Passive fire protection is a crucial element to any building’s overall fire safety strategy. The purpose of passive fire protection (PFP) is to slow or prevent the spread of fire within the building through the use of fire rated materials. Passive fire protection systems work by using fire resistant doors, walls, and floors to contain fire, heat, and smoke, with the aim of limiting fire spread to a single compartment within the building.
Passive systems do not seek to extinguish fire, but rather focus on minimising the spread of fire throughout a building. These systems work by containing a fire to its area of origin, providing safe egress for the occupants of the building and containing the fire to a comparatively small size such that the Fire and Rescue service can deal with the fire more easily. Limiting the spread of the fire to the compartment results in a smaller, contained fire which also provides greater resilience for the building structure. Effective PFP systems work by dividing a building into fire protected ‘areas’; this is referred to as compartmentation.
Compartmentation protects the building by containing fire and smoke away from escape routes, hallways, stairwells, and fire exits. Passive fire protection systems also aim to limit structural damage to crucial areas of a building which would otherwise result in large financial loss.
What are passive fire protection systems?
A fire risk assessment survey will provide recommendations for a passive fire protection strategy unique to each building. This will usually consist of one or more of the following fire protection measures:
Fire and smoke doors – A fire and smoke door with a fire resistance and smoke control rating reduces the spread of fire and smoke between compartments and helps to maximise time for occupants to escape from a building.
Fire curtains – A fire curtain may also be used to help prevent a fire from spreading throughout a building. These are triggered by a fire alarm or smoke detector which allows the curtain to fall vertically and obstruct the path of a fire. Fire curtains are often used in open plan buildings which do not have the infrastructure to support other PFP systems such as fire doors.
Fire and smoke dampers – Fire and smoke dampers respond to the detection of fire and close automatically. The device permits the flow of air where fire rated structures (e.g. walls, floors or other fire barriers) are penetrated.
Fire walls – Fire walls are a fire resisting barrier installed into the building structures to aid compartmentation and prevent the spread of fire between areas. Fire walls may also be used as walls to separate a building for other means such as privacy or acoustics.
Intumescent coatings – Fire resistant coatings are designed to keep the material they are protecting from reaching its flammable temperature. PFP coating limits the temperature of the substrate, helping to maintain structural loadbearing capacity by rapidly expanding when exposed to heat to form a stable, carbonaceous, insulative char.
Independent, third-party certificated installers can help to ensure correct installation of the specialist passive fire protection products such that they perform as intended to meet the required standards.
What is the difference between active and passive fire protection?
Unlike active fire protection systems such as sprinkler systems, fire alarms, smoke detectors, fire extinguishers, and fire hoses, passive fire protection systems generally do not ‘activate’ in the event of a fire, merely remaining in place to resist the fire. However, with the advent of more sophisticated systems, such as operable fire curtains, the lines between active and passive systems have become less clearly defined. All systems which are expected to ‘operate’ in the event of a fire, including passive systems such as fire doors need regular testing and ongoing maintenance to ensure their effectiveness.
Active and passive fire protection systems work independently of each other but the overall fire strategy of a building will often consider the presence of both to provide your building and its occupants with the necessary protection in the event of a fire. While these systems will not prevent a fire starting, they aim to detect, alert, restrict, and potentially suppress a developing fire.
In summary, passive fire protection systems work to reduce the spread of fire throughout a building and limit structural damage, while active systems work to detect and suppress a fire. Both systems need to function correctly to provide the intended fire protection for the building.
The Fire Protection Association has been providing fire risk assessment expertise for over 20 years. Our experts can assist you with single or multi-site fire risk assessments including DSEAR risk assessments, fire compartmentation surveys, fire door inspections, and fire strategies. Find out more about the FPA’s Fire Risk Assessment Services.
Please be aware that considerable efforts have been made to ensure the accuracy of the information contained within this article at the time of publication, however any legislative (or other) changes that come into effect after this may render the information out of date until it is reviewed and updated as part of the FPA’s content review cycle.