- Project plans
- Project activities
- Legislation and standards
- Industry context
- Specialist wikis
Last edited 03 Dec 2020
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.
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.
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. BS EN 1995-1-2:2004 provides charring rates for different timber materials for the purposes of informing initial design.
|MATERIAL||CHARRING RATE ßn (mm/min)|
|Softwood glulam and laminated veneer lumber (LVL)||0.7|
|Hardwood timber and hardwood glulam||0.55|
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
Featured articles and news
Creating comfortable climates despite extreme temperatures.
Study examines how adjustable arrangements can succeed.
Government announces plans to improve accessibility.
Resource addresses pandemic-related NEC4 contract issues.
Incorporating EDI into the provision of fair access.
Government announces global innovation strategy.
An architectural biography. Book review.
The house where the future king of France lived.
The teacher, architectural technologist and mum offers her insights.
Careful planning needed as supply chain issues continue.
The sensitive conversion of a neglected Cornwall structure.
Plan stresses local involvement in city, town and village development.