ASTM C168-08b
(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.
1.2 This terminology is not intended to be used to classify insulation materials as having particular properties. Rather, classification of insulation materials is to be done by the material standards themselves.
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Designation:C168–08b
Standard Terminology Relating to
1
Thermal Insulation
This standard is issued under the fixed designation C168; 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 (´) indicates an editorial change since the last revision or reapproval.
DISCUSSION—Thermal conductivity and resistivity are normally con-
1. Scope
sidered to be intrinsic or specific properties of materials and, as such,
1.1 This standard provides definitions, symbols, units, and
should be independent of thickness. When nonconductive modes of
abbreviations of terms used in ASTM standards pertaining to
heat transfer are present within the specimen (radiation, free convec-
thermal insulating materials, and to materials associated with
tion) this may not be the case. To indicate the possible presence of this
them. phenomena (for example, thickness effect) the modifier “apparent” is
used, as in apparent thermal conductivity.
1.2 This terminology is not intended to be used to classify
DISCUSSION—Test data using the “apparent” modifier must be quoted
insulation materials as having particular properties. Rather,
only for the conditions of the measurement. Values of thermal conduc-
classification of insulation materials is to be done by the
tance (material C) and thermal resistance (material R) calculated from
material standards themselves.
apparent thermal conductivity or resistivity, are valid only for the same
1.3 This standard does not purport to address all of the
conditions.
safety concerns, if any, associated with its use. It is the
DISCUSSION—Test data labeled with “apparent” shall not include any
responsibility of the user of this standard to establish appro- equipment related measurement errors induced due to measurement
attempts beyond an apparatus range or calibration.
priate safety and health practices and determine the applica-
DISCUSSION—Useofthe“apparent”modifierwithsystem Corsystem
bility of regulatory limitations prior to use.
R measurements is not permitted.
2. Referenced Documents
apparent thermal resistivity, r , n—a thermal resistivity
a
2.1 ASTM Standards:
assigned to a material that exhibits thermal transmission by
E456 Terminology Relating to Quality and Statistics
several modes of heat transfer resulting in property variation
E2282 Guide for Defining the Test Result of a Test Method
with specimen thickness, or surface emittance. See resistiv-
2.2 ISO Standard:
ity, thermal.
ISO 7345 Thermal Insulation—Physical Quantities and
DISCUSSION—Seeentirediscussionunder apparent thermal conduc-
2
Definitions
tivity.
3. Terminology
area weight, n—weight per unit area for a specified sample, in
2 2
units of lb/ft (kg/m ).
3.1 Definitions:
aerogel, n—a homogeneous, low-density solid phase material
absorptance, n—the ratio of the radiant flux absorbed by a
derived from a gel, in which the liquid component of the gel
body to that incident upon it.
has been replaced with a gas.
absorption, n—transformation of radiant energy to a different
DISCUSSION—The resulting material has a porous structure with an
form of energy by interaction with matter.
average pore size below the mean free path of air molecules at standard
apparent thermal conductivity, l , k , n—a thermal con-
a a
atmospheric pressure and temperature.
ductivity assigned to a material that exhibits thermal trans-
mission by several modes of heat transfer resulting in batt, n—blanket insulation manufactured to dimensions as
property variation with specimen thickness, or surface emit-
required by a specific application.
tance. See conductivity, thermal. blackbody, n—the ideal, perfect emitter and absorber of
thermal radiation. It emits radiant energy at each wavelength
at the maximum rate possible as a consequence of its
temperature, and absorbs all incident radiance.
1
This terminology is under the jurisdiction of ASTM Committee C16 on
blanket, n—flexible insulation product, supplied rolled or flat.
Thermal Insulation and is the direct responsibility of Subcommittee C16.94 on
blanket insulation, n—a relatively flat and flexible insulation
Terminology.
Current edition approved Dec. 15, 2008. Published January 2009. Originally
in coherent sheet form furnished in units of substantial area.
approved in 1941. Last previous edition approved in 2008 as C168 – 08a. DOI:
blanket insulation, metal mesh, n— blanket insulation cov-
10.1520/C0168-08B.
2
ered by flexible metal-mesh facings attached on one or both
Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. sides.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:C168–08a Designation: C 168 – 08b
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Thisstandardprovidesdefinitions,symbols,units,andabbreviationsoftermsusedinASTMstandardspertainingtothermal
insulating materials, and to materials associated with them.
1.2 This terminology is not intended to be used to classify insulation materials as having particular properties. Rather,
classification of insulation materials is to be done by the material standards themselves.
2. Referenced Documents
2.1 ASTM Standards:
E 456 Terminology Relating to Quality and Statistics
E 2282 Guide for Defining the Test Result of a Test Method
2.2 ISO Standard:
2
ISO 7345 Thermal Insulation—Physical Quantities and Definitions
3. Terminology
3.1 Definitions:
absorptance, n—the ratio of the radiant flux absorbed by a body to that incident upon it.
absorption, n—transformation of radiant energy to a different form of energy by interaction with matter.
apparent thermal conductivity, l , k , n— a thermal conductivity assigned to a material that exhibits thermal transmission by
a a
several modes of heat transfer resulting in property variation with specimen thickness, or surface emittance. See conductivity,
thermal .
DISCUSSION—Thermal conductivity and resistivity are normally considered to be intrinsic or specific properties of materials and, as such, should be
independent of thickness. When nonconductive modes of heat transfer are present within the specimen (radiation, free convection) this may not be the
case. To indicate the possible presence of this phenomena (for example, thickness effect) the modifier “apparent” is used, as in apparent thermal
conductivity.
DISCUSSION—Test data using the “apparent” modifier must be quoted only for the conditions of the measurement. Values of thermal conductance
(material C) and thermal resistance (material R) calculated from apparent thermal conductivity or resistivity, are valid only for the same conditions.
DISCUSSION—Test data labeled with “apparent” shall not include any equipment related measurement errors induced due to measurement attempts
beyond an apparatus range or calibration.
DISCUSSION—Use of the “apparent” modifier with system C or system R measurements is not permitted.
apparent thermal resistivity, r , n—a thermal resistivity assigned to a material that exhibits thermal transmission by several
a
modes of heat transfer resulting in property variation with specimen thickness, or surface emittance. See resistivity, thermal.
DISCUSSION—See entire discussion under apparent thermal conductivity.
2 2
area weight, n—weight per unit area for a specified sample, in units of lb/ft (kg/m ).
aerogel, n—a homogeneous, low-density solid phase material derived from a gel, in which the liquid component of the gel has
been replaced with a gas.
DISCUSSION—The resulting material has a porous structure with an average pore size below the mean free path of air molecules at standard
atmospheric pressure and temperature.
batt, n—blanket insulation manufactured to dimensions as required by a specific application.
blackbody, n—the ideal, perfect emitter and absorber of thermal radiation. It emits radiant energy at each wavelength at the
1
This terminology is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.94 on Terminology .
Current edition approved Sept. 1,Dec. 15, 2008. Published September 2008.January 2009. Originally approved in 1941. Last previous edition approved in 2008 as
C 168 – 08a.
2
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
C 168 – 08b
maximum rate possible as a consequence of its temperature, and absorbs all incident radiance.
blanket, n—flexible insulation product, supplied rolled or flat.
blanket insulation, n—a relatively flat and flexible insulation in coherent sheet form furnished in units of substantial area.
blanket insulation, metal mesh, n— blanket insulation
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:C168–08a Designation: C 168 – 08b
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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 Thisstandardprovidesdefinitions,symbols,units,andabbreviationsoftermsusedinASTMstandardspertainingtothermal
insulating materials, and to materials associated with them.
1.2 This terminology is not intended to be used to classify insulation materials as having particular properties. Rather,
classification of insulation materials is to be done by the material standards themselves.
2. Referenced Documents
2.1 ASTM Standards:
E 456 Terminology Relating to Quality and Statistics
E 2282 Guide for Defining the Test Result of a Test Method
2.2 ISO Standard:
2
ISO 7345 Thermal Insulation—Physical Quantities and Definitions
3. Terminology
3.1 Definitions:
absorptance, n—the ratio of the radiant flux absorbed by a body to that incident upon it.
absorption, n—transformation of radiant energy to a different form of energy by interaction with matter.
apparent thermal conductivity, l , k , n— a thermal conductivity assigned to a material that exhibits thermal transmission by
a a
several modes of heat transfer resulting in property variation with specimen thickness, or surface emittance. See conductivity,
thermal .
DISCUSSION—Thermal conductivity and resistivity are normally considered to be intrinsic or specific properties of materials and, as such, should be
independent of thickness. When nonconductive modes of heat transfer are present within the specimen (radiation, free convection) this may not be the
case. To indicate the possible presence of this phenomena (for example, thickness effect) the modifier “apparent” is used, as in apparent thermal
conductivity.
DISCUSSION—Test data using the “apparent” modifier must be quoted only for the conditions of the measurement. Values of thermal conductance
(material C) and thermal resistance (material R) calculated from apparent thermal conductivity or resistivity, are valid only for the same conditions.
DISCUSSION—Test data labeled with “apparent” shall not include any equipment related measurement errors induced due to measurement attempts
beyond an apparatus range or calibration.
DISCUSSION—Use of the “apparent” modifier with system C or system R measurements is not permitted.
apparent thermal resistivity, r , n—a thermal resistivity assigned to a material that exhibits thermal transmission by several
a
modes of heat transfer resulting in property variation with specimen thickness, or surface emittance. See resistivity, thermal.
DISCUSSION—See entire discussion under apparent thermal conductivity.
2 2
area weight, n—weight per unit area for a specified sample, in units of lb/ft (kg/m ).
aerogel, n—a homogeneous, low-density solid phase material derived from a gel, in which the liquid component of the gel has
been replaced with a gas.
DISCUSSION—The resulting material has a porous structure with an average pore size below the mean free path of air molecules at standard
atmospheric pressure and temperature.
batt, n—blanket insulation manufactured to dimensions as required by a specific application.
blackbody, n—the ideal, perfect emitter and absorber of thermal radiation. It emits radiant energy at each wavelength at the
1
This terminology is under the jurisdiction of ASTM Committee C16 on Thermal Insulation and is the direct responsibility of Subcommittee C16.94 on Terminology .
Current edition approved Sept. 1,Dec. 15, 2008. Published September 2008.January 2009. Originally approved in 1941. Last previous edition approved in 2008 as
C 168 – 08a.
2
Available from American National Standards Institute (ANSI), 25 W. 43rd St., 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
1
---------------------- Page: 1 ----------------------
C 168 – 08b
maximum rate possible as a consequence of its temperature, and absorbs all incident radiance.
blanket, n—flexible insulation product, supplied rolled or flat.
blanket insulation, n—a relatively flat and flexible insulation in coherent sheet form furnished in units of substantial area.
blanket insulation, metal mesh, n— blanket insulation
...
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