Fire Spread Characteristics of Cavities in Modular Constructions and Ventilated Facades

ABSTRACT Modular buildings have gained popularity as a sustainable building solution. However, the uncertainty of fire spread through vertical cavity spaces in such buildings has become a concern. Therefore, this study aims to fill the gap in fire behaviour within vertical cavity spaces. First, an experiment was conducted using a parallel panel arrangement to simulate a cavity fire. It was later modelled in the Fire Dynamics Simulator and validated with experimental results. Later, the model was further validated with data in the literature. Then, a parametric study was conducted for a cavity width ranging from 25 to 200 mm and for the heat release rates of 10 and 40 kW. The simulated cavity fires resulted in a flame extension of up to 8.9 times and a plume flow velocity of up to 2.0 times compared to open fire scenarios. The cavity width was mainly identified to be inversely proportional to the considered fire properties. However, under a 40 kW fire, reducing the cavity width from 50 to 25 mm reduced incident radiative heat flux, cavity internal surface temperature, and flow velocity maximum up to 74%, 44%, and 48%, respectively. A set of empirical equations was developed to predict steady‐state cavity fire behaviour. Finally, the overall fire severity level variation with the cavity width is presented.