ASTM_C_680_-_14.pdf

Designation:C68014Standard Practice forEstimate of the Heat Gain or Loss and the SurfaceTemperatures of Insulated Flat,Cylindrical,and SphericalSystems by Use of Computer Programs1This standard is issued under the fixed designation C680;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 provides the algorithms and calculationmethodologies for predicting the heat loss or gain and surfacetemperatures of certain thermal insulation systems that canattain one dimensional,steady-or quasi-steady-state heattransfer conditions in field operations.1.2 This practice is based on the assumption that the thermalinsulation systems can be well defined in rectangular,cylindri-cal or spherical coordinate systems and that the insulationsystems are composed of homogeneous,uniformly dimen-sioned materials that reduce heat flow between two differenttemperature conditions.1.3 Qualified personnel familiar with insulation-systemsdesign and analysis should resolve the applicability of themethodologies to real systems.The range and quality of thephysical and thermal property data of the materials comprisingthe thermal insulation system limit the calculation accuracy.Persons using this practice must have a knowledge of thepractical application of heat transfer theory relating to thermalinsulation materials and systems.1.4 The computer program that can be generated from thealgorithms and computational methodologies defined in thispractice is described in Section 7 of this practice.The computerprogram is intended for flat slab,pipe and hollow sphereinsulation systems.1.5 The values stated in inch-pound units are to be regardedas standard.The values given in parentheses are mathematicalconversions to SI units that are provided for information onlyand are not considered standard.1.6 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:2C168 Terminology Relating to Thermal InsulationC177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded-Hot-Plate ApparatusC335 Test Method for Steady-State Heat Transfer Propertiesof Pipe InsulationC518 Test Method for Steady-State Thermal TransmissionProperties by Means of the Heat Flow Meter ApparatusC585 Practice for Inner and Outer Diameters of ThermalInsulation for Nominal Sizes of Pipe and TubingC1055 Guide for Heated System Surface Conditions thatProduce Contact Burn InjuriesC1057 Practice for Determination of Skin Contact Tempera-ture from Heated Surfaces Using a Mathematical Modeland Thermesthesiometer2.2 Other Document:NBS Circular 564 Tables of Thermodynamic and TransportProperties of Air,U.S.Dept of Commerce3.Terminology3.1 Definitions:3.1.1 For definitions of terms used in this practice,refer toTerminology C168.3.1.2 thermal insulation systemfor this practice,a thermalinsulation system is a system comprised of a single layer orlayers of homogeneous,uniformly dimensioned material(s)intended for reduction of heat transfer between two differenttemperature conditions.Heat transfer in the system is steady-state.Heat flow for a flat system is normal to the flat surface,and heat flow for cylindrical and spherical systems is radial.3.2 Symbols: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 Sept.1,2014.Published December 2014.Originallyapproved in 1971.Last previous edition approved in 2010 as C680-10.DOI:10.1520/C0680-14.2For 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.Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959.United States1 3.2.1 The following symbols are used in the development ofthe equations for this practice.Other symbols will be intro-duced and defined in the detailed description of the develop-ment.where:h=surface transfer conductance,Btu/(hft2F)(W/(m2K)hiat inside surface;hoat outside surfacek=apparent thermal conductivity,Btuin./(hft2F)(W/(mK)ke=effective thermal conductivity over a prescribed tem-perature range,Btuin./(hft2F)(W/(mK)q=heat flux,Btu/(hft2)(W/m2)qp=time rate of heat flow per unit length of pipe,Btu/(hft)(W/m)R=thermal resistance,Fhft2/Btu(Km2/W)r=radius,in.(m);rm+1 rm=thicknesst=local temperature,F(K)ti=inner surface temperat