Computer-simulation study on fire behaviour in the ventilated cavity of ventilated façade systems

Abstract

Abstract. Fire spread through the façades is widely recognized as one of the fastest pathways of fire spreading in the buildings. Fire may spread through the façade in different ways depending on the type of façade system and on the elements and materials from which it is constructed. Ventilated façades are multilayer systems whose main feature is the creation of an air chamber of circulating air between the original building wall and the external cladding. The "chimney effect" in the air cavity is a mechanism that improves the façade's thermal behaviour and avoids the appearance of moisture from rain or condensation. However, in a event of fire, it may contribute to the quickest spreading of fire, representing a significant risk to the upper floors of a building. This study deals with some aspects of fire propagation through the ventilated cavity in ventilated façade systems. Also we review the provisions stipulated by the Spanish building code (Código Técnico de la Edificación, CTE) [1] to avoid fire spread outside the building.The results highlight the importance of the use of proper fire barriers to ensure the compartmentalization of the ventilated cavity, as well as the use of non-combustible thermal insulation materials, among others. In addition, based on the results, it might be considered that the measures stipulated by the CTE are insufficient to limit the risks associated with this kind of façades systems. The study has been performed using field models of computational fluid-dynamics. In particular, the Fire Dynamics Simulator (FDS) software has been used to numerically solve the mathematical integration models.

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

“…Numerical Analysis One of the main advantages of numerical simulation is the ability of studying a number of aspects of the fire propagation avoiding the high costs of laboratory tests [10,11]. In computer-simulation study, Giraldo et al [10] have given a representative image of the spread of fire depending on the barrier type and characteristics, insulation, and the width of the air cavity. Even when non-combustible insulation was used, their study demonstrated that smoke and flame will spread through the cavity of the ventilated facade if horizontal barriers are not used.…”

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

“…Once the fire enters the air cavity, the potential increase in the fire spreading rate depends on the existence and the nature of the thermal insulation materials in the cavity, the construction details of the façade and the geometric characteristics of the cavity. 9,13 Typically, during a compartment fire event, window and door frames may provide a direct entry route to the air cavity. In such a case, flames may enter the cavity and, if appropriate fire barriers or seals have not been installed, they may propagate upwards.…”

“…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).…”

Evacuation-Based Design of Urban Regions for Earthquake Disaster

“…The Delphi method [9] is used for identifying the failure events. Following this process, questionnaires are collected from rescue specialists, emergency managers, and other sources related to retrieving activities.…”