Assess compartmentation

Fire compartmentation is designed to prevent or delay the spread of fire and smoke from one space in a building to another. Occasionally this includes limiting external firespread from the building.

For further information refer to Fires in buildings supplementary information.

Dividing spaces into cells or compartments or constructing compartment walls and floors can restrict firespread within buildings. Factors like the occupancy or population of the building, fire loading, height to its top storey and the presence of sprinkler systems can affect the level of compartmentation. Together these factors help to determine evacuation needs in a fire.

Compartmentation is particularly relevant in residential buildings as the occupants of a house need to be reasonably protected from a fire in an adjoining house – walls separating one residence from another should be compartment walls. Breaches in compartmentation, shared roof voids and air bricks may allow the spread of fire or smoke. Adjacent, rooms and properties should be inspected prior to concluding an incident.

Refer to Operations – Closing an incident too early.

Fire doors are installed at strategic locations in a building, where passage through a line of fire resisting construction is required. Not all doors in a building are fire doors, but general-purpose doors may carry some inherent fire resisting properties.

The effectiveness of fire compartmentation relies on the quality of installation and a good state of repair. Penetrations that are not fire stopped, defects or a lack of maintenance can cause premature failure of compartmentation. There may have been inappropriate alterations to compartmentation by occupants, for example the removal of internal doors or changing of external doors for aesthetic reasons. Consider examining the condition of compartmentation using areas damaged by fire or by cutting away. The state of compartmentation in the building should be investigated.

During an incident, closing doors or leaving unopened doors closed will prevent the unnecessary spread of smoke, fire gases and subsequent damage. This action should be balanced against the need to maintain access, egress and tactical ventilation.

The positioning of hose lines could compromise compartmentation including lobby areas, resulting in smoke spread into unaffected areas and protected firefighting shafts.

Refer to Fires and firefighting.