建築火災安全のシステム分析 : 第2報初期消火設備の有効性

Abstract

Using the data of 3925 building fires occurred in Tokyo during 1981, effectiveness of equipments and systems for fire extinguishment have been analysed. Most of fire fightings by occupants were conducted using fire extinguishers or water from taps with buckets or vinyl hoses. The success rate of fire extinguishment of above measures were almost same which reached more than 50 % when fire fightings were started before fire spread to ceilings. The effectiveness of a) automatic fire detection system, b) fire extinguishers, c) interior fire hydrant system and d) sprinkler system have been analysed. Buildings with one of above equipments had higher success rate of fire extinguishment system whose function was to put out fires in their early stage than the buildings not equipped with them. Calculation shows the success rate of fire detection system with automatic fire detectors is estimated between 346 and . 697 and the success rate of fire extinguishment system with b) fire extinguishers, c) interior fire hydrants and d) sprinklers are estimated between b). 391 and. 438, c). 179 and. 302 and d). 250 and. 750. Reasons of failures of above systems have been analysed using Fault Tree Analysis Method. About eighty percent of failures of automatic fire detection system were caused by human errors half of which were cuttings of electricity or bells and the rest were delay of recognition of fires by occupants. Forty to fifty percent of failures of fire extinguishment system with fire extinguishers or interior fire hydrants were caused by human ignorance of or indifference to the equipments, which made them unused. Sprinkler system had few failures caused by human errors. In order to increase success rate of fire extinguisment system, more consideration of man-machine system that embraces human errors and characteristcs is needed.