1、Designation:D61821Standard Practice forConditioning Plastics for Testing1This standard is issued under the fixed designation D618;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indic
2、ates 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 agencies of the U.S.Department of Defense.1.Scope*1.1 In general,the physical and electrical properties ofplastics are influenced by t
3、emperature and relative humidity ina manner that materially affects test results.In order to makereliable comparisons between different materials and betweendifferent laboratories,it is necessary to standardize the humid-ity conditions,as well as the temperature,to which specimensof these materials
4、are subjected prior to and during testing.Thispractice defines procedures for conditioning plastics(althoughnot necessarily to equilibrium)prior to testing,and the condi-tions under which they shall be tested.1.2 For some materials,it is possible that a material speci-fication exists that requires t
5、he use of this practice,but withsome procedural modifications.The material specificationtakes precedence over this practice.Refer to the materialspecification before using this practice.Table 1 in Classifica-tion D4000 lists the ASTM material specifications that cur-rently exist.1.3 This standard do
6、es 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1This standard and I
7、SO 291 address the same subject matter,but differ in technical content.ISO 291 describes only two temperatureand humidity conditions for conditioning or testing,or both.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization establi
8、shed 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:2D709 Specification for Laminated Thermosetting MaterialsD756 Practice
9、 for Determination of Weight and ShapeChanges of Plastics UnderAccelerated Service Conditions(Withdrawn 1998)3D883 Terminology Relating to PlasticsD4000 Classification System for Specifying Plastic Materi-alsD5032 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Glycerin Soluti
10、onsE104 Practice for Maintaining Constant Relative Humidityby Means of Aqueous Solutions2.2 ISO Standard:ISO 291 PlasticsStandard Atmospheres for Conditioningand Testing43.Terminology3.1 Definitions:3.1.1 For definitions related to plastics,see TerminologyD883.3.1.2 room temperature,na temperature i
11、n the range from20 to 30C(68 to 86F).3.1.3 standard laboratory atmosphere,nan atmospherehaving a temperature of 23C(73.4F)and a relative humidityof 50%with standard tolerances as specified in Section 8 shallbe the standard laboratory atmosphere.3.1.4 standard laboratory temperature,na temperature of
12、23C(73.4F)with standard tolerance as specified in Section 7shall be the standard laboratory temperature.1This practice is under the jurisdiction ofASTM Committee D20 on Plastics andis the direct responsibility of Subcommittee D20.50 on Durability of Plastics.Current edition approved July 15,2021.Pub
13、lished July 2021.Originallyapproved in 1941.Last previous edition approved in 2013 as D618-13.DOI:10.1520/D0618-21.2For 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 st
14、andards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036,http:/www.ansi.org.*A Summary of Changes section appears at the e
15、nd of this standardCopyright 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 theDevelo
16、pment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.14.Significance and Use4.1 Conditioning of specimens is typically conducted:(1)for the purpose of bringing the material into equilibrium withnormal or average room conditions,(2)simply to obtainreproducible results,regardless of previous history ofexposure,or(3)to subject the material to abnormal conditionsof temperature or humidity in order to predict its
