Vertical safe separation distance between openings in multi-storey buildings having a fire resistant spandrel

Fire Safety Engineering Research and Technology Centre, University of Ulster, UK

Abstract

A novel comprehensive methodology is presented for the determination of the vertical separation distance between floor glazing openings in buildings having a fire resistant non-flammable spandrel. The spandrel height is specified by requiring that the heat flux is less than a critical heat flux for glazing failure at the base of the opening of the floor above the floor of fire origin. For a specified room, opening geometries and fuel type, the heat flux at the base of this opening is calculated by using correlations for the flame height and heat flux distribution of the façade flames for under ventilated fire conditions in the compartment of fire origin. As the compartment opening increases a transition occurs from under ventilated to over ventilated conditions reducing the façade fire spread hazard. The methodology and results can also be applied for wooden and lightweight façade walls to predict fire spread behavior on the wall and towards the openings to floors above the floor of fire origin.