FDNY Arson Practice Test 2026 – Complete Exam Prep

Char depth is a critical indicator in fire analysis, primarily because it reflects the intensity and duration of the fire at a specific location. When a fire burns, it affects the materials it comes into contact with, leading to varying levels of carbonization based on how hot the fire becomes and for how long it lasts. By measuring the char depth on a particular surface, investigators can gauge the heat exposure experienced in that area.

Greater char depth typically suggests higher temperatures and prolonged exposure to the fire, whereas shallower char indicates less severe conditions. This information is essential for fire investigators to ascertain how the fire behaved and the environmental conditions present during the event. Therefore, examining char depth aids in reconstructing the fire’s timeline and behavior, helping to pinpoint how intensely and for how long materials were subjected to heat.