What is passive fire protection?

Passive fire protection (PFP) is one of three forms of structural fire protection, along with active fire protection and fire prevention. PFP aims to contain and delay the spread of fires through fire compartmentation.

Fire compartmentation divides buildings into areas that allow fire risks to be better managed. As smoke travels at between 15-90 metres a minute, fire compartmentation is designed to protect escape routes. Ineffective compartmentation also impacts on the activities of firefighters, putting them at even greater risk.

Although many organisations conduct regular fire risk assessments (FRAs), not all undertake full compartmentation surveys. FRAs do not tend to include a full compartmentation survey, especially regarding hard to reach areas such as suspended ceilings.

Fabric and layout alterations throughout the lifetime of a building often means that we have to conduct compartmentation surveys in order to ensure compliance and the safety of residents.

Having previously highlighted the importance of sprinklers (a type of active fire protection), they are most effective in buildings with effective fire compartmentation.

Key components regarding compartmentation include:

Fire doors – fire doors stop fire and smoke from travelling around the building. This minimises damage and allows occupiers time to evacuate. Fire doors are made up of a number of components which all play a critical role in its performance. This includes glazing, signage, door frame, frame and air transfer grilles (ATGs). Replacing a single component with a non-fire rated component has a huge knock on effect on the effectiveness of the fire door.

The main categories of fire door are FD30 and FD60; offering 30 and 60 minutes of fire protection, respectively.

Intumescent seals and smoke seals – intumescent seals are chemically designed to expand when exposed to extremely high temperatures. Once a fire breaks out, the heat causes the strip to expand and form a seal to contain the fire, giving occupiers enough time to escape.

Smoke seals are placed between the door frames and the door, and stop heavy smoke passing through the building.

Pipe collars and wraps – intumescent pipe collars and pipe wraps are used to stop the spread of smoke and fire along pipework that passes through compartment walls and floors. Pipe collars and wraps usually provide protection for two to four hours, depending on the type.

Pipe collars can be fitted in most situations even if the construction is not completely solid, such as timber plasterboards, walls or ceilings. During a fire the intumescent material in the collar expands to seal the hole. A pipe wrap will also seal the hole within the pipe, but has to be fitted within a solid construction masonry wall so that the intumescent material can only expand inwards.

Pipe wraps are cheaper than pipe collars, whilst also being more discreet when installed correctly. If you are retrofitting fire protection, it is usually easier to install a pipe collar as it is difficult to create a new hole big enough to insert the wrap.

Anneka Gill, Bid Manager

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