Flame Heights and Heat Transfer in Façade System Ventilation Cavities

Abstract

Abstract. The design of buildings using multilayer constructions poses a challenge for fire safety and needs to be understood. Narrow air gaps and cavities are common in many constructions, e.g. ventilated fac¸ade systems. In these construction systems flames can enter the cavities and fire can spread on the interior surfaces of the cavities. An experimental program was performed to investigate the influence of the cavity width on the flame heights, the fire driven upward flow and the incident heat fluxes to the inner surfaces of the cavity. The experimental setup consisted of two parallel facing non-combustible plates (0.8 9 1.8 m) and a propane gas burner placed at one of the inner surfaces. The cavity width between the plates ranged from 0.02 m to 0.1 m and the burner heat release rate was varied from 16.5 kW to 40.4 kW per m of the burner length. At least three repeated tests were performed for each scenario. In addition, tests with a single plate were performed. The flame heights did not significantly change for Q 0 /W < 300 kW/m 2 (where Q 0 is the heat release rate per unit length of the burner and W is the cavity width). For higher Q 0 /W ratios flame extensions up to 2.2 times were observed. When the distance between the plates was reduced or the heat release rate was increased, the incident heat fluxes to the inner surface increased along the entire height of the test setup. The results can be used for analysing methodologies for predicting heat transfer and fire spread in narrow air cavities.

Numerical simulation of the fire behaviour of façade equipped with aluminium composite material‐based claddings—Model validation at intermediate scale

“…[3][4][5][6] In recent years, several research studies have investigated the fire performance of ventilated façade systems and shown that flame spread through the air cavity of a ventilated façade can be several times higher than that along the outside the facade. 4,5 Furthermore, the presence of an air cavity tends to increase the energy released by the facade system. 6 Thus, both the materials taken independently and the whole system (combination of materials and assembly) are potentially a source of propagation of a fire.…”

“…In the context of fire safety, it should be noticed that for systems such as ETICS or ventilated façades, the materials used (cladding or insulation) may be combustible . Moreover, in ventilated facades, the air gap may be a vector of fire propagation through chimney effect . In recent years, several research studies have investigated the fire performance of ventilated façade systems and shown that flame spread through the air cavity of a ventilated façade can be several times higher than that along the outside the facade .…”

Numerical simulation of the fire behaviour of facade equipped with aluminium composite material‐based claddings‐Model validation at large scale

“…In the context of fire safety, it should be noted that for systems such as external thermal insulation composite systems (ETICS) or ventilated facades, the materials used (cladding or insulation) may be combustible. In addition, in ventilated facades, the air gap may be a vector of fire propagation via the chimney effect , . Thus, both the materials taken independently and the system as a whole (combination of materials and assembly) can potentially contribute to fire propagation.…”

“…In addition, in ventilated facades, the air gap may be a vector of fire propagation via the chimney effect. 5,[7][8][9]10 Thus, both the materials taken independently and the system as a whole (combination of materials and assembly) can potentially contribute to fire propagation.…”

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

“…These varying configurations have led to a series of issues regarding their hydrothermal, energy, sound and fire performance. 10 Construction details (eg, cladding fixings) 8 or fire barriers 11,12 may also affect flame spreading within the ventilation air cavity.…”