What does a clean burn effect indicate?

A clean burn effect indicates a visible fire effect on noncombustible surfaces. This phenomenon occurs when materials that are not combustible, such as metals or masonry, display signs of thermal exposure without charring or residue typically associated with unburned fuels. In contexts of fire investigation, observing a clean burn can help investigators distinguish between areas that were exposed to flame versus those that were protected from direct fire impact. The presence of a clean burn suggests that the materials in question have been heated, but not consumed by fire, which often points to the intensity and nature of the fire's behavior, assisting in reconstructing the fire's progression and identifying potential origin points. Understanding this effect is crucial in differentiating between various damage patterns and can inform the overall analysis and conclusions drawn in fire investigations.