Fire Dynamics in Informal Settlement “Shacks”: Lessons Learnt and Appraisal of Fire Behavior Based on Full-Scale Testing

Abstract

This paper presents discussions regarding informal settlement (also known as slums, shantytowns, favelas, etc.) fire dynamics and lessons learnt from full-scale tests on dwellings, typically referred to as "shacks" in South Africa. Smoldering and flaming fire setups are considered, and both timber and representative household contents are used as fuel sources. It is shown that due to the small size of shacks flashover can be obtained within minutes. Maximum temperatures recorded are typically around, or in excess of, 1000°C, depending on the fuel and structural configurations. Due to the poor construction methods used for such structures they can collapse, or walls can open up, meaning that ventilation conditions continuously change and are difficult to accurately define. The presence of flammable wall finishes or drapes has a significant effect on the rate of fire spread and fire behavior, and such flammable finishes are often present in dwellings. Computational fluid dynamic (CFD) software (Fire Dynamics Simulator (FDS)) is utilized to analyze certain tests, which generally shows good correlation. However, due to significant variations in fuel contents, ventilation conditions, structural configurations and wall finishes there is a high degree of uncertainty inherent in developing models for such environments. From the work a greater understanding of fire dynamics in low income, temporary structures (comparable with some refugee camps) can be obtained through which better solutions and interventions can be developed. Recommendations are provided for how to simulate shack fire scenarios in experimental testing more effectively.