ASTM_D_3847_-_01_2012.pdf

Designation:D384701(Reapproved 2012)Standard Practice forRubberDirections for Achieving Subnormal TestTemperatures1This standard is issued under the fixed designation D3847;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.1.Scope1.1 This practice covers the general requirements forachieving and maintaining temperatures below 21C for ther-mal conditioning and physical testing of rubber.1.2 This practice describes the acceptable types and con-struction of low-temperature cabinets for conditioning andtesting of rubber,the composition and circulation of heat-transfer media,and the required uniformity and precision oftemperature control.1.3 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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.Referenced Documents2.1 ASTM Standards:2D746 Test Method for Brittleness Temperature of Plasticsand Elastomers by ImpactD832 Practice for Rubber Conditioning For Low Tempera-ture TestingD945 Test Methods for Rubber Properties in Compression orShear(Mechanical Oscillograph)D1053 Test Methods for Rubber PropertyStiffening atLow Temperatures:Flexible Polymers and Coated FabricsD1229 Test Method for Rubber PropertyCompression Setat Low TemperaturesD1329 Test Method for Evaluating Rubber PropertyRetraction at Lower Temperatures(TR Test)D1415 Test Method for Rubber PropertyInternationalHardnessD2136 Test Method for Coated FabricsLow-TemperatureBend TestD2137 Test Methods for Rubber PropertyBrittleness Pointof Flexible Polymers and Coated FabricsD2240 Test Method for Rubber PropertyDurometer Hard-nessD2632 Test Method for Rubber PropertyResilience byVertical ReboundE197 Specification for Enclosures and Servicing Units forTests Above and Below Room Temperature(Withdrawn1981)33.Significance and Use3.1 Low temperatures are often needed for conditioning ofrubber prior to testing,as well as during the test.Conditioningis required to attain a specific temperature that is uniformthroughout the specimen or for producing time-dependenteffects.Specimens may be conditioned and tested in the sameor different chambers.3.2 This practice is intended to apply particularly,but notexclusively,to the following ASTM Standards:Test MethodsD746,D945,D1053,D1229,D1329,D1415,D2136,D2137,D2240,D2632,Practice D832,and Specification E197.4.General Equipment Requirements44.1 The low-temperature cabinet may be refrigeratedmechanically,or by dry ice or liquid nitrogen,either directly orindirectly.4.1.1 The heat-transfer medium in the test chamber shouldbe air or air mixed with carbon dioxide or nitrogen,unless aliquid medium is specified.Although liquids cool the speci-mens faster than gases,they are more likely to cause propertychanges in addition to those caused by temperature change.Water,ethyl alcohol,and ethylene glycol are usually acceptablefor immersion times that are kept to the minimum for therequired tests.1This practice is under the jurisdiction ofASTM Committee D11 on Rubber andis the direct responsibility of Subcommittee D11.10 on Physical Testing.Current edition approved Dec.1,2012.Published February 2013.Originallyapproved in 1979.Last previous edition approved in 2007 as D3847 01(2007).DOI:10.1520/D3847-01R12.2For 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.3The last approved version of this historical standard is referenced onwww.astm.org.4For more detailed information,see Specification E197.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 4.1.2 The temperature variation within 250 mm of the testspecimen shall be within 61C of the specified testing tem-perature.4.1.3 The heat-transfer medium should be circulated thor-oughly in the test chamber by means of mechanical agitation.Afan or stirrer suitably located in the test chamber can be usedfor this purpose.4.1.4 Automatic temperature control should be used.4.2 The size of the test chamber is optional.4.3 The door can be located either in the top of the testcabinet or in the side.A side-opening door is convenient,andis necessary where the equipment involved must be operatedfrom the side.However,it has the disadvantage of allowing thecold air to pour out when the door is opened.In general,awindow in the door is desired for observation and the readingof test equipment indic