Investigation of damage to fire protection systems in buildings due to the 2016 Kumamoto earthquake: derivation of damage models for post-earthquake fire risk assessments

Abstract

Post-earthquake fire safety is an important functional requirement of seismic-resilient buildings and depends on seismic damage to fire protection systems. Probabilistic fire risk assessments are useful in ensuring safety and consider the post-earthquake reliability of fire protection systems. This study therefore investigated damage to fire protection systems due to the 2016 Kumamoto earthquake through a questionnaire survey among hospitals to collect data available for modeling the post-earthquake reliability. Ten types of component of a fire protection system were surveyed: emergency generators, fire detectors, water tanks used for firefighting, fire pumps, sprinkler heads, indoor fire hydrant boxes, fixed glass smoke curtains, fire doors, fire shutters, and fire exit signs. The data show that there was much damage to fire detectors, sprinkler heads, fixed glass smoke curtains, and fire doors. Zero-inflated Poisson regression analysis was conducted to derive statistical damage models that describe the association of building response quantities with the number of instances of damage. Results of a case study using the models show that building shaking exceeding a peak response acceleration of 10 m/s² may reduce the probability of successful functioning to below 40% for a sprinkler system and to below 90% for a smoke-activated door system.