ASTM G19-88(1996)e1
(Test Method)Standard Test Method for Disbonding Characteristics of Pipeline Coatings by Direct Soil Burial
Standard Test Method for Disbonding Characteristics of Pipeline Coatings by Direct Soil Burial
SCOPE
1.1 This test method describes the determination of the relative disbonding characteristics of damaged coatings on steel pipe by cathodic protection potentials in direct soil burial. This test method is intended to apply to the testing of all types of nonmetallic pipeline coatings and tapes including thermoplastics, thermoset, and bituminous materials.
1.2 Results may vary widely when test sites are in different geographical areas of the country, and even in different localities.
1.3 This test method is limited to nonconducting, or nonmetallic pipe coatings and is not applicable to conducting materials such as zinc coatings on steel pipe.
1.4 This test method may involve hazardous operations and equipment. This test method does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this test method to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
1.5 The values stated in SI units to three significant decimals are to be regarded as the standard.
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Designation:G19–88(Reapproved 1996)
Standard Test Method for
Disbonding Characteristics of Pipeline Coatings by Direct
Soil Burial
ThisstandardisissuedunderthefixeddesignationG19;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
e NOTE—Keywords were added editorially in June 1996.
1. Scope removed, the exposed area measured, and comparisons are
made to other specimens similarly exposed.
1.1 This test method describes the determination of the
relative disbonding characteristics of damaged coatings on
4. Significance and Use
steelpipebycathodicprotectionpotentialsindirectsoilburial.
4.1 Coated pipe is seldom, if ever, buried without some
This test method is intended to apply to the testing of all types
damage to the coating. Hence, an actual soil-burial test can
of nonmetallic pipeline coatings and tapes including thermo-
contribute significant data, provided the method of testing is
plastics, thermoset, and bituminous materials.
controlledandthetestspecimenmonitoredandtherelationship
1.2 Results may vary widely when test sites are in different
betweentheareadisbonded,thecurrentdemand,andthemode
geographical areas of the country, and even in different
of failure is fully understood.
localities.
4.2 Means are provided for measuring and following the
1.3 This test method is limited to nonconducting, or non-
electrical potential and current flow and relating these data to
metallic pipe coatings and is not applicable to conducting
the final measurement of disbonded area.
materials such as zinc coatings on steel pipe.
1.4 This standard does not purport to address all of the
5. Apparatus
safety concerns, if any, associated with its use. It is the
5.1 Anode—A standard packaged magnesium anode, mini-
responsibility of the user of this standard to establish appro-
mum 4.082 kg (9 lb), with a factory-sealed, 4107-cmil (14-
priate safety and health practices and determine the applica-
gage Awg) minimum, insulated copper wire shall be used. A
bility of regulatory limitations prior to use.
solution potential of not less than−1.45 V with respect to a
1.5 The values stated in SI units to three significant deci-
copper-copper sulfate reference electrode is required. Use
mals are to be regarded as the standard. The values given in
sufficient anodes to maintain required potential.
parentheses are for information only.
5.2 Connectors—The wiring circuit from anode to test
specimen and from specimen to reference electrode should be
2. Referenced Documents
4107-cmil (14-gage Awg) minimum insulated copper wire.
2.1 ASTM Standards:
Attach the wires to the test specimen as shown in Fig. 1 by
G12 TestMethodforNondestructiveMeasurementofFilm
2 soldering or brazing at the air-exposed end, and coat the place
Thickness of Pipeline Coatings on Steel
of attachment with insulating material. A junction box is
G62 Test Methods for Holiday Detection in Pipeline Coat-
2 optionalforconnectingtheresistorinseriesbetweentheanode
ings
and the test specimen.
3. Summary of Test Method 5.3 The instruments used shall include the following:
5.3.1 Voltmeter, a suitable instrument such as a high imped-
3.1 Apparatus and materials are described whereby protec-
ance (>10mV) analog multimeter having a sensitivity of
tive coatings on steel pipe are subjected to disbonding by an
50 000V/ V minimum and a multiple range from 0.01 to 2 V
electrical stress. Specimens with intentionally damaged areas
for direct current is used for measuring the potential between
are buried in soil at an outdoor site and electrically connected
specimen and the reference electrode, current between speci-
to a magnesium anode. After test, the disbonded coating is
men and anode, and the resistance of the circuit. The same
instrument shall be used for measuring current between speci-
This test method is under the jurisdiction of ASTM Committee D-1 on Paint
men and anode. Alligator clips on the leads are permissible.
and Related Coatings, Materials, andApplications and is the direct responsibility of
Subcommittee D01.48 on Durability of Pipeline Coatings and Linings.
Current edition approved May 27, 1988. Published July 1988. Originally
published as G19–71T. Last previous edition G19–83. A pipe-to-soil Voltmeter-Ammeter, Agra Engineering Co., Tulsa, Okla., has
Annual Book of ASTM Standards, Vol 06.02. been found suitable for this test.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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G19–88 (1996)
FIG. 1 Three Specimens in a Circle with a Common Anode
5.3.2 Volt-Ohm-Meter for measuring resistance of the cir- 5.3.4 A suitable instrument is used to measure the soil
resistivity using the four-pin method. Pins should be spaced
cuit.
762 mm (30 in.) apart.
5.3.3 Reference Electrode, consisting of a copper-copper
5.3.5 Thickness Gages, to be used in accordance with Test
sulfate half cell in a conventional glass or plastic tube with
MethodG12.
porousplugconstruction,butpreferablynotover19.05mm( ⁄4
5.3.6 Holiday Tools—Holidays in the specimen are made
in.)indiameter,havingapotentialof−0.316Vwithrespectto
with conventional drills of the required diameter. A9.525-mm
a standard hydrogen electrode. A calomel electrode may be
used, but measurements made with it should be converted to
the copper-copper sulfate reference electrode for reporting, by
A Vibroground instrument, Associated Research Inc., 3758 Belmont Ave.,
adding−0.092 V to the observed reading. Chicago, Ill., has been found suitable for measuring soil resistivity.
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G19–88 (1996)
(0.375-in.) drill modified by substantially reducing the cone 8.2.1 Dig suitable holes with an auger or posthole digger to
angle has been found effective in preventing perforation of accommodate the anode and test specimens at the test site.
thin-wall pipe or tubing. A sharp-pointed knife with a safe 8.2.2 Insert the anode at the center of the circle. The center
handle is required for removing disbonded coatings to make of the anode should be 457.2 mm (18 in.) below ground. Pipe
physical examinations. A micrometer-type depth gage is used specimens should be inserted so that 304.8 mm (12 in.) are
for measuring coating thicknesses at the edge of holidays. above the ground level, and oriented so that the single
5.3.7 Holiday Detectors—Selected in accordance with Test intentional holiday faces the anode and the remaining two
MethodG
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