On the use of scenario analysis in combination with prescriptive fire safety design requirements

Abstract

Experience with fire safety engineering under a performance-based fire safety regulation regime shows that the majority of the analyses performed are scenario based. A comparison with purely pre-accepted performance requirement is made in order to assess the relative safety level of the alternative design compared with the pre-accepted design. We find this approach problematic because it undermines the value of performing analyses. The approach accepts oversimplification and justifies unrealistic assumptions on the basis that it will not affect the comparison. This distances the analyses from reality and reduces their value to answer a yes/no question on acceptability. The considerable time and resources spent on searching for and analyzing a pre-accepted design could be spent on analyzing the design at hand. If fire safety analyses are to have any real impact on design, it is necessary that regulators strengthen the position of analytical design. This must include a provision of a clear set of performance goals, which are possible to transform into quantitative evaluation criteria by the engineers, to avoid comparisons with pre-accepted performance requirements.