What is the cause of exposure fire to an adjacent structure?

• A. Radiation
• B. Conduction
• C. Convection
• D. Spontaneous combustion

Answer: (A)

Radiant heat from the burning structure travels through space and can heat the exterior of a neighboring building to its ignition temperature even without direct flame contact. This radiant transfer is the primary way an exposure fire starts in an adjacent structure, since heat moves independently of the air and can preheat or ignite siding, roofing, or other exposed materials at a distance. Conduction would require physical contact with a hot surface, which isn’t typical for exposure at a distance. Convection involves hot gases and flames moving through the air, which can contribute but is not the main ignition mechanism for an adjacent structure. Spontaneous combustion isn’t the usual cause in this scenario.