ASTM G8-96(2003)
(Test Method)Standard Test Methods for Cathodic Disbonding of Pipeline Coatings
Standard Test Methods for Cathodic Disbonding of Pipeline Coatings
SCOPE
1.1 These test methods cover accelerated procedures for simultaneously 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 in contact with inland soils and may or may not receive cathodic protection. They are intended for use with samples of coated pipe taken from commercial production and are 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 room temperature. When it is impractical to submerge or immerse the test specimen, Test Method G 95 may be considered where the test cell is cemented to the surface of the coated pipe specimen. If higher temperatures are required, see Test Method G 42. If a specific test method is required with no options, see Test Method G 80.
1.3 The values stated in SI units to 3 significant decimals are to be regarded as the standard. The values given in parentheses are for information only.
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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Designation:G8–96 (Reapproved 2003)
Standard Test Methods for
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Cathodic Disbonding of Pipeline Coatings
ThisstandardisissuedunderthefixeddesignationG8;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope G12 TestMethodforNondestructiveMeasurementofFilm
Thickness of Pipeline Coatings on Steel
1.1 These test methods cover accelerated procedures for
G42 Test Method for Cathodic Disbonding of Pipeline
simultaneously determining comparative characteristics of in-
Coatings Subjected to Elevated Temperatures
sulating coating systems applied to steel pipe exterior for the
G80 Test Method for Specific Cathodic Disbonding of
purposeofpreventingormitigatingcorrosionthatmayoccurin
Pipeline Coatings
underground service where the pipe will be in contact with
G95 Test Method for Cathodic Disbondment Test of Pipe-
inland soils and may or may not receive cathodic protection.
line Coatings (Attached Cell Method)
They are intended for use with samples of coated pipe taken
from commercial production and are applicable to such
3. Summary of Test Methods
samples when the coating is characterized by function as an
3.1 Both of the two test methods described subject the
electrical barrier.
coating on the test specimen to electrical stress in a highly
1.2 This test method is intended for testing coatings sub-
conductive, alkaline electrolyte. Electrical stress is obtained
merged or immersed in the test solution at room temperature.
either by means of a sacrificial magnesium anode or from an
When it is impractical to submerge or immerse the test
impressed current system. The coating is perforated before
specimen,Test MethodG95 may be considered where the test
starting the test.
cell is cemented to the surface of the coated pipe specimen. If
3.1.1 In Method A, a magnesium anode is used with no
higher temperatures are required, see Test MethodG42.Ifa
electrical monitoring during the test period. The results are
specific test method is required with no options, see Test
determined by physical examination after the test period is
MethodG80.
concluded.
1.3 ThevaluesstatedinSIunitsto3significantdecimalsare
3.1.2 In Method B, either a magnesium anode or an im-
toberegardedasthestandard.Thevaluesgiveninparentheses
pressedcurrentsystemmaybeused.Electricalinstrumentation
are for information only.
is provided for measuring the current in the cell circuit. The
1.4 This standard does not purport to address all of the
electrical potential is also measured, and upon conclusion of
safety concerns, if any, associated with its use. It is the
the test period, the test specimen is physically examined.
responsibility of the user of this standard to establish appro-
3.1.3 In both test methods physical examination is con-
priate safety and health practices and determine the applica-
ducted by comparing the extent of loosened or disbonded
bility of regulatory limitations prior to use.
coating at the perforations in the immersed area with extent of
2. Referenced Documents loosened or disbonded coating at a newtest hole in the coating
2 made in an area that was not immersed.
2.1 ASTM Standards:
4. Significance and Use
4.1 Breaksorholidaysinpipecoatingsmayexposethepipe
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These test methods are under the jurisdiction of ASTM Committee D01 on
to possible corrosion, since after a pipe has been installed
Paint and Related Coatings, Materials, and Applications and are the direct
underground, the surrounding earth will be more or less
responsibility of Subcommittee D01.48 on Durability of Pipeline Coating and
moisture-bearing and it constitutes an effective electrolyte.
Linings.
Damage to pipe coating is almost unavoidable during trans-
Current edition approved Dec. 1, 2003. Published December 2003. Originally
approved in 1969. Last previous edition approved in 1996 asG8–96.
portation and construction. Normal soil potentials as well as
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
applied cathodic protection potentials may cause loosening of
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
the coating, beginning at holiday edges, in some cases increas-
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. ing the apparent size of the holiday. Holidays may also be
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
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G8–96 (2003)
caused by such potentials. While apparently loosened coating 5.1.2 Magnesium Anode—The anode shall be made of a
and cathodic holidays may not result
...
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