ASTM_C_1155_-_95_2013.pdf

Designation:C115595(Reapproved 2013)Standard Practice forDetermining Thermal Resistance of Building EnvelopeComponents from the In-Situ Data1This standard is issued under the fixed designation C1155;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 how to obtain and use data fromin-situ measurement of temperatures and heat fluxes on build-ing envelopes to compute thermal resistance.Thermal resis-tance is defined in Terminology C168 in terms of steady-stateconditions only.This practice provides an estimate of thatvalue for the range of temperatures encountered during themeasurement of temperatures and heat flux.1.2 This practice presents two specific techniques,thesummation technique and the sum of least squares technique,and permits the use of other techniques that have been properlyvalidated.This practice provides a means for estimating themean temperature of the building component for estimating thedependence of measured R-value on temperature for thesummation technique.The sum of least squares techniqueproduces a calculation of thermal resistance which is a functionof mean temperature.1.3 Each thermal resistance calculation applies to a subsec-tion of the building envelope component that was instru-mented.Each calculation applies to temperature conditionssimilar to those of the measurement.The calculation of thermalresistance from in-situ data represents in-service conditions.However,field measurements of temperature and heat flux maynot achieve the accuracy obtainable in laboratory apparatuses.1.4 This practice permits calculation of thermal resistanceon portions of a building envelope that have been properlyinstrumented with temperature and heat flux sensing instru-ments.The size of sensors and construction of the buildingcomponent determine how many sensors shall be used andwhere they should be placed.Because of the variety of possibleconstruction types,sensor placement and subsequent dataanalysis require the demonstrated good judgement of the user.1.5 Each calculation pertains only to a defined subsection ofthe building envelope.Combining results from different sub-sections to characterize overall thermal resistance is beyond thescope of this practice.1.6 This practice sets criteria for the data-collection tech-niques necessary for the calculation of thermal properties(seeNote 1).Any valid technique may provide the data for thispractice,but the results of this practice shall not be consideredto be from an ASTM standard,unless the instrumentationtechnique itself is an ASTM standard.NOTE1Currently only Practice C1046 can provide the data for thispractice.It also offers guidance on how to place sensors in a mannerrepresentative of more than just the instrumented portions of the buildingcomponents.1.7 This practice pertains to light-through medium-weightconstruction as defined by example in 5.8.The calculationsapply to the range of indoor and outdoor temperatures ob-served.1.8 The values stated in SI units are to be regarded asstandard.No other units of measurement are included in thisstandard.1.9 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 InsulationC1046 Practice for In-Situ Measurement of Heat Flux andTemperature on Building Envelope ComponentsC1060 Practice for Thermographic Inspection of InsulationInstallations in Envelope Cavities of Frame BuildingsC1130 Practice for Calibrating Thin Heat Flux TransducersC1153 Practice for Location of Wet Insulation in RoofingSystems Using Infrared Imaging1This 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 Nov.1,2013.Published March 2014.Originallyapproved in 1990.Last previous edition approved in 2007 as C1155 95(2007).DOI:10.1520/C1155-95R13.2For 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.Terminology3.1 DefinitionsFor definitions of terms relating to thermalinsulating materials,see Terminology C168.3.2 Definitions of Terms Specific to This Standard:3.2.1 building envelope componentthe portion of thebuilding envelope,such as a wall,roof,floor,window,or door,that