The Fire Safety Design for High-Tech Factories - An Assessment for Evacuation
Prof. Chiun-Hsun Chen
The fire safety design of a cleanroom is given and evaluated by this thesis, which can be divided into two parts. One is the simulation of fire growth and smoke movement by using Fire Dynamics Simulator developed by NIST. Then, it is followed by the corresponding assessment of the available evacuation time and routes by using a set of simple calculation models, including DRES, and a dynamic computer model, Simulex. Throughout the complete design procedure, several comments and suggestions are made accordingly as the references for the future possible revision of building or fire codes.The predicted results of part one indicate that the fires originated from the corner or wall are dangerous and not easy to be detected. The most severe one is on the wall. The downward laminar air flow will make the smoke unconfined by smoke curtain. And it can spread out throughout the whole cleanroom to threaten the people and properties there. In the second part, the DRES Model finds that the available evacuation time is 125.5 seconds under the specified building configuration and number of exits, whereas the smoke descending time, endangering people, is 222.9 seconds. Consequently, the cleanroom is safe if a fire occurs. As to the evacuation time evaluated by “Fire Engineering Design Guide” of New Zealand, it is found that the difference between evacuation times is resulted from the adaptation of various detection times. The simulation results of Simulex show that all escapees can reach safe place in time. The predicted evacuation time is shorter than these obtained by the last two simple calculation models, because the personnel can evacuate by full speed due the low population density in cleanroom.Summarize the conclusions drawn from the above two parts, it is suggested that the building code should regulate the fire load, population density and walking speed of crowd movement in the building. And those data should be provided by means of science-based measurements or calculation, rather than just adopted from the other countries without any modification.
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