What does a fire investigator typically assess to determine fire behavior?

A fire investigator assesses patterns of damage and the structure to determine fire behavior because these elements provide critical information about how a fire developed and progressed. By analyzing burn patterns, heat damage, and the extent of the destruction to various materials within the structure, the investigator can infer the fire's origin, direction, and the way it interacted with the materials present.

Patterns such as "V" shapes on walls indicate the fire's origin point and demonstrate how flames spread. Additionally, the condition of fire debris and availability of fuels can help determine how intense and rapidly the fire grew. Understanding the structure itself—such as its design and materials—further aids in piecing together the fire's behavior and potential causes, allowing investigators to draw conclusions that are critical for both determination of cause and legal purposes.

While visible flames and witness statements can provide useful information, they alone do not give a comprehensive understanding of fire behavior. Weather conditions are important, but they are just one of many factors that can influence how a fire burns and spreads. Therefore, assessing damage patterns and the structure is fundamental in fire investigation for accurately determining the behavior of the fire.