ASTM_D_7340_-_07_2012e1.pdf

Designation:D734007(Reapproved 2012)1Standard Practice forThermal Conductivity of Leather1This standard is issued under the fixed designation D7340;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.1NOTEThe k value in 5.1 was corrected editorially in April 2012.1.Scope1.1 This practice is intended to determine the thermalconductivity of a sheet material.This practice is not limited toleather,but may be used for any poorly conductive materialsuch as rubber,textile and cork associated with the construc-tion of shoes.1.2 A constant heat source is sandwiched between twoidentical metal cylinders which are mounted with their axesvertical.A test specimen is placed on the top surface of theupper cylinder and a third identical metal cylinder is placed ontop of the test specimen so that all the cylinders and the testspecimen are concentrically aligned(see Fig.1).The heatsource is switched on and the temperatures of the three blocksallowed to reach equilibrium.The thermal conductivity of thetest specimen is then determined from the steady-state tem-peratures of the three blocks,the exposed surface areas of theblocks and test specimen and the thickness of the test speci-men.1.3 This practice does not apply to wet blue.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:2D1610 Practice for Conditioning Leather and Leather Prod-ucts for TestingD1813 Test Method for Measuring Thickness of LeatherTest Specimens2.2 Other Standard:SATRA TM 146 Thermal Conductivity3.Terminology3.1 Definitions:3.2 thermal conductivitythe quantity of heat conductedper unit time through unit area of a slab of unit thicknesshaving unit temperature difference between its faces.4.Summary of Practice4.1 A conditioned specimen of leather(see Practice D1610)is placed between two plates at different temperatures.Theupper plate is at a constant temperature while the temperatureof the lower plate is slowly changing.The temperature differ-ence is measured by thermocouples.The rate of flow of heatthrough the specimen is proportional to the area and thetemperature difference of the faces of the specimen,andinversely proportional to the thickness.Assuming no heat loss,the amount of heat flowing through the specimen per unit timeis equal to the amount of heat received by the lower plate(copper block receiver)per unit time.5.Significance and Use5.1 Part of the function of a shoe is to assist the foot inmaintaining body temperature and to guard against large heatchanges.The insulating property of a material used in shoeconstruction is dependent on porosity or the amount of airspaces present.A good insulating material has a low thermalconductivity value,k.The thermal conductivity value increaseswith an increase in moisture content since the k value for wateris high,0.0014 cal/s cm C(0.59 W/mK).6.Apparatus and Materials6.1 A“Lees disc”apparatus,see Fig.1,consisting of:6.1.1 A metal,see 11.1.2,cylindrical block,which willsubsequently be referred to as block B1,with:6.1.1.1 Adiameter of(D),in millimetres,which is known toan accuracy of 0.2 mm(see 11.1.1).6.1.1.2 Aheight of(H),in millimetres,which is known to anaccuracy of 0.2 mm(see 11.2).6.1.1.3 A small hole of diameter 2 6 1 mm drilled radiallyto its center.6.1.1.4 A type K thermocouple inserted into the hole untilits junction is at the bottom of the hole.1This practice is under the jurisdiction ofASTM Committee D31 on Leather andis the direct responsibility of Subcommittee D31.03 on Footwear.Current edition approved April 1,2012.Published April 2012.Originallyapproved in 2007.Last previous edition approved in 2007 as D7340-07.DOI:10.1520/D7340-07R12E01.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 6.1.1.5 The remaining volume of the hole filled with a highthermal conductivity compound with a thermal conductivity ofbetter than 0.8 W/(mC),for example a metal oxide filled pasteof the type used between high power semiconductor electronicdevices and heat sinks.6.1.2 A circular electrical heater element which:6.1.2.1 Has a diameter of(D)6 0.5 mm.6.1.2.2 Is capable of dissipating a minimum power densityof 400 W/m2from each of its circular faces.See 11.1.1.6.1.2.3 Has a cylindrical metal block,see 11.1.3,withthermocouple as