What is the purpose of a fire stop?

A fire stop, commonly known as firestopping, is a fundamental part of passive fire protection which works to protect people and property.

Fire compartmentation means to contain a fire to one area, preventing the spread of fire between compartment walls and floors, for as long as possible.

Fire compartmentation is compromised with openings (for example doors and windows), service penetrations (such as pipes, ducts, and cables) and linear gaps. Different areas of passive fire protection are designed to retain the fire rating of compartment walls and floors compromised by these various openings.

Service penetration seals and linear gap seals are mostly referred to as fire stops. While cavity barriers can be categorised as fire stops, they are mostly considered to be a separate category of passive fire protection.

A service penetration seal is a passive fire protection system that is intended to maintain the fire resistance of a compartment wall or floor where services such as cables, pipes or ventilation ducts go through them.

As the construction industry uses many different materials, services, and types of penetrations, this also means that there is a wide variety of firestopping solutions that are used to seal around these service penetrations.

In the event of a fire, combustible pipes, for instance, will melt causing larger holes to be left in their place. It is important that these holes are sealed so that fire and smoke does not spread into the next compartment. In this type of application, intumescent is a common material that offers an effective solution by expanding and forming a char.

Linear gap seals, otherwise known as linear joint seals, are also used to maintain the fire resistance of a building and some can offer a degree of movement, if required. Linear gap seals can be found in walls, floors, and in head of wall applications, which is a linear gap between wall and ceiling or wall and floor. Linear gap seals effectively close junctions between building elements.

Cavity barriers are situated in line with each floor of a high-rise building and are typically pieces of firestopping material that work to close a cavity between two building elements. They can also be found in walls, enclosed by structural beams, floors, ceilings, and roofs.

Regulations in firestopping

The legal obligations requiring businesses to have effective firestopping installed applies to all buildings: existing buildings, new builds and residential, or non-residential premises.

In the amended Approved Document B: Fire safety, section 9.1, it states:

“Every joint, imperfect fit and opening for services through a fire-separating element should be sealed with firestopping to ensure that the fire resistance of the element is not impaired. Firestopping delays the spread of fire and, generally, the spread of smoke as well.”

Why is firestopping important?

Firestopping is important because ultimately, it saves lives!

Choosing firestopping products that have been tested and actively installing them according to the manufacturer’s guidance, limits the risk of destructive fire.

If fire stops are not installed correctly, both fire and smoke can rapidly dominate a building, structurally damaging it and risking the lives of its residents.

Moreover, fire stops are widely recognised to support the emergency services when arriving at the scene of the fire. Through successful compartmentation, this gives the fire and rescue service more time to get the fire under control and rescue anyone still in the building.

Firestopping is an important part of a building’s fire safety strategy and should not be taken lightly. Therefore, the construction industry needs to ensure that the correct firestopping products are installed and start to utilise the support offered by relevant experts.

Craig Wells

This question was answered by Craig Wells

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