1、Designation: D5162 15Standard Practice forDiscontinuity (Holiday) Testing of Nonconductive ProtectiveCoating on Metallic Substrates1This standard is issued under the fixed designation D5162; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, the 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 practice covers procedures for determining discon-tinuities using two types of test equipment
3、:1.1.1 Test Method ALow Voltage Wet Sponge, and1.1.2 Test Method BHigh Voltage Spark Testers.1.2 This practice addresses metallic substrates. For concretesurfaces, refer to Practice D4787.1.3 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for inf
4、ormationonly.1.4 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-bility of regulatory limitations prior to use.2.
5、 Referenced Documents2.1 ASTM Standards:2G62 Test Methods for Holiday Detection in Pipeline Coat-ingsD4787 Practice for Continuity Verification of Liquid orSheet Linings Applied to Concrete Substrates2.2 NACE Standard Practices:3SP01882006 Discontinuity (Holiday) Testing of ProtectiveCoatingsSP02742
6、011 High Voltage Electrical Inspection of PipelineCoatingsSP04902007 Holiday Detection of Fusion Bonded Epoxy2.3 ISO Standard:4ISO 29601 Paints and varnishes. Corrosion protection byprotective paint systems. Assessment of porosity in a dryfilm3. Terminology3.1 Definitions of Terms Specific to This S
7、tandard:3.1.1 discontinuity, as used in this standard, na flaw, void,crack, thin spot, foreign inclusion, or contamination in thecoating film that significantly lowers the dielectric strength ofthe coating film. A discontinuity may also be identified as aholiday or pinhole.3.1.2 holiday, as used in
8、this standard, na term thatidentifies a discontinuity.3.1.3 holiday detector, as used in this standard, na devicethat locates discontinuities in a nonconductive coating filmapplied to an electrically conductive surface.3.1.4 pinhole, as used in this standard, na film defectcharacterized by small por
9、e like flaws in the coating which,when extended entirely through the film, will appear as adiscontinuity. A pinhole in the finish coat may not appear as adiscontinuity.4. Significance and Use4.1 A coating is applied to a metallic substrate to preventcorrosion, reduce abrasion or reduce product conta
10、mination, orall three. The degree of coating continuity required is dictatedby service conditions. Discontinuities in a coating are fre-quently very minute and not readily visible. This practiceprovides a procedure for electrical detection of minute discon-tinuities in nonconductive coating systems.
11、4.2 Electrical testing to determine the presence and numberof discontinuities in a coating film is performed on a noncon-ductive coating applied to an electrically conductive surface.The allowable number of discontinuities should be determinedprior to conducting this test since the acceptable quanti
12、ty ofdiscontinuities will vary depending on coating film thickness,design, and service conditions.1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.46 on Industrial Protective C
13、oatings.Current edition approved Dec. 1, 2015. Published December 2015. Originallyapproved in 1991. Last previous edition approved in 2008 as D5162 08. DOI:10.1520/D5162-15.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For A
14、nnual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from NACE International (NACE), 1440 South Creek Dr., Houston,TX 77084-4906, http:/www.nace.org.4Available from International Organization for Standardization (ISO), ISOCentral
15、Secretariat, BIBC II, Chemin de Blandonnet 8, CP 401, 1214 Vernier,Geneva, Switzerland, http:/www.iso.org.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States14.3 The low voltage wet sponge test equipment is generallyused for determining t
16、he existence of discontinuities in coatingfilms having a total thickness of 0.5 mm (20 mil) or less. Highvoltage spark test equipment is generally used for determiningthe existences of discontinuities in coating films having a totalthickness of greater than 0.5 mm (20 mil).4.4 Coatings that are appl
17、ied at a thickness of less than 0.5mm (20 mil) may be susceptible to damage if tested with highvoltage spark testing equipment. Consult the coating manufac-turer for proper test equipment and inspection voltages.4.5 To prevent damage to a coating film when using highvoltage test instrumentation, tot
18、al film thickness and dielectricstrength in a coating system shall be considered in selecting theappropriate voltage for detection of discontinuities. Atmo-spheric conditions shall also be considered since the voltagerequired for the spark to gap a given distance in air varies withthe conductivity o
19、f the air at the time the test is conducted.Suggested starting voltages are provided in Table 1.4.6 The coating manufacturer shall be consulted to obtainthe following information, which would affect the accuracy ofthis test to determine discontinuities:4.6.1 Establish the length of time required to
20、adequately dryor cure the applied coating film prior to testing. Solventsretained in an uncured coating film may form an electricallyconductive path through the film to the substrate.4.6.2 Determine whether the coating contains electricallyconductive fillers or pigments that may affect the normaldie
21、lectric properties.4.7 This practice is intended for use with new coatingsapplied to metal substrates. Its use on a coating previouslyexposed to an immersion condition has often resulted indamage to the coating and has produced erroneous detection ofdiscontinuities due to permeation or moisture abso
22、rption of thecoating. Deposits may also be present on the surface causingtelegraphing (current traveling through a moisture path to adiscontinuity, giving an erroneous indication) or current leak-age across the surface of the coating due to contamination. Theuse of a high voltage tester on previousl
23、y exposed coatings hasto be carefully considered because of possible spark-through,which will damage an otherwise sound coating.Although a lowvoltage tester can be used without damaging the coating, it mayalso produce erroneous results.5. Test MethodsTEST METHOD ALOW VOLTAGE WET SPONGETESTING5.1 App
24、aratus:5.1.1 Low Voltage Holiday Detectoran electronic devicepowered by a self-contained battery with voltages ranging from5 to 90 V dc, depending on the equipment manufacturerscircuit design. It is used to locate discontinuities in a noncon-ductive coating applied to a conductive substrate. Operati
25、onincludes the use of an open-cell sponge electrode wetted witha solution for exploring the coating surface, a signal returnconnection, and an audible or visual indicator, or both, forsignaling a point of coating discontinuity.5.1.2 Low Voltage Wet Sponge Testera sensitivity devicewith the operating
26、 voltage being of little importance other thanbeing part of the particular electronic circuit design.5.1.3 Wet Sponge Type Instrumentsa number of commer-cially available, industry-accepted, instruments are available.The following electronic principle describes two types ofdevices generally used; oth
27、ers may be available but are notdescribed in this practice.5.1.3.1 Lightweight, Self-Contained, Portable Devicesbased on the electrical principle of an electromagnetic sensitiverelay or a solid-state electronic relay circuit that energizes anaudible or visual indicator when a coating discontinuity i
28、sdetected. Generally this equipment is capable of being recali-brated in the field by the user.5.1.3.2 Lightweight, Self-Contained, Portable Devicesalso based on the principle of an electronic relaxation oscillatorTABLE 1 Suggested Voltages for High Voltage Spark TestingTotal Dry Film ThicknessSugge
29、stedInspection, Vmm mil0.5000.590 19.723.2 27000.6000.690 23.627.2 33000.7000.790 27.631.1 39000.8000.890 31.535.0 45000.9000.990 35.439.0 50001.0001.090 39.442.9 55001.1001.190 43.346.9 60001.2001.290 47.250.8 65001.3001.390 51.254.7 70001.4001.490 55.158.7 75001.5001.590 59.162.6 80001.6001.690 63
30、.066.5 85001.7001.790 66.970.5 90001.8001.890 70.974.4 100001.9001.990 74.878.3 108002.0002.090 78.782.3 115002.1002.190 82.786.2 120002.2002.290 86.690.2 125002.3002.390 90.694.1 130002.4002.490 94.598.0 135002.5002.590 98.4102.0 140002.6002.690 102.4105.9 145002.7002.790 106.3109.8 150002.8002.890
31、 110.2113.8 155002.9002.990 114.2117.7 160003.0003.090 118.1121.7 165003.1003.190 122.0125.6 170003.2003.290 126.0129.5 175003.3003.390 129.9133.5 180003.4003.490 133.9137.4 185003.5003.590 137.8141.3 190003.6003.690 141.7145.3 195003.7003.790 145.7149.2 200003.8003.890 149.6153.1 210003.9003.990 15
32、3.5157.1 218004.0004.190 157.5165.0 225004.2004.290 165.4168.9 230004.3004.390 169.3172.8 240004.4004.490 173.2176.8 250004.5004.590 177.2180.7 258004.6004.690 181.1184.6 264004.7004.790 185.0188.6 268004.8004.890 189.0192.5 274004.9004.990 192.9196.5 280005.0005.290 196.9208.3 285005.3005.500 208.7
33、216.5 290005.6008.000 220.5307.1 30000NOTE 1Alternative methods for selecting a suitable test voltage aregiven in Test Methods G62 and NACE RP0188, SP0274, and SP0490.D5162 152circuit that reacts significantly to the abrupt drop in electricalresistance between the high dielectric value of the coatin
34、g filmand the conductive substrate at the point of coating filmdiscontinuity. This results in a rise in oscillator frequency aswell as in the audible signal from the device. Generally, thisequipment is incapable of being recalibrated in the field by theuser.5.2 Procedure:5.2.1 Sufficient drying or c
35、uring of the coating shall beallowed prior to conducting a test. The length of time requiredshall be obtained from the coating manufacturer. Solventsretained in the coating film could produce erroneous indicators.5.2.2 The surface shall be clean, dry, and free of oil, dirt andother contaminates. Mea
36、sure the film thickness of the coatingwith a nondestructive dry film thickness gage. If the coatingfilm exceeds 0.5 mm (20 mil), use the procedures for highvoltage spark testing described in Test Method B, High VoltageSpark Testing.5.2.3 Test the instrument for sensitivity in accordance with5.3.5.2.
37、4 Attach the signal return wire from the instrumentterminal to the metallic substrate and ensure a good electricalcontact.5.2.5 Attach the exploring sponge lead to the other terminal.5.2.6 Wet the sponge with a solution consisting of tap waterand a low sudsing wetting agent, combined at a ratio of n
38、otmore than12 fluid oz of wetting agent to 1 gal water. Anexample of a low sudsing wetting agent is one used inphotographic development. The sponge shall be wetted suffi-ciently to barely avoid dripping of the solution while thesponge is moved over the coating. The wetting agent residuemust be remov
39、ed prior to executing repairs to the coating.5.2.7 Sodium chloride (salt) shall not be added to thewetting solution because of the potential erroneous indicationsof discontinuities. The salt, after drying on the coated surface,may form a continuous path of conductivity across the surface.It will als
40、o interfere with intercoat adhesion of additional coats.5.2.8 Contact a bare spot on the conductive substrate withthe wetted sponge to verify that the instrument is properlyconnected. This procedure shall be repeated periodically dur-ing the test.5.2.9 For open areas move the sponge over the surface
41、 ofthe coating at a moderate rate, with a maximum rate of 0.3 m/s(1 ft/s), using a double pass over each area. For internal pipecoatings a single pass is appropriate as a double pass could leadto telegraphing and false positives. Apply sufficient pressure tomaintain a wet surface. If a discontinuity
42、 is detected, turn thesponge on end to determine the exact location of the discon-tinuity. Improved accuracy of location can be achieved using acorner of the sponge if practical. It should be noted that thedetection of pinholes depends on the migration of the moisturein to the holes and therefore th
43、e sponge may have to be movedover the surface at a slower rate to maximize detection,particularly for small holes in thicker coatings.5.2.10 Discontinuities that require repair shall be identifiedwith a marker that is compatible with the repair coating or onethat is easily removed. Marking the defec
44、ts with making tape isacceptable providing the tape adhesive does not affect thesubsequent repair.5.2.11 To prevent telegraphing take care to ensure that thesolution is wiped dry from a previously detected discontinuitywhere possible before continuing the test.5.2.12 The wetting agent must be comple
45、tely removed byrinsing the holiday area prior to repair.5.2.13 Wet sponge holiday detection is not recommendedbetween coats of a multicoat system. However, when a test isconducted between coats of a multicoat system, a wetting agentshall not be used and all residue left by the test water must becomp
46、letely removed prior to applying additional coats.5.3 Verifying Operation of Equipment:5.3.1 The instrument shall be tested for sensitivity prior toinitial use and periodically thereafter, in accordance with theequipment manufacturers instructions.5.3.2 Test the battery for proper voltage output. Re
47、fer to themanufacturers instructions.5.3.3 Switch the instrument to the “on position,” if appli-cable.5.3.4 Wet the sponge with a wetting solution consisting oftap water and a wetting agent (see 5.2.6).5.3.5 Connect the signal return wire to the instrumentground output terminal.5.3.6 Touch the signa
48、l return wire alligator clip to the wettedsponge. The instrument signal should signal in accordance withthe instrument manufacturers instructions.5.3.7 If the instrument should fail to signal, it shall beconsidered defective.5.4 Verifying Instrument Calibration:5.4.1 Verify instrument calibration in
49、 accordance with themanufacturers latest published instructions. If out ofcalibration, the instrument shall be calibrated in accordancewith the instrument manufacturers latest publishedinstructions, or returned for calibration. A certificate ofcalibration, renewed annually, may be required if the qualitymanagement system that controls the testing dictates.TEST METHOD BHIGH VOLTAGE SPARKTESTING5.5 Apparatus:5.5.1 High Voltage Detector (in excess of 500 V)anelectron
