Steps to successful tactical ventilation
Understanding ventilation's effect on fire behavior and its safe techniques is key to a safe firefight
Tactical ventilation involves opening ventilation paths with the intent to make the fire behave or travel in a certain direction. This direction is meant to help maintain the life safety of both firefighters and civilians.
In today's fires, the amount of smoke waiting for enough oxygen to reignite at the seat of the fire is exacerbated by the products we have in our homes and work places. This non-flaming fire is simply waiting for us to open the door.
If a firefighter is wandering the fireground with cans of gasoline with the plan of throwing gas on the fire, he'd be arrested. Opening the vent path to a well-involved fire without proper ventilation is simply throwing a different part of the fire tetrahedron (oxygen) on to the fire.
Vertical ventilation is one definitive way to remove the products of combustion out of the building, but strategic and tactical consideration must be given. Poorly timed and poorly placed ventilation will simply allow the fire to follow its natural upward path faster.
Understanding how long it takes your crews on average to carry out ventilation tactics is a key aid in strategic decision making. Ventilation decisions are not only made based on where the fire is, but where it will be by the time the vent hole is opened.
Constant practice in vertical ventilation based on construction in the department's area will allow commanders and firefighters to understand how quickly and efficiently they can carry out this task.
Clearly roof operations can be fraught with hazards. The basics of sounding the roof and getting on and off as quickly as possible should be driven home at all drills. Safety officers and sector officers need to be vigilant in keeping the minimum number of people necessary on the roof and monitoring roof conditions.
Learning roof styles, terminology and tactics before the fire is immensely helpful. Touring the district and identifying different types of roof styles naturally leads to discussion on venting obstacles that will be encountered. It also helps when first-arriving officers announce the roof style, so that truck company size up can begin while en route.
It's imperative that crews communicate what they're encountering on the roof. Depending on roof size or commands location, ventilation already occurring may not be visible from the ground or may mask other issues. Command must listen to the roof sector and believe what they report, especially when what the roof crew sees doesn't match the incident action plan.
Teamwork is, of course, important on the roof as well. However, the roof isn't the place for a truck company social function.
It is critical not to add too much live load to a roof that may already be undergoing rapid demolition via oxidation. At the same time, recognize that with a two firefighter team it's easy for both sets of eyes to be focused on the vent hole, rather than safety.
The officer or second roof firefighter should assist in both the initial and continual sounding of the roof. That person should keep an eye open for changing conditions or other indicators of possible roof failures.
In the saw man's efforts to get the vent hole open he might not see a change in smoke coming from the kerf cuts or inspection holes. Keep in mind that the roof collapse might be rapid. This set of eyes and mental focus should also keep track of two ways off the roof.
The use of the thermal imaging camera on the roof is very beneficial. It can indicate locations of higher heat, likely great areas for the vent hole. It also will give an indication of the rafters' direction and spacing. TICs can also greatly aid in monitoring for changing fire conditions.
On older buildings, row houses and flat roofs, the TIC can aid in finding shafts where fire can be hiding. Always remember that a fire in a shaft must be conveyed to command as it might not be visible to interior crews, and may even be jumping into an exposure.
The danger of using a TIC is the temptation for firefighters to spend so much time looking at the screen that they don't use their other senses.
When it comes time for the cut, work from the escape route to the cut location, constantly sounding the area as the crew moves forward and continually during the evolution. And never a make vent hole between the crew and the escape routes.
And finally, the engine crews are waiting for the roof crew to pop the top to make their jobs easier and give victims a chance for some cooler cleaner air. It's usually easier to start a hole and enlarge it, rather than waiting to make the perfect hole.