Performance analysis of a self‐protection system for vehicles in case of WUI fire entrapment

Abstract

Sheltering inside a civilian vehicle has proved to be a high risk strategy in case of wildfire entrapment. Survival is by no means guaranteed, especially in moderate to high-intensity wildfires. However, vehicles do offer a certain degree of fire protection, which can be reinforced by ad-hoc fire resistant technology. In this paper, we present the experimental performance analysis of a self-protection system that has been designed to protect people's life in case of fire entrapment. Similar to a firefighter fire shelter, the designed system can be quickly deployed covering the whole vehicle. In case of fire exposure, this fabric provides additional heat protection to the occupants and the vehicle itself. An experimental burning was designed in order to simulate real fire exposure conditions in case of vehicle entrapment in a rural road. An ex-situ 2-m high fuel bed composed of Pinus halepensis fine logging slash was arranged in a 13 m long x 6 m wide area. Fire was ignited at one end of the fuel bed and spread driven by an induced constant air flow (3 m/s midflame wind speed). 2.8 m away from the other fuel bed end, a car covered with the fire protection fabric was placed, parallel to the fire. Data analysis provided mean values of fire rate of spread (2 m/s), fireline intensity (1800 kW/m), flame height (6.5 m), flame tilt angle (30º), flame depth (2 m), flame temperature (800 ºC) and flame emissive power (47.5 kW/m 2). Maximum air temperatures inside the vehicle ranged around 41-42.5 ºC during a period between 20 min and 35 min after ignition. A thermocouple in contact with the internal side of the driver's window registered a maximum value of 47.3 ºC. These results evidenced the good performance of the fabric when protecting eventual vehicle occupants against thermal exposure from wildfires of moderate intensity.