Fire safety of multistorey timber buildings

Fire safety is the main precondition for the use of wood for multistorey timber buildings and is therefore an important criterion for the choice of material for buildings. The Institute of Structural Engineering at ETH Zurich has accomplished several research projects on the fire behaviour of timber structures over the past 15 years. The research projects aimed at supplying basic data and information on the safe use of timber, in particular for multistorey buildings. Further novel fire design concepts and models have been developed based on extensive theoretical studies, element and full- scale testing as well as a large statistical database on fires in timber. The better knowledge in the area of fire design of timber structures from the research projects, combined with technical measures, especially sprinkler and smoke detection systems, as well as well- trained and equipped fire brigades allow the safe use of timber and a wider field of application of timber for buildings. As a result the Swiss fire regulations of 2005 allow the use of timber structures in multistorey medium- rise residential buildings with up to six storeys. Many other countries have also liberalised the use of timber for buildings or introduced fire regulations that allow for the use of timber on the basis of performance. This paper describes the background of the design concept assumed for multistorey medium- rise buildings. It further presents an overview of two novel calculation models for the verification of the separating function of wall- and- floor timber assemblies as well as for the fire resistance of timber connections.