Developing an experimental database of burning characteristics of combustible informal dwelling materials based on South African informal settlement investigation

Globally, the number of informal settlement dwellings are increasing rapidly; these areas are often associated with numerous large fires. Unfortunately, until recently, very little research has been focused on informal settlement fire issues leaving any attempts to improve their fire safety lacking the evidence base to support effective-decision making. However, over the past 4 years, a limited number of researchers have looked at better understanding these fires through full-scale experimentation and numerical modelling; starting to provide the necessary evidence base and future research directions. It is with this background in mind that this paper seeks to provide a more fundamental understanding of the effect of dwelling separation distance on informal settlement fire spread based on full-scale experiments and analytical equations. In this paper two full-scale experiments were conducted. Both experiments consisted of multiple dwellings, with the main difference between the experiments being the separation distance. Fire spread times, heat release rates, door and window flow velocities, ceiling temperatures and incident heat fluxes were recorded and are reported for both experiments. Theoretical neutral planes are derived and compared to the experimental neutral planes, which show relatively good correlation. The paper continues by calculating the expected incident radiation and time-to-ignition, using the flux-time product method, of the two fire scenarios (i.e., the two experiments) through means of analytical equations, and these findings are compared to the experimental results. Through configuration factors, the paper shows the effect of separation distance, dwelling height and dwelling length on the times-to-ignition, where it is clear that the heat flux received by an adjacent dwelling decrease approximately exponentially as the distance between dwellings increases, and consequently, the time-to-ignition increases exponentially as the separation distance between dwellings increases.

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“…Baker et al Figure 25. Correlation of ignition times and incident heat flux (cone calorimeter data from [35,36]). Figure 26.…”

Section: Time-to-ignitionmentioning

confidence: 99%

The Effect of Separation Distance Between Informal Dwellings on Fire Spread Rates Based on Experimental Data and Analytical Equations

et al. 2020

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“…The samples were exposed to an external heat flux until sustained flaming ignition occurred or until no ignition had occurred within 1200 s of exposure. More information about the cone tests results can be found in the authors' another work in which a database about the burning characteristic of these combustible materials in the informal settlement has been created [4]. It should be noted that, due to the very different properties, the ignition definition was unified for all the tests: the specimen was considered as ignited after sustained flaming for 4 s in each test [24].…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…It should be noted that, due to the very different properties, the ignition definition was unified for all the tests: the specimen was considered as ignited after sustained flaming for 4 s in each test [24]. Smouldering, glowing or flash were not consid- The Material List for the Cone Calorimeter Tests [4] No.…”

Section: Experimental Conditionsmentioning

confidence: 99%

“…The PU foam, which is normally used as mattresses in an informal settlement, is the easiest material to be ignited with a critical distance of 3.14 m. However, as it is always placed inside the room, so both the distance between the PU foam and fire would be larger than that between dwellings and there would be a large shielding affect from the walls which will decrease the probability of ignition. More information about these combustible materials and how they might contribute to the fire development and spread can be found in [4]. In addition, to make these risk assessments more specific, the type, layout and amount of the combustible materials in informal settlement should be investigated, which can be obtained from our survey data (analysis in process).…”

Section: The Prediction Of the Critical Distancementioning

confidence: 99%

“…However, with local populations lacking in resources and opportunity to build more robust homes, materials that are easily obtainable, including cardboard, paper, wood, galvanized steel sheeting and plastic, are often used in construction of an informal settlement dwelling [4]. Housing rarely complies with current planning and building regulations, and is often situated in geographically and environmentally hazardous areas [5].…”

Section: Introductionmentioning

confidence: 99%

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Determination of Critical Separation Distance Between Dwellings in Informal Settlements Fire

et al. 2021

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Approximately one billion people across the globe are living in informal settlements with a large potential fire risk. Due to the high dwelling density, a single informal settlement dwelling fire may result in a very serious fire disaster leaving thousands of people homeless. In this work, a simple physics-based theoretical model was employed to assess the critical fire separation distance between dwellings. The heat flux and ejected flame length were obtained from a full-scale dwelling tests with ISO 9705 dimension (3.6 m × 2.4 m × 2.4 m) to estimate the radiation decay coefficient of the radiation heat flux away from the open door. The ignition potential of combustible materials in adjacent dwellings are analyzed based on the critical heat flux from cone calorimeter tests. To verify the critical distance in real informal settlement fire, a parallel method using aerial photography within geographic information systems (GIS), was employed to determine the critical separation distances in four real informal settlement fires of 2014–2015 in Masiphumelele, Cape Town, South Africa. The fire-spread distances were obtained as well through the real fires. The probabilistic analysis was conducted by Weibull distribution and logistic regression, and the corresponding separation distances were given with different fire spread probabilities. From the experiments with the assumption of no interventions and open doors and windows, it was established that the heat flux would decay from around 36 kW/m2 within a distance of 1.0 m to a value smaller than 5 kW/m2 at a distance of 4.0 m. Both experiments and GIS results agree well and suggest the ignition probabilities at distances of 1.0 m, 2.0 m and 3.0 m are 97%, 52% and 5% respectively. While wind is not explicitly considered in the work, it is implicit within the GIS analyses of fire spread risk, therefore, it is reasonable to say that there is a relatively low fire spread risk at distances greater than 3 m. The distance of 1.0 m in GIS is verified to well and conservatively predict the fire spread risk in the informal settlements.

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Eco-friendly vs Fire Safe? Conceptualising Fire Risk for Construction Systems Incorporating Waste and Biomass

Walls,

Shewalul,

Babafemi

et al. 2024

Lecture Notes in Civil Engineering

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Developing an experimental database of burning characteristics of combustible informal dwelling materials based on South African informal settlement investigation

Abstract: Developing an experimental database of burning characteristics of combustible informal dwelling materials based on South African informal settlement investigation

Cited by 25 publications

References 23 publications

The Effect of Separation Distance Between Informal Dwellings on Fire Spread Rates Based on Experimental Data and Analytical Equations

The Effect of Separation Distance Between Informal Dwellings on Fire Spread Rates Based on Experimental Data and Analytical Equations

Determination of Critical Separation Distance Between Dwellings in Informal Settlements Fire

Eco-friendly vs Fire Safe? Conceptualising Fire Risk for Construction Systems Incorporating Waste and Biomass

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