What is fire compartmentation? Firestopping FAQs

Passive fire protection relies on the effective compartmentation of a building. It is made up of fire doors, walls, and floors, and works alongside active systems such as sprinklers and fire alarms.

Elements of the compartmentation, like the service penetration seals, are hidden within the building’s makeup, often making them the ‘unsung heroes’ of building safety. Their silent but crucial role in containing and slowing the spread of fire is often overlooked, but they’re a key factor in saving lives and limiting damage in the event of a fire. But more on that later!

The implementation of fire compartmentation is crucial in high-rise buildings, which Approved Document B defines as those exceeding 18 metres in height or having more than seven storeys, with at least two residential units. However, we believe that compartmentation should not be limited to high-rise buildings or those over 18 metres; each case should be reviewed individually.

Compartmentation has long been a requirement in Approved Document B, B3: Internal Fire Spread (Structure). It states:

Where reasonably necessary to inhibit the spread of fire within the building, measures shall be taken, to an extent appropriate to the size and intended use of the building, comprising either or both of the following—

(a)  sub-division of the building with fire-resisting construction;

(b)  installation of suitable automatic fire suppression systems.

It also highlights that all compartment walls and floors should achieve a complete barrier between the compartments they separate, and the appropriate fire resistance must be implemented.

The purpose of fire compartmentation

Fire compartmentation works to contain a fire to its areas of origin for as long as possible.

Despite it being a regulatory requirement, it is sometimes overlooked as an important life safety measure that construction professionals must take seriously.

When the appropriate service penetration sealing products are installed according to relevant test evidence, they provide time for occupants to safely evacuate or wait for rescue, while also reducing damage in the event of a fire. Simply, it puts those living in the building first.

Getting technical – how is fire compartmentation achieved?

A building’s compartmentation is created by dividing the premises into areas of manageable risk. This is done using fire-resistant barriers, such as masonry and fire-rated plasterboard walls, concrete and fire-resistant ceilings, and floors.

In our experience, it is doubtful that a building’s compartmentation will remain a solid box due to required openings. For a home to be habitable, it needs windows, doors, a kitchen, and a bathroom, which require service penetrations like pipes and cables. These form ‘openings’, which consequently void the fire-resistance rating of the compartment wall or floor.

Due to this, every penetration that breaks the compartment line must be adequately firestopped to reinstate the required fire rating. This is where test evidence and firestopping products – such as fire collars, fire sleeves, wraps, and compounds, to name a few – will be utilised.

What needs to be considered?

When it comes to restoring a building’s compartmentation, all factors must be considered. This includes the supporting construction and its required fire rating, the actual service penetration type and material, whether it is insulated, and the thickness of any insulation. Knowing whether the application is a single or multi-service penetration is also beneficial.

However, it can be challenging to reinstate certain applications’ fire ratings due to insufficient test evidence or mismatched integrity and insulation ratings.

At Quelfire, we provide the Information Collection Form, which helps our customers gather this amount of information efficiently.

In summary

Compliant fire compartmentation saves lives. Therefore, properly designing, installing, and maintaining the compartmentation, especially regarding service penetration openings, is crucial to ensure firestopping systems work correctly in the event of a fire.

You don’t have to go it alone. Please contact technical@quelfire.co.uk if you have any further questions on fire compartmentation or need help choosing the best solution for your application.