Testing and factors relevant to the evaluation of the structural adequacy of steel members within fire-resistant elevator shafts

For multi-storey buildings, structural steel members may be used to provide vertical and lateral support. These members may be incorporated within fire-resistant enclosures that are provided to house elevators, stairs and other services. In the case of elevator shafts, structural members located within the shaft are usually required to achieve high levels of fire resistance, despite the fact that they are located within fire-resistant enclosures. Such requirements appear to be unnecessarily onerous, imposing a financial burden on developer and owners. This paper considers this issue and presents the results of some full-scale fire tests undertaken to directly investigate this matter. The outcomes of these tests and the discussion of factors presented in this paper provide useful data and background to assist the fire-engineering assessment of this situation. Such an assessment will be necessary where it is intended to utilise unprotected steel construction or structural members within elevator shafts which have a lesser level of fire resistance than that required by the prescriptive regulations.