A full-scale fire test to investigate the fire behaviour of the ventilated façade system

The ventilated façade (VF) system is a double-wall construction, comprising an external lightweight cladding panel and the building's existing façade, which is used to increase indoor comfort levels (e.g. temperature, humidity) in buildings. During a fire event, VF systems may contribute to fire spreading on the facade, representing a significant risk to the upper floors of a building, especially in the case of emerging externally venting flames. Aiming to investigate the fire behaviour of a typical VF system, a large scale compartment-facade fire test is carried out. An extensive set of sensors is installed both inside and outside the test compartment, aiming to record the temporal variation of several important physical parameters, such as gas and wall surface temperatures, gas velocities and fuel mass loss rate. Emphasis is given on the estimation of the thermal characteristics of the externally venting flames, emerging close to the facade, since these are the main physical parameters affecting the heat exposure of the VF system. A commercial VF system is employed; no thermal insulation is used, aiming to investigate the main aerodynamic and thermal phenomena affecting the flow of hot gases and flames in the air cavity. In addition, no fire barriers are installed on the VF system, thus representing a “worst case” scenario for a VF system with no combustible materials. Analysis of the experimental data suggests that even though gaseous combustion products may manage to penetrate into the air cavity of the VF system, no consistent flaming conditions are established. In addition, wall surface temperatures on the unexposed side of the system remain constantly below 180oC throughout the duration of the fire test.