RSET/ASET, a flawed concept for fire safety assessment

Fire and Materials (Impact Factor: 1.21). 10/2010; 34(7):341 - 355. DOI: 10.1002/fam.1025

ABSTRACT For the evaluation of occupant safety in the case of building fires, the Required Safe Egress Time/Available Safe Egress Time (RSET/ASET) concept has become widespread and is now commonly used in the fire safety engineering profession. It has also become commonly used by smoke detector (smoke alarm) manufacturers in assessing whether a particular detector technology is adequate. It is shown in this paper that the concept is intrinsically flawed and its use promotes the diminishment of fire safety available to building occupants. The concept innately ignores the wide variations in capabilities and physical condition of persons involved in fire. It is based on implicitly assuming that, after a brief period where they assess the situation and mobilize themselves, occupants will proceed to the best exit in a robotic manner. This assumption completely fails to recognize that there are very few fires, especially in residential occupancies, where occupants perished or were seriously injured who had endeavored to exit in this robotic manner. Instead, in the vast majority of fire death and serious injury cases, the occupants did not move in such a manner and their evacuation took longer than anticipated on the basis of robotic movement. There is a wide variety of reasons for this, and these are well known in the profession. The concept also ignores that there can be a wide variation in fire scenarios. The same building and the same fire protection features can be evaluated, but both RSET and ASET can change drastically, depending on the scenario used. The consequence of using the RSET/ASET concept for fire safety engineering or product design purposes is that fire deaths and injuries are permitted to occur, which are preventable. Copyright © 2010 John Wiley & Sons, Ltd.

  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: This article presents building fire risk analysis model based on scenario clusters and its application in fire risk management of buildings. Building fire risk analysis is a process of understanding and characterizing the fire hazards, the unwanted outcomes that may result from the fire, and the probabilities of fire and unwanted outcomes occurring. The purpose is to evaluate and make a decision about the level of fire risk to determine whether to take appropriate risk management measures or not. Therefore, building fire risk analysis serves as a basis for fire risk management. In the paper, scenario clusters are constructed in the process of building fire risk analysis, and the number of deaths and directive property loss are selected as building fire risk indexes. Finally, the average fire risk of residential buildings is quantified in detail. With the types of detailed fire risk models developed here, fire risk management measures could be taken to improve the building fire safety grading and reduce fire risk levels and subsequent damage.
    Fire Safety Journal 11/2013; 62:72–78. · 1.06 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In part I of the paper, an assembly building was analyzed in order to compute the failure probabilities, and thus the safety level, of current code-compliant buildings. In this second part, various fire protection systems are modeled within the fire and egress simulations in order to quantify their magnitude of impact. Since all fire protection systems can fail to perform as designed on demand, the potential failure along with its probability is accounted for in an event tree analysis. Comparing the resulting failure probabilities of the performance-based analyses with and without fire protection systems yields information about the magnitude of impact of the fire protection systems on the level of safety and hence allows a direct, objective, and quantitative comparison to other systems and designs. Accounting for the cost of the systems, a direct cost–benefit analysis can be conducted.
    Fire Safety Journal 02/2014; · 1.06 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A fire experiment conducted in a British 1950s-style house is described. Measurements of temperature, smoke, CO, CO2 , and O2 were taken in the Lounge, stairwell, and front and back bedrooms. The front bedroom door was wedged open, while the door to the back bedroom was wedged closed. Contrary to expectations and despite the relatively small fire load, analysis and hazard calculations show permeation of toxic fire gases throughout the property with lethal concentrations of effluent being measured at each sampling point. A generally poor state of repair and missing carpets in the upper story contributed to a high degree of gas and smoke permeation. The available egress time was calculated as the time before the main escape route became impassable. Given known human responses to fire, such an incident could have caused fatalities to sleeping or otherwise immobile occupants.
    Journal of Forensic Sciences 12/2013; · 1.31 Impact Factor

Full-text (2 Sources)

Available from
Jun 1, 2014