For architects, an essential component of designing safe buildings is understanding the key principles of structural fire protection. In particular, the concept of compartmentation is key to the relationship between fire safety and building design. In this article, we’ll explore how understanding compartmentation can help architects design safer buildings and minimise the many risks associated with fire damage.
What is compartmentation?
In the context of passive fire protection, ‘compartmentation’ is the process of sectioning off different spaces or cavities within a building to limit the spread of flames and smoke. Unprotected cavities create a ‘chimney effect’ when a fire occurs. This is where the buoyancy of the air is changed due to the increased air temperature, pulling heat, flames and smoke to travel upwards and through a building at a very rapid and uncontrollable speed. To prevent this, compartmentation seals gaps and reinforces each space with passive fire protection solutions including fire-resistant materials, fire doors, and cavity barriers.
Fire engineering solutions such as compartmentation don’t impact the usability or aesthetics of the building, but rather work behind the scenes to prevent flames and smoke from travelling quickly or at all through the building. This ensures that emergency responders have time to extinguish flames and gives occupants and tenants time to safely evacuate the building.Fire safety regulations to consider when designing or renovating a building
Architects looking to review structural fire safety regulations (especially those related to compartmentation) can find most of what they need in Approved Document B, which includes measures such as:
- Required minimum fire resistance periods for compartment walls or floors based on the building’s purpose and the inclusion of other fire safety systems.
- Installing fully compliant compartment floors for any buildings exceeding 30 metres in height, and compartment walls where walls are common to two or more buildings.
- Ensuring that fire-resistant ceilings and cavity barriers can resist fire for a minimum of 15 minutes and hold their structural integrity for at least 30 minutes if exposed to extreme temperatures.
Fireproofing design considerations for architects
Here are some of the most critical steps architects can take to ensure that buildings are designed with due consideration for structural fire protection.
The building’s size and intended purpose
Size and intended use are two risk factors that must be incorporated into structural fire safety design. For example, a large multi-storey building of residential flats has various fire risk points, such as kitchens, as well as an increased evacuation time and more people and property at risk than a small, 4-flat residential building. Similarly, a hospital has increased fire risks due to onsite storage of flammable materials, vulnerable patients, complex electrics, and oxygen storage. A compartmentation survey is invaluable for noting fire risk areas and developing a passive fire protection plan based on a building’s design.
Cavity barriers
Cavity barriers are composed of inert or intumescent materials that expand when they are exposed to heat, closing off gaps that fire and smoke can travel through. Without a cavity barrier, fire has easy access to oxygen and flammable materials, allowing it to spread across walls and between floors quickly. These are often installed in enclosed spaces that are typically unused within the building such as extraction vents, windows and door openings, and at junctions where wall cavities align with the wall or floor of a building compartment.
Preserving escape routes
When compartmentation is effectively incorporated into a building’s design, it creates additional layers of defence so that escape routes are not compromised in the event of a fire. Even if adjoining spaces have been damaged, escape routes can be protected through the inclusion of compartment walls and floors or cavity barriers. During the construction phase, these can then be reinforced using firestopping seals, which prevent the egress of flame or smoke through gaps between building materials and structural elements.
Preventing the spread of fire to adjoining properties
If buildings are designed with common walls, compartmentation needs to be factored into the design to prevent fire from spreading to any adjoining structures. This primarily involves factoring compartment walls and floors into designs, but it should also be noted that any features such as rafters, joints or even windows and doors located near a neighbouring property must be protected using firestopping seals.
Ultimately, to ensure not only a safe building but also an efficient design and build process, architects should consider compartmentation and other structural fire protection principles from the outset. This will also help building owners save countless direct and indirect costs associated with fire damage and respective remedial works. Hopefully, structural fire protection provides a stimulating parameter to help architects design more practical and innovative buildings.
Jordan Coleman is a Marketing Executive at CLM Fireproofing, one of the UK’s leading providers of passive fire protection with clients including The Shard and Battersea Power Station.