Thermal resistance - Revision history

Designing Buildings at 09:19, 30 October 2020

2020-10-30T09:19:18Z

← Older revision		Revision as of 09:19, 30 October 2020
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	* U-value.		* U-value.

−	[[Category:~~Standards_/_measurements~~]] [[Category:DCN_Standard]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Standard]] [[Category:Standards_/_measurements]]

Editor at 15:14, 21 November 2018

2018-11-21T15:14:50Z

← Older revision		Revision as of 15:14, 21 November 2018
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	R-values are not directly relatable to U-values however, as unlike U-values, R-values do not include surface heat transfers at the boundary of the element by convection and radiation, they are only a measure of the thermal resistance of the materials themselves.		R-values are not directly relatable to U-values however, as unlike U-values, R-values do not include surface heat transfers at the boundary of the element by convection and radiation, they are only a measure of the thermal resistance of the materials themselves.

−	~~= Find out more =~~	+	= Related articles on Designing Buildings Wiki =
−		+
−	=== Related articles on Designing Buildings Wiki ===	+

	* G-value.		* G-value.
		+	* Heat loss.
	* Heat transfer.		* Heat transfer.
	* K-value.		* K-value.
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	* U-value.		* U-value.

−	[[Category:Standards_/_measurements]]	+	[[Category:Standards_/_measurements]] [[Category:DCN_Standard]]

Designing Buildings at 11:59, 18 February 2018

2018-02-18T11:59:01Z

← Older revision		Revision as of 11:59, 18 February 2018
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	For more information, see R-value.		For more information, see R-value.

−	Thermal resistance ~~is often described as being the reciprocal of thermal transmission, and can be derived from the thermal conductivity and the thickness of the materials. It~~ is the temperature difference between two defined material surfaces that induces a unit heat flow rate through a unit area. ~~However~~, ~~unlike U-values, R-values do not include surface heat transfers at~~ the ~~boundary~~ of the ~~element by convection and radiation~~.	+	Thermal resistance is the temperature difference between two defined material surfaces that induces a unit heat flow rate through a unit area. It is often described as the reciprocal of thermal transmittance, and can be derived from the thermal conductivity and the thickness of the materials.

−	The value of ~~the thermal resistance~~ can be calculated by ~~dividing~~ the ~~thickness with~~ the thermal ~~conductivity~~.	+	R-values can be calculated by dividing the thickness of a material (in metres) by its thermal conductivity (k-value or lambda value (λ) in W/mK). R-values are therefore expressed in m2K/W (or ft2·°F·hr/Btu in the USA). The overall R-value of a multi-layered element can be calculated by adding the R-values of its component materials.
		+
		+	R-values are not directly relatable to U-values however, as unlike U-values, R-values do not include surface heat transfers at the boundary of the element by convection and radiation, they are only a measure of the thermal resistance of the materials themselves.

	= Find out more =		= Find out more =

Editor: Created page with "The thermal resistance of a material is a measure of how resistant it is to the transfer of heat across it. The thermal resistance of a material is measured by its R-value. The h..."

2018-02-16T15:24:35Z

Created page with "The thermal resistance of a material is a measure of how resistant it is to the transfer of heat across it. The thermal resistance of a material is measured by its R-value. The h..."

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The thermal resistance of a material is a measure of how resistant it is to the transfer of heat across it. The thermal resistance of a material is measured by its R-value. The higher the R-value of a material, the more effective it is as an insulator.

For more information, see R-value.

Thermal resistance is often described as being the reciprocal of thermal transmission, and can be derived from the thermal conductivity and the thickness of the materials. It is the temperature difference between two defined material surfaces that induces a unit heat flow rate through a unit area. However, unlike U-values, R-values do not include surface heat transfers at the boundary of the element by convection and radiation.

The value of the thermal resistance can be calculated by dividing the thickness with the thermal conductivity.

= Find out more =

=== Related articles on Designing Buildings Wiki ===

* G-value.
* Heat transfer.
* K-value.
* Insulation.
* Shading coefficient.
* Thermal admittance.
* Thermal bridge.
* Thermal mass.
* U-value.

[[Category:Standards_/_measurements]]