Performance of structural stainless steel following a fire

Stainless steel offers excellent mechanical properties as well as corrosion resistance and performs better in a fire compared to carbon steel in that it retains its strength and stiffness for a longer duration. The current paper is focussed on the post-fire condition, which has received limited attention to date from the research community. The motivation for the work is to show that stainless steel elements that have been exposed to fire can be reinstated with minimal additional costs in a short time frame. The paper proceeds with a description of recent material tests into the residual properties of grade 1.4301 austenitic stainless steel, following exposure to elevated temperature. Two different types of test were conducted and these are described. Firstly, a series of tensile tests were completed on coupons taken from a loaded stainless steel beam previously examined under fire conditions. Secondly, a set of virgin coupons (i.e. which have not been previously heated or tested) were exposed to different levels of elevated temperature and cooling procedures. This is with a view to understanding the ability of structural elements made from this material to survive a fire and continue in service. The results are employed along with other data obtained from the literature to conduct a detailed study into the design considerations. The collected data includes information on the proof and ultimate strengths, ultimate strain and Young?s modulus and the extent to which these are affected following the occurrence of a fire. The study is done for ferritic, austenitic and duplex stainless steel. By focusing on the effect of a fire on the mechanical properties after cooling using a statistical approach, safety factors are proposed together with a reduced reliability index based on economic and social considerations.

Automated summary

This paper focuses on the post-fire condition of stainless steel elements, showing that they can be reinstated with minimal additional costs in a short time frame. Tensile tests were conducted on samples taken from loaded stainless steel beams previously examined under fire conditions, as well as on virgin coupons exposed to elevated temperatures. The study provides a detailed analysis of the mechanical properties of stainless steel after exposure to fire and proposes safety factors and a reduced reliability index based on economic and social considerations.