What heat transfer method generally has the greatest impact during a fire on the leeward side of a structure?

During a fire, radiation is the heat transfer method that generally has the greatest impact on the leeward side of a structure. This occurs because radiative heat transfer can travel through the air without needing a medium like a solid or liquid. As flames and hot gases produce radiant heat, structures located downwind or on the leeward side receive this heat directly from the fire source, often resulting in significant heating and potential ignition of materials in those areas.

In contrast to conduction and convection, which rely on the presence of a medium (like solid materials for conduction or air for convection), radiation can affect structures at a distance. Conduction may take place through the building materials themselves, which is a slower process, while convection currents will typically not carry heat effectively to the leeward side when the fire is located on the opposite side of the wind direction. Insulation can mitigate heat transfer but is not a proactive heat transfer method in this context. Therefore, radiant heat plays a critical role on the leeward side during a fire, presenting a significant risk of fire spread and damage to those structures.