1、Designation: G20 10Standard Test Method forChemical Resistance of Pipeline Coatings1This standard is issued under the fixed designation G20; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in par
2、entheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method is intended for evaluating the resis-tance of pipe coating materials when exposed to variousconcentrations of reagents or suspected
3、 soil contaminants. Thetest serves as a guide to investigators wishing to compare therelative merits of pipe-coating materials in specific environ-ments. The choice of reagents, concentrations, duration ofimmersion, temperature of test, and properties to be reportedare necessarily arbitrary and shou
4、ld be chosen to reflectconditions known to exist along the pipeline right-of-way.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.3 This standard does not purport to address all of thesafety concerns, if any, associated wi
5、th its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2D543 Practices for Evaluating the Resistance of Plastics toChemica
6、l ReagentsD883 Terminology Relating to PlasticsG8 Test Methods for Cathodic Disbonding of PipelineCoatingsG12 Test Method for Nondestructive Measurement of FilmThickness of Pipeline Coatings on SteelG17 Test Method for Penetration Resistance of PipelineCoatings (Blunt Rod)3. Summary of Test Method3.
7、1 This test method consists of an immersion-type test in aclosed container where coated pipe specimens are in long-termcontact with both the liquid and vapor phase of the test reagent.Specimens exposed in this manner are inspected for visiblesigns of chemical attack. Subsequent tests for cathodic di
8、s-bonding in accordance with Test Method G8, or penetrationunder load in accordance with Test Method G17, may beapplied to determine if the specimens have undergone any lossof mechanical or bonding properties.4. Significance and Use4.1 The data obtained for short-term tests are of interestonly in el
9、iminating the most unsuitable materials or forindicating a probable order of resistance in any particularmedia.4.2 Test conditions should take into account the manner andduration of immersion, the reagent, the temperature of thesystem, the area exposed above and below the liquid level, andother perf
10、ormance factors selected for the particular test.5. Apparatus5.1 Thickness Gage, capable of measuring the coatingthickness in the manner prescribed by Test Method G12.5.2 Test ContainerAtransparent closed container, sized tocompletely encase the pipe specimen and large enough toprovide adequate expo
11、sure to both the liquid and vapor statesof reagent.NOTE 1For example, a 2-L (2.0-qt) capacity, Mason-type jar with a70-mm (2.75-in.) diameter neck has been found suitable for use with 2 in.pipe and is illustrated in Fig. 1.5.2.1 To avoid pressure build-up within the test containers,the threaded cup
12、shall be replaced with a solid-rubber stopper.A positive venting device, such as a water seal, shall be usedwhen testing with volatile solvents at elevated temperatures.5.2.2 A separate container shall be used for each testspecimen.5.3 Oven or Constant-Temperature Room or BathTo en-sure uniformity o
13、f test results, the test cells and specimen shallbe maintained at the test temperature 65C (9F) over theduration of the test period.5.4 Auxiliary Testing DevicesSupplemental equipmentused to determine specific mechanical properties of specimensbefore and after immersion shall conform to the requirem
14、entsprescribed in the applicable ASTM test method.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.48 on Durability of Pipeline Coating and Linings.Current edition approved
15、Dec. 1, 2010. Published December 2010. Originallyapproved in 1971. Last previous edition approved in 2002 as G20 88 (2002). DOI:10.1520/G0020-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards
16、volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.6. Reagents6.1 The reagents selected for coating-resistance tests shouldbe those anticipated to occur
17、 in the environment or in theproduct being carried in the pipeline at the temperatures and inthe concentrations expected. The numbers in parentheses referto the list of standard reagents given in Section 4 of PracticesD543.6.1.1 Acetic Acid (5 %) (4.4.2).6.1.2 Acetone (4.4.3).6.1.3 Carbon Disulfide.
18、6.1.4 Gasoline.6.1.5 Hydrochloric Acid (10 %) (4.4.23).6.1.6 Kerosine (4.4.28).6.1.7 Lime Water, Saturated.6.1.8 Methyl Alcohol (4.4.29).6.1.9 Methyl Ethyl Ketone.6.1.10 Nitric Acid (10 %) (4.4.33).6.1.11 Sodium Carbonate Solution (20 %) (4.4.38).6.1.12 Sodium Chloride Solution (10 %) (4.4.40).6.1.1
19、3 Sodium Hydroxide Solution (10 %) (4.4.42).6.1.14 Sulfuric Acid (30 %) (4.4.46).6.1.15 Toluene (4.4.48).6.1.16 Transformer Oil (4.4.49).6.1.17 Trichlorethylene.6.1.18 Other selected environments.7. Hazards7.1 Take safety precautions to avoid personal contact, toeliminate toxic vapors, and to guard
20、against explosion hazardsin accordance with the hazardous nature of the particularreagents being used.8. Test Specimen8.1 The test specimen shall be prepared with its surfacepreparation and coating procedures equivalent to that of coatedpipe. A control specimen shall be retained for comparison.8.2 I
21、n order to utilize the test container specified in 4.2, thepipe specimen, with end caps, shall be restricted to a maximumoverall length of 180 mm (7.0 in.) and a diameter of 65 mm(2.5 in.).8.3 Both ends of the pipe specimens shall be plugged withinert stoppers and coated with an epoxy-base or other
22、suitablecoating material.8.4 Specimens with Holidays:8.4.1 A holiday shall be made in the surface of the coatedpipe specimen at a point 25 % of the distance between the endcaps. It shall be made by drilling a radial hole through thecoating so that the angular cone point of the drill will fullyenter
23、the steel where the cylindrical portion of the drill meetsthe steel surface. The drill diameter shall not be less than threetimes the coating thickness, but it shall never be smaller than 6mm (0.25 in.) in diameter. The steel wall of the pipe shall notbe perforated.8.4.2 A second identical holiday s
24、hall be drilled into thecoating surface at a point 25 % of the distance between the endcaps of the specimen (see Fig. 1). Both holidays should lie inthe same pipe axis.8.5 Specimens without intentional holidays shall also beprepared for testing.NOTE 2Intentional holidays shall be made in only those
25、specimensfor which a comparison of disbonding properties is desired. Other samplesused for supplemental mechanical testing shall be run without holidays.9. Procedure9.1 Place a single specimen in a vertical position in each testcontainer.9.2 Fill the container with the selected reagent so that theli
26、quid level covers one half of the coated pipe specimen up toa point midway between the two intentional holidays. Stopperthe 704 Container to prevent evaporation of the reagent andagainst contamination.9.3 Maintain the reagent level at the original level.9.4 The basic immersion test for a particular
27、coating mate-rial shall consist of twelve specimens, six with holidays and sixwithout, each in an individual test cell. Remove duplicatesamples of each from the test at 30, 60, and 90 day intervals.Additional investigations of pre- and post immersion mechani-cal properties will require additional sp
28、ecimens. It is recom-mended that in all cases provisions be made for duplicate testspecimens.9.5 Remove the specimen after 30, 60, and 90 days ofimmersion. Wash with running water all specimens removedfrom acid, alkali, or other aqueous solutions and wipe them drywith a soft, clean, cotton cloth or
29、paper tissue. Specimensremoved from volatile solvents such as acetone, alcohol, etc.,need no rinsing before wiping dry.9.6 Observe and report before, immediately after, and 2 hlater the appearance of specimen after exposure to reagent onthe basis of visual examination for evidence of loss of gloss,d
30、eveloped texture, decomposition, discoloration, softening,swelling, injury, bubbling, blistering, cracking, solubility, etc.as defined in Terminology D883.9.7 Mechanically probe each of the intentional holidays inaccordance with Section 8.3.3 of Test Method G8 to see if therehas been any loss of coa
31、ting bond during the test period.DimensionsA70 mm (2.75 in.) Jar OpeningB45 mm (1.75 in.) Holiday LocationC90 mm (7.00 in.) Length of Pipe SpecimenNOTE 1Dimensions shown for 2 in. IPS pipe.FIG. 1 Chemical Immersion Test Schematic of Test CellG201029.8 Perform other planned mechanical tests to determ
32、ine ifany degradation of coating properties has occurred throughreagent exposure.10. Report10.1 The report shall include the following:10.1.1 Complete identification of the material tested, includ-ing type, source, manufacturers code, and previous history,10.1.2 Method of preparing test specimen,10.
33、1.3 Temperature of test,10.1.4 Description of media, including ASTM designation,10.1.5 Duration of immersion,10.1.6 Outside diameter of test specimen,10.1.7 Initial thickness of coating,10.1.8 General appearance of specimen after immersion,10.1.9 Immersion area in square millimetres (squareinches),1
34、0.1.10 Vapor phase area in square millimetres (squareinches), and10.1.11 Disbonded area after immersion in square millime-tres (square inches).11. Precision and Bias11.1 As there are no direct measurements involved with thistest method, no precision and bias statement is necessary.Measurements made
35、by procedures for other test methodsshould refer to the precision and bias statements therein.12. Keywords12.1 chemical resistance; pipeline coatingsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users
36、 of this standard are expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every f
37、ive years andif not revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical
38、 committee, which you may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken,
39、PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).G20103
