In order to effectively manage the risk or the potential danger, it is a fundamental necessity for firefighters to be made aware of the danger so that it can be properly managed. It is a currently accepted practice for firefighters arriving at the scene of structure fires to consider the associated fireground factors and when appropriate to initiate a fast and aggressive interior attack from the unburned side. When the occupancy is residential, having a potential life safety hazard, an offensive strategy is viewed as the acceptable practice.
In general, during an interior attack from the unburned side, fire and smoke is pushed away from uninvolved portions of the structure by advancing firefighters, thereby providing a means for occupants to exit the structure. However, during seemingly "normal" appearing wind-driven residential structure fires, the firefighters were unaware or did not recognize the potential danger associated with the prevailing wind speed and direction in relation to the position of the fire. In many cases, it ended in defensive operations and in the tragic loss of firefighters when offensive strategies were initially used. If firefighters are unaware of the danger:
- There will be no situational awareness
- No one will have a reason to speak up and utilize crew resource management
- Firefighters will not have the information needed to calculate the risk as advocated by the rules of engagement
- An accurate risk-benefit analysis cannot be made.
The Wind Factors
During the course of any structure fire, the wind may influence interior conditions and firefighter safety. The wind may:
- Not be a factor
- Help firefighters during the interior attack
- Injure or kill firefighters during the interior attack
Since there is always a possibility that the wind may cause life threatening conditions, without exception, every firefighter must be aware of and must consider the wind hazard on each occasion they respond to a structure fire.
Wind Not A Factor
During working structure fires managed by firefighters on a national basis, and when relatively safe, firefighters will conduct an offensive strategy. During many of these particular fires however, the wind was not a factor. The wind speed may have been light or calm or may have been blowing in a direction which did not act to adversely move the fire within the structure during the incident.
Wind Helps Firefighters
During other structure fires and whether observed or unobserved by firefighters working at the scene, the prevailing wind was actually pressurizing the structure on the Alpha side, the same side the front door was located and which firefighters used to enter and quickly advance into the structure. During these fires, the wind speed and direction, which was at the backs of advancing firefighters, actually helped the firefighters by pressurizing the Alpha side of the structure as well as pushing the smoke and heat in a forward direction and away from advancing firefighters. The wind provided the additional benefit of venting the smoke and heat out of the building through openings on the Bravo, Charlie or Delta side of the structure. The wind also served to cool the interior, reducing the onset of flashover as well as improving visibility to facilitate the primary search.
Wind Injures Firefighters
During certain structure fires, conditions were right for the wind to rapidly push the fire into the structure. Although the point of origin can be on any side of the structure, when the origin of the fire was on the Charlie side of the structure, openings into the structure such as windows were vented allowing wind to enter and spread fire rapidly through the structure (from Charlie side to Alpha side) when a vent point on the Alpha side was created. During a pressurized Charlie side scenario, the vent point was usually the front door which was the arriving firefighters point of entry.
The Wind Trap
In addition to oversight associated with hazards of the wind, another troubling aspect of a fire originating on the Charlie side under pressurized wind conditions has to do with a misinterpretation of the initial size-up factors. In this scenario, smoke and or fire originating at the rear may be visible on the approach or over the roof line from the front of the structure. This condition, at first glance, will appear to be ideal to initiate a traditional fast and aggressive interior attack from the unburned side (Alpha side) while PPVs are set up at the front door to assist in forcing the smoke and heat forward to vent out the Charlie side of the structure.