A decision-support framework for early-stage economic evaluation of Performance-Based Fire Design in high-rise steel modular buildings

As steel modular construction expands into high-rise developments, prescriptive fire protection standards impose a critical economic barrier. This study proposes a decision-support framework for early-stage economic evaluation of Performance-Based Fire Design (PBFD) in high-rise steel modular buildings. Structural analysis was extended to 14 configurations spanning 13 to 33 stories, and a direct construction cost model was applied across all configurations. PBFD delivers its greatest economic value within the 13-to-18-story “Opportunity Zone,” where prescriptive requirements are substantial but structural load ratios remain sufficiently moderate, yielding unit savings of 78,000–84,000 KRW/m². Beyond this range, savings decline non-linearly as cumulative gravity loads erode PBFD advantage. Horizontal plan expansion exhibits high cost-inelasticity, suggesting that unit savings indices are transferable across similar plan configurations. Column section enlargement increases fire protection savings but incurs height-dependent steel cost penalties, underscoring the importance of integrated cost evaluation. The framework provides construction managers and project owners with a quantitative basis for preliminary Go/No-Go economic judgment at the early project planning stage. Findings are specific to the tested structural configurations, Korean cost standards, and standard fire exposure assumptions.