Citation

Rogowski B. Fire Safety J. 1985; 8(2): 119-134.

Copyright

(Copyright © 1985, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

The risk of fire spread in buildings, from one room/compartment to another, through cavity walls filled with a range of combustible insulating materials has been investigated.Tests have been carried out on small-scale or storey-high walls having two masonry facings, insulated with typical examples of loose fill, board or in situ foamed plastics products. A small localized penetration of both facings simulating for example an ineffectively sealed air brick was built into the lower part of the experimental wall and two 'eave' conditions were investigated viz with the perimeter either sealed or partially open. A small crib was positioned adjacent to the cavity penetration and the subsequent extent of spread of fire and smoke was noted visually; temperature measurements within the cavity were recorded together with heat flux measurements in the combustion zone.The experiments showed the dependence of the extent of fire spread on the air supply to the combustion zone; in this type of wall with the upper perimeter sealed, the risk of flame or smoke spread from one area to another is negligible. With the upper edge partially unsealed, no flame and only negligible smoke spread was noted with in situ foamed insulations. With granular fill, retained in position within the cavity, some smoke percolated upwards but the risk of eventual spread of fire through the eave opening was restricted to three products, which have subsequently been withdrawn from the market. Thermoplastic bead flowed through the hole into the fire area contributing to the fuel load but when installed with an adhesive the bead was effectively maintained in position and performed like the in situ foamed products. It was found with one specific test condition that slow flame spread could be sustained through a continuous cavity adjacent to expanded polystyrene insulating boards provided the eave perimeter of the cavity was unsealed. Whilst such flame spread is unlikely to affect directly any inhabited areas of the building, sealing of cavities insulated with combustible boards is considered to be essential to prevent smoke spread, possible roof fires and destruction of the insulant.