 |
| Purchase Information |
| Use this form to request purchase information on ORG online subscriptions. |
|
|
Document ASTM C 177 is offered by IHS as part of an online subscription. This subscription contains many documents on the same topic.
You may also purchase this document alone from the IHS Standards Store.
ASTM C 177 Document Information:
Title
Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus
ASTM International
Publication Date:
Nov 1, 2004
Scope:
This test method establishes the criteria for the laboratory
measurement of the steady-state heat
flux through flat, homogeneous specimen(s) when their surfaces are in
contact with solid, parallel
boundaries held at constant temperatures using the guarded-hot-plate
apparatus.
The test apparatus designed for this purpose is known as a
guarded-hot-plate apparatus and is a
primary (or absolute) method. This test method is comparable, but not
identical, to ISO 8302.
This test method sets forth the general design requirements necessary
to construct and operate a
satisfactory guarded-hot-plate apparatus. It covers a wide variety of
apparatus constructions, test
conditions, and operating conditions. Detailed designs conforming to
this test method are not given
but must be developed within the constraints of the general
requirements. Examples of analysis
tools, concepts and procedures used in the design, construction,
calibration and operation of a
guarded-hot-plate apparatus are given in Refs (1-41).(Footnote 2)
This test method encompasses both the single-sided and the
double-sided modes of measurement. Both
distributed and line source guarded heating plate designs are
permitted. The user should consult
the standard practices on the single-sided mode of operation, Practice
C 1044, and on the line
source apparatus, Practice C 1043, for further details on these heater
designs.
The guarded-hot-plate apparatus can be operated with either vertical
or horizontal heat flow. The
user is cautioned however, since the test results from the two
orientations may be different if
convective heat flow occurs within the specimens.
Although no definitive upper limit can be given for the magnitude of
specimen conductance that is
measurable on a guarded-hot-plate, for practical reasons the specimen
conductance should be less
than 16 W/(m ²K).
This test method is applicable to the measurement of a wide variety of
specimens, ranging from
opaque solids to porous or transparent materials, and a wide range of
environmental conditions
including measurements conducted at extremes of temperature and with
various gases and pressures.
Inhomogeneities normal to the heat flux direction, such as layered
structures, can be successfully
evaluated using this test method. However, testing specimens with
inhomogeneities in the heat flux
direction, such as an insulation system with thermal bridges, can
yield results that are location
specific and shall not be attempted with this type of apparatus. See
Test Methods C 976 or C 236
for guidance in testing these systems.
Calculations of thermal transmission properties based upon
measurements using this method shall be
performed in conformance with Practice C 1045.
In order to ensure the level of precision and accuracy expected,
persons applying this standard
must possess a knowledge of the requirements of thermal measurements
and testing practice and of
the practical application of heat transfer theory relating to thermal
insulation materials and
systems. Detailed operating procedures, including design schematics
and electrical drawings, should
be available for each apparatus to ensure that tests are in accordance
with this test method. In
addition, automated data collecting and handling systems connected to
the apparatus must be
verified as to their accuracy. This can be done by calibration and
inputting data sets, which have
known results associated with them, into computer programs.
It is not practical for a test method of this type to establish
details of design and construction
and the procedures to cover all contingencies that might offer
difficulties to a person without
technical knowledge concerning theory of heat flow, temperature
measurements and general testing
practices. The user may also find it necessary, when repairing or
modifying the apparatus, to
become a designer or builder, or both, on whom the demands for
fundamental understanding and
careful experimental technique are even greater. Standardization of
this test method is not
intended to restrict in any way the future development of new or
improved apparatus or procedures.
This test method does not specify all details necessary for the
operation of the apparatus.
Decisions on sampling, specimen selection, preconditioning, specimen
mounting and positioning, the
choice of test conditions, and the evaluation of test data shall
follow applicable ASTM Test
Methods, Guides, Practices or Product Specifications or governmental
regulations. If no applicable
standard exists, sound engineering judgment that reflects accepted
heat transfer principles must be
used and documented.
This test method allows a wide range of apparatus design and design
accuracy to be used in order to
satisfy the requirements of specific measurement problems. Compliance
with this test method
requires a statement of the uncertainty of each reported variable in
the report. A discussion of
the significant error factors involved is included.
The values stated in SI units are to be regarded as the standard. The
values given in parentheses
are for information only. Either SI or Imperial units may be used in
the report, unless otherwise
specified.
This standard does not purport to address all of the safety concerns,
if any, associated with its
use. It is the responsibility of the user of this standard to
establish appropriate safety and
health practices and determine the applicability of regulatory
limitations prior to use. Specific
precautionary statements are given in Note 21.
Major sections within this test method are arranged as follows:
Footnote 2 - The boldface numbers given in parentheses refer to the
list of references at the end
of this standard.
Keywords:
- error analysis
- guarded-hot-plate
- heat flow
- heat flux
- steady-state
- thermal conductivity
- thermal resistance
- thermal transmission
- thermal conductance
- thermal testing
About IHS
IHS (NYSE: IHS) is a leading global provider of critical technical information, decision-support tools and related services in a number of industries including aerospace and defense, automotive, construction, electronics, and energy. IHS serves customers ranging from large governments and multinational corporations to smaller companies and technical professionals in more than 100 countries. IHS been in business for more than 45 years and employ more than 2,300 people around the world.
