NIST Reacher Dan Madrzykowski Reviews Ventilation and Firefighter LODDs at FDIC 2011

At FDIC 2011, Dan Madrzykowski, a fire protection engineer at the National Institute of Standards and Technology (NIST) and major contributor to fire service research, reviewed how ventilation can lead to flashover and how it factored into several firefighter line-of-duty deaths.

Madrzykowski focused on incidents where the fire conditions changed dramatically because of changes in ventilation. The additional oxygen mixed with hot, fuel rich combustion products resulting in flames and hot gases spreading through the structure.

One such case was an NFPA 1403 live burn at a single-family home in Florida in which firefighters assigned to search for a mannequin were in the fire room when an outside window was vented, leading to flashover. Although the burn was conducted with two attack teams and multiple safety officers in place, two firefighters were killed because of the sudden introduction of a new source of oxygen to the fire.
 
In each of the cases, the victims were found in the flow path of the fire–between the fire and where the fire wanted to go due to the ventilation openings.
 
Ventilating a fuel rich fire can lead to increased energy generation, that is, more heat. For every kilogram of oxygen consumed, 13 MegaJoules of heat is released. This runs counter to the notion that ventilation will cool the conditions in the structure.
 
“I hope that the presentation will make departments think about their protocols on ventilation,” Madrzykowski said. “The cases reviewed show the trend that changing ventilation on fire fighters in a building, before they have control of the fire, resulted in tragedy. It is important to cool the unburned fuel in the hot gas layer.”

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