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

Status
Withdrawn
Publication Date
29-Sep-2011
Withdrawal Date
30-Dec-2011
Current Stage
9060 - Closure of 2 Year Review Enquiry - Review Enquiry
Start Date
15-Dec-2016
Completion Date
15-Dec-2016

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SLOVENSKI STANDARD
SIST EN 675:2011
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
SIST EN 675:2011 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST EN 675:2011
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SIST EN 675:2011
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.
---------------------- Page: 3 ----------------------
SIST EN 675:2011
EN 675:2011 (E)
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

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SIST EN 675:2011
EN 675:2011 (E)
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.
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SIST EN 675:2011
EN 675:2011 (E)
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.
---------------------- Page: 6 ----------------------
SIST EN 675:2011
EN 675:2011 (E)
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.
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SIST EN 675:2011
EN 675:2011 (E)
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

W/ m ⋅K

h is the internal surface heat transfer coefficient in watts per square metre Kelvin

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
...

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