What characterizes saddle burns?

Saddle burns are characterized by their curve-shaped and deeply charred patterns, which often appear localized on top of floor joists. This type of burn results from the intense heat generated during a fire, often where structural members are compromised or where combustible materials are positioned in a manner that allows for maximum heat concentration. The curvilinear shape is indicative of the way heat climbs and becomes trapped in these areas. Specifically, when a floor joist or similar structure serves as a "saddle" for the fire, it can create areas of severe charring directly above it, resulting in the distinctive pattern associated with saddle burns.

The other options do not accurately describe saddle burns. While faint and superficial burns could occur in different contexts, they don’t align with the deep char typically seen in saddle burns. Saddle burns are unique to areas like joists and not predominantly found on vertical surfaces, which typically feature other burn patterns. Additionally, while circular burns around appliances can occur, they are not representative of the characteristics of saddle burns, which are more focused on structural elements and their interaction with heat and flames.