1、Designation:D709122Standard Practice forNondestructive Measurement of Dry Film Thickness ofNonmagnetic Coatings Applied to Ferrous Metals andNonmagnetic,Nonconductive Coatings Applied to Non-Ferrous Metals1This standard is issued under the fixed designation D7091;the number immediately following the
2、 designation indicates the year oforiginal adoption or,in the case of revision,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.This standard has been approved for use by
3、agencies of the U.S.Department of Defense.1.Scope1.1 This practice describes the use of magnetic and eddycurrent gages for dry film thickness measurement.This prac-tice is intended to supplement the manufacturers instructionsfor the manual operation of the gages and is not intended toreplace them.It
4、 includes definitions of key terms,referencedocuments,the significance and use of the practice,theadvantages and limitations of coating thickness gages,and adescription of test specimens.It describes the methods andrecommended frequency for verifying the accuracy of gagesand for adjusting the equipm
5、ent and lists the reporting recom-mendations.1.2 These procedures are not applicable to coatings that willbe readily deformed under the load of the measuring gages/probes,as the gage probe must be placed directly on thecoating surface to obtain a reading.Provisions for measuringon soft or tacky coat
6、ings are described in 5.7.1.3 Coating thickness can be measured using a variety ofgages.These gages are categorized as“magnetic pull-off”and“electronic.”They use a sensing probe or magnet to measurethe gap(distance)between the base metal and the probe.Thismeasured distance is displayed as coating th
7、ickness by thegages.1.4 Coating thickness can vary widely across a surface.Asa result,obtaining single-point measurements may not accu-rately represent the actual coating system thickness.SSPC-PA2 prescribes a frequency of coating thickness measurementbased on the size of the area coated.A frequency
8、 of measure-ment for coated steel beams(girders)and coated test panels isalso provided in the appendices to SSPC-PA 2.The governingspecification is responsible for providing the user with theminimum and the maximum coating thickness for each layer,and for the total coating system.1.5 The values stat
9、ed in SI units are to be regarded asstandard.The values given in parentheses after SI units areprovided for information only and are not considered standard.1.6 This standard does not purport to address all of thesafety concerns,if any,associated with its use.It is theresponsibility of the user of t
10、his standard to establish appro-priate safety,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.1.7 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Deci
11、sion 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:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint,Varnish,Co
12、nversion Coatings,andRelated Coating ProductsD823 Practices for Producing Films of Uniform Thicknessof Paint,Coatings and Related Products on Test PanelsD1730 PracticesforPreparationof AluminumandAluminum-Alloy Surfaces for Painting2.2 SSPC Standard:3SSPC-PA 2 Procedure for Determining Conformance t
13、o DryCoating Thickness Requirements1This practice is under the jurisdiction of ASTM Committee D01 on Paint andRelated Coatings,Materials,and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved June 1,2022.Publishe
14、d June 2022.Originallyapproved in 2005.Last previous edition approved in 2021 as D7091 21.DOI:10.1520/D7091-22.2For 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 standa
15、rds Document Summary page onthe ASTM website.3Available from Society for Protective Coatings(SSPC),800 Trumbull Dr.,Pittsburgh,PA 15205,http:/www.sspc.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United StatesThis international standard was devel
16、oped 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.12.3 ISO Standard:4ISO 19840 Paints and varnishescorrosion protection ofsteelstructuresbyprotectivepaintsystemsMeasurement of,and acceptance criteria for,the thicknessof dry films on rough surfaces3.Terminology3.1 Definitio
