Engineering analysis of hazards to life safety in fires: the fire effluent toxicity component

A methodology is described for addressing the smoke toxicity component of fire hazard in a manner that permits the flexible application of exposure criteria according to desired fire safety objectives. Fundamental to the methodology is the concept of upper and lower limits on exposure of occupants to toxic fire gases. Exposure in excess of an upper limit would be expected to result in serious harm to a significant number of occupants, while exposure below a lower limit should ensure that essentially all occupants would be safe from harmful consequences. A user has the flexibility to set exposure criteria over this range as may be appropriate for a desired fire safety objective with a particular occupancy. The status of exposed occupants is assessed at discrete time intervals throughout the progress of a fire scenario, with the time at which such exposure has the potential to compromise occupants' health and safety being determined. Comparison of this time against the time required for occupants' movement and escape to a place of refuge serves to evaluate the effectiveness of a building's fire safety design.