ASTM D6676/D6676M-21
(Test Method)Standard Test Method for Cathodic Disbonding of Exterior Pipeline Coatings at Elevated Temperatures Using Interior Heating
Standard Test Method for Cathodic Disbonding of Exterior Pipeline Coatings at Elevated Temperatures Using Interior Heating
SIGNIFICANCE AND USE
4.1 Damage to a 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. Usually exterior pipeline coatings applied over pipes carrying hot media (oil, gas) are exposed to high temperature inside the pipe and low temperature outside and subjected to temperature gradient. Heat flux is directed from metal (substrate) to the coating. This test method provides accelerated conditions for cathodic disbondment to occur under simulated heating and provides a measure of resistance of coatings to this type of action.
4.2 The effects of the test are to be evaluated by physical examinations and monitoring the current drawn by the test specimens. 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.
4.3 Assumptions associated with test results include:
4.3.1 Maximum adhesion, or bond, is found in the coating that was not immersed in the test liquid, and
4.3.2 Decreased adhesion in the immersed test area is the result of cathodic disbondment.
4.4 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...
SCOPE
1.1 This test method describes an accelerated procedure for determining comparative characteristics of coating systems applied to the exterior of steel pipe for the purpose of preventing or mitigating corrosion that may occur in underground or immersion where the pipe is carrying heated media and is under cathodic protection. This test method is intended for use with samples of coated pipe, or with a specimen cut from the section of coated pipe or flat plates and is applicable to such samples when the coating is characterized by function as an electrical barrier.
1.2 This test method is intended to simulate conditions when external coatings are exposed to high temperature inside the pipe and to an ambient temperature outside, and thus are subjected to temperature gradient. If elevated temperatures are required but without temperature gradient, see Test Method G42.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.
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
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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: D6676/D6676M − 21
Standard Test Method for
Cathodic Disbonding of Exterior Pipeline Coatings at
1
Elevated Temperatures Using Interior Heating
This standard is issued under the fixed designation D6676/D6676M; 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 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 This test method describes an accelerated procedure for
D7091Practice for Nondestructive Measurement of Dry
determining comparative characteristics of coating systems
Film Thickness of Nonmagnetic Coatings Applied to
applied to the exterior of steel pipe for the purpose of
Ferrous Metals and Nonmagnetic, Nonconductive Coat-
preventing or mitigating corrosion that may occur in under-
ings Applied to Non-Ferrous Metals
ground or immersion where the pipe is carrying heated media
G12Test Method for Nondestructive Measurement of Film
and is under cathodic protection. This test method is intended
Thickness of Pipeline Coatings on Steel (Withdrawn
for use with samples of coated pipe, or with a specimen cut
3
from the section of coated pipe or flat plates and is applicable 2013)
G42Test Method for Cathodic Disbonding of Pipeline
to such samples when the coating is characterized by function
as an electrical barrier. Coatings Subjected to Elevated Temperatures
G62Test Methods for Holiday Detection in Pipeline Coat-
1.2 This test method is intended to simulate conditions
ings
when external coatings are exposed to high temperature inside
G95TestMethodforCathodicDisbondmentTestofPipeline
the pipe and to an ambient temperature outside, and thus are
Coatings (Attached Cell Method)
subjected to temperature gradient. If elevated temperatures are
required but without temperature gradient, see Test Method
3. Summary of Test Method
G42.
3.1 The test method described, subjects the coating on the
1.3 The values stated in either SI units or inch-pound units
testspecimentoelectricalstressinahighlyconductivealkaline
are to be regarded separately as standard. The values stated in
electrolyte. Electrical stress is obtained from an impressed
each system are not necessarily exact equivalents; therefore, to
direct-current system. An intentional holiday is to be made in
ensure conformance with the standard, each system shall be
the coating prior to starting of test.
used independently of the other, and values from the two
3.1.1 Electrical instrumentation is provided for measuring
systems shall not be combined.
the current and the potential throughout the test cycle. At the
conclusion of the test period, the test specimen is physically
1.4 This standard does not purport to address all of the
examined.
safety concerns, if any, associated with its use. It is the
3.1.2 Physical examination is conducted by comparing the
responsibility of the user of this standard to establish appro-
extent of loosened or disbonded coating at the intentional
priate safety, health, and environmental practices and deter-
holiday in the immersed area with extent of loosened or
mine the applicability of regulatory limitations prior to use.
disbondedcoatingatareferenceholidaymadeinthecoatingin
1.5 This international standard was developed in accor-
an area that was not immersed.
dance with internationally recognized principles on standard-
3.1.3 The cathodic stress is applied under conditions of a
ization established in the Decision on Principles for the
constant temperature gradient, simulating a heated pipeline
Development of International Standards, Guides and Recom-
with an exterior coating.
mendations issued by the World Trade Organization Technical
3.1.4 Specimensthatcanbeusedare:(a)pieceofpipe(Fig.
Barriers to Trade (TBT) Committee.
1)or(b) samples cut from pipe or flat plate (Fig. 2 and Fig. 3).
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. 1, 2021. Published December 2021. Originally theASTM website.
3
approved in 2001. Last previous edition approved in 2013 as D6676/D6676M–13. The last approved version of this historical standard is referen
...
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: D6676/D6676M − 13 D6676/D6676M − 21
Standard Test Method for
Cathodic Disbonding of Exterior Pipeline Coatings at
1
Elevated Temperatures Using Interior Heating
This standard is issued under the fixed designation D6676/D6676M; 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 describes an accelerated procedure for determining comparative characteristics of coating systems applied
to the exterior of steel pipe for the purpose of preventing or mitigating corrosion that may occur in underground or immersion
where the pipe is carrying heated media and is under cathodic protection. This test method is intended for use with samples of
coated pipe, or with a specimen cut from the section of coated pipe or flat plates,plates and is applicable to such samples when
the coating is characterized by function as an electrical barrier.
1.2 This test method is intended to simulate conditions when external coatings are exposed to high temperature inside the pipe
and to an ambient temperature outside, and thus are subjected to temperature gradient. If elevated temperatures are required but
without temperature gradient, see Test Method G42.
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used
independently of the other, and values from the two systems shall not be combined.
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 safety, health, and healthenvironmental 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.
2. Referenced Documents
2
2.1 ASTM Standards:
G8D7091 Test Methods for Cathodic Disbonding of Pipeline CoatingsPractice for Nondestructive Measurement of Dry Film
Thickness of Nonmagnetic Coatings Applied to Ferrous Metals and Nonmagnetic, Nonconductive Coatings Applied to
Non-Ferrous Metals
3
G12 Test Method for Nondestructive Measurement of Film Thickness of Pipeline Coatings on Steel (Withdrawn 2013)
G42 Test Method for Cathodic Disbonding of Pipeline Coatings Subjected to Elevated Temperatures
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 Nov. 1, 2013Nov. 1, 2021. Published November 2013December 2021. Originally approved in 2001. Last previous edition approved in 20012013
ε1
as D6676 – 01D6676/D6676M – 13. which was withdrawn January 2010 and reinstated in November 2013. DOI: 10.1520/D6676_D6676M-13.DOI: 10.1520/D6676_
D6676M-21.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3
The last approved version of this historical standard is referenced on www.astm.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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D6676/D6676M − 21
G62 Test Methods for Holiday Detection in Pipeline Coatings
G95 Test Method for Cathodic Disbondment Test of Pipeline Coatings (Attached Cell Method)
3. Summary of Test Method
3.1 The test method described, subjects the coating on the test specimen to electrical stress in a highly conductive alkaline
electrolyte. Electrical stress is obtained from an impressed direct- current direct-current system. An intentional holiday is to be
made in the coating prior to starting of test.
3.1.1 Electrical instrumentation is provided for measuring the current and the potentia
...
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