This Part of BS 7899 is intended to provide guidance, for fire safety practitioners, including manufacturers, architects, planners and engineers, on the factors which need to be considered when assessing the hazard to life and health presented by fires in structures (buildings and transport). The assessment can be applied to various possible fire scenarios in order to determine if conditions hazardous to life could develop, and to estimate the risk that they might occur. If the development of hazardous conditions is considered possible in any particular scenario it is necessary to estimate the time taken for the development of conditions capable of incapacitating occupants and to compare it with the time required for escape. Where conditions are considered unacceptable it is possible to estimate the effects that alterations may have on the possible hazards.

Because of the great complexity of fires, the standard cannot provide an absolute guarantee of safety, but it does set out the major parameters that need to be considered, with guidance on practical methods for making assessments.