With this article continue the series of articles dedicated to fire risk assessment in buildings. [1] [2]
In order to prepare a fire risk assessment, all data generated during the frequency and consequences analysis fire scenarios are combined and analysed. This can be achieved in a variety of ways, including qualitative, semi-quantitative and quantitative methods.
Qualitative and quantitative methods for fire risk estimation, risk matrices
The qualitative approach addresses both frequency and consequences and includes methods such as risk matrix, risk indices, and risk clustering. Examples are shown in Tables 1 and 2 and Figure 2.
Semi-quantitative methods combine quantitative and qualitative tools. Semi-quantitative methods use sources such as actuarial data, which provide data for quantitative frequency analysis, but qualitative analysis of consequences. Other methods use fire effects modelling for quantitative consequence analysis, but treat frequency analysis qualitatively. These approaches can be used with an event tree or other analytical methods. The event tree method is often used to analyse complex situations with several possible scenarios where several fire or safety systems are in place or are being considered. Event trees are developed for a scenario with frequencies and consequences already described, and then the risk is calculated.
One method of quantifying the fire risk from multiple fire scenarios is shown below:
Σ Ri = Σ Li x Fi
where
Ri = Risk associated with a scenario i
Li = Loss associated with a scenario i
Fi = Frequency occurrence of scenario i
The last type of risk assessment tool is the benefit-cost approach, which can determine the costs required to achieve different levels of risk reduction or determine the optimal levels of fire protection based on expected losses. These approaches are often used in the insurance industry and by facility managers to balance acceptance, mitigation, transfer or avoidance decisions in risk management. The result is often expressed as expected losses or costs, which include capital costs, maintenance costs and expected losses.
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References:
[1] http://fire-techinfo.com – Fire risk assessment in buildings – a general overview
[2] http://fire-techinfo.com – Fire risk assessment in buildings – identification and analysis of hazards, events and scenarios
[3] http://sfpe.org – Аn оverview of аpproaches and resources for building fire risk assessment
[4] SFPE Engineering Guide – Fire Risk Assessment, Society of Fire Protection Engineers
