Approved Document B - Update
The current Building Regulations Part B Approved Document (AD B) covering England and Wales came into effect in April 2007. The changes and highlights that affect cavity barriers and fire stopping can be summarised as follows:
- The ‘Concealed Spaces' section of AD B has been completely restructured and the previous Table 13 incorporated into text to reduce confusion.
- Extensive cavities in floor voids should now be subdivided with cavity barriers, a provision which was omitted from the previous edition. Cavity barriers are also required in floor voids to continue protection of escape route corridors and separating doors, as well as below certain bedroom walls.
- In tall buildings (where the top floor is 18m or more above ground) stringent requirements apply to external wall insulation and filler material - including cavity barriers - which must all be of ‘limited combustibility' (as defined in Table 7 of AD B Appendix A). Cavity barriers generally must also be tested for a minimum of 30 minutes integrity and 15 minutes insulation. Unlike the Lamatherm system, many cavity barriers designed for rainscreen and other cladding constructions fail to comply with these requirements. It is therefore essential that specifiers and building control officers satisfy themselves that cavity barriers in high rise buildings will perform as intended.
For specific queries on Approved Document B, please contact our Technical Department.
For full details of all Lamatherm cavity barrier, fire stopping and compartment floor upgrade systems, please see Fire Stopping Solutions.