Fire risk assessments in buildings evaluate the potential dangers that unwanted fires pose to occupants, the building and operations, the environment and adjacent properties. They follow the fundamental principles of risk assessments applicable in other fields. A risk assessment, in general, examines the likelihood of specific unwanted events occurring and the potential outcomes of those events. A fire risk assessment considers all credible fire scenarios and their impacts. This process connects anticipated fire events to the effectiveness or failure of the provided fire protection measures.
Fire protection organizations such as the National Fire Protection Association (NFPA) and the Society of Fire Protection Engineers (SFPE) have established guidelines for conducting fire risk assessments. These guidelines aim to benefit fire protection engineers, building and business owners, and regulators by providing a common understanding of the requirements and processes related to fire risk assessments.[/vc_column_text][vc_column_text]The general approach for performing a fire risk assessment starts with defining the scope of the review. This is followed by developing a fire risk modelling approach. A first step is data collection to identify the fire hazards and the provided fire protection measures. A next step is to define fire scenarios and evaluate potential consequences. The next step is to quantify the risk, which involves calculating the risk associated with the identified fire scenarios based on their likelihood or frequency and potential consequences. A crucial part when performing any fire risk assessment is to complete a sensitivity analysis which is to assess the impact of uncertainties on the results of the fire risk assessment.
A fire scenario which is a vital component of a fire risk assessment is a chronological sequence of fire events that are interconnected through the success or failure of the provided fire protection measures. A set of fire scenarios are usually developed using the event tree concept where fire events are linked together. The event tree can be constructed based on five fire events which each is considered to be a major phase of fire development. These five fire events are: fire ignition, fire growth, smoke spread, failure of occupants to evacuate, and failure of fire department to respond (Yung and Benichou, 2003).
Each of these five events can occur if the fire protection measures designed to prevent them fail. Consequently, the fire protection measures for each event can be considered a fire barrier to that specific event. For instance, a sprinkler system serves as a barrier against fire growth. Likewise, measures that facilitate occupant evacuation act as barrier that can prevent failure of occupants to evacuate.
Fire protection measures that are put in a building depend on the building regulations and the effectiveness of the fire protection design. The more effective the fire barriers are, the lower the likelihood that those fire scenarios will pose a risk to building occupants, property, or the environment. The documentation of a fire risk assessment should be created as the study progresses. This is crucial as fire risk assessments often involve numerous assumptions, observations, walkdowns, and decisions that must be recorded at the time. This becomes especially important when the fire risk results are intended for regulatory purposes, where all factors influencing the resulting risk values will be closely examined.
While fire risk assessment can be challenging, the process of quantifying fire risk often yields valuable insights that can enhance fire safety. PLC Fire Safety Engineering has a team of experts specializing in fire risk assessments for facilities across all industry sectors, both in Canada and internationally.