Fire barriers explained: everything you need to know

Given that fire barriers are our stock and trade, we thought it was about time that we explained a bit more about them. While you can find plenty of technical information and resources about fire barriers on our website, we haven’t explained many of the simpler questions about fire barriers before, and why they are so important.

Here then are a few of the most common questions about fire barriers, from what they are and what they do, to some of the varieties of fire barriers, where they are needed, and why they are so valuable. If we’ve missed anything, please get in touch, or check out our Systems pages in the menu above for a deeper understanding of Durasteel.

What are fire barriers?

Fire barriers are structural elements of a building that help to stop the spread of fire. They can be used to prevent fire from breaking out of a space such as a room or enclosure, or from progressing along a space such as a corridor. This helps to slow the spread of fire, which protects property, allows people to escape, and grants more time to emergency responders.

Fire barriers are made out of fire-resistant materials, which are tested to resist fire for a specific period of time. A 60-minute fire barrier for instance can resist fire for a minimum of one hour until the fire may be able to breach the barrier. Fire barriers typically resist fires from both directions, but can be built to prevent heat transfer from one or both locations. They may also be built to resist blasts, such as a transformer explosion.

Fire barriers are an important aspect of fire safety. As opposed to active fire protection measures such as fire alarms and sprinklers, fire barriers are a form of passive fire protection. This means that they do not need to be activated to function in the event of a fire, and provide reliable and extensive fire protection with relatively low maintenance requirements.

What is a fire barrier wall?

Fire barrier refers to any form of barrier that prevents the spread of fire, which can include things like fire-rated ceilings, floors, or other partitions. A fire wall is a kind of fire barrier that is designed to prevent and slow the spread of fire through a building. These are comprehensive and continuous barriers that aim to completely seal rooms or or compartmentalise large spaces, stopping a fire from spreading to parallel spaces.

Whereas the rating of other fire barriers will depend on the location and use-case, fire walls tend to offer extremely high fire resistance by default. Our fire walls for instance offer 4-hour fire integrity in either direction, preventing the spread of fire from both sides. They can be provided either in integrity-only or integrity and insulation formats, with the latter resisting heat transfer and providing additional acoustic insulation.

While fire walls may be more complex to install than other types of fire barriers, our fire walls benefit from the modular nature of Durasteel. This means that they can be installed quickly and with minimal disruption, particularly as compared to other materials typically used for fire walls with high fire resistance. As they are commonly integrated into the building structure, they can also be more easily concealed than some other fire barriers, which may be freestanding.

Where are fire barriers required?

Building regulations require different levels of fire protection for different types of buildings. The key document governing fire safety requirements for buildings in England is known as Approved Document B, which provides separate guidelines for residential buildings and all other kinds of building. Several recent amendments have been made to Approved Document B, with the first having come into effect in 2025.

As laid out in the document, fire barriers are generally required at the edge of any cavities or openings that adjoin a floor, wall, or ceiling. This could include:

• Compartments (e.g. rooms)
• Services (e.g. cable passthroughs)
• Stairwells or lifts

There are certain circumstances outlined in the document where a fire barrier may not be required for a ceiling cavity, but this is only allowable where a fire may not reasonably originate within that space, and where a robust fire alarm system is fitted, among other requirements.

Health and safety laws in England are constructed in a way that entrusts building owners and managers to do everything that is ‘reasonably practicable’ to guard against a fire, and protect individuals from the effects of fire. While fire barriers may not be detailed as a mandatory requirement in legislation, they are considered a core component of a fire safe building design, and should be widely used to provide effective fire compartmentation in most buildings, particularly residential ones such as flats or care homes.

What regulation covers the fire barriers within a trunking?

Fire barriers within trunking are also governed by the Building Regulations 2010 (Part B), otherwise known as Approved Document B. Fire barriers are important for trunking as the electrical cables, plumbing and other services that run through trunking can cause a fire to spread quickly along a building, and potentially breach multiple compartments. Cables can naturally also be an ignition source, adding an extra layer of risk.

Approved Document B provides guidance for the necessary fire resistance of barriers securing service openings and trunking within a building. Any openings for trunking must be kept to a minimum and made as small as possible, with effective fire stopping providing an internal and external seal. Materials typically used for trunking fire barriers include cement mortar, gypsum-based plaster, and glass fibre. However, the precise materials used will depend entirely on what is appropriate for a given situation.

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We hope this guide has been helpful, and has answered some of your questions around fire barriers. Visit our fire barriers page or other Systems pages to learn more about our Durasteel fire protection systems, or get in touch if you have any further questions.