A Beginner’s Guide to Compartmentation

What is Compartmentation?

To put it simply, compartmentation is the process of dividing a structure into ‘compartments’ for effective risk management. Each compartment is reinforced by fire-resistant materials or by installing measures such as fire doors or cavity barriers.

Why is compartmentation so important?

Compartmentation is a highly critical element of buildings fire safety for several reasons:

• It stops fire, heat and smoke from spreading rapidly through a building. As a fire grows, it dramatically increases in temperature, speed, and combustible power.
• It protects occupants seeking to evacuate or stay put in a building.
• It preserves the building’s structural integrity.
• It provides time to enable people to evacuate safely or for the fire brigade to extinguish the fire before it spreads further.

Compartments in buildings can range in size from a single flat in a housing block to an entire floor of business premises. Each compartment’s size and fire resistance depends on the building, the compartments’ use and the occupancy type. For example, a small block of flats would have lower levels of compartmentation & fire resistance requirements due to the ability of the occupants to evacuate quickly. In contrast, a hospital would have much higher levels & increased complexity due to the need to prioritise patient care.

How is compartmentation achieved in a building?

Passive fire protection is a term you may have heard concerning compartmentation and is a key area. In simple terms, it is the addition of passive fire protection to the existing elements and structure of a building that enables compartmentation to be fully achieved.

Compartmentation, along with passive fire protection, enables the following areas to be protected: 

• Raising the Fire Resistance of the Structure

This ensures that the structure of the building, i.e. the construction elements holding the building together, can withstand a fire for longer. This is critical to ensure the building remains stable for long enough that it won’t distort or collapse upon people evacuating and firefighters attending the fire.

• Providing Resistant Physical Barriers Against Flame and Smoke

These barriers are elements of a structure or passive protection that are non-combustible/combust slowly enough to substantially slow a fire spread through the building. As we’ve mentioned, this gives people time to evacuate before fire & smoke overwhelms the building. Additionally, it allows the fire brigade to attend the scene in time to extinguish the fire or assist in evacuating the building.

• Providing Insulating Barriers Against Heat

Whilst every fire compartment in a building is required to resist the spread of flames and smoke, often the compartments are required to withstand heat too. This is especially important for areas like escape routes or where occupants must pass near a fire. Fires generate significant amounts of radiant heat. Even if a wall or ceiling physically resists flames, if it is not thermally protected, it can allow heat to transfer through until the neighbouring compartment or escape route reaches catastrophic temperatures.

Where does compartmentation fail, and what are the issues to look out for?

In Approved Document B, it states, “All compartment walls and compartment floors should achieve the following:

a)Form a complete barrier to fire between the compartments they separate.

b)Have appropriate fire resistance.”

As such, it is these two areas where many compartmentation issues fall.

So if we take the first point (a), it requires the compartments to form a complete barrier to stop the fire from spreading.

Service penetrations through the walls and ceilings are the most common issue that causes a compartment to fail. Most buildings require a multitude of services to operate, such as water pipes, waste pipes, electrical cables, ventilation ducting, and more, depending on the use of the building. These services often have to pass through fire compartments to reach areas of the building, and in doing so, they effectively breach the compartments leaving an unsealed hole or gap that a fire could exploit. 

As we see in point (b), it is not just about having a wholly sealed or protected compartment but also ensuring that the compartment can achieve the correct fire resistance level. 

This means the walls, ceilings, and the firestopping product’s sealing breaches must be constructed and installed correctly to ensure the fire resistance period is met. 

Moreover, this requires specialist knowledge from both the builder & the firestopping installers to ensure that they know what products are necessary and how to install them correctly.

An issue we commonly see is the high use of pink foam to seal service penetrations across the industry. Many establishments sell pink foam as fire foam; however, this is a common misconception. Pink foam’s application area is very limited, and 90% of the time, it is not suitable for the area it is used in. 

In conclusion

Overall the main issue that affects compartmentation is builders and installers not having adequate knowledge of the fire safety requirements of a building, what firestopping products to specify and how to install them correctly.

This is what makes it so important to use third-party accredited contractors like Harmony Fire, who have the proper knowledge and tools to aid your fire safety strategy and help make your properties compliant and safe.

If you’d like to find out more about our solutions, you can get in touch here.