Influence of the place of the expiration of gases from the placement at the fire for critical time of formation of dangerous factors of the fire

摘要

In normative documents for definition of time of approach of critical values of dangerous factors of the fire (DFF) use medium-volume characteristics of temperature, concentration of O_(2)oxygen, toxiferous gases and smoke. The purpose of this work – to show that for calculating time of approach of dangerous factors of the fire it is necessary to consider the place of the expiration of gases and their initial parameters. The expressions received in work can serve for determination of values of the dangerous factors of the fire parameters indoors depending on time, taking into account the place of the expiration of gases and their initial parameters. From the dependences given in work it is visible that differences in time taking into account the place of the expiration for the room of 5000 m~(3)are made by not less than 30 c with on reaching critical temperature and critical concentration of O_(2). Especially it should be noted that at change of height of a working zone the time difference increases to 40 c with in both parameters.