BRE DG490 PDF

This Digest is part of a suite of related documents containing guidance for the construction industry on structural fire engineering design. The intention is to produce performance based guidance that brings together fire engineering and structural engineering providing a framework within which designers are free to develop site specific solutions based on real performance criteria. The Digests contain information complementary to the existing and emerging fire engineering codes and standards. Each Digest may be used in isolation or as part of the full integrated suite.

This Digest covers life safety aspects of fire engineering design and, in particular, life safety implications for structural engineering design. Minimum requirements are set out in Approved Document B of the Building Regulations. Designers must consider adequate escape route provision and fire separation (protection between compartments and protection of escape routes). The design of manual or automatic fire detection and alarm systems depends on the evacuation strategy which must take into account the occupant type (occupant numbers, state of alertness - awake or asleep - and familiarity with the building and its systems) and the building characteristics (single or multiple enclosures and spatial complexities). Consideration also needs to be given to the needs of firefighters in terms of access to burning buildings. The factors that affect the behaviour of occupants escaping from fire are discussed. Evacuation times for different occupant populations are calculated. Fire or smoke can spread from compartment to compartment due to design or structural faults or failures (e.g. via ducts or facades) or via windows or fire doors left open. Examples taken from real fires illustrate the importance of preventing a failure or compartmentation that could lead to the occupants suffering from smoke exposure.