ASTM_D_2842_-_19.pdf

Designation:D284219Standard Test Method forWater Absorption of Rigid Cellular Plastics1This standard is issued under the fixed designation D2842;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 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 agencies of the U.S.Department of Defense.1.Scope*1.1 This test method covers the determination of the waterabsorption of rigid cellular plastics by measuring the change inbuoyant force resulting from immersion under a 5.1-cm(2-in.)head of water for the specified immersion period of 96 h.1.2 This test method describes two procedures that shall beused to measure the change in buoyant force.ProcedureAshallbe used for materials that either experience rapid waterabsorption or that show an increase in volume during theexposure period,or both.Materials that do not exhibit either ofthese characteristics shall be evaluated by Procedure B.1.3 For specific applications,immersion periods varyingfrom the normal 96-h test requirement shall be agreed uponbetween the manufacturer and the purchaser.1.4 The values stated in SI units are to be regarded as thestandard.1.5 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,health,and environmental practices and deter-mine the applicability of regulatory limitations prior to use.NOTE1This test method is equivalent to ISO 2896.1.6 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established 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:2D883 Terminology Relating to PlasticsD3576 Test Method for Cell Size of Rigid Cellular PlasticsD4968 Practice for Annual Review of Test Methods andSpecifications for PlasticsE96 Test Methods for Water Vapor Transmission of Materi-alsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE456 Terminology Relating to Quality and StatisticsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE2935 Practice for Conducting Equivalence Testing inLaboratory Applications2.2 ISO Standard:ISO 2896 Cellular Plastics,RigidDetermination of WaterAbsorption33.Terminology3.1 DefinitionsTerms used in this standard are defined inaccordance with Terminology D883,unless otherwise speci-fied.3.2 For terms relating to precision and bias and associatedissues,the terms used in this standard are defined in accordancewith Terminology E456.4.Summary of Test Method4.1 The buoyant force of an object less dense than water isequal to the weight of water it displaces when submerged,lessthe dry weight of the object.Water absorbed into the objectlowers the buoyant force by increasing the weight of thesample.By knowing the volume and initial dry weight of thesample,the initial buoyant force can be calculated or the initialbuoyant force can be determined by direct measurement.Thefinal buoyant force at the end of the immersion period ismeasured with an underwater weighing assembly.The differ-ence between the initial and final buoyant force is the weight ofthe water absorbed per unit of specimen volume.1This test method is under the jurisdiction of ASTM Committee D20 on Plasticsand is the direct responsibility of Subcommittee D20.22 on Cellular Materials-Plastics and Elastomers.Current edition approved May 1,2019.Published May 2019.Originallyapproved in 1969.Last previous edition approved in 2012 as D2842-12.DOI:10.1520/D2842-19.2For 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 standards Document Summary page onthe ASTM website.3Available from American National Standards Institute(ANSI),25 W.43rd St.,4th Floor,New York,NY 10036.*A Summary of Changes section appears at the end 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 theDevelopment of International Standards,Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade(TBT)Committee.1 5.Significance and Use5.1 The purpose of this test method is to provide a means forcomparing relative water absorption tendencies between dif-ferent cellular plastics.It is intended for use in specifications,product evaluation,and quality con