Charring on the underside of doors may be an indication of what?

• A. door material degradation
• B. accelerant used
• C. smoke from other sources
• D. hinge failure

Answer: (B)

Charring on the underside of doors is a telltale sign of accelerant use. When a fuel accelerant is involved, ignition often starts near the floor and flames travel up along the bottom edge, scorching the lower portion of the door. That bottom-edge char pattern is distinct from what you'd expect from normal door aging or from smoke coming from unrelated sources, and it isn’t explained by hinge wear or other mechanical failures. So the dark, burned area on the door’s underside points to rapid, low-lying combustion driven by an accelerant.