ASTM_C_1043_-_16.pdf

Designation:C104316Standard Practice forGuarded-Hot-Plate Design Using Circular Line-HeatSources1This standard is issued under the fixed designation C1043;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 design of a circular line-heat-source guarded hot plate for use in accordance with TestMethod C177.NOTE1Test Method C177 describes the guarded-hot-plate apparatusand the application of such equipment for determining thermal transmis-sion properties of flat-slab specimens.In principle,the test methodincludes apparatus designed with guarded hot plates having eitherdistributed-or line-heat sources.1.2 The guarded hot plate with circular line-heat sources isa design in which the meter and guard plates are circular plateshaving a relatively small number of heaters,each embeddedalong a circular path at a fixed radius.In operation,the heatfrom each line-heat source flows radially into the plate and istransmitted axially through the test specimens.1.3 The meter and guard plates are fabricated from acontinuous piece of thermally conductive material.The platesare made sufficiently thick that,for typical specimen thermalconductances,the radial and axial temperature variations in theguarded hot plate are quite small.By proper location of theline-heat source(s),the temperature at the edge of the meterplate is made equal to the mean temperature of the meter plate,thus facilitating temperature measurements and thermal guard-ing.1.4 The line-heat-source guarded hot plate has been usedsuccessfully over a mean temperature range from 10to+65C,with circular metal plates and a single line-heatsource in the meter plate.The chronological development ofthe design of circular line-heat-source guarded hot plates isgiven in Refs(1-9).21.5 This practice does not preclude(1)lower or highertemperatures;(2)plate geometries other than circular;(3)line-heat-source geometries other than circular;(4)the use ofplates fabricated from ceramics,composites,or other materials;or(5)the use of multiple line-heat sources in both the meterand guard plates.1.6 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.7 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:3C168 Terminology Relating to Thermal InsulationC177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC1044 Practice for Using a Guarded-Hot-Plate Apparatus orThin-Heater Apparatus in the Single-Sided ModeE230 Specification and Temperature-Electromotive Force(EMF)Tables for Standardized Thermocouples2.2 ASTM Adjuncts:Line-Heat-Source Guarded-Hot-Plate Apparatus43.Terminology3.1 DefinitionsFor definitions of terms and symbols usedin this practice,refer to Terminology C168.For definitions ofterms relating to the guarded-hot-plate apparatus refer to TestMethod C177.3.2 Definitions of Terms Specific to This Standard:3.2.1 gap,na separation between the meter plate andguard plate,usually filled with a gas or thermal insulation.3.2.2 guard plate,nthe outer ring of the guarded hot platethat encompasses the meter plate and promotes one-dimensional heat flow normal to the meter plate.1This practice is under the jurisdiction of ASTM Committee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved March 1,2016.Published March 2016.Originallyapproved in 1985.Last previous edition approved in 2010 as C1043 06(2010).DOI:10.1520/C1043-16.2The boldface numbers in parentheses refer to a list of references at the end ofthis practice.3For 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.4Available from ASTM Headquarters.Order Adjunct:ADJC1043.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.3 guarded hot plate,nan assembly,consisting of ameter plate and a co-planar,concentric guard plate thatprovides the heat input to the specimens.3.2.4 line-heat-source,na thin or fine electrical heatingelement that provides uniform heat generation per unit length.3.2.5 meter area,nthe mathematical area through whichthe heat input to the meter plate flows normally under idealguarding conditions into the meter section of the specime