Flashover Training

On Sunday, July 16, more than a dozen volunteers from Libertytown Volunteer Fire Department attended an exercise aimed at understanding the behavior of fire during flashover conditions. Each year, more than 470 firefighters are killed, many as a result of flashover during primary search and rescue operations.

Flashover occurs when heat generated by a fire can no longer be absorbed by ceilings, walls, and room contents. Heat begins to radiate back toward the room, raising the temperature of unburned gases, room contents, walls and flooring. At approximately 750 degrees the entire room ignites creating an inferno. Firefighters wear protective clothing, referred to as turn-out gear, to protect themselves. However, a flashover creates such extreme temperatures that turn-out gear cannot provide adequate protection. A firefighter trapped in a flashover has only 2 seconds to escape the harsh conditions before being overcome. This represents only 5 feet of movement once the flashover occurs.

Training is essential to understand the signs to look for during possible flashover conditions. The Montgomery County Training Facility was used to create actual flashover conditions. The images below show the various stages from an outsiders perspective.

	Training was performed in two groups. Here, the second group watches and waits while the first group is inside the flashover container.

An outside view of the container shows the different colors of smoke being generated. The raised portion on the right contains fuel in the form of excelsior, wood and particle board walls. Notice the white smoke escaping from the center "smoke stack." This is a vent that can be opened or closed to control the rate of burn. Seven firefighters and two trainers are located in the left hand portion of the container. They are approximately 3 feet below the floor level where flashover will occur. Nevertheless, they will experience temperatures in excess of 500 degrees during the exercise.

	In this image you can clearly see the darker brown smoke being generated. It is this smoke that will suddenly begin to burn during a flashover. Prior to the actual flashover, "fingers" of flame can be seen snaking through the smoke near the ceiling, a clear indication that flashover is about to occur. From the outside, an observer will note that smoke is beginning to swirl back into the structure. As oxygen is sucked in to fuel the fire, smoke vortices are created.

The first group exits the simulator. There turn-out gear is still so hot that they must keep their gloves on to remove helmet, face mask and outer clothing. They have been inside for almost 30 minutes under extreme temperature conditions, viewing actual flashovers many times.



A close-up image of a firefighter just exiting the simulator. The protective helmet is designed to provide added protection during flashover simulation. An additional reflective cloth covers the helmet and drapes across the ears and neck. Underneath the helmet the firefighter wears additional protective clothing. Although it is difficult to see in this image, the face mask has sustained heat glazing from the high temperatures present in the flashover container.