Which type of flame is considered the upper region of the flame?

The upper region of a flame is referred to as the intermittently flaming region. This area is located above the continuous flaming region and is characterized by its periodic bursts of flame. In this region, combustion is less stable compared to the continuous burning below, which can lead to fluctuations in the intensity and color of the flame.

This understanding is crucial for fire investigators as it helps in assessing the fire's behavior, spread, and heat release, allowing them to analyze fire dynamics thoroughly. The intermittent nature of this region can also affect how combustion gases rise and disperse, providing insight into the overall fire structure and potential hazards.

In the context of flame structure, other regions like the continuous flaming and ignition regions have distinct characteristics and temperatures that serve different roles in the combustion process, but they do not encompass the dynamics found specifically in the intermittently flaming region.