ASTM C168-02

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.

General Information

• Status: Historical
• Publication Date: 09-Jul-2002
• ICS: 01.040.91 - Construction materials and building (Vocabularies)
• ICS: 91.100.60 - Thermal and sound insulating materials
• Technical Committee: C16 - Thermal Insulation
• Drafting Committee: C16.94 - Terminology

Relations

• Replaces: ASTM C168-01 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 10-Jul-2002
• Replaced By: ASTM C168-03 - Standard Terminology Relating to Thermal Insulation
• Effective Date: 10-Apr-2003
• Referred By: ASTM E398-20 - Standard Test Method for Water Vapor Transmission Rate of Sheet Materials Using Dynamic Relative Humidity Measurement
• Effective Date: 10-Jul-2002
• Referred By: ASTM C450-18 - Standard Practice for Fabrication of Thermal Insulating Fitting Covers for NPS Piping, and Vessel Lagging
• Effective Date: 10-Jul-2002
• Referred By: ASTM C755-20 - Standard Practice for Selection of Water Vapor Retarders for Thermal Insulation
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1263-95(2021) - Standard Test Method for Thermal Integrity of Flexible Water Vapor Retarders
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1303/C1303M-22 - Standard Test Method for Predicting Long-Term Thermal Resistance of Closed-Cell Foam Insulation
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1483/C1483M-17(2022) - Standard Specification for Exterior Solar Radiation Control Coatings on Buildings
• Effective Date: 10-Jul-2002
• Referred By: ASTM C449-07(2019) - Standard Specification for Mineral Fiber Hydraulic-Setting Thermal Insulating and Finishing Cement
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1767-21 - Standard Specification for Stainless Steel Jacketing for Insulation
• Effective Date: 10-Jul-2002
• Referred By: ASTM C534/C534M-23 - Standard Specification for Preformed Flexible Elastomeric Cellular Thermal Insulation in Sheet and Tubular Form
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1060-23 - Standard Practice for Thermographic Inspection of Insulation Installations in Envelope Cavities of Frame Buildings
• Effective Date: 10-Jul-2002
• Referred By: ASTM C727-19 - Standard Practice for Installation and Use of Reflective Insulation in Building Constructions
• Effective Date: 10-Jul-2002
• Referred By: ASTM C1321-15(2020) - Standard Practice for Installation and Use of Interior Radiation Control Coating Systems (IRCCS) in Building Construction
• Effective Date: 10-Jul-2002
• Referred By: ASTM C945-05(2023) - Standard Practice for Design Considerations and Spray Application of a Rigid Cellular Polyurethane Insulation System on Outdoor Service Vessels
• Effective Date: 10-Jul-2002

Standards Content (Sample)

NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: C 168 – 02
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.
1. Scope apparent thermal resistivity, r , n—a thermal resistivity
a
assigned to a material that exhibits thermal transmission by
1.1 This standard provides definitions, symbols, units, and
several modes of heat transfer resulting in property variation
abbreviations of terms used in ASTM standards pertaining to
with specimen thickness, or surface emittance. See resistiv-
thermal insulating materials, and to materials associated with
ity, thermal.
them.
DISCUSSION—See entire discussion under apparent thermal conduc-
2. Referenced Documents
tivity.
2.1 ISO Standard:
batt, n—blanket insulation manufactured to dimensions as
ISO 7345 Thermal Insulation—Physical Quantities and
required by a specific application.
2
Definitions
blackbody, n—the ideal, perfect emitter and absorber of
thermal radiation. It emits radiant energy at each wavelength
3. Terminology
at the maximum rate possible as a consequence of its
3.1 Definitions:
temperature, and absorbs all incident radiance.
absorptance, n—the ratio of the radiant flux absorbed by a
blanket, n—flexible insulation product, supplied rolled or flat.
body to that incident upon it.
blanket insulation, n—a relatively flat and flexible insulation
absorption, n—transformation of radiant energy to a different
in coherent sheet form furnished in units of substantial area.
form of energy by interaction with matter.
blanket insulation, metal mesh, n— blanket insulation cov-
apparent thermal conductivity, l , k , n—a thermal con-
ered by flexible metal-mesh facings attached on one or both
a a
ductivity assigned to a material that exhibits thermal trans-
sides.
mission by several modes of heat transfer resulting in
block insulation, n—rigid insulation preformed into rectangu-
property variation with specimen thickness, or surface emit-
lar units.
tance. See conductivity, thermal.
board insulation, n—semirigid insulation preformed into
rectangular units having a degree of suppleness particularly
DISCUSSION—Thermal conductivity and resistivity are normally con-
related to their geometrical dimensions.
sidered to be intrinsic or specific properties of materials and, as such,
calcium silicate, n—insulation composed principally of hy-
should be independent of thickness. When nonconductive modes of
heat transfer are present within the specimen (radiation, free convec- drous calcium silicate, and which usually contains reinforc-
tion) this may not be the case. To indicate the possible presence of this
ing fibers.
phenomena (for example, thickness effect) the modifier “apparent” is
cellular elastomeric, n—insulation composed principally of
used, as in apparent thermal conductivity.
natural or synthetic elastomers, or both, processed to form a
DISCUSSION—Test data using the “apparent” modifier must be quoted
flexible, semirigid, or rigid foam which has a predominantly
only for the conditions of the measurement. Values of thermal conduc-
closed-cell structure.
tance (material C) and thermal resistance (material R) calculated from
cellular glass, n—insulation composed of glass processed to
apparent thermal conductivity or resistivity, are valid only for the same
conditions.
form a rigid foam having a predominantly closed-cell
DISCUSSION—Test data labeled with “apparent” shall not include any
structure.
equipment related measurement errors induced due to measurement
cellular polystyrene, n—insulation composed principally of
attempts beyond an apparatus range or calibration.
polymerized styrene resin processed to form a rigid foam
DISCUSSION—Use of the “apparent” modifier with system C or system
having a predominantly closed-cell structure.
R measurements is not permitted.
cellular polyurethane, n—insulation composed principally of
the catalyzed reaction product of polyisocyanate and poly-
1
This terminology is under the jurisdiction of ASTM Committee C16 on
hydroxy compounds, processed usually with fluorocarbon
Thermal Insulation and is the direct responsibility of Subcommittee C16.94 on
Terminology. gas to form a rigid foam having a predominantly closed-cell
Current edition approved July 10, 2002. Published September 2002. Originally
structure.
published as C 168 – 41 T. Last previous edition C 168 – 01.
cellulosic fiber, n—insulation composed principally of cellu-
2
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
lose fibers usually derived from paper, paperboard stock, or
4th Floor,
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