1、BRITISH STANDARD BS3533:1981 Glossary of Thermal insulation terms UDC 536.2:001.4BS3533:1981 This British Standard, having been prepared under the directionof the Refrigeration, Heating and Air Conditioning Standards Committee, was published under the authority ofthe Executive Board and comesinto ef
2、fect on 27 February1981 BSI 11-1999 First published August1962 First revision February1981 The following BSI references relate to the work on this standard: Committee reference RHE/9 Draft for comment 79/74975 DC ISBN 0 580 11833 9 Cooperating organizations The Refrigeration, Heating and Air Conditi
3、oning Standards Committee, under whose direction this British Standard was prepared, consists of representatives from the following: The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the prepa
4、ration of this British Standard: Association of Consulting Engineers. Electricity Supply Industry in England and Association of Manufacturers of Domestic Wales* Electrical Appliances Heating and Ventilating Contractors Boiler and Radiator Manufacturers Association Association Limited Hevac Associati
5、on British Combustion Equipment Institute of Fuel Manufacturers Association Institute of Refrigeration British Gas Corporation* Institution of Gas Engineers* British Refrigeration and Air Conditioning Lloyds Register of Shipping Association Manufacturers Association of Radiators it was recognized th
6、at the nomenclature employed required definition in order to avoid misrepresentation. In the present revision the text has been brought up to date with technical developments and takes into account the need for harmony with other standard glossaries in related fields published since1962. It also tak
7、es account of current work being undertaken by the International Organization for Standardization(ISO). This glossary is intended to explain terms used in the insulation industry rather than to provide a full list of relevant scientific definitions. For this reason the term “description” is consider
8、ed more appropriate than “definition” as normally used in British Standard glossaries. The descriptions are however compatible with the scientific definitions given in BS874 and other British Standards publications. Where it has been considered to be helpful, the descriptions have been elaborated by
9、 explanatory notes, references and symbols. Where units are indicated (in parentheses at the end of appropriate definitions), these are given in terms of the Systme International dUnits(abbreviated to “SIunits”). For details seePD5686. The glossary has been divided somewhat arbitrarily into four sec
10、tions dealing respectively with physical properties, insulating materials, descriptive terms, and fittings and accessory materials. In view of the relative infrequency of associated terms, items in the four sections have been tabulated in alphabetical order and an index has been provided for ease of
11、 reference. Preferred terms are printed in bold type, and non-preferred terms in non-bold type. Terms considered undesirable because their use could lead to confusion are followed by the word “deprecated” in italics. A British Standard does not purport to include all the necessary provisions of a co
12、ntract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to16, an inside back c
13、over and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.BS3533:1981 BSI 11-1999 1 References The titles of the publications referred to in this standard are listed on
14、the inside back cover. Section 1. Physical properties NOTEFor more detailed definitions of a number of the terms relating to thermal properties, seeBS874. No. Term Description 101 absorptivity The ratio of the amount of radiation absorbed by a surface to the amount falling on the surface. It can ref
15、er to radiation of any wavelength but commonly refers to solar radiation. 102 air permeability The fluid permeability of a material where air is the given fluid. See113. 103 bulk density The mass per unit volume of the insulating material (kg/m 3 ). 104 compressibility The relation between deformati
16、on and applied mechanical pressure on a material. 105 compressive strength crushing strength The capacity of a material to withstand mechanical pressure up to the point of fracture. NOTEFor materials that do not fail by shattering, the compressive strength may be deduced arbitrarily from a load/defo
17、rmation curve. 106 convection coefficient (f c ) The quantity of heat transferred by convection in unit time to or from unit area of surface, divided by the temperature difference between the surface and the surrounding air or other fluidW/(m 2 K). 107 covering capacity(dry) The area covered to unit
18、 thickness by unit mass of material as supplied, when it has been applied and dried to constant mass in accordance with BS2972(m 2per tonne at unit thickness). 108 creep Progressive permanent deformation of a material under load. 109 dimensional change (expansion or shrinkage) The increase or decrea
19、se in a characteristic dimension, which may be measured in linear, superficial or volumetric units. 110 emissivity (E) The ratio of the thermal radiation from unit area of a surface to the radiation from unit area of a full emitter(“black body”) at the same temperature. 111 equivalent thermal conduc
20、tivity The thermal conductivity assigned to a hypothetical uniform material of the same dimensions as a particular composite insulation that would give the same rate of heat flow under identical conditions. 112 flexural strength modulus of rupture cross-breaking strength The capacity of a material t
21、o withstand bending up to the point of fracture. 113 fluid permeability The property of a material that determines the rate at which a given fluid passes through it under the influence of unit pressure gradient. See102. 114 mean free path The average distance travelled by a gas molecule between succ
22、essive collisions with other molecules. 115 nominal thickness designated thickness Manufactured thickness within agreed tolerances.BS3533:1981 2 BSI 11-1999 No. Term Description 116 packing density The bulk density of loose-fill insulating material after application. 117 permanent set The deformatio
23、n of a material that remains after removal of the deforming stress. 118 porosity(apparent) The volume of open pores in a material expressed as a percentage of the total volume of the material. 119 porosity(true) The combined volume of open and closed pores in a material, expressed as a percentage of
24、 the total volume of the material. 120 radiation coefficient (f r ) The net quantity of heat radiated per unit time from unit area of a surface divided by the temperature difference between the radiating surface and the surroundings with which it is exchanging radiationW/(m 2 K). 121 radiation const
25、ant( ) Stefans constant The constant of proportionality of the Stefan-Boltzman equation relating the radiation loss per unit area of the surface to the fourth power of the absolute temperature of a body. B =5.67 10 8 W/(m 2 K 4 ). 122 reflectivity (r) The ratio of the amount of thermal radiation ref
26、lected from a surface to the amount that falls on the surface. 123 resilience The ability of a material to recover or partly recover its original dimensions after deformation. 124 shape factor A quantity derived from surface area divided by thickness, used in calculating heat transfer by thermal con
27、duction and varying with the geometry of the insulation(m). 125 surface coefficient (f) Thermal transmission per unit area to or from a surface in contact with air or other fluid, due to convection, conduction and radiation, divided by the difference between the temperature of the surface and the ef
28、fectiveambient temperature in “steady state” conditions W/(m2K). NOTE 1The value of the surface coefficient depends on many factors, such as the movement of air or other fluid, the roughness and emissivity of the surface and the temperature and nature of the surroundings. NOTE 2The term “effective a
29、mbient temperature” is used to indicate that the actual measured temperature may need to be corrected for factors such as atmospheric humidity, solar radiation and wind velocity before comparable results can be obtained. 126 surface resistance (1/f) The reciprocal of surface coefficient(see125). 127
30、 tensile strength The capacity of a material to withstand tension up to the point of fracture. 128 thermal capacity The quantity of heat required to raise the temperature of a given structure or quantity of material by1K. 129 thermal capacity per unit mass(c) specific heat capacity The quantity of h
31、eat required to raise the temperature of unit mass by1KJ/(kgK). 130 thermal capacity per unit volume Thermal capacity per unit mass multiplied by bulk densityJ/(m 3 K).BS3533:1981 BSI 11-1999 3 No. Term Description 131 thermal conductance (C) The thermal transmission through unit area of a slab of m
32、aterial, or of a structure, divided by the temperature difference between the hot and cold faces in “steady state” conditionsW/(m 2 K). NOTE 1When the hot face and the cold face are not equal in area, e.g.the internal and external surfaces of insulation on a box or pipe, it is necessary to state the
33、 position at which the area is measured. NOTE 2Thermal conductance depends upon the actual thickness of the material or structure, whereas thermal conductivity refers to unit thickness of the material. 132 thermal conductivity () The thermal transmission through unit area of a slab of a uniform mate
34、rial of unit thickness when unit difference of temperature is established between its facesW/(m K). NOTE 1Thermal conductivity was formerly given the symbol k. NOTE 2W/(m K) is a simplification of W m/m 2 K). 133 thermal diffusivity (!) Thermal conductivity divided by thermal capacity per unit volum
35、e (m 2 /s). 134 thermal resistance (R) The reciprocal of thermal conductance. 135 thermal resistivity (1/) The reciprocal of thermal conductivity. 136 thermal transmission (q) heat flux The quantity of heat flowing in unit time(W). 137 thermal transmittance (U) overall heat transfer coefficient The
36、thermal transmission through unit area of a given structure divided by the difference between the effective ambient temperatures on either side of the structure in “steady state” conditionsW/(m 2 K). NOTE 1If the structure is not a simple slab, it is necessary to state where the area is measured. NO
37、TE 2“Transmittance” differs from “conductance” because the temperature difference is measured between different positions. For conductance the temperature difference is that between the faces; for transmittance it is that between the effective ambient temperatures on either side of the structure. Th
38、us the thermal transmittance (U) of a structure involves both the thermal conductance and the surface coefficient of the structure. NOTE 3The term “effective ambient temperature” is used to indicate that the actual measured temperature may need to be corrected for factors such as atmospheric humidit
39、y, solar radiation and wind velocity before comparable results can be obtained. The U-value is normally referred to a particular combination of these factors. 138 total thermal resistance (1/U) The sum of the surface resistances and the thermal resistance of the structure itself. 139 U-value A conve
40、ntionally used value of thermal transmittance of a structure related to design conditions. NOTEFor calculation of standardized U-values, reference should be made to Building Research Establishment Digest no.108. 140 vapour permeance The property of a material that determines the rate at which vapour
41、 passes through it under the influence of unit partial water vapour pressure difference across the specimeng/(s MN). NOTEFor water vapour permeance conversion factors seeBS2972. 141 vapour permeability The vapour permeance of a material per unit thicknessgm/(s MN). Seealso BS3177. 142 vapour resista
42、nce The reciprocal of vapour permeance(see140). 143 vapour resistivity The reciprocal of vapour permeability(see141).BS3533:1981 4 BSI 11-1999 Section 2. Insulating materials No. Term Description 201 aluminium foil Thin sheets of rolled aluminium(0.15mm thick and under). 202 aluminium silicate fibre
43、 Filaments or fibres produced from a melt of alumina and silica. 203 animal hair Natural fibre obtained from the coats of animals (seealso wool, 276). 204 asbestos The generic name for those silicate minerals that cleave naturally into fibres, the three important forms being chrysotile(white asbesto
44、s), crocidolite(blue asbestos) and amosite. 205 asbestos insulating board A board containing a large percentage(by mass) of asbestos fibre, normally bonded with an inorganic bonding agent substantially insoluble in water. 206 asbestos millboard Board based on a mix that consists mainly of asbestos f
45、ibre and a binder(frequently organic). Fillers may be included. 207 asbestos paper Paper-like material of which the main constituent is asbestos fibre. 208 blowing wool Granulated wool(see230) for application by blowing. 209 calcium silicate insulation Hydrated calcium silicate with added reinforcin
46、g fibres. 210 cellular asbestos paper Sheet insulation formed by combining alternate sheets of flat with corrugated asbestos paper, and securing the adjacent sheets together at their points of contact by means of an adhesive. 211 cellular glass foamed glass A lightweight expanded glass with small ce
47、lls, preferably non-intercommunicating, produced by a foaming process. 212 cellular plastics expanded plastics foamed plastics A generic term for plastics material of which the density is reduced by the presence of numerous small cavities(cells), interconnecting or not, dispersed throughout the mass
48、. NOTESeeBS1755 for individual definitions. 213 cellular rubber A generic term for vulcanized rubber containing numerous thin-walled cells filled with air or other gas. The walls of the cells may be vulcanized to the soft rubber stage or completely to the hard rubber(ebonite) stage. 214 ceramic fibr
49、e Fibrous material, loose or fabricated into convenient forms, mainly intended for use at appropriate elevated temperatures. The fibres may consist of silica(SiO 2 ) or of an appropriate metal silicate, e.g.alumino-silicate. Alternatively, they may be formed synthetically from appropriate refractory metal oxides, e.g.alumina, zirconia. 215 compressed straw slab Natural straw compressed and bonded with its own resin. 216 corkboard Preformed material composed of granulated cork bonded by heating under pressure, with or without added adhesive. 217 di
