SIST EN ISO 10211:2008
(Main)Thermal bridges in building construction - Heat flows and surface temperatures - Detailed calculations (ISO 10211:2007)
Thermal bridges in building construction - Heat flows and surface temperatures - Detailed calculations (ISO 10211:2007)
This International Standard sets out the specifications for a three-dimensional and a two-dimensional geometrical model of a thermal bridge for the numerical calculation of: heat flows, in order to assess the overall heat loss from a building or pa rt of it; minimum surface temperatures, in order to assess the risk of surface condensation. These specifications include th e geometrical boundaries and subdivisions of the model, the th ermal boundary conditions, and the thermal values and relation ships to be used. This International Standard is based upon th e following assumptions: all physical properties are independe nt of temperature; there are no heat sources within the buildi ng element. This International Standard can also be used for t he derivation of linear and point thermal transmittances and o f surface temperature factors.
Wärmebrücken im Hochbau - Wärmeströme und Oberflächentemperaturen - Detaillierte Berechnungen (ISO 10211:2007)
Diese Norm legt die Spezifikationen für geometrische 3-D- und 2-D-Modelle von Wärmebrücken fest zur
numerischen Berechnung:
.von Wärmeströmen zur Abschätzung der Gesamtwärmeverluste eines Gebäudes oder Gebäudeteils;
.der niedrigsten Oberflächentemperaturen zur Abschätzung des Risikos einer Tauwasserbildung.
Diese Spezifikationen enthalten die geometrischen Grenzen, die Unterteilungen des Modells, die
wärmetechnischen Grenzen und die zu verwendenden wärmetechnischen Kennwerte und Beziehungen.
Die Norm beruht auf folgenden Annahmen:
.stationäre Bedingungen;
.alle physikalischen Eigenschaften sind temperaturunabhängig;
.keine Wärmequellen im Bauteil.
Sie darf auch für die Ermittlung von längenbezogenen und punktbezogenen Wärmedurchgangskoeffizienten
und Oberflächentemperaturkennzahlen angewendet werden.
Ponts thermiques dans les bâtiments - Flux thermiques et températures superficielles - Calculs détaillés (ISO 10211:2007)
L'ISO 10211:2007 établit les spécifications sur les modèles géométriques tridimensionnels et bidimensionnels d'un pont thermique, pour le calcul numérique des flux thermiques, afin d'évaluer la déperdition thermique globale d'un bâtiment ou d'une partie de bâtiment, et des températures superficielles minimales, afin d'évaluer le risque de condensation superficielle.
Ces spécifications incluent les limites du modèle géométrique et ses subdivisions, les conditions aux limites et les valeurs thermiques qui lui sont liées à utiliser.
L'ISO 10211:2007 est basée sur les suppositions suivantes: toutes les propriétés physiques sont indépendantes de la température, et absence de source de chaleur à l'intérieur de l'élément de construction.
L'ISO 10211:2007 peut aussi être utilisée pour la détermination des coefficients linéiques ou ponctuels de transmission thermique, ainsi que pour les facteurs de température superficielle.
Toplotni mostovi v stavbah - Toplotni tokovi in površinske temperature - Podrobni izračuni (ISO 10211:2007)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 10211:2008
01-maj-2008
1DGRPHãþD
SIST EN ISO 10211-1:1997
SIST EN ISO 10211-1:1997/AC:2002
SIST EN ISO 10211-2:2002
7RSORWQLPRVWRYLYVWDYEDK7RSORWQLWRNRYLLQSRYUãLQVNHWHPSHUDWXUH3RGUREQL
L]UDþXQL ,62
Thermal bridges in building construction - Heat flows and surface temperatures -
Detailed calculations (ISO 10211:2007)
Wärmebrücken im Hochbau - Wärmeströme und Oberflächentemperaturen - Detaillierte
Berechnungen (ISO 10211:2007)
Ponts thermiques dans les bâtiments - Flux thermiques et températures superficielles -
Calculs détaillés (ISO 10211:2007)
Ta slovenski standard je istoveten z: EN ISO 10211:2007
ICS:
91.120.10
SIST EN ISO 10211:2008 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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EUROPEAN STANDARD
EN ISO 10211
NORME EUROPÉENNE
EUROPÄISCHE NORM
December 2007
ICS 91.120.10 Supersedes EN ISO 10211-1:1995, EN ISO 10211-2:2001
English Version
Thermal bridges in building construction - Heat flows and
surface temperatures - Detailed calculations (ISO 10211:2007)
Ponts thermiques dans les bâtiments - Flux thermiques et Wärmebrücken im Hochbau - Wärmeströme und
températures superficielles - Calculs détaillés (ISO Oberflächentemperaturen - Detaillierte Berechnungen (ISO
10211:2007) 10211:2007)
This European Standard was approved by CEN on 7 December 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 alteration. 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 translation
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, Germany, 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
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
Management Centre: rue de Stassart, 36 B-1050 Brussels
© 2007 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 10211:2007: E
worldwide for CEN national Members.
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EN ISO 10211:2007 (E)
Contents Page
Foreword.3
2
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EN ISO 10211:2007 (E)
Foreword
This document (EN ISO 10211:2007) 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 building 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 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 10211-1:1995, EN ISO 10211-2:2001.
According to the CEN/CENELEC Internal 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, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 10211:2007 has been approved by CEN as a EN ISO 10211:2007 without any modification.
3
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INTERNATIONAL ISO
STANDARD 10211
First edition
2007-12-15
Thermal bridges in building
construction — Heat flows and surface
temperatures — Detailed calculations
Ponts thermiques dans les bâtiments — Flux thermiques et
températures superficielles — Calculs détaillés
Reference number
ISO 10211:2007(E)
©
ISO 2007
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ISO 10211:2007(E)
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ii © ISO 2007 – All rights reserved
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ISO 10211:2007(E)
Contents Page
Foreword. v
Introduction . vi
1 Scope .1
2 Normative references .1
3 Terms, definitions, symbols, units and subscripts.2
3.1 Terms and definitions .2
3.2 Symbols and units.6
3.3 Subscripts .7
4 Principles.7
5 Modelling of the construction .7
5.1 Dimension systems .7
5.2 Rules for modelling .7
5.3 Conditions for simplifying the geometrical model.13
6 Input data.17
6.1 General.17
6.2 Thermal conductivities of materials .18
6.3 Surface resistances.18
6.4 Boundary temperatures .18
6.5 Thermal conductivity of quasi-homogeneous layers .18
6.6 Equivalent thermal conductivity of air cavities .18
6.7 Determining the temperature in an adjacent unheated room .19
7 Calculation method.19
7.1 Solution technique.19
7.2 Calculation rules.19
8 Determination of thermal coupling coefficients and heat flow rate from 3-D calculations .20
8.1 Two boundary temperatures, unpartitioned model.20
8.2 Two boundary temperatures, partitioned model.20
8.3 More than two boundary temperatures .21
9 Calculations using linear and point thermal transmittances from 3-D calculations .21
9.1 Calculation of thermal coupling coefficient.21
9.2 Calculation of linear and point thermal transmittances .22
10 Determination of thermal coupling coefficient, heat flow rate and linear thermal
transmittance from 2-D calculations.23
10.1 Two boundary temperatures .23
10.2 More than two boundary temperatures .23
10.3 Determination of the linear thermal transmittance .23
10.4 Determination of the linear thermal transmittance for wall/floor junctions.24
10.5 Determination of the external periodic heat transfer coefficient for ground floors .25
11 Determination of the temperature at the internal surface .26
11.1 Determination of the temperature at the internal surface from 3-D calculations .26
11.2 Determination of the temperature at the internal surface from 2-D calculations .27
12 Input and output data .28
12.1 Input data.28
12.2 Output data.28
Annex A (normative) Validation of calculation methods .30
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ISO 10211:2007(E)
Annex B (informative) Examples of the determination of the linear and
point thermal transmittances. 37
Annex C (informative) Determination of values of thermal coupling coefficient and temperature
weighting factor for more than two boundary temperatures . 40
Bibliography . 45
iv © ISO 2007 – All rights reserved
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ISO 10211:2007(E)
Foreword
ISO (the International Organization for Standardization) 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 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 Standards 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
International 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 10211 was prepared by Technical Committee ISO/TC 163, Thermal performance and energy use in the
built environment, Subcommittee SC 2, Calculation methods.
This first edition of ISO 10211 cancels and replaces ISO 10211-1:1995 and ISO 10211-2:2001, which have
been technically revised.
The principal changes are as follows:
⎯ this first edition of ISO 10211 merges the title and general contents of ISO 10211-1:1995 and
ISO 10211-2:2001 into a single document;
⎯ Clause 3 indicates that ISO 10211 now uses only temperature factor, and not temperature difference
ratio;
⎯ 5.2.2 specifies that cut-off planes are to be located at the larger of 1 m and three times the thickness of
the flanking element;
⎯ 5.2.4 contains a revised version of Table 1 to correct error for three-dimensional calculations and to clarify
intentions;
⎯ 5.2.7 specifies that acceptable criterion is either on heat flow or on surface temperature; the heat flow
criterion has been changed from 2 % to 1 %;
⎯ 6.3 specifies that surface resistance values are to be obtained from ISO 6946 for heat flow calculations
and from ISO 13788 for condensation calculations; the contents of Annexes E and G of
ISO 10211-1:1995 have been deleted in favour of references to ISO 13788;
⎯ 6.6 specifies that data for air cavities is obtained from ISO 6946, EN 673 or ISO 10077-2; the contents of
Annex B of ISO 10211-1:1995 have been deleted in favour of these references;
⎯ 10.4 contains text formerly in ISO 13370, revised to specify that linear thermal transmittance values for
wall/floor junctions are the difference between the numerical result and the result from using ISO 13370
(a more consistent definition);
⎯ Annex A contains corrections to results for case 3; the conformity criterion for case 3 has been changed
from 2 % of heat flow to 1 %; a new case 4 has been added;
⎯ Annex C contains a corrected procedure;
⎯ all remaining annexes from ISO 10211-1:1995 and ISO 10211-2:2001 have been deleted.
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ISO 10211:2007(E)
Introduction
Thermal bridges, which in general occur at any junction between building components or where the building
structure changes composition, have two consequences compared with those of the unbridged structure:
a) a change in heat flow rate, and
b) a change in internal surface temperature.
Although similar calculation procedures are used, the procedures are not identical for the calculation of heat
flows and of surface temperatures.
A thermal bridge usually gives rise to three-dimensional or two-dimensional heat flows, which can be precisely
determined using detailed numerical calculation methods as described in this International Standard.
In many applications, numerical calculations based on a two-dimensional representation of the heat flows
provide results of adequate accuracy, especially when the constructional element is uniform in one direction.
A discussion of other methods for assessing the effect of thermal bridges is provided in ISO 14683.
ISO 10211 was originally published in two parts, dealing with three-dimensional and two-dimensional
calculations separately.
vi © ISO 2007 – All rights reserved
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INTERNATIONAL STANDARD ISO 10211:2007(E)
Thermal bridges in building construction — Heat flows and
surface temperatures — Detailed calculations
1 Scope
This International Standard sets out the specifications for a three-dimensional and a two-dimensional
geometrical model of a thermal bridge for the numerical calculation of:
⎯ heat flows, in order to assess the overall heat loss from a building or part of it;
⎯ minimum surface temperatures, in order to assess the risk of surface condensation.
These specifications include the geometrical boundaries and subdivisions of the model, the thermal boundary
conditions, and the thermal values and relationships to be used.
This International Standard is based upon the following assumptions:
⎯ all physical properties are independent of temperature;
⎯ there are no heat sources within the building element.
This International Standard can also be used for the derivation of linear and point thermal transmittances and
of surface temperature factors.
2 Normative references
The following referenced documents are indispensable for 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 6946, Building components and building elements — Thermal resistance and thermal transmittance —
Calculation method
ISO 7345, Thermal insulation — Physical quantities and definitions
ISO 13370:2007, Thermal performance of buildings — Heat transfer via the ground — Calculation methods
ISO 13788, Hygrothermal performance of building components and building elements — Internal surface
temperature to avoid critical surface humidity and interstitial condensation — Calculation methods
© ISO 2007 – All rights reserved 1
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ISO 10211:2007(E)
3 Terms, definitions, symbols, units and subscripts
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
thermal bridge
part of the building envelope where the otherwise uniform thermal resistance is significantly changed by full or
partial penetration of the building envelope by materials with a different thermal conductivity, and/or a change
in thickness of the fabric, and/or a difference between internal and external areas, such as occur at
wall/floor/ceiling junctions
3.1.2
linear thermal bridge
thermal bridge with a uniform cross-section along one of the three orthogonal axes
3.1.3
point thermal bridge
localized thermal bridge whose influence can be represented by a point thermal transmittance
3.1.4
three-dimensional geometrical model
3-D geometrical model
geometrical model, deduced from building plans, such that for each of the orthogonal axes the cross-section
perpendicular to that axis changes within the boundary of the model
See Figure 1.
3.1.5
three-dimensional flanking element
3-D flanking element
part of a 3-D geometrical model which, when considered in isolation, can be represented by a 2-D geometrical
model
See Figures 1 and 2.
3.1.6
three-dimensional central element
3-D central element
part of a 3-D geometrical model which is not a 3-D flanking element
See Figure 1.
NOTE A central element is represented by a 3-D geometrical model.
3.1.7
two-dimensional geometrical model
2-D geometrical model
geometrical model, deduced from building plans, such that for one of the orthogonal axes the cross-section
perpendicular to that axis does not change within the boundaries of the model
See Figure 2.
NOTE A 2-D geometrical model is used for two-dimensional calculations.
3.1.8
two-dimensional flanking element
2-D flanking element
part of a 2-D geometrical model which, when considered in isolation, consists of plane, parallel material layers
2 © ISO 2007 – All rights reserved
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ISO 10211:2007(E)
3.1.9
two-dimensional central element
2-D central element
part of a 2-D geometrical model which is not a 2-D flanking element
3.1.10
construction planes
planes in the 3-D or 2-D geometrical model which separate different materials, and/or the geometrical model
from the remainder of the construction, and/or the flanking elements from the central element
See Figure 3.
3.1.11
cut-off planes
construction planes that are boundaries to the 3-D or 2-D geometrical model by separating the model from the
remainder of the construction
See Figure 3.
3.1.12
auxiliary planes
planes which, in addition to the construction planes, divide the geometrical model into a number of cells
3.1.13
quasi-homogeneous layer
layer which consists of two or more materials with different thermal conductivities, but which can be
considered as a homogeneous layer with an effective thermal conductivity
See Figure 4.
3.1.14
temperature factor at the internal surface
difference between internal surface temperature and external temperature, divided by the difference between
internal temperature and external temperature, calculated with a surface resistance R at the internal surface
si
3.1.15
temperature weighting factor
weighting factor which states the respective influence of the temperatures of the different thermal
environments upon the surface temperature at the point under consideration
3.1.16
external boundary temperature
external air temperature, assuming that the air temperature and the radiant temperature seen by the surface
are equal
3.1.17
internal boundary temperature
operative temperature, taken for the purposes of this International Standard as the arithmetic mean value of
internal air temperature and mean radiant temperature of all surfaces surrounding the internal environment
3.1.18
thermal coupling coefficient
heat flow rate per temperature difference between two environments which are thermally connected by the
construction under consideration
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ISO 10211:2007(E)
3.1.19
linear thermal transmittance
heat flow rate in the steady state divided by length and by the temperature difference between 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.
3.1.20
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 influence of a point thermal bridge on the total
heat flow.
Key
F1, F2, F3, F4, F5 3-D flanking elements C 3-D central element
NOTE 3-D Flanking elements have constant cross-sections perpendicular to at least one axis; the 3-D central
element is the remaining part.
Figure 1 — 3-D geometrical model with five 3-D flanking elements and one 3-D central element
4 © ISO 2007 – All rights reserved
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ISO 10211:2007(E)
Key
F2, F3, F4, F5 3-D flanking elements C 3-D central element
NOTE F2 to F5 refer to Figure 1.
Figure 2 — Cross-sections of the 3-D flanking elements in a 3-D geometrical model
treated as 2-D geometrical models
Key
C construction planes perpendicular to the x-axis
x
C construction planes perpendicular to the y-axis
y
C construction planes perpendicular to the z-axis
z
NOTE Cut-off planes are indicated with enlarged arrows; planes that separate flanking elements from central element
are encircled.
Figure 3 — Example of a 3-D geometrical model showing construction planes
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ISO 10211:2007(E)
Figure 4 — Example of a minor point thermal bridge giving rise to three-dimensional heat flow,
incorporated into a quasi-homogeneous layer
3.2 Symbols and units
Symbol Quantity Unit
2
A area m
B′ characteristic dimension of floor m
b width m
d thickness m
f temperature factor at the internal surface _
Rsi
g temperature weighting factor _
h height m
L thermal coupling coefficient from two-dimensional calculation W/(m·K)
2D
L thermal coupling coefficient from three-dimensional calculation W/K
3D
l length m
2
q density of heat flow rate W/m
2
R thermal resistance m ·K/W
2
R external surface resistance m ·K/W
se
2
R internal surface resistance m ·K/W
si
T thermodynamic temperature K
2
U thermal transmittance W/(m ·K)
3
V volume m
w wall thickness m
Φ heat flow rate W
λ thermal conductivity W/(m·K)
θ Celsius temperature °C
∆θ temperature difference K
χ point thermal transmittance W/K
Ψ linear thermal transmittance W/(m·K)
6 © ISO 2007 – All rights reserved
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ISO 10211:2007(E)
3.3 Subscripts
Subscript Definition
e external
i internal
min minimum
s surface
4 Principles
The temperature distribution within, and the heat flow through, a construction can be calculated if the
boundary conditions and constructional details are known. For this purpose, the geometrical model is divided
into a number of adjacent material cells, each with a homogeneous thermal conductivity. The criteria which
shall be met when constructing the model are given in Clause 5.
In Clause 6, instructions are given for the determination of the values of thermal conductivity and boundary
conditions.
The temperature distribution is determined either by means of an iterative calculation or by a direct solution
technique, after which the temperature distribution within the material cells is determined by interpolation. The
calculation rules and the method of determining the temperature distribution are described in Clause 7.
The results of the calculations can be used to determine linear thermal transmittances, point thermal
transmittances and internal surface temperatures. The equations for doing so are provided in Clauses 9, 10
and 11.
Specific procedures for window frames are given in ISO 10077-2.
5 Modelling of the construction
5.1 Dimension systems
Lengths may be measured using internal dimensions, overall internal dimensions or external dimensions,
provided that the same system is used consistently for all parts of a building.
NOTE For further information on dimension systems, see ISO 13789.
5.2 Rules for modelling
5.2.1 General
It is not usually feasible to model a complete building using a single geometrical model. In most cases, the
building may be partitioned into several parts (including the subsoil, where appropriate) by using cut-off
planes. This partitioning shall be performed in such a way that all differences are avoided in the results of
calculation between the partitioned building and the building when treated as a whole. This partitioning into
several geometrical models is achieved by choosing suitable cut-off planes.
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ISO 10211:2007(E)
5.2.2 Cut-off planes for a 3-D geometrical model for calculation of total heat flow and/or surface
temperatures
The geometrical model includes the central element(s), the flanking elements and, where appropriate, the
subsoil. The geometrical model is delimited by cut-off planes.
Cut-off planes shall be positioned as follows:
⎯ at a symmetry plane if this is less than d from the central element (see Figure 5);
min
⎯ at least d from the central element if there is no nearer symmetry plane (see Figure 6);
min
⎯ in the gr
...
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