Fire Safety Science Digital Archive

The air-conditioning flow highly affects the flow pattern of fire gases. However, the combustion and fire detection in the air-conditioned rooms have not fully been investigated, except for the special cases such as in LSI clean rooms (where no false alarms are existent). In the air-conditioned ordinary rooms such as offices or hotels, there may be caused some worst cases; both the delayed detection and accelerated fire combustion happen simultaneously. And recently the number of buildings which are air-conditioned in all seasons is increasing. This study describes the analysis of behavior of accelerated combustion of fires and early fire detection in air-conditioned rooms, experimentally and numerically. It has been found that in some cases the combustion speed of polyurethane sheet is twice or 3 times accelerated by the cool downward air-conditional flow. At the same time, the smoke and fire gases are highly diluted by the air-conditioning flow, where the conventional fire detectors are less effective. The multi-element fire detector including carbon monoxide sensor can detect fires early and reliably, in corporation with the fuzzy expert logic.