How effective are cavity barriers in preventing the spread of fire?

Cavity barriers offer a solution to the issue of gaps within construction. Most buildings have a number of concealed cavities and voids in the walls that can present issues when it comes to the spread of fire. In order to comply with fire safety regulations, and to ensure that your building has the best possible protection, cavity barriers may be necessary.

What are cavity barriers?

Approved document B of the building regulations, Fire Safety, defines a cavity barrier as: “a construction, other than a smoke curtain, provided to close a concealed space against penetration of smoke or flame, or provided to restrict the movement of smoke or flame within such a space.” A concealed space is a part of a building enclosed by the elements of a building but not something like a room, pipe, cupboard or duct. The way that cavity barriers work is to use a firestopping material, which is fitted within the building cavities and helps with fire compartmentation.

How are cavity barriers effective?

Any concealed space or void within a building will essentially act as a chimney under the right conditions if there is a fire. These empty spaces can provide the perfect conduit for flame, hot gases and smoke to spread throughout the building, creating ideal conditions for fire to grow. Cavities that have not been dealt with will effectively allow air to be drawn in and smoke to vent out to these open spaces, resulting in an acceleration of a fire. Cavity barriers are essential in modern buildings and have real impact. In fact, if you don’t have cavity barriers in place in your building then flames may be able to extend somewhere between five and 10 times higher than where there are cavity barriers in place. It doesn’t matter whether the surfaces of the cavity are combustible or not, this will still be the end result.

Cavity barriers and compliance

Regulation and BS 9991 requires that there are measures in place to control the spread of flames over - or within - an external construction wall. Horizontal and vertical cavity barriers can help to divide and compartmentalise concealed cavities so that the fire is contained. Rather than spreading rapidly, the intention is, instead, that the fire is remains in a single compartment.

Integrating cavity barriers into fire protection strategy

Every building is required to have fire protection measures in place and cavity barriers form an essential part in that. They are particularly important if the building has a “stay put” strategy whereby occupants are required to stay in a space while any fire issues are being dealt with.

If you’re considering reviewing or upgrading your fire protection measures, cavity barriers will be key. This type of fire protection ensures that even the parts of the building that you can’t see are contributing towards optimum fire protection. If you’d like to discuss your fire protection options, please get in touch with the Hillmoore Fire team today.

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About Us

Hillmoore Fire Protection Limited are specialist contractors for all forms of passive fire protection. The ethos and aim of Hillmoore is to provide our clients with an un-rivalled service for the Design, Supply and Installation of all passive fire protection requirements, be it within a new build, refurbishment or upgrading project, or as part of the change of use of a property.