Experimental analysis of real-scale burning tests of artificial fuel packs at the Wildland-Urban Interface

Abstract

The combustion of artificial fuels at Wildland-Urban Interface (WUI) homeowner scale has been identified as a contributor to fire spread through a property, often leading to the ignition of structures, hence involving major safety issues at community level. However, little information on the real-scale burning behaviour of these type of fuels is available. These fuels are usually located close to the main structure of a property and are often piled together, forming packs containing different types of materials. Real-scale tests on four different fuel packs have been performed to gather quantitative data on items that are commonly present on WUI properties. The fuel packs consisted of typical combustible materials present in porches, gardens, backyards or stored in secondary structures. Data on Heat Release Rate (HRR), Mass Loss Rate, fire load, smoke species concentration, heat flux, temperature and flame height are provided. The duration of the fires was between 49 and 83 min. Peak HRR values between 383 kW and 2.55 MW were recorded, along with flame heights up to 3.6 m. Radiative heat fluxes were calculated for each test, and safe distances for people were identified. Reported data can be used to quantify vulnerabilities of WUI properties through Performance-Based Design methodologies. Results show that the most hazardous fuel packs out of the four tested are those containing pallets, cardboard, paint, foam mats and garden furniture. In all cases, the flaming area expanded significantly increasing the risk of fire spread through a property even after the passage of the wildfire front.