Extreme Fire Behavior: Flashover

This is the first of three articles dealing with the extreme fire behavior phenomena, flashover, backdraft, and smoke explosion. Rapid fire progress presents a significant threat to firefighters during structural firefighting.

Initial Tactical Operations: Initial response to this incident was a quint (two personnel), engine (three personnel) and chief. On the arrival of the first company firefighters observed a woman and child trapped on the porch roof and received a report of three children still inside the involved unit. Initial tactical operations involved rescue of the woman and child from the roof (performed by a police officer), primary search, and deployment of a (dry) hoseline to the entry way of the involved unit. Firefighting operations were not initiated until approximately nine minutes after arrival due to the commitment of resources to rescue, primary search, and care of injured occupants. (see Figure 5.)

Fire Modeling

The NIST report includes output from computer modeling of this incident (this is also available from NIST on CD). This data provides another way to visualize fire conditions. Figure 6 illustrates temperature conditions at various levels within the structure at approximately 0832, six minutes after the arrival of the first company. Figure 7 illustrates conditions one minute later.

As illustrated by the NIST computer model, thermal conditions changed radically as the fire extended quickly from the kitchen through the dining and living rooms into the floor one hallway and stairwell to floor 2.

Study and Discussion Questions

Use the information presented in the case to answer the following questions.

  1. Was extreme fire behavior involved in this incident? If so, what type of event happened? Use the fire development curve illustrated in figure 8 to work out your answer.(see Figure 8)