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1、BS EN ISO 14683:2007 ICS 91.120.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BRITISH STANDARD Thermal bridges in building construction Linear thermal transmittance Simplified methods and default values (ISO 14683:2007) Licensed Copy: London South Bank University, South B
2、ank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI This British Standard was published under the authority of the Standards Policy and Strategy Committee on 3 ember 2008 BSI 2008 ISBN 978 0 580 64347 7 Amendments/corrigenda issued since publication DateComments BS EN ISO 14683:2007 Nationa
3、l foreword This British Standard is the UK implementation of EN ISO 14683:2007. It supersedes BS EN ISO 14683:1999 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee B/540, Energy performance of materials components and buildings. A list of organizations
4、 represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. 1
5、Dec Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 14683 December 2007 ICS 91.120.10Supersedes EN ISO 14683:1999 English Version Thermal bridges in building construction - Linea
6、r thermal transmittance - Simplified methods and default values (ISO 14683:2007) Ponts thermiques dans les btiments - Coefficient linique de transmission thermique - Mthodes simplifies et valeurs par dfaut (ISO 14683:2007) Wrmebrcken im Hochbau - Lngenbezogener Wrmedurchgangskoeffizient - Vereinfach
7、te Verfahren und Anhaltswerte (ISO 14683:2007) This European Standard was approved by CEN on 7 November 2007. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alter
8、ation. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by tran
9、slation under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germa
10、ny, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG
11、Management Centre: rue de Stassart, 36 B-1050 Brussels 2007 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 14683:2007: E Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (
12、c) BSI BS EN ISO 14683:2007 EN ISO 14683:2007 (E) 3 Foreword This document (EN ISO 14683:2007) has been prepared by Technical Committee ISO/TC 163 “Thermal performance and energy use in the built environment“ in collaboration with Technical Committee CEN/TC 89 “Thermal performance of buildings and b
13、uilding components“, the secretariat of which is held by SIS. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2008, and conflicting national standards shall be withdrawn at the latest by June
14、 2008. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN ISO 14683:1999. According to the CEN/CENELEC Intern
15、al Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malt
16、a, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. Endorsement notice The text of ISO 14683:2007 has been approved by CEN as a EN ISO 14683:2007 without any modification. Licensed Copy: London South Bank University, South Bank Un
17、iversity, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 ISO 14683:2007(E) ISO 2007 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope 1 2 Normative references1 3 Terms, definitions, symbols and units1 3.1 Terms and definitions .1 3.2 Symbols and units.2 3.3
18、Subscripts 2 4 Influence of thermal bridges on overall heat transfer3 4.1 Transmission heat transfer coefficient .3 4.2 Linear thermal transmittance .3 4.3 Internal and external dimensions.4 5 Determination of linear thermal transmittance.4 5.1 Available methods and expected accuracy 4 5.2 Numerical
19、 calculations4 5.3 Thermal bridge catalogues.4 5.4 Manual calculation methods.5 5.5 Default values of linear thermal transmittance.5 Annex A (informative) Default values of linear thermal transmittance6 Annex B (informative) Example of the use of default values of linear thermal transmittance in cal
20、culating the heat transfer coefficient19 Bibliography23 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 ISO 14683:2007(E) iv ISO 2007 All rights reserved Foreword ISO (the International Organization for Standardiza
21、tion) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be
22、represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standard
23、s are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an Interna
24、tional Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 14683 was
25、 prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the built environment, Subcommittee SC 2, Calculation methods. This second edition cancels and replaces the first edition (ISO 14683:1999), which has been technically revised. The following principal changes have been
26、 made to the first edition: the Scope has been amended to remove the restriction on window and door frames and curtain walling, and specifies that the default values of linear thermal transmittance are provided for information; 5.2 is a new subclause replacing some elements previously contained in 4
27、.2; 5.5 is a summary into a short text of the former 5.4, the remainder of which has been transferred into informative Annex A; Annex A contains values of linear thermal transmittance which have all been reviewed, many of them amended upwards as a result of changing the basis in Table A.1 (intermedi
28、ate floor slabs thickness of 200 mm instead of 150 mm; frames in openings of thickness 60 mm instead of 100 mm). Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 ISO 14683:2007(E) ISO 2007 All rights reserved v Intr
29、oduction This International Standard provides the means (in part) to assess the contribution that building products and services make to energy conservation and to the overall energy performance of buildings. Thermal bridges in building constructions give rise to changes in heat flow rates and surfa
30、ce temperatures compared with those of the unbridged structure. These heat flow rates and temperatures can be precisely determined by numerical calculation in accordance with ISO 10211. However, for linear thermal bridges, it is often convenient to use simplified methods or tabulated values to obtai
31、n an estimate of their linear thermal transmittance. The effect of repeating thermal bridges which are part of an otherwise uniform building element, such as wall ties penetrating a thermal insulation layer or mortar joints in lightweight blockwork, needs to be included in the calculation of the the
32、rmal transmittance of the building element concerned, in accordance with ISO 6946. Although not covered by this International Standard, it is worth noting that thermal bridges can also give rise to low internal surface temperatures, with an associated risk of surface condensation or mould growth. Li
33、censed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 INTERNATIONAL STANDARD ISO 14683:2
34、007(E) ISO 2007 All rights reserved 1 Thermal bridges in building construction Linear thermal transmittance Simplified methods and default values 1 Scope This International Standard deals with simplified methods for determining heat flows through linear thermal bridges which occur at junctions of bu
35、ilding elements. This International Standard specifies requirements relating to thermal bridge catalogues and manual calculation methods. Default values of linear thermal transmittance are given in Annex A for information. 2 Normative references The following referenced documents are indispensable f
36、or the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 7345, Thermal insulation Physical quantities and definitions ISO 10211, Thermal bridges in building
37、 construction Heat flows and surface temperatures Detailed calculations 3 Terms, definitions, symbols and units 3.1 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 7345 and the following apply. 3.1.1 linear thermal bridge thermal bridge with a uniform
38、cross section along one of the three orthogonal axes 3.1.2 point thermal bridge localized thermal bridge whose influence can be represented by a point thermal transmittance 3.1.3 linear thermal transmittance heat flow rate in the steady state divided by length and by the temperature difference betwe
39、en the environments on either side of a thermal bridge NOTE The linear thermal transmittance is a quantity describing the influence of a linear thermal bridge on the total heat flow. Licensed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS E
40、N ISO 14683:2007 ISO 14683:2007(E) 2 ISO 2007 All rights reserved 3.1.4 point thermal transmittance heat flow rate in the steady state divided by the temperature difference between the environments on either side of a thermal bridge NOTE The point thermal transmittance is a quantity describing the i
41、nfluence of a point thermal bridge on the total heat flow. 3.1.5 transmission heat transfer coefficient heat flow rate due to thermal transmission through the fabric of a building, divided by the difference between the environment temperatures on either side of the construction 3.2 Symbols and units
42、 Symbol Quantity Unit A area m2 b width m d thickness m HT transmission heat transfer coefficient W/K HD direct transmission heat transfer coefficient W/K HU transmission heat transfer coefficient through unconditioned spaces W/K l length m R thermal resistance m2K/W Rse external surface resistance
43、m2K/W Rsi internal surface resistance m2K/W U thermal transmittance W/(m2K) Celsius temperature C design thermal conductivity W/(mK) heat flow rate W linear thermal transmittance W/(mK) point thermal transmittance W/K 3.3 Subscripts Subscript Definition e external i internal oi overall internal Lice
44、nsed Copy: London South Bank University, South Bank University, 31/01/2009 03:09, Uncontrolled Copy, (c) BSI BS EN ISO 14683:2007 ISO 14683:2007(E) ISO 2007 All rights reserved 3 4 Influence of thermal bridges on overall heat transfer 4.1 Transmission heat transfer coefficient Between internal and e
45、xternal environments with temperatures i and e respectively, the transmission heat flow rate through the building envelope, , is calculated using Equation (1): () Tie H= (1) The transmission heat transfer coefficient, HT, is calculated using Equation (2): TDgU HHHH=+ (2) where HD is the direct heat
46、transfer coefficient through the building envelope defined by Equation (3); Hg is the ground heat transfer coefficient calculated in accordance with ISO 13370; HU is the heat transfer coefficient through unconditioned spaces calculated in accordance with ISO 13789. 4.2 Linear thermal transmittance T
47、he calculation of the transmission heat transfer coefficient includes the contribution due to thermal bridges, according to Equation (3): Diikkj ikj HA Ul=+ (3) where Ai is the area of element i of the building envelope, in m2; Ui is the thermal transmittance of element i of the building envelope, i
48、n W/(m2K); lk is the length of linear thermal bridge k, in m; k is the linear thermal transmittance of linear thermal bridge k, in W/(mK); j is the point thermal transmittance of the point thermal bridge j, in W/K. In general, the influence of point thermal bridges (insofar as they result from the i
49、ntersection of linear thermal bridges) can be neglected and so the correction term involving point thermal bridges can be omitted from Equation (3). If, however, there are significant point thermal bridges, then the point thermal transmittances should be calculated in accordance with ISO 10211. Linear thermal bridges are generally liable to occur at the following locations in a building envelope: at junctions between external elements (corners of walls, wall to roof, wall to floor);