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Containing a fire once it begins

Fire compartments and non-combustible façade systems are crucial for containing a building fire once it’s begun.

With fires developing much faster today compared to 50 years ago (see “What happens in a fire”) it is critical in relation to personal safety and the future use of the building that once a fire begins, it is contained to the smallest possible area – the so-called “fire compartment”.

After fire reaches the flashover point (see “What happens in a fire"), the only way to keep it from engulfing much larger areas of the building from the inside is to ensure that the walls, ceilings, floors and doors of the fire compartment can withstand being exposed to a fully developed fire on one side while not transporting heat, flames or toxic gases to the other side. How long they need to be able to contain the fire depends on the size, complexity and function of the building.

That said, post-flashover, the fire’s heat is intense and can break through the windows, which risks exposing the building façade to the fire and thus circumventing the fire compartment. If the façade system, including cladding and/or insulation, consists of non-combustible materials, however, the flames might eventually reach and breach the windows of the floor above, but the process will be comparatively slow as the façade wouldn’t contribute to the spread of the fire (and resulting smoke).

Effective fire compartments coupled with non-combustible façade systems contribute to slowing the fire’s spread, thus giving building occupants more time to escape and the fire brigades more time to extinguish the blaze. This is especially important in medium- and high-rise buildings.

ROCKWOOL insulation is an important component in a fire compartment as its stone wool fibres are inherently non-combustible and can resist temperatures up to 1,000º C. This is crucial to containing a fire locally and securing that a fire in a building will not become a building on fire. And with minimal organic content, ROCKWOOL insulation will not produce any significant toxic smoke.