Review of thermal behaviour of firebrands and their role in fuel bed and structure ignition

Firebrands or embers are a crucial phenomenon in wildfire behaviour. Firebrands – small, burning or smouldering pieces of wood or other flammable materials – can be carried by wind considerable distances, leading to ignition of new fires ahead of the main fire front. This process, called spotting, significantly contributes to the rapid spread of fires, particularly in wildland–urban interface (WUI) areas. Spot fires pose a severe threat to people and properties. Better understanding the thermal behaviour of firebrands and their ability to ignite various natural fuel beds and structural materials is crucial for developing effective fire prevention and mitigation strategies. This paper presents a comprehensive review of recent studies investigating the thermal behaviour of firebrands and their interaction with natural and structural fuels. These intensive research efforts have focused on predicting firebrand behaviour in spot fires through experimental studies, numerical simulations and statistical modelling to identify factors influencing ignition likelihood. This review explores the mechanisms through which firebrands interact with vegetative and building materials, focusing on ignition and subsequent fire spread. Critical factors, such as material composition, moisture content and firebrand accumulation, are discussed. This study also identifies critical knowledge gaps and proposes future research directions to ultimately contribute to more effective wildfire mitigation and management strategies.