquids
specific test method is required with no options, see Test
Method G80.
3. Summary of Test Method
1.3 The values stated in SI units to three significant deci-
3.1 This test method subjects the coating on the test speci-
mals are to be regarded as the standard. The values given in
men to electrical stress in a highly conductive electrolyte. The
parentheses are for information only.
coating is artificially perforated before starting the test. The
electrical stress is produced by connecting the test specimen to
1.4 Warning—Mercury has been designated by EPA and
the negative terminal of a source of direct current and by
many state agencies as a hazardous material that can cause
connecting an anode to the positive terminal. Electrical instru-
central nervous system, kidney, and liver damage. Mercury, or
mentation is provided for measuring the current flowing in the
its vapor, may be hazardous to health and corrosive to
cell.Theelectricalpotentialisalsomeasuredandthespecimen
materials.Cautionshouldbetakenwhenhandlingmercuryand
is physically examined at intervals during the test period and
mercury-containing products. See the applicable product Ma-
upon conclusion of the test.
terial Safety Data Sheet (MSDS) for details and EPA’s website
3.1.1 The cathodic stress is applied under conditions of a
(http://www.epa.gov/mercury/faq.htm) for additional informa-
constant-elevated temperature.
tion. Users should be aware that selling mercury or mercury-
containingproducts,orboth,inyourstatemaybeprohibitedby
4. Significance and Use
state law.
4.1 Damage to pipe coating is almost unavoidable during
1.5 This standard does not purport to address all of the
transportation and construction. Breaks or holidays in pipe
safety concerns, if any, associated with its use. It is the
coatings may expose the pipe to possible corrosion since, after
responsibility of the user of this standard to establish appro-
1 2
This test method is under the jurisdiction of ASTM Committee D01 on Paint For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Related Coatings, Materials, andApplications and is the direct responsibility of contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Subcommittee D01.48 on Durability of Pipeline Coating and Linings. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved Nov. 15, 2011. Published January 2012. Originally the ASTM website.
3
approvedin1975.Lastpreviouseditionapprovedin2003asG42–96(2003).DOI: The last approved version of this historical standard is referenced on
10.1520/G0042-11. www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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G42−11
a pipe has been installed underground,
...
This document is not anASTM standard and is intended only to provide the user of anASTM 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:G42–96(Reapproved2003) Designation: G42 – 11
Standard Test Method for
Cathodic Disbonding of Pipeline Coatings Subjected to
1
Elevated Temperatures
ThisstandardisissuedunderthefixeddesignationG42;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method describes an accelerated procedure for determining comparative characteristics of insulating coating
systems applied to steel pipe exterior for the purpose of preventing or mitigating corrosion that may occur in underground service
where the pipe will be exposed to high temperatures and is under cathodic protection. This test method is intended for use with
samples of coated pipe taken from commercial production and is applicable to such samples when the coating is characterized by
function as an electrical barrier.
1.2 This test method is intended for testing coatings submerged or immersed in the test solution at elevated temperature.When
it is impractical to submerge or immerse the test specimen, Test Method G95 may be considered where the test cell is cemented
to the surface of the coated pipe specimen. If room temperatures are required, see Test Methods G8. If a specific test method is
required with no options, see Test Method G80.
1.3 ThevaluesstatedinSIunitstothreesignificantdecimalsaretoberegardedasthestandard.Thevaluesgiveninparentheses
are for information only.
1.4
1.4 Warning—Mercury has been designated by EPA and many state agencies as a hazardous material that can cause central
nervous system, kidney, and liver damage. Mercury, or its vapor, may be hazardous to health and corrosive to materials. Caution
should be taken when handling mercury and mercury-containing products. See the applicable product Material Safety Data Sheet
(MSDS) for details and EPA’s website (http://www.epa.gov/mercury/faq.htm) for additional information. Users should be aware
that selling mercury or mercury-containing products, or both, in your state may be prohibited by state law.
1.5 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.
2. Referenced Documents
2
2.1 ASTM Standards:
G8 Test Methods for Cathodic Disbonding of Pipeline Coatings
G12 Test Method for Nondestructive Measurement of Film Thickness of Pipeline Coatings on Steel
G80 Test Method for Specific Cathodic Disbonding of Pipeline Coatings
G95 Test Method for Cathodic Disbondment Test of Pipeline Coatings (Attached Cell Method) Test Method for Cathodic
Disbondment Test of Pipeline Coatings (Attached Cell Method)
E1 Specification for ASTM Liquid-in-Glass Thermometers
E2251 Specification for Liquid-in-Glass ASTM Thermometers with Low-Hazard Precision Liquids
3. Summary of Test Method
3.1 Thistestmethodsubjectsthecoatingonthetestspecimentoelectricalstressinahighlyconductiveelectrolyte.Thecoating
is artificially perforated before starting the test. The electrical stress is produced by connecting the test specimen to the negative
terminal of a source of direct current and by connecting an anode to the positive terminal. Electrical instrumentation is provided
for measuring the current flowing in the cell. The electrical potential is also measured and the specimen is physically examined
1
This test method is under the jurisdiction of ASTM Committee D01 on Paint and Related Coatings, Materials, and Applications and is the direct responsibility of
Subcommittee D01.48 on Durability of Pipeline Coating and Linings.
Current edition approved Dec. 1, 2003. Published December 2003. Originally approved in 1975. Last previous edition approved in 1996 as G42–96. DOI:
10.1520/G0042-96R03.
Current edition approved Nov. 15, 2011. Published January 2012. Originally approved in 1975. Last previous edition approved in 2003 as G42–96(2003). DOI:
10.1520/G0042-11.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.ForAnnualBookofASTMStandards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
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