ASTM_D_7984_-_16.pdf

Designation:D798416Standard Test Method forMeasurement of Thermal Effusivity of Fabrics Using aModified Transient Plane Source(MTPS)Instrument1This standard is issued under the fixed designation D7984;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.INTRODUCTIONThis standard provides a test method for measuring the thermal effusivity of fabrics under still airconditions.Other standards,Test Methods F1868 and D1518,measure the thermal insulation ofmaterials under steady-state conditions;however,this test method is used to measure transient heatexchange between a fabric specimen and a heated surface.It has been established that there is a strongpositive correlation between the thermal effusivity and the initial perceived coldness between humanskin and different materials.2,31.Scope1.1 This test method covers the quantitative measurement ofthermal effusivity of woven,knitted,or non-woven fabricsusing a guarded modified transient plane source(MTPS)instrument.4This test method is applicable to a wide range ofthicknesses;however,the thickness of the specimen must begreater than the penetration depth of the heat flux during themeasurement time.1.2 This test method is comparative since specimens ofknown thermal effusivity are used to calibrate the apparatus atthe factory level.Thermal effusivity of the calibration speci-mens are confirmed through calculations that use establishedproperties of thermal conductivity,density,and specific heat.1.3 This test method is intended for measuring fabrics in adry state at ambient conditions.1.4 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.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 and health practices and determine the applica-bility of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:5D123 Terminology Relating to TextilesD1518 Test Method for Thermal Resistance of BattingSystems Using a Hot PlateD1776 Practice for Conditioning and Testing TextilesD4920 Terminology Relating to Conditioning,Chemical,and Thermal PropertiesE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsF1868 Test Method for Thermal and Evaporative Resistanceof Clothing Materials Using a Sweating Hot Plate3.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 modified transient plane source(MTPS),nan appa-ratus that has a one sided planar heat source and a guard,orguard ring,mounted perpendicular to the planar heat source,that is put in contact with one side of a test specimen,so thata short duration heat pulse can penetrate into the specimen.1This test method is under the jurisdiction ofASTM Committee D13 on Textilesand is the direct responsibility of Subcommittee D13.51 on Conditioning,Chemicaland Thermal Properties.Current edition approved Feb.15,2016.Published March 2016.DOI:10.1520/D7984-16.2Marin,E.,“Teaching Thermal Physics by Touching,”Latin-American Journalof Physics Education,Vol 2,No.1,January 2008,pp.15-17.3Wongsriruska,S.,Howes,P.,Conreen,M.,Miodownik,M.,“The Use ofPhysical Property Data to Predict the Touch Perception of Materials,”Materials andDesign,Vol 42,2012,pp.238-244.4The sole source of supply of the TCi instrument known to the committee at thistime is C-Therm Technologies,Ltd.,C/O RPC,921 College Hill Rd.,Fredericton,New Brunswick,Canada,E3B 6Z9.If you are aware of alternative suppliers,pleaseprovide this information to ASTM International Headquarters.Your comments willreceive careful consideration at a meeting of the responsible technical committee,1which you may attend.5For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.1.1.1 DiscussionThe purpose of the guard(or guardring)is to maintain a consistent unidirectional heat flow acrossthe test specimen.3.1.2 penetration depth,nthe functional depth to whichthe initial radiation applied at the surface travels into thespecimen.3.1.2.1 DiscussionTo ensure that the heat wave is con-tained within the test specimen,the thickness of the testspecimen must be greater than the penetration depth.3.1.3 thermal effusivity,na material property that de-scribes its ability to exchange thermal energy with anothermaterial with which it is in contact.e 5=cp(1)