In the latest BS 9991:2015 guidance on open plan flats, requires the provision of a suppression system within the flat. However, the overall maximum size of an open plan flat before the kitchen also needs to be enclosed is 8m by 4m. The implication of this reduction in flat size is any open plan flats larger than this size, would now need the kitchen to be separated from the rest of the flat with 30 minutes construction and an FD30S fire door.
This recommendation seems to go against the desire of flat owners who want an open plan arrangement for the communal areas within their flats. A significant number of the open plan flats that will be built in the future will exceed 8m x 4m. Therefore, this new guidance will affect a large number of open plan flats by forcing the kitchen to be enclosed in fire rated construction. However, there is an alternative.
BS 9991 is a guidance document showing only one way of achieving the functional requirements of the Building Regulations. An alternative fire engineered approach can be developed which allows the kitchen to be completely open whilst still meeting the functional requirements of the Building Regulations.
The acceptability of having the kitchen area open in a flat with dimensions over 8m x 4m can be demonstrated through using computational fluid dynamics (CFD) modelling.
This is one example of were a fire engineered approach can be used to meet the functional requirements of the Building Regulations. This is an acceptable alternative to following prescriptive guidance which would constrain the design.
Content provided by James Brady of Innovation Fire