Fire resistance of light timber-framed floors

Collier, P. C. R. (1995) Fire resistance of light timber-framed floors. [Proceedings Paper]

The fire resistance of a load bearing light timber-framed floor is usually established by testing a full sized specimen. However, due to limitations on the size of the available test equipment and the cost of testing, it is impractical to test all possible combinations of dimensional variations. This paper describes the development and application of an empirical method, based on a tested prototype, that allows extrapolation to similar constructions, which may be of a different span and/or load bearing capacity. The method requires a fire resistance test on a prototype load bearing floor to prove both the fire performance of a ceiling lining and flooring material and the extent of structural damage to the supporting joists. This lining/flooring configuration can then be applied to a different size of timber frame with the knowledge that the damage, at the end of a specified period of fire resistance, will be the same as for the prototype test. The design of new floors is based on the residual load bearing capacity of the damaged joists and floor covering of the tested prototype. A few simple rules of extrapolation are required which set boundaries to ensure safety of design. The rules, while limiting, can be used to advantage when designing a prototype for testing. In combination with a similar method for design of light timber-framed walls for fire resistance, presented as the first paper of this pair, a guide has been established for design of multi-storey timber buildings. The principal application to date in New Zealand and Australia has been in residential construction, where the prevailing fire regulations have been met using timber as the main construction material. The field of light timber-framed construction for fire resistance is under continual development internationally in countries including Australia, USA, Sweden and New Zealand. The emphasis now is moving away from empirical methods, based on and always limited to tested systems, to computer modelling of timber assemblies. This offers exciting possibilities. The most important of these is the ability to separate from the standard ISO fire exposure to realistic fires based on the time-temperature expected for a particular fire load and ventilation condition. This could be as straightforward as modelling, on a PC, a proposed wall or floor design against a realistic fire scenario and establishing that the required stability, integrity and insulation criteria are satisfied for the period required. Obviously, the success of such models will depend on reliable data input which will still depend on some limited testing for validation.

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Abstract

The fire resistance of a load bearing light timber-framed floor is usually established by testing a full sized specimen. However, due to limitations on the size of the available test equipment and the cost of testing, it is impractical to test all possible combinations of dimensional variations. This paper describes the development and application of an empirical method, based on a tested prototype, that allows extrapolation to similar constructions, which may be of a different span and/or load bearing capacity. The method requires a fire resistance test on a prototype load bearing floor to prove both the fire performance of a ceiling lining and flooring material and the extent of structural damage to the supporting joists. This lining/flooring configuration can then be applied to a different size of timber frame with the knowledge that the damage, at the end of a specified period of fire resistance, will be the same as for the prototype test. The design of new floors is based on the residual load bearing capacity of the damaged joists and floor covering of the tested prototype. A few simple rules of extrapolation are required which set boundaries to ensure safety of design. The rules, while limiting, can be used to advantage when designing a prototype for testing. In combination with a similar method for design of light timber-framed walls for fire resistance, presented as the first paper of this pair, a guide has been established for design of multi-storey timber buildings. The principal application to date in New Zealand and Australia has been in residential construction, where the prevailing fire regulations have been met using timber as the main construction material. The field of light timber-framed construction for fire resistance is under continual development internationally in countries including Australia, USA, Sweden and New Zealand. The emphasis now is moving away from empirical methods, based on and always limited to tested systems, to computer modelling of timber assemblies. This offers exciting possibilities. The most important of these is the ability to separate from the standard ISO fire exposure to realistic fires based on the time-temperature expected for a particular fire load and ventilation condition. This could be as straightforward as modelling, on a PC, a proposed wall or floor design against a realistic fire scenario and establishing that the required stability, integrity and insulation criteria are satisfied for the period required. Obviously, the success of such models will depend on reliable data input which will still depend on some limited testing for validation.

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Item Type:	Proceedings Paper
Additional Information:	Available at Perpustakaan Sultan Abdul Samad, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia. TH1073 N277 1995 Call Number
AGROVOC Term:	wood
AGROVOC Term:	floors
AGROVOC Term:	fire resistance
AGROVOC Term:	structural engineering
AGROVOC Term:	analysis
AGROVOC Term:	equipment testing
AGROVOC Term:	engineers
AGROVOC Term:	building industry
Geographical Term:	New Zealand
Depositing User:	Nor Hasnita Abdul Samat
Date Deposited:	02 Nov 2025 10:42
Last Modified:	10 Nov 2025 01:12
URI:	http://webagris.upm.edu.my/id/eprint/1202

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