ASTM C1363-97

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Designation: C 1363 – 97
Standard Test Method for
the Thermal Performance of Building Assemblies by Means
of a Hot Box Apparatus
This standard is issued under the fixed designation C 1363; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope metering area. Special calibration specimens and procedures
are required for these tests. The general testing procedures for
1.1 This test method covers the laboratory measurement of
these cases are described in Annex A4.
heat transfer through a specimen under controlled air tempera-
1.6 Specific procedures for the thermal testing of window
ture, air velocity, and thermal radiation conditions established
and door systems are described in Test Method C 1199 and
in a metering chamber on one side and in a climatic chamber
Practice E 1423. The hot box also may be used to investigate
on the other side.
the effect of non-homogeneous building assemblies such as
1.2 This test method generally is used for large homoge-
structural members, piping, electrical outlets, or construction
neous or nonhomogeneous specimens. This test method may
defects such as insulation voids.
be applied to any building structure or composite assemblies of
1.7 This test method governs steady-state tests and does not
building elements for which it is possible to build a represen-
establish procedures or criteria for conducting dynamic tests or
tative specimen of a size that is appropriate for the apparatus.
for analysis of dynamic test data. However, several hot box
NOTE 1—This test method was prepared for the purpose of replacing
apparatuses have been operated under dynamic (non-steady-
Test Methods C 236 and C 976. The test method was developed by
state) conditions (1). Dynamic control strategies have included
combining the technical information contained in the two existing hot box
both periodic or non-periodic temperature cycles, for example,
methods with some additional information added to improve the test
to follow a diurnal cycle.
accuracy and reproducibility. Test apparatus, designed and operated under
Test Methods C 236 and C 976, should, in most cases, meet the require- 1.8 This test method does not permit intentional mass
ments of this test method with only slight modifications to calibration and
transfer of air or moisture through the specimen during
operational procedures.
measurements of energy transfer. Air infiltration or moisture
migration can significantly alter net heat transfer. Complicated
1.3 Thistestmethodisintendedforuseatconditionstypical
interactions and dependence upon many variables, coupled
of normal building applications. The usual consideration is to
withonlyalimitedexperienceintestingundersuchconditions,
duplicate naturally occurring outside conditions that in temper-
have made it inadvisable to include this type of testing in this
ate zones may range from approximately –48 to 85°C and
test method. ASTM Subcommittee C16.30 has several task
normal inside residential temperatures of approximately 21°C.
groups that are researching this testing need, and will be
Building materials used to construct the specimens are gener-
preparing a separate standard. Further considerations for such
ally pre-conditioned to typical laboratory conditions of 23°C
testing are given in Appendix X1.
and 50 % relative humidity prior to assembly. Practice C 870
1.9 This test method sets forth the general design require-
may be used as a guide for sample conditioning. Further
ments necessary to construct and operate a satisfactory hot box
conditioning prior to testing may be performed to provide
apparatus, and covers a wide variety of apparatus construc-
moisture conditioned samples, if necessary.
tions, test conditions, and operating conditions. Detailed de-
1.4 This test method permits operation under natural or
signs conforming to this test method are not given, but must be
forced convective conditions at the specimen surface. The
developed within the constraints of the general requirements.
direction of air flow motion may be either perpendicular or
Examples of analysis tools, concepts, and procedures used in
parallel to the surface.
thedesign,construction,calibration,andoperationofahotbox
1.5 The hot box apparatus also can be used for measure-
apparatus are provided in Refs (1-26).
ments of individual building elements that are smaller than the
1.10 This test method does not specify all details necessary
for the operation of the apparatus. Decisions on sampling,
This test method is under the jurisdiction of ASTM Committee C-16 on
specimen selection, preconditioning, specimen mounting and
Thermal Insulation and is the direct responsibility of Subcommittee C16.30 on
positioning, the choice of test conditions, and the evaluation of
Thermal Measurements.
test data shall follow applicable ASTM test methods, guides,
Current edition approved Aug. 10, 1997. Published August 1998.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
C 1363
practices, or product specifications or government regulations. C 1199 Test Method for Measuring the Steady State Ther-
If no applicable standard exists, sound engineering judgment malTransmittance of Fenestration Systems Using Hot Box
that reflects accepted heat transfer principles shall be used and Methods
documented. E 230 Standard Temperature-Electromotive Force (EMF)
1.11 In order to ensure the level of precision and accuracy Tables for Thermocouples
expected, persons applying this test method must possess a E 283 Test Method for Rate of Air Leakage Through
knowledge of the requirements of thermal measurements and Exterior Windows, Curtain Walls and Doors
testing practice and of the practical application of heat transfer E 1423 Practice for Determining the Steady State Thermal
theory relating to thermal insulation materials and systems. Transmittance of Fenestration Systems
Detailed operating procedures, including design schematics E 1424 Test Method for Determining the Rate of Air Leak-
and electrical drawings, should be available for each apparatus age Through Exterior Windows, Curtain Walls, and Doors
to ensure that tests are in accordance with this test method. Under Specified Pressure and Temperature Differences
1.12 The hot box apparatus, when constructed to measure Across the Specimen
heat transfer in the horizontal direction, can be used for testing 2.2 Other Documents:
walls and other vertical structures. When constructed to mea-
ASHRAE Handbook 1993 Fundamentals Volume, Ameri-
sure heat transfer in the vertical direction, the hot box can be
can Society of Heating, Refrigerating and Air Condition-
used for testing roof, ceiling, floor, and other horizontal
ing Engineers, Inc.
structures. Other orientations are also permitted. The same
ISO Standard 8990 Thermal Insulation Determination of
apparatus may be used in several orientations but may require
SteadyStateThermalProperties—CalibratedandGuarded
special design capability to permit repositioning to each
Hot Box, ISO 8990-1994(E)
orientation. Whatever the test orientation, the apparatus per-
formance first shall be verified at that orientation with a
3. Terminology
traceable specimen in place to confirm its ability to accurately
3.1 Definitions—Definitions of terms relating to insulating
obtain results at that orientation.
materials and testing used herein are governed byTerminology
1.13 This standard does not purport to address all of the
C 168.All terms discussed in this test method can be assumed
safety concerns, if any, associated with its use. It is the
to be those associated with thermal properties of the tested
responsibility of the user of this standard to establish appro-
specimen unless otherwise noted.
priate safety and health practices and determine the applica-
3.2 Definitions of Terms Specific to This Standard:
bility of regulatory limitations prior to use.
3.2.1 metering box energy flow, n—The time rate of energy
loss or gain through the walls of the metering box that must be
2. Referenced Documents
subtracted from or added to the energy input to the metering
2.1 ASTM Standards:
chamber as part of the determination of the net energy flow
C 168 Terminology Relating to Thermal Insulating Materi-
through the test specimen. A more complete discussion of the
als
metering box loss is provided in Annex A1.
C 177 Test Method for Steady-State Heat Flux Measure-
3.2.2 flanking path energy flow, n—The time rate of energy
ments and Thermal Transmission Properties by Means of
lossorgainfromthemeteringchambertotheclimaticchamber
the Guarded-Hot-Plate Apparatus
that passes through the sample or sample holder beyond the
C 236 Test Method for Steady-State Thermal Performance
boundaries of the metering chamber. This energy exchange
of Building Assemblies by Means of a Guarded Hot Box
mustalsobesubtractedfromoraddedtotheenergyinputtothe
C 518 Test Method for Steady-State Heat Flux Measure-
meteringchamberaspartofthedeterminationofthenetenergy
ments and Thermal Transmission Properties by Means of
flow through the test specimen.Amore complete discussion of
the Heat Flow Meter Apparatus
the flanking loss is provided in Annex A3.
C 870 Practice for Conditioning of Thermal Insulating Ma-
3.2.3 surface resistance, R—the quantity determined by the
i
terials
temperature difference, at steady state, between an isothermal
C 976 Test Method for Steady-State Thermal Performance
surface and its surroundings that induces a unit heat flow per
ofBuildingAssembliesbyMeansofaCalibratedHotBox
unit area by the combined effects of conduction, convection,
C 1045 Practice for Calculating Thermal Transmission
and radiation. Subscripts h and c are used to differentiate
Properties from Steady-State Heat Flux Measurements
between hot side and cold side surface resistances, respec-
C 1058 Practice for Selecting Temperatures for Reporting
tively. Surface resistances are calculated as follows (see Note
andEvaluatingThermalPropertiesofThermalInsulations
5):
C 1114 TestMethodforSteady-StateThermalTransmission
A • t – t
~ !
env,h 1
Properties by Means of the Thin-Heater Apparatus
R 5 (1)
h
Q
C 1132 Practice for Calibration of the Heat Flow Meter
Apparatus
C 1130 Practice for Calibrating Thin Heat Flux Transduc-
ers
Annual Book of Standards, Vol 14.01.
Annual Book of Standards, Vol 04.07.
Available from ASHRAE Inc., 1791 Tullie Circle, NE, Atlanta, GA 30329.
2 6
Annual Book of Standards, Vol 04.06. AvailablefromANSI,105-111SouthStateSt.,Hackensack,NewJersey07601.
C 1363
A • ~t – t !
2 env,c t 5 average air temperature 75 mm or more from the
h
R 5 (2)
c
Q
hot side surface, K or °C
t 5 area weighted temperature of specimen hot sur-
3.2.4 Overall thermal resistance, R – the quantity deter-
u
face, K or °C
mined by the temperature difference, at steady state, between
t 5 area weighted temperature of the specimen cold
the environments on the two sides of a body or assembly that
surface, K or °C
induces a unit heat flow per unit area by the combined effects
t 5 average air temperature 75 mm or more from the
c
of conduction, convection and radiation. It is equal to the sum
cold side surface, K or °C
of the resistances of the body or assembly and of the two
t 5 average specimen temperature—average of two
m
surface resistances and may be calculated as follows:
opposite surface temperatures, K or °C
A • t – t !
~ Dt 5 temperature difference between two planes of
env,h env,c
R 5 (3)
u
Q
interest, K or °C
Dt 5 temperature difference—surface to surface, K or
5 R 1 R 1 R
s-s
c h
°C
3.2.5 Surface Coefficient Determination – An expanded
Dt 5 temperature difference—air to air, K or °C
a-a
discussion of the interactions between the radiation and con-
t 5 effective thermal time constant of combined appa-
eff
vective heat transfer at the surfaces of the test sample is
ratus and specimen, s
included in Annex A6. The material presented in Annex A6
U 5 thermal transmittance, W/(m •K)
must be used to determine the magnitude of the environmental
3.4 Equations—The following equations are defined here to
temperaturewhichmayberequiredtocorrectforradiationheat
simplify their use in the Calculations section of this test
flow from the air curtain baffle.
method.
3.2.6 For very non-uniform specimens where the heat trans- 3.4.1 apparent thermal conductivity:
fer is greatly different from one area to another, and if detailed
Q • L
l5 (4)
temperature profiles are not known, only the net heat transfer
A t – t !
~
1 2
through the specimen may be meaningful. In these cases, only
NOTE 2—Materials are considered homogeneous when the value of the
the overall resistance, R , and transmission coefficient, U, are
u
thermal conductivity is not significantly affected by variations in the
permitted.
thickness or area of the sample within the range of those variables
normally used.
3.3 Symbols:Symbols—The following are symbols, terms,
and units used in this test method.
3.4.2 thermal resistance, R:
A • ~t – t !
1 2
R 5 (5)
Q
A 5 metered area, m
l5 thermal conductivity, W/(m•K)
3.4.3 thermal conductance, C:
C 5 thermal conductance, W/(m •K)
Q
E 5 emf output of heat flux transducer or thermo-
C 5 (6)
A • ~t – t !
1 2
couple, V
h 5 surface heat transfer coefficient, hot side,
NOTE 3—Thermal resistance, R, and the corresponding thermal con-
h
W/(m •K) ductance, C, are reciprocals, that is, their product is unity. These terms
apply to specific bodies or constructions as used, either homogeneous or
h 5 surface heat transfer coefficient, cold side,
c
heterogeneous, between two specified isothermal surfaces.
W/(m •K)
h 5 convective surface heat transfer coefficient,
conv 3.4.4 surface heat transfer coeffıcient, h, is often called
W/(m •K)
surface conductance or film coefficient. Subscripts h and c are
h 5 radiative surface heat transfer coefficient,
rad
used to differentiate between hot side and cold side surface
W/(m •K)
conductances, respectively. These conductances are calculated
L 5 length of the heat loss path (usually the thickness
as follows:
of the test panel), m
Q
q 5 heat flux (time rate of heat flow through unit area
h 5 (7)
h
A • ~t – t !
env,h 1
A), W/m
Q 5 time rate of heat flow, total power input to the Q
h 5 (8)
c
A • ~t – t !
metering box, W
2 env,c
R 5 thermal resistance m •K/W
NOTE 4—Thesurfaceheattransfercoefficient,h,andthecorresponding
2 i
R 5 surface resistance, hot side, m •K/W
h
surface resistance, R, (see 3.5.1) are reciprocals, that is, their prod
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