Developing a fire robustness index for the built environment

Abstract

In recent years, resilience in fire has been recognised as a potential complement in risk assessments to achieve a more sustainable future. Robustness is a key component of resilience, in order to avoid the structure’s disproportionate failure to the original cause. The aim of this project is to develop an assessment methodology for the fire robustness of buildings, in the form of a risk index. The lack of available metrics, the relative immaturity of the discipline, rapid developments in the field of fire safety regulation, and issues around the potential liability of users and developers rendered this project a challenging endeavour.

In the first part of this work, insurance rating methods were investigated. Their mechanics, development history, and impact are outlined, given their thematic relativity to the focus of this work. Fire risk indexing, which is a multi-attribute evaluation to produce a single ordinal measure of risk, and its existing body of knowledge was reviewed. This clarified issues of terminology and navigated concepts that up until now were convoluted, all in a harmonised body of work. Finally, modern fire risk indexing methods were presented in an exhaustive historical order, explaining the motivation for their creation, links with other methods, developmental tools used, along with their utility and impact.

The dearth of information available in the published literature led to a series of interviews with past developers to address knowledge gaps and document unpublished findings. This is presented in a dedicated chapter. The review in the first part of this thesis, with the collation of the unpublished information, allowed for a historical highlighting of patterns and tendencies in the employment of fire risk indexing in fire safety, placing even this project within this pattern. This can inform practitioners and developers of potential pitfalls that have been repeated historically, yet remained unrecognised prior to this analysis In the last part of the work, tools from Decision Theory are explained and employed, expanding the existing scientific base of fire risk indexing approaches as it was suggested in existing works, but also highlighting their limitations. Prior to outlining an assessment methodology, a review of resilience and robustness is conducted, to link these concepts to the fire safety practice. A discussion on the practicalities of each available metric to quantify robustness is presented, supporting the developmental decisions of this work. Using these tools, a proposed fire robustness index structure is conceptualised, but the principles followed remain of value for building methods assessing any design objective that future developers would need to address. Following this approach is intended to improve the transparency of the decision-making in the design process, allow the comparison of different solutions, potentially reduce costs, and eventually lead to safer and more robust buildings while avoiding unintended consequences and pitfalls of the past. The assessment of a structure’s fire robustness through this method can facilitate an easier communication to stakeholders of different backgrounds, using this method as a means to promote fire safety in the design process.