Assessing the risk in an emergency situation such as a fire is not as simple and easy as with other types of risks that we may face in our daily lives. Fire risks include multiple factors such as the fire itself, the products released as a result of combustion, the impact on people, etc. in addition to potential damage to tangible assets and the building. Quick recognition and proactive measures to protect against a potential fire will ensure safety for people, property and the building.
The challenge facing fire protection engineers is that no one knows exactly when or where a fire will occur, under what conditions, and who will be at risk. It is common for building and fire regulations to be used to manage risk. But that is not enough. Buildings and the fire regulatory system are complex and comprehensive, which for most buildings results in a generally acceptable level of fire protection. This means that unknown or poorly estimated safety issues may exist in any building, especially if there are features related to architecture, occupants, work processes or purpose that are not specifically addressed by applicable regulations and standards. One way to determine whether such a potential exists is by performing a fire risk assessment of the building or facility.
FIRE RISK ASSESSMENT
The ultimate goal of the fire risk assessment is to identify and characterize dangerous fire risks and provide sufficient information to make decisions about managing that risk. The aim is to answer three main questions:
1. What can happen (what can go wrong)?
2. What is the probability of this happening? And if it happens
3. What are the consequences?
Fire risk assessment is distinguished from fire hazard analysis and consequence analysis by also assessing the probability of a fire occurring in addition to assessing those factors that could lead to a fire and assessing the impact if a fire occurs.
Fire risk assessment involves several steps, including defining assessment objectives, assessment metrics, hazards and potential fire scenarios, conducting analyses of the frequency and consequences of fire scenarios, as well as calculating the risk associated with the identified scenarios. In some cases, the fire risk assessment may extend to assessing risk mitigation options (by reducing the likelihood of occurrence or magnitude of consequences) as a part of the risk management process. Figure 1 shows the framework of the fire risk assessment process.
![Figure 1: Fire risk assessment process. Source: © SFPE [2]](https://fire-techinfo.com/wp-content/uploads/2023/07/Fire-Risk-Assessment-1-en-749x1024.png "Figure 1: Fire risk assessment process. Source: © SFPE [2]")
Objectives, indicators and thresholds for fire risk assessment
Some of the most important steps in the fire risk assessment process are determining the objectives of the assessment, the metrics that will be used to express the risk, and how those metrics will be communicated for decision-making purposes.
For example, a primary objective might be: “Providing a fire-safe environment for occupants not in the immediate vicinity of the initial fire development and improving fire protection for occupants in the vicinity of the initial fire development.”
The first question that may arise is: Which inhabitants – all, only the most sensitive group, another subgroup? Then the question must be answered: Under what conditions – smoke inhalation, exposure to thermal energy, high temperature, other impacts, at any time of day or under what circumstances? Answering these questions and determining acceptable risk thresholds are important as they will help to establish fire scenarios against which risk will be calculated later in the process.
The same approach to work is applicable to the assessment of financial losses that may be associated with the loss of tangible assets (direct) or business continuity (indirect). Is the focus only on the structure of the building, the content – all or only part of it, or is the focus on both content and structure? Is the impact only on local operations or is there an impact somewhere along the supply chain or delivery to market? What the assessor chooses to address can affect the assessment, and whether all hazard scenarios are selected or only a subset of them depends on the focus.
The way in which risk is measured and presented is also very important and can significantly affect the perception of risk. For example, the risk to humans discussed above can be expressed by the ratio of fire deaths, for example 9.6×10-6 overall or 2.99×10-7 for non-residential buildings only. Expressed in this way it is not possible to estimate precisely what the risk is, so a comparative number can be given, for example the risk of death in a car accident, 1.03×10-4, is much higher. An even easier way to estimate is to use reciprocals of 1 in 104,161, 1 in 3,344,481, and 1 in 9,708, respectively. A specific risk related to the type and characteristics of the building, risk of occurrence of unforeseen circumstances or some other indicator can also be chosen for evaluation.
Follow the upcoming articles on the topic!
References:
[1] http://sfpe.org – an оverview of аpproaches and resources for building fire risk assessment
[2] SFPE Engineering Guide – Fire Risk Assessment, Society of Fire Protection Engineers
