BS 5268-4.2:1990 gives recommendations for calculating the fire resistance of timber framed walls and partitions and joisted floors as an alternative to testing. The recommendations are applicable to single and double leaf walls and partitions; and to floors in which the joists are fully or partly concealed.
The recommendations are applicable to loadbearing wall and partition constructions where actual stud sizes are not less than 62mm x 37mm (depth x breadth) and to non-loadbearing wall and partition constructions where the actual stud sizes are not less than 48mm x 37mm (depth x breadth).
The recommendations are also applicable to joisted floor construction where the actual joist breadth is not less than 37mm.
BS 5268-4.2:1990 is limited to construction having a fire resistance requirement of 1 hour or less.