ASTM C168-2019 pdf free download

ASTM C168-2019 pdf free download,Standard Terminology Relating to Thermal Insulation
1. 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. 1.3 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 appro- priate safety, health, and environmental practices and deter- mine the applicability ofregulatory limitations prior to use. 1.4 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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, λ a , k a , n—a thermal conduc- tivity assigned to a material that exhibits thermal transmis- sion by several modes of heat transfer resulting in property variation with specimen thickness, or surface emittance. See conductivity, thermal. D ISCUSSION —Thermal conductivity and resistivity are normally con- sidered 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 convec- tion) 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. D ISCUSSION —Test data using the “apparent” modifier must be quoted only for the conditions of the measurement. Values of thermal conduc- tance (material C) and thermal resistance (material R) calculated from apparent thermal conductivity or resistivity, are valid only for the same conditions. D ISCUSSION —Test data labeled with “apparent” shall not include any equipment related measurement errors induced due to measurement attempts beyond an apparatus range or calibration. D ISCUSSION —Use ofthe “apparent” modifier with system C or system R measurements is not permitted.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. 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 cov- ered by flexible metal-mesh facings attached on one or both sides. block insulation, n—rigid insulation preformed into rectangu- lar units. board insulation, n—semirigid insulation preformed into rect- angular units having a degree of suppleness particularly related to their geometrical dimensions. calcium silicate, n—insulation composed principally of hy- 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 flexible, semirigid, or rigid foam which has a predominantly closed-cell structure. cellular glass, n—insulation composed of glass processed to form a rigid foam having a predominantly closed-cell structure. cellular polyimide, n—insulation composed of the reaction product in which the bonds formed between monomers during polymerization are essentially imide units forming a cellular structure. cellular polystyrene, n—insulation composed principally of polymerized styrene resin processed to form a rigid foam having a predominantly closed-cell structure. cellular polyurethane, n—insulation composed principally of the catalyzed reaction product of polyisocyanate and poly- hydroxy compounds, processed usually with fluorocarbon gas to form a rigid foam having a predominantly closed-cell structure. cellulosic fiber, n—insulation composed principally of cellu- lose fibers usually derived from paper, paperboard stock, or wood, with or without binders.