What type of surface does a clean burn effect typically appear on?

The clean burn effect is typically associated with noncombustible surfaces. This phenomenon occurs when a fire burns away the combustible material, resulting in a clear or untouched area surrounding the area that was actually involved in the fire. Noncombustible surfaces do not ignite or burn, allowing for this distinctive pattern to form. Such surfaces can include concrete, metal, or brick that remain unaffected by the flames, demonstrating a clean or uncharred appearance.

In the context of fire investigations, recognizing patterns like the clean burn effect on noncombustible surfaces provides essential clues regarding the fire's behavior and spread, leading to a better understanding of its dynamics. This differentiation is useful for investigators in determining the origin and cause of the fire, as well as for assessing the materials involved. The absence of combustion on these surfaces can indicate that certain areas were shielded from the flames or that the fire was controlled in a manner that kept these areas intact.