Large-scale urban conflagrations in informal settlements are a frequent global event, however there is a lack of experimental research and knowledge within literature on how informal settlements fires spread to support local or national intervention strategies. This paper, therefore, presents results and analysis of a full-scale fire spread experiment of a mock 20 dwelling test settlement with a 4 by 5 layout aimed at understanding settlement-scale fire spread behaviour. A "fire line" scenario was created by simultaneously igniting four dwellings in a row, and then allowing the fire to propagate through the settlement to replicate fire disasters involving large numbers of homes. Results highlight the critical hazard posed by the close proximity of neighbouring dwellings (1-2 m), with wind playing a primary role in directing and driving the spread process. Even with a relatively mild wind speed of 15-25 km/h, the fire spread through the entire mock settlement within a mere 5 minutes. Following ignition of a given dwelling, flashover is reached very quickly, with the temperatures reaching more than 1000°C within one minute, and downwind neighbour structures igniting less than a minute thereafter. The results suggest that multi-dwelling effects are not dominant in these types of fires, but may become meaningful at a larger scale when branding and topography play a role. Findings show that on a global scale fire behaviour is analogous to a wildfire with a continuous fire front moving through an area, although individual dwellings still do follow the distinct phases of enclosure fires, Powered by Editorial Manager® and ProduXion Manager® from Aries Systems Corporation[1.3] The wind acceleration downwind is interesting. Were you able to capture the temperature of the air at the location of the measurements?Unfortunately not, but it would be something to keep in mind for future experiments.[1.4] I also imagine that in your future research, you may want to scale the experiment up (or maybe model larger settlement configurations). I would like to point your attention to the fact that in extremally larger fires the ambient wind effects may be different than in the scale reported here. As the size of the burning area increases, the fire may cause it's own wind conditions (buoyant plume forcing airflow from all directions). Such events are often referred to as firestorms or mass conflagrations, and some aspects of this phenomena were recently reviewed in the wind and fire review paper in Fire Technology BLIND Response to Reviewer Comments

SummaryFires originating in informal settlements (ie, slums, ghettos, shantytowns, squatter camps) spread rapidly, due to the presence of densely packed, highly combustible dwellings, thereby making these communities inherently susceptible to large conflagrations. By the time, the fire brigades are notified and can get to the scene of the fire, the resulting conflagrations can be large. Thus, it is necessary to equip communities with the ability to combat smaller fires, although it is acknowledged that this is not ideal. Previous full‐scale testing and firefighter experience have shown that water application through ‘bucket brigades’ can be very effective at suppressing fires. In this article, a model is developed for approximately quantifying the amount of water, and discharge rate, that is, required for communities to suppress fires of various sizes using bucket brigades. This is done to answer the question: based on the water supply infrastructure in an area could a community put out post‐flashover fires of certain sizes? If this is not feasible, it would highlight the importance of communities having readily available pre‐filled water buckets at homes. The model presented is developed in fire dynamics simulator and is calibrated based on full‐scale experiments utilizing the bucket brigade technique. It is shown that standpipe discharge rates of 23 to 40 lpm are suitable for fire sizes of around 3.85 MW, based on a dwelling size of 2.4 x 3.6 x 2.4 m. This means that in communities with a single stand‐pipe (water supply point) with flow rates less than 23 lpm, that fires greater than 3.85 MW (as produced by a home of 2.4 x 3.6 m with a timber fuel load of 25 kg/m2) cannot be suppressed in time without resulting in substantial fire spread to adjacent dwellings.

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