R.C.DE VEKEY Building Research Establishment

There is a dearth of data on the performance of contemporary masonry wall forms in fire, in an earlier BRE project the known database was reviewed, many of the newer watt materials and arrangements were examined, and some recommendations were made for further research.
This work addresses four key issues raised earlier: a) the performance of cavity walls with non-flammable insulants b) the performance of cavity walls with flammable insulants (including part-fills), c) the performance of plastic ties, d) the re-usability of wall components after fires.
It is concluded that there are no immediate concerns raised about the stability of insulated domestically (lightly) loaded walls of this type subjected to fires and that the presence of insulants did not appear to have a deleterious effect on fire performance and, under the particular circumstances of the test, demonstrated smaller deflections and less thermal penetration of the fire affected leaf than the clear cavity. There was no fire in the cavity even with flammable insulants. Further work is advocated on the influence of moisture, the post-fire re-usability of masonry and the effect of fire on plastic ancillary products and thermoplastic insulants. Fibreglass insulants are likely to survive all but the most severe fires.