The performance of laminated glass subjected to constant heat fluxes related to building fires

Abstract

SummaryA series of six exploratory experiments are presented investigating the behaviour of laminated glass when exposed to radiative heating of 25, 50 and 75 kW/m2. The laminated glass type used is typical of that which might be used in balustrades. Three experiments examined the potential for achieving flaming ignition of the inter‐layer should the glass break. At a radiant heat flux of 25 kW/m2, although the glass did not shatter, piloted ignition of the volatile gases released from the specimen edge was possible. At radiant heat fluxes of 50 and 75 kW/m2, the exposed glass layer shattered after 5 minutes 7 seconds and 2 minutes 24 seconds, respectively, and subsequently there was auto‐ignition of the volatile gases from the inter‐layer. Eventually flames were observed over the whole face of the specimen. Using an average measured mass loss and representative heat of combustion for the inter‐layer result in calculated heat release rates per unit area of 65 to 69 kW/m2. A further three experiments were carried out to examine the potential for the glass layers to separate when heated. Only one layer of glass was supported, and unsupported layer nearest the radiant heat source was observed to slip away from the other layer, exposing the inter‐layer, resulting in ignition and flaming.