ASTM_F_1868_-_14.pdf

Designation:F186814Standard Test Method forThermal and Evaporative Resistance of Clothing MaterialsUsing a Sweating Hot Plate1This standard is issued under the fixed designation F1868;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.INTRODUCTIONClothing is often made of materials that impede the flow of heat and moisture from the skin to theenvironment.Consequently,people may suffer from heat stress or cold stress when wearing clothingin different environmental conditions.Therefore,it is important to quantify the thermal resistance andevaporative resistance of clothing materials and to consider these properties when selecting materialsfor different clothing applications.1.Scope1.1 This test method covers the measurement of the thermalresistance and the evaporative resistance,under steady-stateconditions,of fabrics,films,coatings,foams,and leathers,including multi-layer assemblies,for use in clothing systems.1.2 The range of this measurement technique for intrinsicthermal resistance is from 0.002 to 0.5 Km2/W and forintrinsic evaporative resistance is from 0.0 to 1.0 kPam2/W.1.3 The values in SI units shall be regarded as standard.Noother units of measurement are included in this standard.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 consult andestablish appropriate safety and health practices and deter-mine the applicability of regulatory limitations prior to use.2.Referenced Documents2.1 ASTM Standards:2C177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusD1518 Test Method for Thermal Resistance of BattingSystems Using a Hot PlateE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test MethodF1291 Test Method for Measuring the Thermal Insulation ofClothing Using a Heated ManikinF1494 Terminology Relating to Protective ClothingF2370 Test Method for Measuring the Evaporative Resis-tance of Clothing Using a Sweating Manikin2.2 Other Standards:ISO 11092 TextilesPhysiological EffectsMeasurement ofThermal and Water-Vapour Resistance Under Steady-State Conditions(Sweating Guarded-Hotplate Test)33.Terminology3.1 Definitions:3.1.1 clo,na unit of thermal resistance(insulation)equalto 0.155 Km2/W.3.1.1.1 DiscussionThe value of the clo was selected asroughly the insulation value of typical indoor clothing,whichshould keep a resting man(producing heat at the rate of 58W/m2)comfortable in an environment at 21C,air movement0.1 m/s.3.1.2 evaporative resistance,nThe resistance to the flowof moisture vapor from a saturated surface(high vaporpressure)to an environment with a lower vapor pressure.3.1.2.1 Discussion The evaporative resistance in units ofkPam2/W can be calculated for several different cases.RefA=apparent total evaporative resistance of the fabric testspecimen only,when evaluated non-isothermally.The termapparent is used as a modifier for total evaporative resistance to1This test method is under the jurisdiction ofASTM Committee F23 on PersonalProtective Clothing and Equipment and is the direct responsibility of SubcommitteeF23.60 onHuman Factors.Current edition approved Feb.1,2014.Published February 2014.Originallyapproved in 1998.Last previous edition approved in 2012 as F1868-12.DOI:10.1520/F1868-14.2For 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,http:/www.ansi.org.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 reflect the fact that condensation may occur within the speci-men.RetA=apparent total evaporative resistance of the fabric testspecimen,liquid barrier,and surface air layer when evaluatednon-isothermally.The term apparent is used as a modifier fortotal evaporative resistance to reflect the fact that condensationmay occur within the specimen.Rebp=evaporative resistance of the air layer on the surface ofthe liquid barrier without a fabric test specimen(that is,bareplate).This property reflects the instrument constant and theresistance of the liquid barrier,and in conjunction with Ret,isused in the calculation of Ref.Ref=intrinsic evaporative resistance of the fabric test specimenonly.In the calculation of this value,the assumption is madethat the boundary layers of the bare plate and the boundarylayers of the fabric are equa