Smoke Flow in Sloped Tunnels

Abstract

Fires in road tunnels are a major concern due to the casualties they may cause. Therefore, forced ventilation is mandatory in long tunnels, despite the significant associated costs. In shorter tunnels, however, natural ventilation may be sufficient to comply with safety regulations. Accordingly, the analysis of natural fire smoke flow is relevant for road tunnels shorter than 1 000 m. In a previous work, the smoke propagation in horizontal tunnels was investigated either without or in the presence of atmospheric wind. This communication is an extension of the previous work and presents a computational investigation of the influence of the tunnel slope (between 1% and 5%) on the contamination of the lower cold layer with smoke and discusses how it impairs the user’s egress.