What is a ceiling jet in fire dynamics?

A ceiling jet is characterized by the movement of hot gases that flow horizontally along the underside of a ceiling during a fire. When a fire ignites, it generates heat that causes the air above it to rise rapidly, creating a region of high temperature and pressure. As the hot gases rise and reach the ceiling, they spread out horizontally, resulting in the formation of a ceiling jet. This phenomenon is vital in understanding fire behavior as it influences the spread of heat and smoke within a confined space, affecting both firefighting strategies and safety measures. Recognizing the characteristics and dynamics of ceiling jets also helps investigators determine how the fire may have spread through a structure and identify combustible materials that may have contributed to the fire's intensity.