“INTERIOR” INDIRECT AND COMBINATION ATTACKS: A MISUNDERSTANDING?

Many articles have been written explaining the different methods of fire attack and options for applying water during firefighting operations. However, to this day the debate continues, and few topics stir more emotion at the fire station kitchen table than the age-old question, “What is the best way to extinguish a fire when conducting an aggressive, interior structural fire attack?”

First, let us review the three most commonly accepted and applied methods of structural fire attack. Prior to the mid-1950s, most fire departments practiced direct fire attack using primarily smooth bore nozzles, producing a solid stream. The essence of direct attack is simple: apply water in the form of a straight or solid stream directly onto burning fuel in an effort to cool it below the point at which the fuel produces flammable vapors. The concept is very simple: If more water [gallons per minute (gpm)] is applied to the burning fuel than heat (Btus) being produced by the fire and a negative heat balance is achieved, the fire will go out. The other key factor to consider when using a direct attack is whether the water is actually reaching the burning fuel, emphasizing the importance of reach and penetration when attacking a fire using the direct method.

During World War II, Chief Lloyd Layman developed a method of fire attack using water fog to extinguish fuel-oil fires on ships. This method was developed on a decommissioned Liberty ship by Layman’s forces in the Coast Guard Firefighting School. Following the war, Layman refined this method for use in structural fire attack. In 1950 at the Fire Department Instructors Conference in Memphis, Tennessee, Layman introduced this indirect method of fire attack. The premise behind the success of the indirect method of attack is the rapid production of large quantities of steam within a relatively confined environment with little or no ventilation. This method of attack was designed primarily as one to be initiated from outside, remote positions through a window into the fire area. The indirect attack was not intended for aggressive interior structural fire attack. In fact, Layman, the father of fog firefighting, warned of the potential danger to the nozzle team if this method is applied from interior positions, because of the disruption of thermal balance and the hurricane of scalding steam produced.