Sacrificial timber - Revision history

Designing Buildings at 07:05, 3 December 2020

2020-12-03T07:05:12Z

← Older revision		Revision as of 07:05, 3 December 2020
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	* Timber preservation.		* Timber preservation.

−	[[Category:~~Health_and_safety_/_CDM~~]] [[Category:~~Construction_techniques~~]] [[Category:~~Products_~~/~~_components~~]] [[Category:~~DCN_Product_Knowledge~~]]	+	[[Category:DCN_Definition]] [[Category:DCN_Guidance]] [[Category:DCN_Product_Knowledge]] [[Category:Health_and_safety_/_CDM]] [[Category:Construction_techniques]] [[Category:Products_/_components]]

Editor at 15:02, 30 January 2019

2019-01-30T15:02:53Z

← Older revision		Revision as of 15:02, 30 January 2019
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	* Fire-separating element.		* Fire-separating element.
	* Fire-stopping.		* Fire-stopping.
		+	* In-situ reinforcement of timber beams.
	* Timber frame.		* Timber frame.
	* Timber framed buildings and fire.		* Timber framed buildings and fire.
	* Timber preservation.		* Timber preservation.

−	[[Category:Health_and_safety_/_CDM]] [[Category:Construction_techniques]] [[Category:Products_/_components]]	+	[[Category:Health_and_safety_/_CDM]] [[Category:Construction_techniques]] [[Category:Products_/_components]] [[Category:DCN_Product_Knowledge]]

Designing Buildings at 11:19, 31 July 2018

2018-07-31T11:19:30Z

← Older revision		Revision as of 11:19, 31 July 2018
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−	The term ‘sacrificial timber’ ~~is used to refer~~ to timber in a structural assembly that is oversized ~~purposely as a means of enhancing~~ its fire resistance. ~~Because timber~~ burns at a regular and measurable rate, exposed timber sections can be designed with an additional sacrificial ~~timber – with an~~ increased width and/or depth – that will char slowly and protect the inner timber from fire damage.	+	The term ‘sacrificial timber’ refers to timber in a structural assembly that is intentionally oversized in order to enhance its fire resistance. Timber burns at a regular and measurable rate, so exposed timber sections can be designed with an additional 'sacrificial' element (ie increased width and/or depth) that will char slowly and protect the inner, structural timber from fire damage.

−	~~The outer surface of a~~ timber ~~element will char, and usually temperatures at the surface in excess of 350°C will~~ be ~~necessary for flaming to occur. The charred portion of the~~ timber ~~acts as an insulator and, although some will~~ be ~~irreparably damaged~~ (or ~~‘sacrificed’~~)~~, the main timber retains its stability and structural integrity~~.	+	Sacrificial timber can be a design solution if a solid timber member is to be exposed – either fully or partly – or if full fire resistance cannot be provided by plasterboard (or other) fire insulating materials.

−	~~Sacrificial~~ timber ~~can often be~~ a ~~design solution if a solid~~ timber ~~member is to~~ be ~~exposed – either fully~~ or ~~partly – or if full fire resistance cannot be provided by plasterboard insulating materials~~.	+	The outer surface of a timber element will typically char in a fire, with temperatures in excess of 350°C necessary for flaming to occur. The charred portion of the timber then acts as an insulator and, although some will be irreparably damaged (or ‘sacrificed’), the core timber retains its stability and structural integrity.

−	The density, and therefore the charring rate, of the timber element will determine the required quantity of sacrificial timber.	+	The density, and therefore the charring rate, of the timber element will determine the required quantity of sacrificial timber. BS EN 1995-1-2:2004 provides charring rates for different timber materials for the purposes of informing initial design.
−		+
−	BS EN 1995-1-2:2004 provides charring rates for different timber materials for the purposes of informing initial design.	+

	Notional charring rates (the charring rates apply to each face exposed to fire):		Notional charring rates (the charring rates apply to each face exposed to fire):
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	\|}		\|}

−	For example, if a softwood element ~~was~~ exposed on all four of its sides to 20 minutes of fire:	+	For example, if a softwood element is exposed on all four of its sides to 20 minutes of fire:

	2 x 20 x 0.8 = 32 mm		2 x 20 x 0.8 = 32 mm

Editor: Created page with "The term ‘sacrificial timber’ is used to refer to timber in a structural assembly that is oversized purposely as a means of enhancing its fire resistance. Because timber burn..."

2018-04-13T12:35:48Z

Created page with "The term ‘sacrificial timber’ is used to refer to timber in a structural assembly that is oversized purposely as a means of enhancing its fire resistance. Because timber burn..."

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The term ‘sacrificial timber’ is used to refer to timber in a structural assembly that is oversized purposely as a means of enhancing its fire resistance. Because timber burns at a regular and measurable rate, exposed timber sections can be designed with an additional sacrificial timber – with an increased width and/or depth – that will char slowly and protect the inner timber from fire damage.

The outer surface of a timber element will char, and usually temperatures at the surface in excess of 350°C will be necessary for flaming to occur. The charred portion of the timber acts as an insulator and, although some will be irreparably damaged (or ‘sacrificed’), the main timber retains its stability and structural integrity.

Sacrificial timber can often be a design solution if a solid timber member is to be exposed – either fully or partly – or if full fire resistance cannot be provided by plasterboard insulating materials.

The density, and therefore the charring rate, of the timber element will determine the required quantity of sacrificial timber.

BS EN 1995-1-2:2004 provides charring rates for different timber materials for the purposes of informing initial design.

Notional charring rates (the charring rates apply to each face exposed to fire):

{|
| MATERIAL
| CHARRING RATE ßn (mm/min)
|-
| Softwood timber
| 0.8
|-
| Softwood glulam and laminated veneer lumber (LVL)
| 0.7
|-
| Hardwood timber and hardwood glulam
| 0.55
|}

For example, if a softwood element was exposed on all four of its sides to 20 minutes of fire:

2 x 20 x 0.8 = 32 mm

The width and depth of the element would require 32 mm of sacrificial timber.

= Find out more =

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

* Fire.
* Fire protection engineering.
* Fire resistance.
* Fire-separating element.
* Fire-stopping.
* Timber frame.
* Timber framed buildings and fire.
* Timber preservation.

[[Category:Health_and_safety_/_CDM]] [[Category:Construction_techniques]] [[Category:Products_/_components]]