Fire risk assessment: what it is and which methods are used to calculate it
When planning fire protection in any space, a key aspect to determine is the existing fire risk. This risk can be influenced by a wide range of factors and calculated using various methods—some of which are used worldwide.
In this article, we explore fire risk assessment in the context of fire protection.
What is fire risk assessment in fire protection?
A fire can only occur if the “fire triangle” is formed, which refers to the combination of three elements:
Fuel
Fuel is any material used to produce energy in the form of heat through different reactions.
Oxidizer
An oxidizer is any substance that, under certain pressure and temperature conditions, reacts with the fuel to produce combustion. Oxidizers cause the fuel to oxidize, but they cannot do so on their own.
Activation energy
The third necessary factor is activation energy or ignition source. This is the minimum amount of energy required to initiate a combustion reaction, which could be as little as a small amount of heat.
To prevent a fire, it’s essential to eliminate at least one of these elements, avoiding their coexistence. Several methods are used to assess fire risk in prevention projects, each based on different parameters depending on their purpose, protection priorities, or the criteria adopted by the respective authors or institutions.
Common methods for assessing fire risk
When evaluating any fire risk, two aspects are generally considered:
First, based on an analysis of the amount of fuel and the likelihood of an ignition source, the probability of fire initiation must be assessed.
Second, it is equally important to evaluate the consequences of a fire, considering elements such as emergency equipment, fire extinguishing systems, evacuation routes, fire compartmentation with fire curtains, and more.
Several methods are commonly used for these evaluations:
The Gretener method
One of the most well-known and regarded as the pioneer in fire risk assessment methods, Max Gretener developed this approach in the 1950s. It is still used today for quantitatively evaluating risk in both public or commercial spaces and industrial environments.
This method is helpful for decision-making regarding risk assessment and protective measures. It takes into account factors such as the distance between buildings, evacuation routes, installed protection systems, and emergency signage.
The Purt method
A simplified version of the Gretener method, the Purt method offers a quick and indicative assessment focused on two areas: buildings and their contents.
The E.R.I.C method
This method provides a broader and more detailed evaluation of safety measures, equipment, and risks to both people and property. It is applied across various building types and distinguishes, for example, between industrial facilities and office buildings.
Unlike other methods, this one addresses aspects such as smoke toxicity and evacuation times, emphasizing detection, alarms, alerts, and protection systems as key components.
The F.R.A.M.E method
Based on the ERIC and Gretener methods, this approach expands the scope of risk analysis from asset protection to include personal safety and economic losses. Many professionals consider it the most comprehensive and useful method currently available, as it evaluates three main areas: people, activities, and assets.
The intrinsic risk level method (IRL)
This method is used in the Spanish fire safety regulation for industrial establishments (RSCIEI) and was introduced in 1981. It is the only method based on calculating the thermal load, adjusted according to the activity carried out in a specific fire compartment within a building. However, its application is limited to industrial settings.