Heat-related damage patterns at a fire scene yield clues as to where a fire originated. This article is a third in a series that discusses burn patterns and interpretations when attempting to determine the origin of a fire. The first article¹ dealt with burn and damage patterns on buildings and interpretations of the damage. The second article² dealt with selected case studies regarding analysis of burn patterns. This third article presents additional case studies not mentioned in the previous two articles.

Photographs facilitate the discussion of burn patterns and are unique to a particular loss. Consequently, this article contains several photos of burn patterns from actual losses in a picture book format to act as a reference when analyzing a particular fire-related claim. 

A review of fire analysis methodology suggests that the classic "V" thermal damage pattern is used by analysts to determine the origin of the fire, the base of the V being the likely origin of the fire. The damage that forms the shape of the V can be a result of soot deposition, direct flame impingement, combustion of a fuel or melting. Fire development by convective means often results in flames or hot gases rising and diffusing upward, forming a V. The example in Figure 1 at the bottom left illustrates the base of the V-shaped pattern (yellow dashed line), which is at the ice dispensing unit (denoted by a red arrow). There is some minor damage below the V as a result of "drop down" debris (the green arrow) often discounted as an indicator of the fire origin. The red arrow points to the probable origin of the fire. The inherent assumption is that fire generated natural convection (gas movement as a result of gas density differences) has resulted in a V-shaped damage pattern. Forced convection such as wind or mechanical influences can distort the pattern such that it does not resemble a V, adding difficulty in determining the fire origin.