EN 675:2011
(Main)Glass in building - Determination of thermal transmittance (U value) - Heat flow meter method
Glass in building - Determination of thermal transmittance (U value) - Heat flow meter method
This European Standard specifies a measurement procedure to determine the thermal transmittance of glazing with flat and parallel surfaces. For the purpose of this Standard, structured surfaces may be considered to be flat..
This European Standard applies to multiple glazing with outer panes which are not transparent to far infrared radiation (in the wavelength range 5 to 50μm), which is the case for soda lime silicate glass products, borosilicate glass and glass ceramics. Internal elements can be far infrared transparent.
The procedure specified in this European Standard determines the U value (thermal transmittance) in the central area of glazing. The edge effects due to the thermal bridge through the spacer of an insulating glass unit or through the window frame are not included.
The edge effects due to the thermal bridge through the spacer of an insulating glass unit or through the window frame are excluded. Energy transfer due to solar radiation is also excluded.
The procedure specified in this European Standard should be considered only when the thermal transmittance of the glazing cannot be calculated in accordance with EN 673.
The determination of the thermal transmittance is performed for conditions which correspond to the average situation for glazing in practice.
NOTE Patterned glass is an example of a glass with a structured surface;
For the purposes of product comparison, a vertical position of the glazing is specified (see Clause 10).
U values evaluated according to the present standard are used for product comparison as well as for other purposes, in particular for predicting:
- heat loss through glazing;
- conduction heat gains in summer;
- condensation on glazing surfaces;
- the effects of the absorbed solar radiation in determining the solar factor (see A.2).
Reference should be made to A.3, A.4, A.5 or other European Standards dealing with heat loss calculations for the application of glazing U values determined by this Standard.
The determination of the thermal transmittance is performed for conditions which correspond to the average situation for glazing in practice.
NOTE Patterned glass is an example of a glass with a structured surface;
Glas im Bauwesen - Bestimmung des Wärmedurchgangskoeffizienten (UWert) - Wärmestrommesser-Verfahren
Diese Europäische Norm legt ein Messverfahren fest, das zur Bestimmung des Wärmedurchgangs-koeffizienten von Verglasungen mit ebenen und parallelen Oberflächen dient. Für die Anwendung dieser Norm dürfen strukturierte Oberflächen, z. B. Ornamentglas, ebenfalls als eben angesehen werden.
Diese Europäische Norm gilt für Mehrfachverglasungen mit äußeren Scheiben, die für die Strahlung im fernen Infrarotbereich (d. h. in Wellenlängenbereich zwischen 5 µm und 50 µm) undurchlässig sind, z. B. Produkte aus Kalknatronglas, Borosilicatglas und Glaskeramik. Innere Elemente können jedoch für Strahlung im fernen Infrarotbereich durchlässig sein.
Mit dem in dieser Europäischen Norm festgelegten Verfahren wird der U-Wert (Wärmedurchgangs¬koeffizient) im mittleren Bereich einer Verglasung bestimmt. Die Randwirkungen infolge der Wärmebrücke durch den Abstandshalter einer hermetisch abgeschlossenen Verglasung oder durch den Fensterrahmen werden nicht berücksichtigt. Die Energieübertragung durch Sonnenstrahlung wird ebenfalls nicht berücksichtigt.
Das in dieser Europäischen Norm festgelegte Verfahren sollte nur dann in Betracht gezogen werden, wenn der Wärmedurchgangskoeffizient der Verglasung nicht nach EN 673 berechnet werden kann.
Die Bestimmung des Wärmedurchgangskoeffizienten wird unter Bedingungen durchgeführt, die den durch-schnittlichen Bedingungen für Verglasungen in der Praxis entsprechen.
ANMERKUNG Ornamentglas ist ein Beispiel für Glas mit strukturierter Oberfläche.
Verre dans la construction - Détermination du coefficient de transmission thermique, U - Méthode du fluxmètre
La présente Norme européenne spécifie une méthode de mesure visant à déterminer le coefficient de transmission thermique, U, de vitrages dont les faces sont planes et parallèles. Pour les besoins de la présente norme, les surfaces structurées peuvent être considérées comme planes.
La présente Norme européenne est applicable aux vitrages multiples dont les faces externes ne sont pas transparentes au rayonnement infrarouge lointain (longueurs d’ondes comprises entre 5 µm et 50 µm), ce qui est le cas du verre de silicate sodo-calcique, du verre borosilicate et du verre céramique. Toutefois, les éléments internes peuvent être transparents au rayonnement infrarouge lointain.
La procédure définie dans la présente norme européenne détermine l’expression de la valeur de U (coefficient de transmission thermique) pour la partie centrale du vitrage. Les effets de bord dus au pont thermique de l’intercalaire d’un vitrage isolant ou du châssis de fenêtre, ne sont pas pris en compte.
Le mode opératoire spécifié dans la présente Norme européenne n'est pris en considération que lorsque la transmission thermique du vitrage ne peut pas être calculée conformément à l’EN 673.
La détermination du coefficient de transmission thermique est effectuée dans des conditions d’utilisation moyenne des vitrages.
NOTE Le verre imprimé est un exemple de vitrage comportant une surface structurée.
Steklo v gradbeništvu - Ugotavljanje toplotne prehodnosti (U-vrednost) - Metoda toplotnega pretoka
Ta evropski standard določa merilni postopek za ugotavljanje toplotne prehodnosti zasteklitve s ploskimi in vzporednimi površinami. Pri tem standardu se lahko strukturirane površine štejejo za ravne. Ta evropski standard velja za večkratno zasteklitev z zunanjimi šipami, ki pri skrajni infrardeči svetlobi niso prozorne (pri razponu valovne dolžine od 5 μm do 50 μm), kot so mešanice natrijevega hidroksida in kalcijevega hidroksida, borosilikatno steklo in steklena keramika. Notranji elementi so lahko prozorni pri skrajni infrardeči svetlobi. S postopkom, ki ga opredeljuje ta evropski standard, se določa vrednost U (toplotna prehodnost) v osrednjem delu stekla. Robni učinki zaradi toplotnega mostu med vmesnikom izolacijske steklene enote ali skozi okvir okna niso zajeti. Tudi prenos energije zaradi sončnega sevanja ni upoštevan. Postopek, opredeljen v tem evropskem standardu, se upošteva le, če se toplotna prehodnost zasteklitve ne more izračunati v skladu z EN 673. Ugotavljanje toplotne prehodnosti se izvaja za pogoje, ki ustrezajo povprečnemu stanju zasteklitve v praksi.
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-november-2011
1DGRPHãþD
SIST EN 675:1999
Steklo v gradbeništvu - Ugotavljanje toplotne prehodnosti (U-vrednost) - Metoda
toplotnega pretoka
Glass in building - Determination of thermal transmittance (U value) - Heat flow meter
method
Glas im Bauwesen - Bestimmung des Wärmedurchgangskoeffizienten (UWert) -
Wärmestrommesser-Verfahren
Verre dans la construction - Détermination du coefficient de transmission thermique, U -
Méthode du fluxmètre
Ta slovenski standard je istoveten z: EN 675:2011
ICS:
81.040.20 Steklo v gradbeništvu Glass in building
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD
EN 675
NORME EUROPÉENNE
EUROPÄISCHE NORM
June 2011
ICS 81.040.20 Supersedes EN 675:1997
English Version
Glass in building - Determination of thermal transmittance (U
value) - Heat flow meter method
Verre dans la construction - Détermination du coefficient de Glas im Bauwesen - Bestimmung des
transmission thermique, U - Méthode du fluxmètre Wärmedurchgangskoeffizienten (U-Wert) -
Wärmestrommesser-Verfahren
This European Standard was approved by CEN on 12 May 2011.
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-CENELEC 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-CENELEC Management Centre has the same
status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, 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: Avenue Marnix 17, B-1000 Brussels
© 2011 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 675:2011: E
worldwide for CEN national Members.
Contents Page
Foreword .3
Introduction .4
1 Scope .5
2 Normative references .5
3 Terms and definitions .5
4 Basic formula .6
5 Brief outline of the measuring procedure .6
6 Test apparatus .6
7 Calibration of the test apparatus . 10
8 Dimensions of the specimens . 10
9 Preparation of the specimens . 10
10 Performance of the measurements. 11
11 Evaluation of the results . 11
11.1 Thermal resistance of the multiple glazing . 11
11.2 Declared U value . 11
11.3 Design U value . 12
12 Expression of results . 12
12.1 U values . 12
12.2 Thermal resistance . 12
12.3 Intermediate values . 12
13 Test report . 12
13.1 Identification of the specimens . 12
13.2 Cross section of the specimen . 13
13.3 Results . 13
Bibliography . 14
Foreword
This document (EN 675:2011) has been prepared by Technical Committee CEN/TC 129 “Glass in building”,
the secretariat of which is held by NBN.
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 December 2011, and conflicting national standards shall be withdrawn
at the latest by December 2011.
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 675:1997.
The main change in this edition is that the internal and external heat transfer coefficients have been amended
slightly to reflect changes to EN 673. Clarification is also given in the scope that the procedure specified in this
European Standard should generally only be considered when the calculation method detailed in EN 673 is
inappropriate or unsuitable.
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, Croatia, 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.
Introduction
CEN/TC 129/WG 9 "Light and energy transmission, thermal insulation" prepared a working draft based on the
document ISO/DIS 10293 "Glass in building - Determination of steady-state U values (thermal transmittance)
of multiple glazing - Heat flow meter method", document that was prepared by ISO/TC 160, "Glass in
building". This was published in 1997 as EN 675.
The document for the calculation of the overall U value of windows, doors and shutters (see [2]) gives
normative reference to the U value evaluated for the glazing components according to this standard.
For the purposes of product comparison, a vertical position of the glazing is specified (see Clause 10).
U values evaluated according to the present standard are used for product comparison as well as for other
purposes, in particular for predicting:
heat loss through glazing;
conduction heat gains in summer;
condensation on glazing surfaces;
the effects of the absorbed solar radiation in determining the solar factor (see [1]).
Reference should be made to [2], [3], [4] or other European Standards dealing with heat loss calculations for
the application of glazing U values determined by this Standard.
1 Scope
This European Standard specifies a measurement procedure to determine the thermal transmittance of
glazing with flat and parallel surfaces. For the purpose of this Standard, structured surfaces may be
considered to be flat.
This European Standard applies to multiple glazing with outer panes which are not transparent to far infrared
radiation (in the wavelength range 5µm to 50µm), which is the case for soda lime silicate glass products,
borosilicate glass and glass ceramics. Internal elements can be far infrared transparent.
The procedure specified in this European Standard determines the U value (thermal transmittance) in the
central area of glazing. The edge effects due to the thermal bridge through the spacer of an insulating glass
unit or through the window frame are not included. Energy transfer due to solar radiation is also excluded.
The procedure specified in this European Standard should be considered only when the thermal transmittance
of the glazing cannot be calculated in accordance with EN 673.
The determination of the thermal transmittance is performed for conditions which correspond to the average
situation for glazing in practice.
NOTE Patterned glass is an example of a glass with a structured surface;
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.
EN 673, Glass in building — Determination of thermal transmittance (U value) — Calculation method
EN 12898, Glass in building — Determination of the emissivity
ISO 8301, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Heat flow meter apparatus
ISO 8302, Thermal insulation — Determination of steady-state thermal resistance and related properties —
Guarded hot plate apparatus
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply:
3.1
U value
parameter of glazing which characterizes the heat transfer through the central part of the glazing, i.e. without
edge effects, and states the steady-state density of heat transfer rate per temperature difference between the
environmental temperatures on each side.
NOTE The U value is given in watts per square metre Kelvin [W/(m ⋅K)]
3.2
declared value
U value obtained under standardized boundary conditions.
NOTE See 11.2.
4 Basic formula
The U value depends on the thermal resistance of the multiple glazing and on the external and internal
surface heat transfer coefficients according to the relation:
1 1 1
= R + +
U h h
e i
(1)
where
R is the thermal resistance of the multiple glazing in square metres Kelvins per Watt
mK⋅ W
()
h is the external surface heat transfer coefficient in watts per square metre Kelvin
e
W/ m ⋅K
()
[]
h is the internal surface heat transfer coefficient in watts per square metre Kelvin
i
W/ m ⋅K
()
[]
According to this standard the surface to surface thermal resistance is determined by measurements taken
using the heat flow meter method. Thereupon the declared U value is determined according to Equation (1)
with the values for the internal and external heat transfer coefficients specified in 11.2.
The external surface is the surface of the glazing intended to face the outside of the building in use. The
internal surface is the surface of the glazing intended to face the inside of the building in use.
5 Brief outline of the measuring procedure
The surface to surface thermal resistance of the multiple glazing is determined by means of the heat flow
meter method laid down in ISO 8301. The recommendations of that standard shall be complied with except for
variations contained in this standard and for variations resulting from the special structure of the specimen.
Within the present context further requirements are necessary, viz. the size of the test specimens and the
performance of the measurements are laid down to meet special requirements for measuring multiple glazing
(see Clauses 6 to 13).
6 Test apparatus
For the measurement of the thermal resistance of the specimen, the single-specimen apparatus with
symmetrical configuration or a double specimen apparatus as shown in Figures 1 and 2 is used.
The single-specimen apparatus consists of a heating and a cooling unit between which the specimen or a
reference sample for the calibration of the apparatus is sandwiched. The cooling unit has surface dimensions
as large as those of the heating unit.
A heat flow meter is positioned in the centre of the hot plate surface and the cold plate surface. These heat
flow meters face each other on either sides of the specimen or the reference sample. On each side of the heat
flow meters a thin natural or synthetic foam rubber sheet is placed to ensure sufficient thermal contact.
Surface contact is obtained by applying pressure. The foam rubber sheets have the same dimensions as the
surface area of the heating unit.
EN
...
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