ASTM C168-05a
(Terminology)Standard Terminology Relating to Thermal Insulation
Standard Terminology Relating to Thermal Insulation
SCOPE
1.1 This standard provides definitions, symbols, units, and abbreviations of terms used in ASTM standards pertaining to thermal insulating materials, and to materials associated with them.
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Standards Content (Sample)
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Designation:C168–05a
Standard Terminology Relating to
1
Thermal Insulation
This standard is issued under the fixed designation C 168; 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.
DISCUSSION—Test data labeled with “apparent” shall not include any
1. Scope
equipment related measurement errors induced due to measurement
1.1 This standard provides definitions, symbols, units, and
attempts beyond an apparatus range or calibration.
abbreviations of terms used in ASTM standards pertaining to
DISCUSSION—Useofthe“apparent”modifierwithsystem Corsystem
thermal insulating materials, and to materials associated with
R measurements is not permitted.
them.
apparent thermal resistivity, r , n—a thermal resistivity
a
assigned to a material that exhibits thermal transmission by
2. Referenced Documents
several modes of heat transfer resulting in property variation
2.1 ISO Standard:
with specimen thickness, or surface emittance. See resistiv-
ISO 7345 Thermal Insulation—Physical Quantities and
2 ity, thermal.
Definitions
DISCUSSION—Seeentirediscussionunder apparent thermal conduc-
3. Terminology
tivity.
3.1 Definitions:
area weight, n—weight per unit area for a specified sample, in
2 2
absorptance, n—the ratio of the radiant flux absorbed by a units of lb/ft (kg/m ).
batt, n—blanket insulation manufactured to dimensions as
body to that incident upon it.
absorption, n—transformation of radiant energy to a different required by a specific application.
blackbody, n—the ideal, perfect emitter and absorber of
form of energy by interaction with matter.
apparent thermal conductivity, l , k , n—a thermal con- thermal radiation. It emits radiant energy at each wavelength
a a
at the maximum rate possible as a consequence of its
ductivity assigned to a material that exhibits thermal trans-
mission by several modes of heat transfer resulting in temperature, and absorbs all incident radiance.
property variation with specimen thickness, or surface emit- blanket, n—flexible insulation product, supplied rolled or flat.
blanket insulation, n—a relatively flat and flexible insulation
tance. See conductivity, thermal.
in coherent sheet form furnished in units of substantial area.
DISCUSSION—Thermal conductivity and resistivity are normally con-
blanket insulation, metal mesh, n— blanket insulation cov-
sidered to be intrinsic or specific properties of materials and, as such,
ered by flexible metal-mesh facings attached on one or both
should be independent of thickness. When nonconductive modes of
sides.
heat transfer are present within the specimen (radiation, free convec-
tion) this may not be the case. To indicate the possible presence of this
block insulation, n—rigid insulation preformed into rectangu-
phenomena (for example, thickness effect) the modifier “apparent” is
lar units.
used, as in apparent thermal conductivity.
board insulation, n—semirigid insulation preformed into
DISCUSSION—Test data using the “apparent” modifier must be quoted
rectangular units having a degree of suppleness particularly
only for the conditions of the measurement. Values of thermal conduc-
related to their geometrical dimensions.
tance (material C) and thermal resistance (material R) calculated from
calcium silicate, n—insulation composed principally of hy-
apparent thermal conductivity or resistivity, are valid only for the same
conditions. drous calcium silicate, and which usually contains reinforc-
ing fibers.
cellular elastomeric, n—insulation composed principally of
natural or synthetic elastomers, or both, processed to form a
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This terminology is under the jurisdiction of ASTM Committee C16 on
flexible, semirigid, or rigid foam which has a predominantly
Thermal Insulation and is the direct responsibility of Subcommittee C16.94 on
Terminology.
closed-cell structure.
Current edition approved Nov. 1, 2005. Published December 2005. Originally
cellular glass, n—insulation composed of glass processed to
approved in 1941. Last previous edition approved in 2005 as C 168 – 05.
2 form a rigid foam having a predominantly closed-cell
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036. structure.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
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C168–05a
cellular polyimide, n—insulation composed of the reaction conductivity, thermal, l or k, n—the time rate of steady state
product in which the bonds formed between monomers heat flow through a unit area of a homogeneous material
during polymeri
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