1、Designation:C20305a(Reapproved 2012)Standard Test Methods forBreaking Load and Flexural Properties of Block-TypeThermal Insulation1This standard is issued under the fixed designation C203;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revisi
2、on,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.Scope1.1 These test methods cove
3、r the determination of thebreaking load and calculated flexural strength of a rectangularcross section of a preformed block-type thermal insulationtested as a simple beam.It is also applicable to cellular plastics.Two test methods are described as follows:1.1.1 Test Method IA loading system utilizin
4、g centerloading on a simply supported beam,supported at both ends.1.1.2 Test Method IIA loading system utilizing two sym-metric load points equally spaced from their adjacent supportpoints at each end with a distance between load points of onehalf of the support span.1.2 Either test method is capabl
5、e of being used with the fourprocedures that follow:1.2.1 Procedure ADesigned principally for materials thatbreak at comparatively small deflections.1.2.2 Procedure BDesigned particularly for those materi-als that undergo large deflections during testing.1.2.3 Procedure CDesigned for measuring at a
6、constantstress rate,using a CRL(constant rate of loading)machine.Used for breaking load measurements only.1.2.4 Procedure DDesigned for measurements at a con-stant crosshead speed,using either a CRT(constant rate oftraverse)or CRE(constant rate of extension)machine.Usedfor breaking load measurements
7、 using a fixed crosshead speedmachine.1.3 Comparative tests are capable of being run according toeither method or procedure,provided that the method orprocedure is found satisfactory for the material being tested.1.4 These test methods are purposely general in order toaccommodate the widely varying
8、industry practices.It isimportant that the user consult the appropriate materialsspecification for any specific detailed requirements regardingthese test methods.1.5 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are provided forinformation only.1.6 T
9、his 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.For specificprecautiona
10、ry statements,see Section 112.Referenced Documents2.1 ASTM Standards:2C133 Test Methods for Cold Crushing Strength and Modu-lus of Rupture of RefractoriesC168 Terminology Relating to Thermal InsulationC390 Practice for Sampling and Acceptance of ThermalInsulation LotsC870 Practice for Conditioning o
11、f Thermal Insulating Ma-terialsD76 Specification for Tensile Testing Machines for TextilesE4 Practices for Force Verification of Testing Machines3.Terminology3.1 Terminology C168 shall be considered applied to theterms used in this method.4.Summary of Test Methods4.1 A bar of rectangular cross secti
12、on is tested in flexure asa beam as follows:4.1.1 Test Method IThe bar rests on two supports and isloaded by means of a loading fitting or piece midway betweenthe supports(see Fig.1).4.1.2 Test Method IIThe bar rests on two supports and isloaded at the two quarter points(by means of two loadingfitti
13、ngs),each an equal distance from the adjacent support1These test methods are under the jurisdiction of ASTM Committee C16 onThermal Insulation and are the direct responsibility of Subcommittee C16.32 onMechanical Properties.Current edition approved March 1,2012.Published May 2012.Originallyapproved
14、in 1945.Last previous edition approved 2005 as C203 05a.DOI:10.1520/C0203-05AR12.2For 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 onth
15、e ASTM website.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 point.The distance between the loading fittings is one half ofthe support span(see Fig.2).4.2 The specimen is deflected until rupture occurs,unlessthe materials specification
16、indicates termination at a particularmaximum strain level.NOTE1One criteria used is to limit the strain to 5%.If failure doesnot occur at 5%strain,the strain rate is increased and the test repeated ona new specimen.4.3 Procedures A and B allow for testing at two differentstrain rates.Procedure C specifies a stress rate.Procedure Dspecifies a rate of extension or traverse.4.3.1 Procedure A specifies a strain rate of 0.01 in./in.(mm/mm)that is useful for testing insulations that are very stiffor b
