1、Designation:C178517Standard Test Method forConcentration of Pinhole Detections in Moisture Barriers onMetal Jacketing1This standard is issued under the fixed designation C1785;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year
2、of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon()indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the determination of the con-centration of pinhole detections in a moisture barrier film orcoati
3、ng that is applied to the interior surface of metal jacketing.1.2 Since this method relies on the completion through themetal jacketing of an electrical circuit,this method is onlyapplicable to jacketing that is electrically conductive and has amoisture barrier applied which is not electrically cond
4、uctive.1.3 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.4 This standard does not purport to address all of thesafety concerns,if any,
5、associated with its use.It is theresponsibility of the user of this standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.5 This international standard was developed in accor-dance with internationally r
6、ecognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recom-mendations issued by the World Trade Organization TechnicalBarriers to Trade(TBT)Committee.2.Referenced Documents2.1 ASTM Standards:2C168 Terminology Rela
7、ting to Thermal InsulationC1729 Specification for Aluminum Jacketing for InsulationC1767 Specification for Stainless Steel Jacketing for Insula-tionE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision
8、 of a Test Method3.Terminology3.1 DefinitionsDefinitions in Terminology C168 apply toterms used in this specification.3.2 Definitions of Terms Specific to This Standard:3.2.1 continuous pinhole detectionwhile the test is beingconducted,a continuous sounding of the audible test equip-ment alarm over
9、an area larger than the contact area of thecellulose sponge.3.2.1.1 DiscussionIn some cases,large portions of one ormore of the test areas(see 8.2.1)or even all of one or more testareas will yield a continuous pinhole detection.This concept ofa continuous pinhole detection and the area yielding this
10、performance is necessary to quantify the number of pinholedetections in a sample exhibiting this phenomenon(see 9.2 and9.3)3.2.2 moisture barrier(moisture retarder)a layer of plas-tic film or other material applied to the inner side of metaljacketing to inhibit jacket corrosion by interfering with t
11、heformation of a galvanic cell between the dissimilar metals ofthe pipe and jacket or by preventing crevice or pittingcorrosion.3.2.3 pinholea hole completely through a moisture barriertypically too small to be seen by the eye.3.2.4 pinhole detectiona single sounding of the audibletest equipment ala
12、rm while the test is being conducted.3.2.4.1 DiscussionBecause pinholes are very small andthe dampened cellulose sponge contacts the moisture barrier inan area larger than a single pinhole(see 6.4),it is theoreticallypossible that multiple pinholes in close proximity to each otherwould register as a
13、 single detection.For this reason,this testmethod measures the concentration of pinhole detections ratherthan pinholes.3.2.5 holidaysynonymous with pinhole.4.Summary of Test Method4.1 A voltage is applied across the nonconductive moisturebarrier on metal jacketing using an electrode consisting of ac
14、ellulose sponge dampened with an electrically conductive1This test method is under the jurisdiction ofASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved Sept.1,2017.Published October 2017.Origina
15、llyapproved in 2013.Last previous edition approved in 2016 as C1785 16a.DOI:10.1520/C1785-17.2For 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 Summa
16、ry page onthe ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 liquid such as tap water.Holes in the moisture ba