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1、BRITISH STANDARD BS EN ISO 14683:1999 Incorporating Corrigendum No. 1 Thermal bridges in building construction Linear thermal transmittance Simplified methods and default values The European Standard EN ISO 14683:1999 has the status of a British Standard ICS 91.120.10 NO COPYING WITHOUT BSI PERMISSI
2、ON EXCEPT AS PERMITTED BY COPYRIGHT LAW Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS EN ISO 14683:1999 This British Standard, having been prepared under the direction of the Sector Committee for Building and Civil Engineering, was publ
3、ished under the authority of the Standards Committee and comes into effect on 15 August 1999 BSI 03-2001 ISBN 0 580 32255 6 National foreword This British Standard is the English language version of EN ISO 14683:1999, including corrigendum December 1999. The UK participation in its preparation was e
4、ntrusted by Technical Committee B/540, Energy performance of materials, components and buildings, to Subcommittee B/540/1, European standards for thermal insulation, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any
5、 enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references
6、 The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue.
7、 A British Standard does not purport to include all the necessary provisions of a contract. 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
8、 a front cover, an inside front cover, the EN ISO title page, pages 2 to 23 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No.DateComments 10921 Corr No. 1 March 2001 Annex ZA inserted. Licen
9、sed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 14683 June 1999 ICS 91.120.10Incorporating corrigendum December 1999 English version Thermal bridges in building construction Linear thermal
10、transmittance Simplified methods and default values (ISO 14683:1999) Ponts thermiques dans les btiments Coefficient de transmission thermique linique Mthodes simplifies et valeurs par dfaut (ISO 14683:1999) Wrmebrcken im Hochbau Lngenbezogener Wrmedurchgangskoeffizient Vereinfachte Verfahren und Anh
11、altswerte (ISO 14683:1999) This European Standard was approved by CEN on 4 April 1999. 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 alteration. Up-to-date lists
12、 and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the respons
13、ibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Nethe
14、rlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1999 CEN All rights of exploitation in any form and by any means
15、reserved worldwide for CEN national Members.Ref. No. EN ISO 14683:1999 E Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 14683:1999 BSI 03-2001 2 Foreword The text of EN ISO 14683:1999 has been prepared by Technical Committee CEN/TC 8
16、9 “Thermal performance of buildings and building components”, the Secretariat of which is held by SIS, in collaboration with Technical Committee ISO/TC 163 “Thermal insulation”. This European Standard shall be given the status of a national standard, either by publication of an identical text or by
17、endorsement, at the latest by December 1999, and conflicting national standards shall be withdrawn at the latest by December 1999. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria
18、, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. This standard is one of a series of standards on calculation methods for the design and evaluation of the therm
19、al performance of buildings and building components. Contents Page Foreword2 Introduction3 1Scope3 2Normative references3 3Definitions, symbols and units3 3.1Definitions3 3.2Symbols and units4 4Influence of thermal bridges on overall heat loss4 4.1Transmission heat loss coefficient4 4.2Linear therma
20、l transmittance5 5Determination of linear thermal transmittance6 5.1Available methods and expected accuracy6 5.2Thermal bridge catalogues6 5.3Manual calculations7 5.4Default values of linear thermal transmittance7 Annex A (informative) Calculation basis for the default values of linear thermal trans
21、mittance19 Page Annex B (informative) Example of the use of default values of linear thermal transmittance in calculating the thermal coupling coefficient19 Annex ZA (informative) A-deviations23 Figure 1 Building showing the location and type of commonly occurring thermal bridges according to the sc
22、heme given in Table 28 Figure B.1 Schematic diagram of a building with the overall internal dimensions given and the location of the thermal bridges marked20 Table 1 Methods for calculating linear thermal transmittance6 Table 2 Default values of linear thermal transmittance29 Table B.1 Thermal coupl
23、ing coefficient through the plane building elements using overall internal dimensions20 Table B.2 Thermal coupling coefficient through the two-dimensional thermal bridges using overall internal dimensions21 Table B.3 Thermal coupling coefficient through the plane building elements using external dim
24、ensions21 Table B.4 Thermal coupling coefficient through the two-dimensional thermal bridges using external dimensions21 Table B.5 As Table B.2 but with bridge type IW2 replaced with IW5 and W8 with W1122 Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Co
25、py, (c) BSI EN ISO 14683:1999 BSI 03-2001 3 Introduction Thermal bridges in building constructions give rise to changes in heat flow rates and surface temperatures compared with those of the unbridged structure. These heat flow rates and temperatures can be precisely determined by numerical calculat
26、ion in accordance with EN ISO 10211-1 (three-dimensional heat flow) or prEN ISO 10211-2 (two-dimensional heat flow). However, for linear thermal bridges, it is convenient to use simplified methods to obtain an estimate of their linear thermal transmittance. The effect of repeating thermal bridges wh
27、ich are part of the otherwise uniform building element, such as wall ties penetrating the thermal insulation layer or mortar joints in lightweight blockwork, should be included in the calculation of the thermal transmittance of the particular building element in accordance with EN ISO 6946, Building
28、 components and building elements Thermal resistance and thermal transmittance Calculation method (ISO 6946:1996). Although not covered by this standard, it should be borne in mind that thermal bridges can also give rise to low internal surface temperatures, with an associated risk of surface conden
29、sation or mould growth. 1 Scope This standard deals with simplified methods for determining heat flows through linear thermal bridges which occur at junctions of building elements. It is not applicable to thermal bridging associated with window and door frames or curtain walling. It specifies requir
30、ements relating to thermal bridge catalogues and manual calculation methods, and provides a limited number of tabulated default values of linear thermal transmittances. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These
31、 normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated refere
32、nces the latest edition of the publication referred to applies. EN ISO 7345, Thermal insulation Physical quantities and definitions. (ISO 7345:1987) EN ISO 10211-1, Thermal bridges in building construction Heat flows and surface temperatures Part 1: General calculation methods. (ISO 10211-1:1995) pr
33、EN ISO 10211-2, Thermal bridges in building construction Calculation of heat flows and surface temperatures Part 2: Linear thermal bridges. (ISO/FDIS 10211-2:1999) EN ISO 13370, Thermal performance of buildings Heat transfer via the ground Calculation method. (ISO 13370:1998) prEN ISO 13789, Thermal
34、 performance of buildings Transmission heat loss coefficient Calculation method. (ISO/DIS 13789:1997) 3 Definitions, symbols and units 3.1 Definitions For the purposes of this standard the definitions given in EN ISO 7345 and the following definitions apply. 3.1.1 linear thermal bridge thermal bridg
35、e with a uniform cross section in one direction 3.1.2 point thermal bridge thermal bridge with no uniform cross section in any direction 3.1.3 thermal coupling coefficient heat flow rate divided by temperature difference between two environments which are thermally connected by the construction unde
36、r consideration Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 14683:1999 4 BSI 03-2001 3.1.4 linear thermal coupling coefficient thermal coupling coefficient obtained from a two-dimensional calculation 3.1.5 linear thermal transmitt
37、ance heat flow rate in the steady state divided by length and by the temperature difference between the environments on either side of the thermal bridge NOTEThe linear thermal transmittance is used as a correction term for the linear influence of a thermal bridge when calculating the thermal coupli
38、ng coefficient from one-dimensional calculations. 3.2 Symbols and units 4 Influence of thermal bridges on overall heat loss 4.1 Transmission heat loss coefficient Between internal and external environments with temperatures ?i and ?e respectively, the transmission heat flow rate through the building
39、 envelope, ?, can be calculated from the equation: The transmission heat loss coefficient, HT, is calculated from the equation: SymbolPhysical quantityUnit Aaream2 HTtransmission heat loss coefficientW/K Lthermal coupling coefficientW/K L2Dlinear thermal coupling coefficientW/(mK) Rthermal resistanc
40、em2K/W Rseexternal surface resistancem2K/W Rsiinternal surface resistancem2K/W Uthermal transmittanceW/(m2K) bwidthM dthicknessM hsurface coefficient of heat transferW/(m2K) llengthM ?Celsius temperature?C ?design thermal conductivityW/(mK) ?heat flow rateW ?linear thermal transmittanceW/(mK) ?point
41、 thermal transmittanceW/K List of subscripts: eexternal iinternal oioverall internal ? = HT (?i ?e)(1) HT = L + Ls + HU(2) Licensed Copy: sheffieldun sheffieldun, na, Mon Nov 20 03:06:26 GMT+00:00 2006, Uncontrolled Copy, (c) BSI EN ISO 14683:1999 BSI 03-2001 5 where 4.2 Linear thermal transmittance
42、 When calculating the thermal coupling coefficient, L, the effect of thermal bridges is often ignored. However, buildings can contain significant thermal bridges, one effect of which is to increase the overall heat loss from the building. In this case, to obtain the correct thermal coupling coeffici
43、ent, it is necessary to add correction terms involving linear and point thermal transmittances as follows: where Generally the influence of point thermal bridges (insofar as they result from the intersection of linear thermal bridges) can be neglected and so the correction term involving point therm
44、al 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 EN ISO 10211-1. Linear thermal transmittance values depend on the system of building dimensions used in calculating the
45、areas of one-dimensional heat flow i.e. in the calculation of ?UiAi in equation (3). The linear thermal transmittance, ?, can be calculated from the equation: where Any calculation of linear thermal transmittance, ?, shall state the system of dimensions on which it is based. Table 2 in 5.4 gives def
46、ault values of ? rounded to the nearest 0,05 W/(mK) based on three systems of building dimensions: internal dimensions, measured between the finished internal faces of each room in a building (thus excluding the thickness of internal partitions); overall internal dimensions, measured between the fin
47、ished internal faces of the external elements of a building (thus including the thickness of internal partitions); external dimensions, measured between the finished external faces of the external elements of a building. NOTEThese three common dimension systems are described in prEN ISO 13789. Table
48、 2 also gives, for each detail, the linear thermal coupling coefficient, L2D, so that for any other dimension system, the appropriate default value of? can be calculated using equation (4), with the values of U taken from Annex A and the lengths l according to the chosen dimension system. Lis the th
49、ermal coupling coefficient through the building envelope defined by equation (3); LSis the ground thermal coupling coefficient calculated in accordance with EN ISO 13370; HUis the heat loss coefficient through unheated spaces calculated in accordance with prEN ISO 13789. L = ? Ui Ai + ? ?k Ik + ? ?j(3) Lis the thermal coupling coefficient; Uiis the thermal transmittance of part i of the building envelope; Aiis the area over which the value of Ui applies; ?kis the linear thermal tr