Kappa value - thermal mass value - Revision history

Designing Buildings at 09:06, 13 October 2020

2020-10-13T09:06:15Z

← Older revision		Revision as of 09:06, 13 October 2020
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−	~~NB see k-value for alternative meaning.~~
−
−	~~-----~~
	In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with Part L of the building regulations, k-value (short for Kappa value or thermal mass value) refers to the heat capacity per square metre of a material, measured in kJ/m2K. This is used to quantify the thermal mass of building elements such as walls and floors. The higher the k-value, the greater the thermal mass, that is the more heat the element is able to store.		In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with Part L of the building regulations, k-value (short for Kappa value or thermal mass value) refers to the heat capacity per square metre of a material, measured in kJ/m2K. This is used to quantify the thermal mass of building elements such as walls and floors. The higher the k-value, the greater the thermal mass, that is the more heat the element is able to store.

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	NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.		NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.
		+
		+	NB see k-value for alternative meaning.

	= Related articles on Designing Buildings Wiki =		= Related articles on Designing Buildings Wiki =
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	* U-value conventions in practice: Worked examples using BR 443.		* U-value conventions in practice: Worked examples using BR 443.

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

Designing Buildings: moved Kappa value to Kappa value - thermal mass value

2020-05-22T08:02:08Z

moved Kappa value to Kappa value - thermal mass value

← Older revision

Revision as of 08:02, 22 May 2020

Editor at 18:15, 12 June 2019

2019-06-12T18:15:40Z

← Older revision		Revision as of 18:15, 12 June 2019
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	NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.		NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.

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

		+	* Environmental performance.
	* g-value.		* g-value.
	* k-value.		* k-value.
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	* U-value conventions in practice: Worked examples using BR 443.		* U-value conventions in practice: Worked examples using BR 443.

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

Designing Buildings at 07:25, 9 July 2016

2016-07-09T07:25:07Z

← Older revision		Revision as of 07:25, 9 July 2016
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		+	NB see k-value for alternative meaning.

−	~~NB see~~ k-value for ~~alternative meaning.<br~~/>	+	-----
		+	In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with Part L of the building regulations, k-value (short for Kappa value or thermal mass value) refers to the heat capacity per square metre of a material, measured in kJ/m2K. This is used to quantify the thermal mass of building elements such as walls and floors. The higher the k-value, the greater the thermal mass, that is the more heat the element is able to store.

−	~~----~~	+	Thermal mass can be used to even out variations in internal and external conditions, absorbing heat as temperatures rise and releasing it as they fall. In building design, this can useful for evening out and delaying extremes in thermal conditions, stabilising the internal environment and so reducing the demand for building services systems.

−	~~In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with Part L of the building regulations, k~~-~~value~~ (~~short for Kappa value) refers to~~ the ~~heat capacity per square metre of a material, measured in kJ~~/~~m2K~~. ~~This is used to quantify the~~ thermal mass ~~of building elements such as walls and floors~~. ~~The higher the k~~-~~value~~, ~~the greater the~~ thermal mass~~, that is the more heat the element is able to store.<br/>~~	+	Typical K-values might be (ref the Concrete Centre [http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.wienerberger.co.uk%2Fsustainability%2Fsustainability-products%2Fmpa-thermal-mass-report.html&ei=1ywXU5KsGc-rhAec_4CgBw&usg=AFQjCNEsgLDyb3SqkpP-_OBLbEKICtQokg&bvm=bv.62286460,d.ZG4 SAP 2009 – Fabric energy efficiency & thermal mass]):

−	~~Thermal mass can be used to even out variations in internal and external conditions, absorbing heat as temperatures rise and releasing it as they fall~~. ~~In building design, this can useful for evening out and delaying extremes in thermal conditions, stabilising the internal environment and so reducing the demand for building services systems~~.~~<br~~/>	+	* Timber frame wall: 9 kJ/m2K.
		+	* Dense concrete block wall with a plaster finish: 190 kJ/m2K.
		+	* Timber floor/ceiling: 9/18 kJ/m2K.
		+	* Concrete floor/celing: 120/160 kJ/m2K.

−	~~Typical K-values might be~~ (ref the Concrete Centre [http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.wienerberger.co.uk%2Fsustainability%2Fsustainability-products%2Fmpa-thermal-mass-report.html&ei=1ywXU5KsGc-rhAec_4CgBw&usg=AFQjCNEsgLDyb3SqkpP-_OBLbEKICtQokg&bvm=bv.62286460,d.ZG4 SAP 2009 – Fabric energy efficiency & thermal mass]):	+	The kappa value (k) of a material is calculated as:
−	*Timber frame wall: 9 kJ/m2K.<br/>	+
−	*Dense concrete block wall with a ~~plaster finish: 190 kJ/m2K.<br/>~~	+
−	*Timber floor/ceiling: 9/18 kJ/m2K.	+
−	*Concrete floor/celing: ~~120/160 kJ/m2K.<br/>~~	+

−	~~The kappa value (k) of a material is calculated as:<br/>~~	+	k = 10-6 × Σ (dj rj cj) (ref [http://builddesk.co.uk/software/builddesk-u/thermal-mass/ BuildDesk])
−		+
−	k = 10~~<sup>~~-6~~</sup>~~ × Σ (dj rj cj) (ref [http://builddesk.co.uk/software/builddesk-u/thermal-mass/ BuildDesk])	+

	where:		where:
−	*dj is the thickness of a layer (mm)	+
−	*rj is density of a layer (kg/m³)	+	* dj is the thickness of a layer (mm)
−	*cj is specific heat capacity of a layer (J/kg·K)	+	* rj is density of a layer (kg/m³)
		+	* cj is specific heat capacity of a layer (J/kg·K)

	The limiting value for thickness is where:		The limiting value for thickness is where:
−	*The total thickness of the layers exceeds 100mm.	+
−	*Or, the mid-point of the construction is reached.	+	* The total thickness of the layers exceeds 100mm.
−	*Or an insulation layer is reached.	+	* Or, the mid-point of the construction is reached.
		+	* Or an insulation layer is reached.

	Following the Standard Assessment Procedure, k-values are used to determine a Thermal Mass Parameter (TMP, expressed in J/m2K), which is used to calculate the contribution of thermal mass to the efficiency of the dwelling. TMP is calculated from the sum of the area x heat capacity of all construction elements, divided by total floor area of the dwelling (TFA).		Following the Standard Assessment Procedure, k-values are used to determine a Thermal Mass Parameter (TMP, expressed in J/m2K), which is used to calculate the contribution of thermal mass to the efficiency of the dwelling. TMP is calculated from the sum of the area x heat capacity of all construction elements, divided by total floor area of the dwelling (TFA).
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	NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.		NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.

−	= Find out more~~<br/>~~ =	+	= Find out more =
		+
		+	=== Related articles on Designing Buildings Wiki ===

−	~~=== Related articles on Designing Buildings Wiki<br/> ===~~	+	* g-value.
−	*g-value.~~<br/>~~	+	* k-value.
−	*k-value.~~<br/>~~	+	* R-value.
−	*R-value.	+	* Shading coefficient.
−	*Shading coefficient.	+	* Solar heat gain coefficient.
−	*Solar heat gain coefficient.	+	* Specific heat capacity.
−	*Specific heat capacity.~~<br/>~~	+	* Simplified Building Energy Model.
−	*Simplified Building Energy Model.~~<br/>~~	+	* Standard Assessment Procedure.
−	*Standard Assessment Procedure.~~<br/>~~	+	* Thermal mass.
−	*Thermal mass.	+	* U-value.
−	*U-value.	+	* U-value conventions in practice: Worked examples using BR 443.

	[[Category:Standards_/_measurements]]		[[Category:Standards_/_measurements]]

188.92.238.131 at 12:34, 17 March 2015

2015-03-17T12:34:41Z

← Older revision		Revision as of 12:34, 17 March 2015
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	The kappa value (k) of a material is calculated as:<br/>		The kappa value (k) of a material is calculated as:<br/>

−	k = 10<sup>-6</sup> × Σ (dj rj cj) (ref [http://builddesk.co.uk/software/builddesk-u/thermal-mass/ ~~Build Desk~~])	+	k = 10<sup>-6</sup> × Σ (dj rj cj) (ref [http://builddesk.co.uk/software/builddesk-u/thermal-mass/ BuildDesk])

	where:		where:

Designing Buildings at 15:22, 8 July 2014

2014-07-08T15:22:38Z

← Older revision		Revision as of 15:22, 8 July 2014
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	*U-value.		*U-value.

−	[[Category:~~Sustainability]]~~	+	[[Category:Standards_/_measurements]]
−	~~[[Category:Theory~~]]	+

Designing Buildings: Created page with " NB see k-value for alternative meaning.
---- In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with P..."

2014-03-05T15:23:52Z

Created page with " NB see k-value for alternative meaning. ---- In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with P..."

New page

NB see k-value for alternative meaning. 

----

In the Standard Assessment Procedure (SAP) and Simplified Building Energy Model (SBEM), used to demonstrate compliance with Part L of the building regulations, k-value (short for Kappa value) refers to the heat capacity per square metre of a material, measured in kJ/m2K. This is used to quantify the thermal mass of building elements such as walls and floors. The higher the k-value, the greater the thermal mass, that is the more heat the element is able to store. 

Thermal mass can be used to even out variations in internal and external conditions, absorbing heat as temperatures rise and releasing it as they fall. In building design, this can useful for evening out and delaying extremes in thermal conditions, stabilising the internal environment and so reducing the demand for building services systems. 

Typical K-values might be (ref the Concrete Centre [http://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CCoQFjAA&url=http%3A%2F%2Fwww.wienerberger.co.uk%2Fsustainability%2Fsustainability-products%2Fmpa-thermal-mass-report.html&ei=1ywXU5KsGc-rhAec_4CgBw&usg=AFQjCNEsgLDyb3SqkpP-_OBLbEKICtQokg&bvm=bv.62286460,d.ZG4 SAP 2009 – Fabric energy efficiency & thermal mass]):
*Timber frame wall: 9 kJ/m2K. 
*Dense concrete block wall with a plaster finish: 190 kJ/m2K. 
*Timber floor/ceiling: 9/18 kJ/m2K.
*Concrete floor/celing: 120/160 kJ/m2K. 

The kappa value (k) of a material is calculated as: 

k = 10-6 × Σ (dj rj cj) (ref [http://builddesk.co.uk/software/builddesk-u/thermal-mass/ Build Desk])

where:
*dj is the thickness of a layer (mm)
*rj is density of a layer (kg/m³)
*cj is specific heat capacity of a layer (J/kg·K)

The limiting value for thickness is where:
*The total thickness of the layers exceeds 100mm.
*Or, the mid-point of the construction is reached.
*Or an insulation layer is reached.

Following the Standard Assessment Procedure, k-values are used to determine a Thermal Mass Parameter (TMP, expressed in J/m2K), which is used to calculate the contribution of thermal mass to the efficiency of the dwelling. TMP is calculated from the sum of the area x heat capacity of all construction elements, divided by total floor area of the dwelling (TFA).

NB Rather confusingly, the term k-value (sometimes referred to as a k-factor or lambda value λ) is also used to refer to the thermal conductivity of a material, that is, how easily heat passes across it. This is a fundamental property, independent of the quantity of material. It represents the steady-state heat flow through a unit area of a material resulting from a temperature gradient perpendicular to that unit area. It is expressed in W/mK.

= Find out more =

=== Related articles on Designing Buildings Wiki ===
*g-value. 
*k-value. 
*R-value.
*Shading coefficient.
*Solar heat gain coefficient.
*Specific heat capacity. 
*Simplified Building Energy Model. 
*Standard Assessment Procedure. 
*Thermal mass.
*U-value.

[[Category:Sustainability]]
[[Category:Theory]]