Probability-Based Fire Safety Code

Abstract

The paper provides a probabilistic framework for identifying a fire protection system or combinations of systems likely to meet any standard for fire safety implicit in a building code. The standard can be quantified in terms of target values for probable damage or probability of damage (or fire spread) exceeding a level acceptable to the society. This approach incorporates overall systematic procedures and would introduce flexibility in designing, particularly industrial and other large buildings, for fire safety. For example, as discussed in the paper, buildings equipped with sprinklers and detectors can be allowed some concessions in regard to compartment or building size, fire resistance requirement and evacuation time. The framework recognizes the interaction between structural (passive) fire protection and active fire protection systems.Subject to some limitations, the use of fire incidence statistics in the estimation of probabilities is explained with examples. Problems for further studies and research are also suggested for refining the framework and validating the numerical results. These include the application of the framework based on "collective risk" for evaluating the risk for a specific building. I NTRODUCTIONThe first line of provision for life safety in buildings under threat from fire has traditionally been achieved through the implementation of passive fire protection measures. These include the provision of compartmentation and the selection of building materials and methods to reduce the risk of fire spread and limit the size of the fire. At the same time, the building design incorporates features of layout and facilities such that it is possible for people to escape from the effects of fire.Standards for fire protection in new buildings have been applied through Bylaws or Regulations for over a century. Regulatory control has mainly been achieved through a framework of prescriptive rules which depend heavily on simple standard fire tests and Codes of Practice. Levels of performance have been arrived at and are modified largely on the basis of experience.It has been argued that prescriptive rules are highly empirical and enforced more or less rigidly and could lead to costly over-designs, particularly for large buildings which may present a potential for major disaster. For such buildings, the safety level implicit in the Regulations or any other level acceptable to the society can possibly be achieved through combinations of passive and active fire protection measures which are appropriate to the hazard involved, having due regard to practicability. Active measures such as sprinklers which are primarily designed for property protection can provide life safety as well. This approach which incorporates overall systematic procedures would introduce flexibility in designing buildings for fire safety with due allowances for trade-offs between different measures.Among the combinations of measures providing equivalent safety level, the property owner may be permitted to select one which minimizes...

Fire safety management and risk assessment

“…Values of the constants in these equations for major occupancy types are available but they need to be updated (see Rutstein (1979)). Figure 1 (Ramachandran, 1990(Ramachandran, , 1995a) on a (log 6 log) scale is an example (textiles industries, UK) showing the application of the``power'' relationship for estimating the probable area damage in a compartment. According to this Figure, if a damage of 153m 2 is acceptable, a sprinklered compartment of about 4,000m 2 is equivalent in damage potential to a compartment of 500m 2 without sprinklers.…”

Response surface modelling of monte carlo fire data

“…Therefore, an advanced engineering methodology for the cost -effective design of fire safety and protection in buildings has been proposed and widely accepted [5]. The risk analysis should incorporate an uncertainty analysis because many variables of fire are associated with uncertainty [3][71] [72] [73]. However, a detailed methodology for implementing a realistic risk analysis, which can nevertheless be used by practising engineers, has not been developed to date.…”

Non-Deterministic Modelling of Fire Spread

“…A value of w = 0.5 with would generally indicate, as discussed with reference to Equation 5, an equal balance between fire fighting efforts and the propensity of fire to spread and cause damage. It may also be seen that with c = 0 or p = 1/2 and k = 1 in Equation 6, Equation 4 reduces to Equation 8.…”