Development of Full‐Scale Experiment‐Based Seismic Fragility Functions for Code‐Compliant Fire Sprinkler Piping Systems

Fire sprinkler systems are critical for fire safety, but their functionality can be impaired by seismic damage. This study develops new seismic fragility functions for acceleration‐sensitive damage requiring monitoring, maintenance, and repair in code‐compliant fire sprinkler piping systems, using experimental data from full‐scale experimental tests. These new fragility functions benchmark existing FEMA P‐58 fragility functions. Three estimation methods, namely, Method of Moments (MM), Sum of Squared Errors (SSE), and Maximum Likelihood Estimation (MLE) were applied, with MLE‐derived parameters selected for the final fragility functions. Statistical analysis of no‐leakage cases revealed that several of the FEMA P‐58's Damage State 1 (minor leakage) fragility functions are conservative compared to experimental evidence. This study proposes updated fragility functions comprising: (a) a new experimental fragility function for the Minor Repair damage state; (b) data‐informed adjustments to existing judgment‐based FEMA P‐58 functions for minor leakage; and (c) the original FEMA P‐58 judgment‐based functions. The proposed fire sprinkler fragility functions are expected to improve the accuracy of post‐earthquake assessments of building re‐occupancy and functional recovery times.