The landscape of complexity in fire safety design of buildings

The increasing use of the terms ‘complex’ and ‘complexity’ in Fire Safety Engineering (FSE) literature reflects a shifting context in the design and delivery of fire-safe buildings. Recent studies emphasize the importance of recognizing and managing complexity in building fire safety design. However, the concept of complexity remains unclear, posing challenges for fire safety professionals seeking to manage it in practice. To begin addressing this gap, this qualitative study examines how the terms ‘complex’ and ‘complexity’ are applied in peer-reviewed literature related to building fire safety design from 1946 to 2024. Using document review and thematic analysis, five themes were constructed that reflect the diverse ways authors subjectively use these terms: (1) epistemic complexity; (2) knowable technical complexity; (3) computational modelling complexity; (4) uncommon building complexity; and (5) requirement complexity. These themes are expected to help fire safety professionals reflect on the nature of complexity in design processes, reduce ambiguity, improve professional discourse, support resource planning and stakeholder engagement, and encourage the integration of sociotechnical factors in the design process. This study is a first attempt to connect complexity theory with FSE, helping clarify the concept and introduce insights from a broader discourse. • Complexity is widely used in fire safety but rarely defined or described • Peer-reviewed fire safety literature was examined and thematically analyzed • Authors use ‘complexity’ in varied, subjective ways across five distinct themes • Themes support reflection and discussion on complexity in fire safety practice