U-Wert

English translation: U-value, see attached dictionary entry

07:46 May 9, 2000
German to English translations [PRO]
Tech/Engineering
German term or phrase: U-Wert
context: construction of "Systemtechnikstandorten" (for operating fiber optics lines)

In the section entitled Betonarbeiten:
"Der U-Wert der Bodenkonstruktion wird ein Minimum von 0,37 W/m2K haben."

This appears to some type of insulation value. Does anyone know what the U stands for?
BKantus
English translation:U-value, see attached dictionary entry
Explanation:
Edc is quite right that a LOW U-value is desirable in insulation, not a high one. However, perhaps this is what the sentence is saying, i.e. that with the given construction, it will not be possible to bring the U-value down further??
I see with interest that the German uses U-Wert. Until very recently, this has been called k-Wert. European standardization has introduced the U.
Concerning the rendering of this in English, I offer the corresponding entry taken from a Dictionary of Environmental Policy which I have been working on for some time:

Wärmedurchgangskoeffizient (oder -zahl), k-Wert, U:
(eines Bauteils, zwischen der beiderseits angrenzenden Luft) U-value; U-factor, U; thermal transmittance; coefficient of heat transfer, area weighted heat transfer coefficient; watts per square metre degree [W/(m2K)]

linearer W. einer Wärmebrücke, y: linear thermal transmittance of a linear thermal bridge, y [W/(mK)]

punktueller W. einer Wärmebrücke, c: point thermal transmittance of a point thermal bridge, c [W/K]

k-Wert in Scheibenmitte (Fenster) centre-of-glass U-value

Thermal transmittance, a building element property, is not to be confused with thermal conductivity (Wärmeleitfähigkeit), a material property, the latter being the measure of heat flow rate by conduction through a unit of distance in the material per unit of area per degree of temperature difference, and called – confusingly enough – in English the k-value!!!

Während prEN 832: 1995 <engl.> thermal transmittance verwendet, wird in der Literatur meist vom U-value gesprochen. ASHRAE nennt U-value "improper terminology", und schreibt stattdessen die Verwendung von U-factor vor. In der Fachsprache scheint jedoch der Bannstrahl der ASHRAE noch keine Wirkung entfaltet zu haben.
Weiterhin gibt es eine Unterscheidung zwischen "imperial U" und "metric U". Imperial U ist der in den USA übliche Parameter, ausgedrückt in Btu/(hft2°F). Metric U wird in Europa verwendet, und ausgedrückt in W/(m2K). Das Verhältnis imperial U zu metric U beträgt 1 zu 5,678 (unter Zugrundelegung des Btu-Wertes aus der "International Table", also 1 Btu = 1055 Joule).

Zitierte Quellen:
l ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers): ASHRAE Terminology of Heating, Ventilation, Air Conditioning, & Refrigeration.– Atlanta (Georgia, USA): ASHRAE, 2nd edition 1991 (ISBN: 0-910110-77-8).
l prEN 832: 1995 <engl.>: Preliminary European Standard, Final Draft December 1995: Thermal performance of buildings - Calculation of energy use for heating - Residential Buildings
Selected response from:

Christopher Hay
Germany
Local time: 06:42
Grading comment
Very good explanation. Thanks!
4 KudoZ points were awarded for this answer



Summary of answers provided
naU-value
Ed Colaianni
naU = Uebertragung or Uebergang
Bruce Sanderson
naU-value, see attached dictionary entry
Christopher Hay


  

Answers


18 mins
U-value


Explanation:
"wird ein Minimum von 0,37 W/m2K haben."

"shall have a minimum of .37 W/m2K (watts per square meter per centigrade degree)"

I presume that "maximum" is meant, not minimum, unless they really do want to transfer heat in or out of the structure readily (but in that case .37 watt per square meter per degree isn't very good).
U is just the letter often used in physics to represent energy or energy transfer.
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Ed Colaianni
Local time: 06:42
Native speaker of: Native in EnglishEnglish
PRO pts in pair: 62
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48 mins
U = Uebertragung or Uebergang


Explanation:
As it has the dimensions of emissivity (power radiated or transferred per sq m and per ° Kelvin), U must mean something like Uebertragung or Uebergang

Regarding your earlier question on fiber optics, take a look at http://www.fiber--optics.de/index.htm; it might help.



Bruce Sanderson
Local time: 06:42
Native speaker of: Native in EnglishEnglish, Native in FrenchFrench
PRO pts in pair: 22
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4 hrs
U-value, see attached dictionary entry


Explanation:
Edc is quite right that a LOW U-value is desirable in insulation, not a high one. However, perhaps this is what the sentence is saying, i.e. that with the given construction, it will not be possible to bring the U-value down further??
I see with interest that the German uses U-Wert. Until very recently, this has been called k-Wert. European standardization has introduced the U.
Concerning the rendering of this in English, I offer the corresponding entry taken from a Dictionary of Environmental Policy which I have been working on for some time:

Wärmedurchgangskoeffizient (oder -zahl), k-Wert, U:
(eines Bauteils, zwischen der beiderseits angrenzenden Luft) U-value; U-factor, U; thermal transmittance; coefficient of heat transfer, area weighted heat transfer coefficient; watts per square metre degree [W/(m2K)]

linearer W. einer Wärmebrücke, y: linear thermal transmittance of a linear thermal bridge, y [W/(mK)]

punktueller W. einer Wärmebrücke, c: point thermal transmittance of a point thermal bridge, c [W/K]

k-Wert in Scheibenmitte (Fenster) centre-of-glass U-value

Thermal transmittance, a building element property, is not to be confused with thermal conductivity (Wärmeleitfähigkeit), a material property, the latter being the measure of heat flow rate by conduction through a unit of distance in the material per unit of area per degree of temperature difference, and called – confusingly enough – in English the k-value!!!

Während prEN 832: 1995 <engl.> thermal transmittance verwendet, wird in der Literatur meist vom U-value gesprochen. ASHRAE nennt U-value "improper terminology", und schreibt stattdessen die Verwendung von U-factor vor. In der Fachsprache scheint jedoch der Bannstrahl der ASHRAE noch keine Wirkung entfaltet zu haben.
Weiterhin gibt es eine Unterscheidung zwischen "imperial U" und "metric U". Imperial U ist der in den USA übliche Parameter, ausgedrückt in Btu/(hft2°F). Metric U wird in Europa verwendet, und ausgedrückt in W/(m2K). Das Verhältnis imperial U zu metric U beträgt 1 zu 5,678 (unter Zugrundelegung des Btu-Wertes aus der "International Table", also 1 Btu = 1055 Joule).

Zitierte Quellen:
l ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers): ASHRAE Terminology of Heating, Ventilation, Air Conditioning, & Refrigeration.– Atlanta (Georgia, USA): ASHRAE, 2nd edition 1991 (ISBN: 0-910110-77-8).
l prEN 832: 1995 <engl.>: Preliminary European Standard, Final Draft December 1995: Thermal performance of buildings - Calculation of energy use for heating - Residential Buildings


Christopher Hay
Germany
Local time: 06:42
Native speaker of: Native in EnglishEnglish
PRO pts in pair: 23
Grading comment
Very good explanation. Thanks!
Login to enter a peer comment (or grade)



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