From the beginning of time Mother Nature has presented mankind with all kinds of meteorological phenomenon’s and the one we are going to discuss in this article is wind its effect on us as firefighters. As we know we cannot fight with Mother Nature but instead work with her when the weather-related challenges are presented to us on fire scenes.
It has been estimated that been 2002 and 2010 approximately 24 firefighters were killed in structure fires due to wind as a factor most notably was the April 12, 2009 house fire in Houston, Texas that claimed the lives of two firefighters operating in a ranch style home. More recently was the March 26, 2014 fire in the Back Bay of Boston, MA that claimed the lives of two firefighters operating in a brownstone style home. May these firefighters and all those who lost their lives, rest in peace.
The first thing we should understand is that no matter what type of firefighter we are – structural, wildland, hazmat – what is wind in respect to fire? According to the National Institute of Standards and Technology, wind speeds as little as 10 miles per hour can cause rapid fire progression in a structure regardless of the structure. Prevailing winds that enter a fire-vented location of the structure could create a flow path of blowtorch-effect flames and untenable temperatures when a secondary opening is created.
The next thing we should understand is how to identify and attack wind driven fires because we cannot predict or stop when wind will affect fires.
1. Understand wind and its effect on fires.
2. Understand the blowtorch effect
3. Size up the structure with a complete 360-degree size up. Pressurized wind
4. If there is a wind-driven condition found, notify all units on the fire ground.
5. Coordinate and control all vent points.
6. If possible, avoid advancing through a downwind opening. Determine the wind pattern and adjust your tactics. Advancing through a downwind opening from the unburned side will create a wind trap for firefighters and possible victims involved in a potentially dangerous flow path.
7. Understand flow path.
8. Implement LCES
9. Lastly, consider a transitional attack on the fire. Attack from the involved side to the uninvolved side and if possible conduct search, rescue and additional and final fire control operations from the involved side as well.
Flow Path with no Wind & Flow Path with Wind
First, what is a flow path? A flow path is the area between where the fire is and where the fire wants to go.
To establish a flow path in a structure with no wind, we need to remember two key concepts.
1. Windows create a bidirectional flow with fresh air coming in through the bottom and exhaust coming out from the top.
2. Once the ceiling is vented, it will pull the superheated gas, smoke and fire to the vent point creating a flow path.
To establish a flow path in a structure with wind, we need to remember these two key concepts.
1. The wind in the structure will override the pressure of the outlet in the window creating a unidirectional flow path into the structure instead of out of the structure.
2. The ceiling vent will provide the only exit for the exhaust. The wind will force all the superheated gases, smoke and fire rapidly through the structure to that single outlet thus causing what is known as the Blowtorch Effect.
The blowtorch effect is the area of wind driven fires that is sadly and untimely claiming the lives of firefighters entering wind driven affected structures. Like the fire triangle & tetrahedron, the blowtorch effect has a similar shape: The Blowtorch Triangle. This triangle consists of an inlet, out and heat. Just like the fire triangle and tetrahedron if we remove one side we reduce the possibility of the triangle.
Removing the Outlet
To remove the outlet we need to remember door control throughout the exterior and interior openings as fire personnel pass through or encounter during their operations. This reduces the potential flow path and reduces the potential for the blowtorch effect. Also, stay in coordination with the vent team. Any uncoordinated ventilation will create an additional flow path to the vent opening.
To remove heat, consider using a transitional attack. Begin with an exterior attack prior to entry to extinguish the gases and bring the fire to a contents fire to allow for more ideal conditions for interior crews about to go in. This is done by a straight stream directed solely at the ceiling through a window opening or door. This will not push the fire, only cool it.
Removing the Inlet
Considering using Wind Control Devices and salvage covers on open windows and doors especially in high rise buildings. The WCD’s will minimize the winds impact on fire spread throughout the structure.
Lookouts: Command must be aware of changing conditions. Door control firefighter should monitor smoke conditions and location of firefighters inside. RIC should perform a 360 size up and constantly watch for changing conditions. Everyone on scene is considered a lookout.
Communication: Report wind conditions upon arrival, status of doors and windows that are opened/closed and report any changes in conditions.
Escape Routes: Operating from the upwind size can make for easier escape routes and safety zones. It may not be possible to ensure escape routes and safety zones on the downwind side due to the potential of unpredictable fire behavior.
Safety Zones: Closing doors behind you as your advance through the structure can provide as a temporary area of refuge and increase survival time until you can escape or rescue crews get to you.
Understanding wind and wind driven fires can be tricky and cause for a long day at the office but our goal is to go home to our families after it’s all said and done.
Until next time; work hard, stay safe and live inspired.
About the Author
NICHOLAS J. HIGGINS is a firefighter with 15 years in the service all within departments in Piscataway, NJ. Nick has held the ranks of Lieutenant and Captain as well as being a township elected District Fire Commissioner for 1 term (3 years) in Piscataway, NJ. He is also a NJ State certified level 2 fire instructor. He holds a B.S. in Accounting from Kean University working in Corporate Taxation and is the founder/contributor of the Firehouse Tribune website.