ASTM G62-2007(2013) Standard Test Methods for Holiday Detection in Pipeline Coatings《管道涂层中漏涂检查的标准试验方法》.pdf
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1、Designation: G62 07 (Reapproved 2013)Standard Test Methods forHoliday Detection in Pipeline Coatings1This standard is issued under the fixed designation G62; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision
2、. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 These test methods cover the apparatus and procedurefor detecting holidays in pipeline type coatings.1.2 Method A is designed to de
3、tect holidays such as pin-holes and voids in thin-film coatings from 0.0254 to 0.254 mm(1 to 10 mils) in thickness using ordinary tap water and anapplied voltage of less than 100 V d-c. It is effective on filmsup to 0.508 mm (20 mils) thickness if a wetting agent is usedwith the water. It should be
4、noted, however, that this methodwill not detect thin spots in the coating, even those as thin as0.635 mm (25 mils). This may be considered to be a nonde-structive test because of the relatively low voltage.1.3 Method B is designed to detect holidays such aspinholes and voids in pipeline coatings; bu
5、t because of thehigher applied voltages, it can also be used to detect thin spotsin the coating. This method can be used on any thickness ofpipeline coating and utilizes applied voltages between 900 and20 000 V d-c.2This method is considered destructive becausethe high voltages involved generally de
6、stroy the coating at thinspots.1.4 The values stated in SI units to three significant deci-mals are to be regarded as the standard. The values given inparentheses are for information only.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
7、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:3A742/A742M Specification for Steel Sheet, Metallic Coatedand Polymer Precoated for C
8、orrugated Steel Pipe3. Terminology3.1 Definitions:3.1.1 holiday, nsmall faults or pinholes that permit currentdrainage through protective coatings on steel pipe or polymericprecoated corrugated steel pipe.3.1.2 mil, n0.001 in.3.2 Definitions of Terms Specific to This Standard:3.2.1 holiday detector,
9、 na highly sensitive electrical de-vice designed to locate holidays such as pinholes, voids, andthin spots in the coating, not easily seen by the naked eye.These are used on the coatings of relatively high-electricalresistance when such coatings are applied to the surface ofmaterials of low-electric
10、al resistance, such as steel pipe.3.2.2 pipeline type coating, ncoatings of relatively high-electrical resistance applied to surfaces of relatively low-electrical resistance, such as steel pipe.4. Summary of Test Methods4.1 Both methods rely on electrical contact being madethrough the pipeline coati
11、ng because of a holiday or alow-resistance path created by metal particles, or thin spots inthe coating. This electrical contact will activate an alarmalerting the operator of the incidence of a holiday.4.2 In Method A, the applied voltage is 100 V d-c or less.4.3 In Method B, the applied voltage is
12、 900 to 20 000V d-c.5. Significance and Use5.1 Method AMethodAdescribes a quick, safe method fordetermining if pinholes, voids, or metal particles are protruding1These test methods are under the jurisdiction of ASTM Committee D01 onPaint and Related Coatings, Materials, and Applications and are the
13、directresponsibility of Subcommittee D01.48 on Durability of Pipeline Coating andLinings.Current edition approved June 1, 2013. Published June 2013. Originallyapproved in 1979. Last previous edition approved in 2007 as G62 07. DOI:10.1520/G0062-07R13.2This was taken from the pamphlet “Operating Inst
14、ructions for Tinker and RasorModel EP Holiday Detector.” Other manufacturers holiday detectors can beexpected to have similar voltage specifications.3For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStanda
15、rds 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 States1through the coating. This method will not, however, find anythin spots in the coating. This method
16、 will determine theexistence of any gross faults in thin-film pipeline coatings.5.2 Method BMethod B describes a method for determin-ing if pinholes, voids, or metal particles are protruding throughthe coating, and thin spots in pipeline coatings. This methodcan be used to verify minimum coating thi
17、cknesses as well asvoids in quality-control applications.6. Apparatus6.1 Low-Voltage Holiday DetectorA holiday detector tes-ter having an electrical energy source of less than 100 V d-c,such as a battery; an exploring electrode having a cellulosesponge dampened with an electrically conductive liquid
18、 suchas tap water; and an audio indicator to signal a defect in ahigh-electrical resistance coating on a metal substrate. Aground wire connects the detector with the low-resistancemetal surface.6.2 High-Voltage Holiday DetectorAholiday detector tes-ter having an electrical energy source of 900 to 20
19、 000 V d-c;an exploring electrode consisting of wire brush, coil-spring, orconductive silicon electrode capable of moving along thepipeline coating; and an audio indicator to signal a defect in ahigh-electrical resistance coating on a metal substrate. Aground wire connects the detector with the low-
20、resistancemetal surface.6.3 Peak or Crest Reading VoltmeterA kilovoltmeter ca-pable of detecting a single pulse and holding it long enough forthe meter circuits to indicate.47. Reagents and Materials7.1 Tap Water, plain or with a wetting agent.NOTE 1Ordinary tap water will suffice to wet the sponge
21、electrodewhen inspecting coatings up to 0.254 mm (10 mils) in thickness. On filmsbetween 0.254 and 0.508 mm (10 and 20 mils), a nonsudsing type wettingagent added to the water is recommended to allow for faster penetrationof the liquid into pinhole defects.8. Test Specimen8.1 The test specimen shall
22、 be a representative length ofproduction-coated pipe or polymeric precoated corrugated steelpipe.9. Standardization of Instruments9.1 The instruments shall be standardized with respect tovoltage output in accordance with the manufacturersinstructions, using a peak or crest reading voltmeter. This is
23、used more commonly with Method B where voltage may varyfrom test to test but can also be used for verification of thevoltage on a Method A test.9.2 The low-voltage holiday detector shall be standardizedwith respect to sensitivity by having the alarm activated whena selected resistance, having a12 W
24、rating, is placed across itsterminals. A common factory setting for sensitivity is 100 000. Most units can be reset to any predetermined sensitivityvalue in this manner.10. Procedure for Method A10.1 Use the low-voltage holiday detector described in 6.1.10.2 Assemble the wand and electrode according
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