Experimental study of fire spread through discontinuous fuels without flame contact

Abstract

There is a strong need to increase the basic understanding of the propagation mechanisms in wildfires to improve the scientific tools needed for firefighting and fire prevention. This study focuses on the fire spread mechanisms by radiation. Three contiguous trees were ignited and the mechanisms leading to flame spread to a target tree were analyzed. The experiments were designed to avoid fire spread by flame contact and study how radiation heat transfer could ignite the target tree. Different measurements were performed, including heat fluxes, temperature and mass loss rate. The vegetation was characterized in details by using terrestrial laser scan reconstruction. The analysis of the experimental results provides a detailed description of the competing mechanisms leading to an ignition or a lack of ignition of the target tree.