1、Designation: G13/G13M 13Standard Test Method forImpact Resistance of Pipeline Coatings(Limestone Drop Test)1This standard is issued under the fixed designation G13/G13M; the number immediately following the designation indicates the yearof original adoption or, in the case of revision, the year of l
2、ast 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. Scope1.1 This test method covers the determination of the relativeresistance of pipeline coatings to impact by observing theeffe
3、cts of falling stones on coated pipe specimens.1.2 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated ineach system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the
4、 two systems may result in non-conformancewith the standard.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and determine the applica-b
5、ility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2G12 Test Method for Nondestructive Measurement of FilmThickness of Pipeline Coatings on SteelG62 Test Methods for Holiday Detection in Pipeline Coat-ings2.2 AASHTO Standard:3M8051 (No. 67) Specification for Coars
6、e Aggregate forPortland Cement Concrete3. Summary of Test Method3.1 The impact resistance of pipeline coatings is determinedby dropping weighed amounts of a specified type of limestonethrough a chute onto a coated pipe specimen. Results arereported as the number of drops required to pierce through t
7、hecoating to bare metal, as determined visually or electrically.4. Significance and Use4.1 This test method is intended to simulate the effects ofbackfilling after pipe has been placed in the trench. The backfillis often rocky soil and, if it is unscreened and the coated pipeis unshielded by sand or
8、 other protective padding, the fallingrocks may seriously damage the coating.5. Apparatus5.1 The impact apparatus shall be essentially as shown inFig. 1 and shall include the following:5.1.1 Box with Chute, providing a means of dropping stonesfrom a height of 1830 mm 6.0 ft measured to the top of ap
9、iece of coated pipe under test. Construction details are shownin Fig. 2.NOTE 1The box and chute described in Fig. 2 are designed for testingcoatings on 100-mm 4-in. and 150-mm 6-in. pipe specimens. Smallerdiameter pipe may be used by inserting wood V-blocks in the trough in thebox below the chute.5.
10、1.2 Stones, hard, coarse, limestone aggregate, conformingto AASHTO Designation: M80-51 (No. 67) which is takenfrom America Association of State Highway and Transporta-tion Officials “Standard Specifications for Coarse Aggregatefor Portland Cement Concrete.”NOTE 2These specifications cover the qualit
11、y and size of coarseaggregate. No. 67 designates a 19-mm 34-in. to No. 4 size stone with thefollowing sieve analysis:Square Opening,mm in.Weight % Passing25 1 10019 14 95to10010 18 20to55No. 4 0 to 105.1.3 BucketAny suitable bucket that will hold 16 kg 35lb of stones.5.1.4 Holiday DetectorsTwo types
12、 are needed as de-scribed in Test Methods G62.NOTE 3A holiday is defined as small faults or pinholes that permitcurrent drainage through protective coatings on steel pipe.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and i
13、s the direct responsibility ofSubcommittee D01.48 on Durability of Pipeline Coating and Linings.Current edition approved Nov. 1, 2013. Published November 2013. Originallyapproved in 1989. Last previous edition approved in 1996 as G13 89 (1996)1which was withdrawn December 2003 and reinstated in Nove
14、mber 2013. DOI:10.1520G0013_G0013M-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from America
15、n Association of State Highway and TransportationOfficials (AASHTO), 444 N. Capitol St., NW, Suite 249, Washington, DC 20001,http:/www.transportation.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.1.5 Thickness GaugesAny instru
16、ments suitable for usewith Test Method G12.6. Test Specimens6.1 Test specimens shall be 600 mm 24 in. long and shallbe cut from a representative piece of coated pipe. Onlyholiday-free specimens shall be used in the test.7. Procedure7.1 Perform the test at a room temperature of 21 to 25C 70to 77F.7.2
17、 The procedure consists of dropping up to 10 buckets ofstones on coated specimens. The number of buckets of stonesrequired represents the resistance of the coating to this type ofimpact.7.3 Place the test specimen in the trough below the chute.Insert the retaining board in the top part of the chute
18、and holdit in place across the chute opening with a suitable metal orwood clip. Weigh 16 6 0.2 kg (35 6 0.5 lb of stones into thebucket. Lift the bucket to the top of the chute. Empty the stonesinto the trough formed by the hopper walls and the retainingboard so that the stones are distributed evenl
19、y in the trough.Detach the holding clip from the retaining board and tilt theboard forward to release the stones. Experience with thisprocedure has indicated that the stones are so constrictedwithin the narrow confines of the chute that they fall in auniform manner.7.4 After each drop, remove the sp
20、ecimen. Examine thespecimen visually for breaks in the coating. If there are novisual breaks, check with the holiday detector appropriate forthe coating thickness for holidays in the coating. If there is novisual or electrical evidence of holidays, repeat the test untilthe first holiday is detected
21、and record the number of drops andthe number of holidays detected. In repeating the test, replacethe specimen in the trough so that the same portion of thecoated surface is always subjected to the falling stones. Afterthe same stones have been used five times, replace them.7.5 If no failure has occu
22、rred after 10 buckets, terminate thetest.NOTE 4As indicated in 7.4, the same charge of stones may be usedfive times. Experiments in which the same charges of stones were droppedmore than five times have shown relatively little attrition of the stones.8. Report8.1 Report the following information:8.1
23、.1 Complete identification of the specimen including:name and code number of the coating, pipe diameter, coatingthickness, source, production data, and production-run number,8.1.2 Approximate pipe temperature at the beginning and atthe end of the test, andFIG. 1 Box, Chute, and BucketNOTE 1Framing l
24、umber 40 by 90 mm 2 by 4 in.; all other material20 mm 34 in.FIG. 2 Construction Details of Box and ChuteG13/G13M 1328.1.3 Number of buckets of stone to produce the firstholiday and the number of holidays produced during this drop.NOTE 5If there is a large number of holidays after a given number ofdr
25、ops, the report should state this by the term “too numerous to count.”9. Keywords9.1 impact resistance; limestone drop; pipeline coatingsASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this sta
26、ndard 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 five years an
27、dif 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 committee,
28、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, PA 19428-295
29、9,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/).G13/G13M 133
