Precast Industrial Buildings with Vault or Shed Roof Subject to Simulated Cellulosic Fire

Precast concrete industrial buildings are typically characterised by high fire risk due to the production or storage of materials/products having high combustion potential and the specific activities carried out in the facility. Due to the large dimensions of these buildings, common simplified and ordinary advanced methods for the determination of the fire-induced demand, both in terms of structural performance and the safety of occupants and firefighters, may be far from accurate. Most large industrial buildings rely on translucid surfaces installed on the roof to let zenithal natural light enter the building. These are typically made with polycarbonate, and lateral windows may eventually be installed. Due to the low glass transition temperature of polycarbonate, these openings can efficiently act as evacuators of smoke and heat, although they are currently neglected by most practitioners, leading to the installation of mechanical evacuators. Moreover, the shape of the roof system of such buildings, especially if wing-shaped elements coupled with either vault or shed elements are used, can naturally ease the smoke and heat evacuation process. This paper aims to provide a contribution to the characterisation of fire development in such buildings, presenting the results of both zone and computational-fluid-dynamic analyses carried out on archetypal precast industrial buildings with a typical arrangement of either vault or shed roof subjected to cellulosic fire. For this purpose, several parameters were investigated, including roof shape (vault and shed) and the effect of short or tall columns. Concerning zone models, other relevant parameters, such as the type of glazing, the installation of smoke and heat evacuators on the roof, and larger window areas, were analysed.