Laboratory experiment of fire spread between two informal settlement dwellings

Fire spread between informal settlement dwellings (ISD) is a primary concern for large scale informal settlements conflagrations. Globally, approximately one billion people live in informal settlements and are exposed to these fires. This paper presents a fire spread experiment between two dwellings, built with ISO 9705 dimension as an approximation of an ISD and separated by 1 m. The fire development and fire spread mechanisms within and between the ISDs were investigated and benchmarked against an independent single dwelling experiment with identical boundary conditions. Parameters, such as mass loss rate of fuel, total heat release rate, gas temperatures, wall and roof temperatures, and gas velocity at the openings were measured, as well as external incident heat fluxes. A comparison between the single and double dwelling experimental results are made. It was established that the existence of the adjacent dwelling, which changes the dynamics of initial burning stage of the wood cribs in dwelling, delayed the flashover of the burning dwelling by more than 150 s (Dwelling 1). The fire spread from dwelling to dwelling that is perpendicular to the plane of the openings is hypothetically concerned with wall collapse or large flame ejections from the burning cardboard linings, rather than the radiation from the heated metal wall, with recorded fluxes of 35, 20, and 5 kW/m2, respectively. Due to the very thin-walls with high conductivity and natural leakage in ISDs, current theories for temperatures, heat release rates, flame shapes, and flashover conditions, based on thermally thick-walled dwellings, do not replicate the data well. A new fire spread model between dwellings, based on accumulated energy, is proposed in this work and conservatively under-predicts the time to ignition by 9 % for this experiment.