1、Designation: C 1199 00Standard Test Method forMeasuring the Steady-State Thermal Transmittance ofFenestration Systems Using Hot Box Methods1This standard is issued under the fixed designation C 1199; the number immediately following the designation indicates the year oforiginal adoption or, in the c
2、ase of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers requirements and guidelinesand specifies calibration procedures
3、required for the measure-ment of the steady-state thermal transmittance of fenestrationsystems installed vertically in the test chamber. This testmethod specifies the necessary measurements to be made usingmeasurement systems conforming to either Test MethodsC 236, C 976, or C 1363 for determination
4、 of fenestrationsystem thermal transmittance.NOTE 1This test method allows the testing of projecting fenestrationproducts (that is, garden windows, skylights, and roof windows) installedvertically in a surround panel. Current research on skylights, roofwindows, and projecting products hopefully will
5、 provide additionalinformation that can be added to the next version of this test method sothat skylight and roof windows can be tested horizontally or at some angletypical of a sloping roof.1.2 This test method refers to the thermal transmittance, U,and the corresponding thermal resistance, R, of a
6、 fenestrationsystem installed vertically in the absence of solar and airleakage effects.NOTE 2The methods described in this document may also be adaptedfor use in determining the thermal transmittance of sections of buildingwall, and roof and floor assemblies containing thermal anomalies, whichare s
7、maller than the hot box metering area.1.3 This test method describes how to determine a fenestra-tion products (also called test specimen) thermal transmit-tance, US, at well-defined environmental conditions. The ther-mal transmittance, which is sometimes called the air-to-airU-factor, is also a rep
8、orted test result from Test Methods C 236,C 976, and C 1363. If only the thermal transmittance isreported using this test method, the test report must alsoinclude a detailed description of the environmental conditionsin the thermal chamber during the test as outlined in 10.3.1.4 For rating purposes,
9、 this test method also describes howto calculate a standardized thermal transmittance, UST, whichcan be used to compare test results from laboratories withdifferent weather side wind directions and thermal chamberconfigurations, and can also be used to directly compare tocalculated results from curr
10、ent computer programs for deter-mining the thermal transmittance of fenestration products.Although this test method specifies two methods of calculatingthe standardized thermal transmittance, only the standardizedthermal transmittance result from one method is reported foreach test. One standardized
11、 thermal transmittance calculationprocedure is the Calibration Transfer Standard (CTS) methodand another is the area weighting (AW) method (see 4.3 andSection 8 for further descriptions of these two methods). Thearea weighting method requires that the surface temperatureson both sides of the test sp
12、ecimen be directly measured asspecified in Practice E 1423 in order to determine the surfaceheat transfer coefficients on the fenestration product during thetest. The CTS method does not use the measured surfacetemperatures on the test specimen and instead utilizes thecalculation of equivalent surfa
13、ce temperatures from calibrationdata to determine the test specimen surface heat transfercoefficients. The area weighting (AW) method shall be usedwhenever the thermal transmittance, US, is greater than 3.4W/(m2K) 0.6 Btu/(hrFt2F), or when the ratio of testspecimen projected surface area to wetted (
14、that is, total heattransfer or developed) surface area on either side of the testspecimen is less than 0.80. Otherwise the CTS method shall beused to standardize the thermal transmittance results.1.5 A discussion of the terminology and underlying assump-tions for measuring the thermal transmittance
15、are included.1.6 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are provided forinformation purposes only.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
16、 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:C 168 Terminology Relating to Thermal Insulating Materi-als21This test method is under the jurisdiction of ASTM Commi
17、ttee C16 on ThermalInsulation and is the direct responsibility of Subcommittee C16.30 on ThermalMeasurement.Current edition approved July 10, 2000. Published September 2000. Originallypublished as C 1199 91. Last previous edition C 1199 97.2Annual Book of ASTM Standards, Vol 04.06.1Copyright ASTM In
18、ternational, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.C 177 Test Method for Steady-State Heat Flux Measure-ments and Thermal Transmission Properties by Means ofthe Guarded Hot Plate Apparatus2C 236 Test Method for Steady-State Thermal Performanceof Building
19、 Assemblies by Means of a Guarded Hot Box2C 518 Test Method for Steady-State Thermal Heat FluxMeasurements and Transmission Properties by Means ofthe Heat Flow Meter Apparatus2C 976 Test Method for Thermal Performance of BuildingAssemblies by Means of a Calibrated Hot Box2C 1045 Practice for Calcula
20、ted Thermal Transmission Prop-erties from Steady-State Heat Flux Measurements2C 1114 Test Method for Steady-State Thermal TransmissionProperties by Means of the Thin-Heater Apparatus2C 1363 Test Method for Thermal Performance of BuildingAssemblies by Means of a Hot Box Apparatus2E 283 Test Method fo
21、r Rate of Air Leakage ThroughExterior Windows, Curtain Walls, and Doors3E 631 Terminology of Building Constructions3E 783 Test Method for Field Measurement of Air LeakageThrough Installed Exterior Windows and Doors3E 1423 Practice for Determining the Steady-State ThermalTransmittance of Fenestration
22、 Systems32.2 ISO Standards:ISO 8990 Thermal Insulation-Determination of Steady-State Thermal Transmission PropertiesCalibrated andGuarded Hot Box4ISO125671:2000 Thermal InsulationDetermination ofThermal Resistance of ComponentsHot Box Methodfor Windows and Doors42.3 Other Standards:NFRC 100-97 Proce
23、dure for Determining FenestrationProduct Thermal U-factors5BS874 Part 3, Section 3.1, 1987, British Standard Methodsfor Determining Thermal Insulation Properties, (Part 3,Tests for Thermal Transmittance and Conductance, Sec-tion 3.1) Guarded Hot Box Method6BS874 Part 3, Section 3.2, 1990, British St
24、andard Methodsfor Determining Thermal Insulation Properties, Part 3,Tests for Thermal Transmittance and Conductance, Sec-tion 3.2 Calibrated Hot Box Method6ASHRAE Fundamentals Handbook, 199773. Terminology3.1 Definitions Definitions and terms are in accordancewith definitions in Terminologies E 631
25、and C 168, from whichthe following have been selected and modified to apply tofenestration systems. See Fig. 1 for temperature locations.3.2 Definitions of Terms Specific to This Standard:3.2.1 calibration transfer standard, n an insulation boardthat is faced with glazing, and instrumented with temp
26、eraturesensors between the glazing and the insulation board core,which is used to calibrate the surface resistances and thesurround panel (see Annex A1 for design guidelines forcalibration transfer standards).3.2.2 overall thermal resistance, RS, nthe temperaturedifference between the environments o
27、n the two sides of a bodyor assembly when a unit heat flow per unit area is establishedthrough the body or assembly under steady-state conditions. Itis defined as follows:RS5 1/US(1)3.2.3 standardized thermal transmittance, UST, nthe heattransmission in unit time through unit area of a test specimen
28、and standardized boundary air films, induced by unit tempera-ture difference between the environments on each side. It iscalculated using the CTS method as follows:1/USTCTS#5 1/US11/hSTh1/hh!11/hSTc1/hc! (2)and using the area weighting (AW) method:1/USTAW#51/US1AS/Ah!1/hSTh1/hh!1AS/Ac!1/hSTc1/hc!(3)
29、where hSThand hSTcare the standardized surface heat transfercoefficients on the room side and weather side, respectively.Their numerical values are specified in 8.2.9.1.3.2.3.1 DiscussionThe calculation of the standardizedthermal transmittance, UST, assumes that only the surface heattransfer coeffic
30、ients change from the calibrated standardizedvalues for the conditions of the test. This assumption may notbe valid if the surface temperature differentials for the stan-dardized calibration conditions are different from the surfacetemperature differential that existed for the fenestration productdu
31、ring the test procedure. Therefore, the standardized thermaltransmittance should only be considered as an approximationfor use in comparing with calculated thermal transmittancevalues with standardized surface heat transfer coefficients.3.2.4 surface resistance, nthe temperature difference be-tween
32、an isothermal surface and its surroundings when a unitheat flow per unit area is established between the surface andthe surroundings under steady-state conditions by the com-bined effects of convection and radiation. Subscripts h and care used to differentiate between room side and weather sidesurfa
33、ce resistances, respectively. Surface resistances are calcu-lated as follows:3Annual Book of ASTM Standards, Vol 04.07.4Available from American National Standards Institute, 11 West 42ndSt., 13thFloor, New York, NY 10036.5Available from National Fenestration Rating Council, 1300 Spring Street, Suite
34、120, Silver Spring, MD 20910.6Available from British Standards Institution, British Standards House, 2 ParkStreet, London W1A 2BS, England.7Available from ASHRAE, 1791 Tullie Circle, N.E., Atlanta, GA 30329.FIG. 1 Schematic Representation of Various Temperatures forFenestration SystemsC1199002rh5 1/
35、hh(4)rc5 1/hc(5)3.2.5 surface heat transfer coeffcient, h, nthe time rate ofheat flow from a unit area of a surface to its surroundings,induced by a unit temperature difference between the surfaceand the environment. (This is sometimes called surface con-ductance or film coeffcient.)3.2.5.1 Discussi
36、onSubscripts are used to differentiate be-tween room side (1 or h) and weather side (2 or c) surfaceconditions (see Fig. 1). It should be recognized that due toradiation effects, the room side or weather side temperature (thand tc, respectively), may differ from the respective room sideor weather si
37、de baffle temperatures (tb1and tb2, respectively).If there is a difference of more than 61C(62.0 F), either onthe room side or weather side, the radiation effects shall beaccounted for to maintain accuracy in the calculated surfaceheat transfer coefficients. The areas used to calculate thesurface he
38、at transfer coefficients (Eq 6 and 8) are differentdepending on which method of standardization is used. Whenthe CTS Method is used to standardize the thermal transmit-tance, the projected area, AS, is used to calculate the surfaceheat transfer coefficients, whereas when using the area weight-ing me
39、thod, the actual “wetted or heat transfer” surface area,Ahor Ac, is used to determine the surface heat transfercoefficients.The room side and weather side surface heat transfer coefficients arecalculated as follows:when:th5 tb161C!, (6)hh5 QS/ASorh!th t1!#when:thtb161 C!, (7)hh5 qr11 qc1!/th t1!when
40、:tc5 tb261C!,hc5 QS/ASorc! t2 tc!#when:tctb26 1C!, (8)hc5 qr21 qc2!/t2 tc! (9)3.2.5.2 DiscussionWhen testing inhomogeneous testspecimens, the test specimen surface temperatures and surfaceheat transfer coefficients will not be exactly the same as thoseobtained using the calibration transfer standard
41、. As a conse-quence, the surface heat transfer coefficients obtained using thecalibration transfer standard cannot be unambiguously definedand hence a test specimen conductance cannot be defined andmeasured. For inhomogeneous test specimens, only the thermaltransmittance, US, can be defined and meas
42、ured. It is thereforeessential to calibrate with surface heat transfer coefficients onthe Calibration Transfer Standard (CTS) which are as close aspossible to the conventionally accepted values for buildingdesign. Likewise, it would be desirable to have a surroundpanel that closely duplicates the ac
43、tual wall where the fenes-tration system would be installed. However, due to the widevariety of fenestration opening designs and constructions, thisis not feasible. Furthermore, for high resistance fenestrationsystems installed in fenestration opening designs and construc-tions that are thermal brid
44、ges, the large relative amount of heattransfer through the thermal bridge will cause the relativelysmall amount of heat transfer through the fenestration systemto have a larger than desirable error. As a result of the pointsstated above, the calculation of a specimen thermal conduc-tance or resistan
45、ce (surface to surface) from a measuredthermal transmittance and the calculated surface heat transfercoefficients is not part of the basic measurement procedure.However, by using the CTS method or the area weighting(AW) method described in Section 8 it is possible to obtain astandardized thermal tra
46、nsmittance, UST, which is a ratheruseful tool for the evaluation and comparison of experimentalresults for fenestration systems with computer calculations ofthe thermal transmittance.3.2.6 surround panel (sometimes called the mask, maskwall, or homogeneous wall), na homogeneous panel with anopening
47、where the test specimen is installed (see 5.1.2 for adescription of a surround panel.)3.2.7 test specimen, nthe fenestration system or productbeing tested.3.2.8 test specimen thermal transmittance, US(sometimescalled the overall coefficient of heat transfer or air-to-airU-factor), n the heat transfe
48、r in unit time through unit area ofa test specimen and its boundary air films, induced by unittemperature difference between the environments on each side.It is determined as follows:US5 QS/ASth tc!# (10)3.3 SymbolsThe symbols, terms, and units used in thistest method are as follows:Ah= total heat t
49、ransfer (or developed) surface areaof test specimen on room side, m2,Ac= total heat transfer (or developed) surface areaof test specimen on weather side, m2,Ab1= area of room side baffle and all other surfacesin view of the test specimen, m2,Ab2= area of weather side baffle and all othersurfaces in view of the test specimen, m2,AS= projected area of test specimen (same as openarea in surround panel), m2,Asp= projected area of surround panel (does notinclude open area in surround panel), m2,a = absorbtance of surface,C
