Andrew Blackwell | Project Manager
The idea behind passive fire protection is to ensure that no one ends up trapped inside a burning building without the means to evacuate.
There’s always a risk that something might cause a fire within a building, which means that measures must be in place to contain that fire in order to give the occupants enough time to exit the building safely.
Passive fire protection enhances a building’s fire resistance and therefore its ability to prevent the spread of flames. This means that the structure of the building will remain largely intact during a fire, which leaves all escape routes clear, reduces the risk of falling debris and ensures safe evacuation while allowing the emergency services a passage back into the building should it be necessary for them to do so.
In order to undertake an effective fire stopping campaign, the correct fire stopping materials are needed, and in this blog we’re going to be looking at these materials and how they work to prevent fires spreading.
Legislation Around Fire Stopping Materials in Buildings
It is possible to restrict the spread of fire by dividing the building into a number of discrete sub-sections. These sub-sections are split up from each other by what is known as compartment walls and floors, which are manufactured to a fire-resistant specification, thereby drastically reducing the chances of the fire spreading from room to room.
Great care must be taken with fire resistant elements during construction to ensure that junctions and crossovers between the different elements aren’t creating openings and areas of structural weakness.
As per the Approved Document B, Fire Safety: “‘if a fire-separating element is to be effective, then every joint, imperfection of fit, or opening – to allow services to pass through the element –should be adequately protected by sealing or fire stopping so that the fire resistance of the element is not impaired.”
Fire Stopping Materials
As we’ve covered, the joints between fire-separating elements, such as compartment walls and floors, should themselves be fire-stopped to ensure there is a continuation of fire resistance throughout the building.
Openings for beams, joists, rafters, pipes, ducts, electrics, and cables that pass through the fire-separating element should be as minimal as is physically possible.
Common fire stopping materials used within a building will often include most of the following:
- Cement mortar.
- Gypsum-based plaster.
- Cement or gypsum-based vermiculite mixes.
- Intumescent mastics.
- Fire resistant doors and fire-door furniture.
- Fire shutters and curtains.
- Compartment walls and floors.
- Fire resisting walls and partitions.
- Suspended ceilings.
- Fire-resistant glazing.
- Fire-fighting shafts and stairwells.
- Mechanical or intumescent fire-resistant dampers.
- Fire-resistant air ducts.
- Linear gap seals.
- Cavity barriers.
- Fire-resistant air transfer grilles.
- The building envelope, i.e. fire-resistant external walls.
What You Need to Know About Fire Stopping Materials
When it comes to the implementation of certain fire stopping materials, there are a few things that you should be aware of:
- In the case of pipes and ducts, the purpose of fire stopping, is to allow thermal movement, to prevent heat build-up. It’s important that the pipes and ducts are inspected by a professional to ensure they are completely safe.
- Where an unsupported span is more than 100mm or where non-rigid materials are utilised (unless they have been shown to be satisfactory upon test), materials used for fire stopping should be fortified with, or supported by, materials that limit the chance of combusting.
- Fire stops should not be confused with cavity barriers, which are used to block smoke and flames from spreading through to concealed spaces, such as those found in walls, floors, ceilings and roofing, as this can present a significant danger to the structural integrity of the building.
- Any fire resistance element within a construction is measured by three key elements:
- Its resistance to collapse.
- Its resistance to fire penetration.
- Its resistance to the transfer of excessive heat.
Ultimately your selection of the correct fire stopping materials is in place to save lives. It is therefore a decision that should include fire stopping professionals and the responsible person for the building. No two buildings are exactly the same, which its why it’s so important to focus on, not just the materials you need, but also the environment and situation into which they are being implemented.
Since each building is different, so it’s highly likely that any previous fire stopping project you’ve undertaken will require a different approach.
After all, a functional firestopping strategy is only effective once a combination of materials are working in tandem.
Efficient and effective fire stopping will necessitate a good understanding of the technical literature and standards. This is particularly key when fire stopping protocols may be left to the end of the construction process or installed by a knowledgeable third-party.
The integrity of all fire stopping implementations should be maintained thoroughly whether the building is a new construction or is being refurbished.
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