However, because the wind is pressurizing the Charlie side of the structure and the fire, in reality, when the front door is opened and firefighters advance to locate the fire and search for occupants, they will be met by a fast moving wall of fire having blow torch characteristics and untenable temperatures. Since the fire burning in the area of the Charlie side will follow the path of least resistance, a rapidly spreading flow path of fire and smoke will be established between the open windows on the pressurized Charlie side (the inlet) and the open door on the Alpha side (the vent point). It is also important to note that the use of PPVs at the point of entry will not be able to overcome the pressure created by the wind.
Without a specific warning, an accurate initial size-up, and predetermined strategy and tactics designed to avoid the danger, today's firefighters may easily become a part of a firefighter disorientation sequence from sudden exposure to an extremely dangerous wind-driven structure fire.
Wind Driven Fire Action Plan
In order to avoid wind-driven fires, firefighters may consider the following action plan based on hard lessons learned.
Firefighters must be trained to understand that a wind speed of only 10 mph or greater pressurizing vented fire on a side of the structure can cause sudden life threatening fire conditions on the interior. As a warning and reminder to consider a wind-driven fire condition with a 10 mph wind, dispatchers must transmit the wind speed and direction to responding companies at the time of dispatch. Command must also be notified of any forecasted change in the wind speed and direction and make tactical changes accordingly. A 360-degree walk around should be conducted to determine if vented fire is being pressurized by the wind and on which side of the structure. When a wind driven fire condition is encountered, the situation must be transmitted to all responding companies. When possible and from the exterior, engine companies should quickly attack the fire on the pressurized side of the structure to knock down the main body of fire. When accomplished and if structurally sound, search and rescue crews may enter the structure through the extinguished side to conduct a primary search as other firefighters advance to check for fire extension.
Note: An exterior attack of vented fire on the pressurized side of a structure should be initiated during both rescue and non-rescue scenarios, since as determined by NIST, advancing through an opening such as a door on the opposite side of the structure will create a vent point which will place firefighters and occupants in the dangerous flow path of fire.
When an unfavorable outcome occurs on the fireground, it may indicate a weakness in our method of operation. This is true unfortunately as it applies to the hazards associated with wind-driven structure fires. However, important lessons have been learned by the study of wind-driven fires and the well documented experiences of firefighters who served before us and therefore change is needed. Wind-driven structure fires are special hazards which will require an understanding of the risk and special wind-driven fire tactics which are summarized here.
Preventing exposure to the hazards of a wind-driven fire, of 10 mph or greater, can be accomplished in part by obtaining reports from dispatchers of the wind speed and direction, by controlling the vent points such as windows and doors and ensuring they are kept closed; not allowing a vent point to be created. Finally, by quickly attacking the vented fire on the exterior of the pressurized side of the structure, and not from the unburned side, the risk associated with wind-driven fires may be reduced and may very well prevent the fatality of firefighters.
Special thanks to Mr. Daniel Madrzkowski and Stephen Kerber of the National Institute of Standards and Technology and to the National Institute for Occupational Safety and Health Fire Fighter Fatality Investigation and Prevention Program, (NIOSH).
Note: This article implements Everyone Goes Home, Courage to be Safe Program, Life Safety Initiative 3, Incorporating risk management with Incident Management at all levels including strategic, tactical and planning responsibilities.
WILLIAM R. MORA, a Firehouse.com Contributing Editor, is a former Captain of the San Antonio, TX, Fire Department. William has done extensive research on the topic of firefighter disorientation including the analysis of 444 structural firefighter fatalities and is the author of the United States Firefighter Disorientation Study 1979-2001. You can reach William by e-mail at firstname.lastname@example.org.