Study of Damage to Shutters Exposed to a Vegetation Fire: Definition of Vulnerability Thresholds

ABSTRACT This study examines the fire behavior of wooden, PVC, and aluminum shutters through laboratory and large‐scale experiments. Laboratory tests were conducted using a cone calorimeter to assess the ignitability of the PVC and wooden shutters, focusing on the critical heat flux of ignition, ignition time and critical Flux Time Product (). Additionally, field experiments on the EXPLORII platform were carried out to assess the damage caused to the three types of shutters when exposed to hedge fires. Key metrics such as heat fluxes, energies received, thermal dose, and FTP were analyzed to determine damage thresholds. The results revealed that aluminum shutters were the most fire‐resistant, withstanding peak of total heat flux of 177 kW m −2 without sustaining any damage. PVC shutters, on the other hand, showed deformation at low fire exposure, when there was no flame contact, that is, when the peak total heat flux was less than 50 kW m −2 . At these exposure levels, the wood shutters showed a greater fire resistance than the PVC shutters, with no damage below this total heat flux. When the flames came into contact with the shutters, resulting in the highest fire exposure, with a total heat flux above 50 kW m −2 , the trend observed previously was reversed, with wooden shutters suffering more damage than PVC shutters for a given total heat flux. Blackening and burning were observed on both shutter types. The study also evaluated the reliability of the FTP as an ignition criterion for wooden and PVC shutters.