ASTM C1785-2013 Standard Test Method for Concentration of Pinhole Detections in Moisture Barriers on Metal Jacketing《金属保护层上水分屏障中的针孔探测混凝土标准试验方法》.pdf
《ASTM C1785-2013 Standard Test Method for Concentration of Pinhole Detections in Moisture Barriers on Metal Jacketing《金属保护层上水分屏障中的针孔探测混凝土标准试验方法》.pdf》由会员分享,可在线阅读,更多相关《ASTM C1785-2013 Standard Test Method for Concentration of Pinhole Detections in Moisture Barriers on Metal Jacketing《金属保护层上水分屏障中的针孔探测混凝土标准试验方法》.pdf(3页珍藏版)》请在麦多课文档分享上搜索。
1、Designation: C1785 13Standard 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
2、year 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 fi
3、lm orcoating 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 electr
4、ically conductive.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 conc
5、erns, 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-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2C168 Terminology Relating to Thermal In
6、sulationC1729 Specification for Aluminum Jacketing for InsulationC1767 Specification for Stainless Steel Jacketing for Insula-tion3. Terminology3.1 DefinitionsDefinitions in Terminology C168 apply toterms used in this specification.3.2 Definitions of Terms Specific to This Standard:3.2.1 moisture ba
7、rrier (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 theformation of a galvanic cell between the dissimilar metals ofthe pipe and jacket or by preventing crevice or pittingcorrosion.3.2.2 pinho
8、lea hole completely through a moisture barriertypically too small to be seen by the eye.3.2.3 pinhole detectiona single sounding of the audibletest equipment alarm while the test is being conducted.3.2.3.1 DiscussionBecause pinholes are very small andthe dampened cellulose sponge contacts the moistu
9、re 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 single detection. For this reason, this testmethod measures the concentration of pinhole detections ratherthan pinholes.3.2.4 holidaysyn
10、onymous with pinhole.4. Summary of Test Method4.1 A voltage is applied across the nonconductive moisturebarrier on metal jacketing using an electrode consisting of acellulose sponge dampened with an electrically conductiveliquid such as tap water. Holes in the moisture barrier lead tocompletion of a
11、n electrical circuit which triggers an audiblealarm in the test equipment. The number of pinhole detectionscollectively in ten specified test areas is determined andreported.5. Significance and Use5.1 Corrosion on the interior surface of metal jacketing canbe caused by the formation of a galvanic ce
12、ll between thedissimilar metals of the pipe and jacket or by crevice or pittingcorrosion.5.2 The application of a moisture barrier to the interiorsurface of the metal jacketing inhibits this corrosion byinterfering with the galvanic cell formation or by preventingwater from contacting the interior m
13、etal surface.5.3 Holes in the moisture barrier decrease its effectivenessin preventing corrosion. Large holes, scratches, or tears in themoisture barrier visible to the naked eye are easily discernedand are cause for rejection of the metal jacketing.1This test method is under the jurisdiction ofASTM
14、 Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.33 on InsulationFinishes and Moisture.Current edition approved Nov. 1, 2013. Published December 2013. DOI:10.1520/C1785-13.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Cus
15、tomer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.4 Small holes called pinholes or
16、holidays that are notvisible to the naked eye but are large enough to allow corrosionare a significant concern and should be avoided to the extentpossible.5.5 This test method is used to quantify the concentration ofpinhole detections present in a moisture barrier for the purposeof quality control o
17、n metal jacketing with an applied moisturebarrier.5.6 Examples of standards which have specific requirementsfor the maximum allowable concentration of pinhole detectionsin the moisture barrier are Specifications C1729 and C1767.6. Apparatus6.1 Test equipment shall be a pinhole or holiday detectorwit
18、h an output voltage of 65 to 75 volts DC that emits anaudible signal when a connection between the two leads isdetected.NOTE 1These instruments can be found by performing a web searchfor “wet sponge pinhole detector” or “wet sponge holiday detector”.6.2 One lead of the pinhole detector shall have a
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