Fire‐performance of a ventilated facade insulated with a B2–classified rigid polyurethane foam

Abstract

A two-storey test rig was used to investigate how an insulated facade would react to the impingement of a simulated room fire. In particular, whether or not a facade insulated with polyurethane foam would promote vertical flame spread. Wooden cribs weighing 40 kg were used as fire sources. One set of tests was run without any steel cladding to study the behaviour of the polyurethane foam alone. In a wall-configuration test as well as under a corner-configuration one limited vertical and horizontal flame propagation were found. The degree of damage was, to some extent, greater under the corner-test conditions than with the wall tests. A ventilated facade construction with the profiled steel cladding fixed to vertilcal support-work was used for the second set of tests. In order to simulate repair conditions, the outer metal cladding was completely removed from the lower 1.5 m of the facade. In both tests a strong chimney-effect behind the cladding was observed. This intensification of the flame impingement led to a flame spread up the top of the facade. The tests indicated that the vertical flame spread would continue unless the method of construction incorporated vertical fire stops.

Influence of Horizontal and Vertical Barriers on Fire Development for Ventilated Façades

“…As early as in 1986, Jeffs et al conducted large-scale testing using the French standard from 1964 [19]. Even then, the significance of fire barriers was noticed.…”

A Critical Appraisal of the UK’s Regulatory Regime for Combustible Façades

“…In many respects, the current BS 8414 test for rainscreen systems could be described as an assessment of the effectiveness of the cladding to protect the underlying combustible insulation. As early as 1986, a paper sponsored by the International Isocyanate Institute [40] recognised the dangers of rigid polyurethane insulation. Polyisocyanurate (PIR) is a rigid polyurethane based polymer which is enhanced by the formation of isocyanurate rings within its structure, by using an excess of isocyanate in the resin formulation, improving its fire performance.…”

Performance of a ventilated‐façade system under fire conditions: An experimental investigation

“…Limited reports can be found in the literature addressing the fire behaviour and hazards associated with façade air cavities, for example, double skin facades, [22][23][24] VF systems 13,25,26 and their construction details, for example, cladding fixings and geometric characteristics of ventilation cavities. 8,9 A series of full-scale SP Fire 105 standard tests on fully ventilated cavities behind plywood cladding were recently performed to study the flame spread characteristics in combustible façade claddings with and without a ventilation cavity (0.02 m width, no fire barriers).…”