Hazard Firespread breaching a compartment
Knowledge and understanding
|Firespread breaching a compartment||
Understand all associated hazard knowledge
Fire compartmentation is achieved with fire-resisting construction, aimed at preventing or delaying the spread of fire and smoke from one space in a building to another. Occasionally this includes limiting external firespread from the building.
Dividing spaces into cells or compartments or separating the buildings by walls and floors constructed as compartment walls and compartment floors, can restrict firespread within buildings. Factors like the occupancy of the building, fire loading, height to its top storey and the presence of sprinkler systems can affect the level of compartmentation. These factors are used to determine evacuation plans in the event of a fire.
Sub-standard installation or a poor state of repair will reduce the effectiveness of fire compartmentation. Penetrations that are not fire stopped, defects, or a lack of maintenance can lead to the early failure of compartmentation.[BH1]
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 house from another need to be compartment walls. The same applies to flats and maisonettes.
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 have some inherent fire resisting properties.
Inappropriate alterations to external compartment doors, for example, changing front doors for aesthetic or security purposes, may allow firespread to breach compartmentation faster than expected.[BH2]
Where there are not enough fire-resisting elements, such as doors or separation that are not designed to provide a level of fire protection, firespread may breach the compartment.
Factors that may lead to firespread breaching a compartment include:
- Retrofitted cabling or pipework with ineffective fire stopping
- Failure of devices such as collars or dampers that are designed to stop the spread of smoke or fire passing through pipework
- Features of the building that may allow for the spread of smoke or fire between compartments, including:
- Severity of fire within the compartment
- Duration of fire development
- Failure of compartmental elements, such as uPVC door and window frames
- Interference with integral fire safety provisions, for example wedged open fire doors
- Firefighting tactics
- Actions of occupants, for example leaving doors open when evacuating