What is passive fire protection?
Passive fire protection is one of three components of an overall strategy to limit the damage to a building in the event of a fire and increase the time available for any occupants to be evacuated:
- Active fire protection; includes detection systems and alarms, sprinkler systems, extinguishers and hose systems.
- Passive fire protection; the use of fire resistant walls, floors and doors to restrict the spread of a fire or slow it’s progress, giving more time for active measures to be applied.
- Fire prevention; educating the users and occupants of a building; how to reduce the chances of a fire starting and what to do in the event of a fire.
Systems used for passive fire protection purposes are tested in order to give them a fire rating. This is usually the time that they are able to withstand a specific test where they are subjected to fire exposure in a realistic situation. Walls, floors and electrical circuits need to be able to withstand a temperature of upto 140 °C, while 550 °C is considered to be the critical point at which structural steel will begin to lose its strength. There is considerable variation in the exact criteria for these tests between different countries.
Passive fire protection includes:
- Fire resistant walls and floors. Building materials such as concrete absorb heat from a fire. Cladding and spray fireproofing (such as intumescent paint) further slow the spread.
- Fire resistant glass in fire doors or walls. This is available in a range of fire-resistance rated types offering varying degrees of protection (30, 60, 90 minutes etc).
- Firestops seal openings and joints, for example where electric cables pass through a wall or floor.
- Enclosures; fireproof boxes, wraps and cabinets can be used to protect specific items or structures such as electrical systems.
Passive fire protection is an important consideration to be undertaken at the planning stage of any building.