Vertical ventilation
Vertical ventilation: A firefighter’s ladder-to-roof guide. Back to basics – sounding and walking on the roof, using roof ladders, working from an aerial, cutting the hole and punching through
Chris DelBello provides a detailed guide into vertical ventilation. DelBello is a 31-year veteran of the fire service. He currently holds the rank of senior captain with the Houston Fire Department, working in the Midtown District. He is also the district training officer, which encompasses all the stations in downtown and midtown. DelBello holds a Training Officer II certification and serves as an adjunct instructor with Houston Community College.
Vertical ventilation is an essential and effective fireground tactic. For well over 100 years, vertical ventilation has been used by the fire service, proven as a viable ventilation method on thousands of incidents across America and beyond. In fact, it has long been considered the optimal method of ventilation.
In some departments, it is still the best option due to budget constraints that would prohibit the purchase of positive-pressure ventilation (PPV) fans. And depending on what the fire conditions are, it may literally be the only option.
Case Study
A ladder company was traveling down a tight residential street, when they rolled up on a wood-frame residential structure with heavy smoke pumping from every crack in the building. The humidity was high that morning. The smoke was initially lifting and then falling to the ground level, making it difficult to see even while outside the building.
Neighbors and other bystanders were yelling and pointing at the house, indicating that there were children inside.
The ladder company officer radioed dispatch, advised them of the fire and requested a box alarm, all while trying to gear up as quickly as possible.
Once the crew was geared up, they attempted a primary search. The crew entered a door on the bravo side. As the officer made entry into the zero-visibility conditions, he quickly began to run into items not typically found inside one’s residence – first a mattress on the floor right in the entryway, then a shopping cart, then a push-mower, then rolled-up cyclone fencing.
As the company officer continued on, it felt like he was also walking upward, not like a run of stairs, but more like a mountain of garbage. Soon the officer’s helmet bumped the ceiling.
The officer stopped and asked himself, “Do I continue on or do I abandon the search?” At this point, the company officer is no more than 10-12 feet inside the doorway, and they were still the only company on location.
The officer decided to abandon the search, opting for vertical ventilation.
As the company returned to the alpha side to retrieve the necessary equipment to perform vertical ventilation, the officer saw that the ladder company chauffeur had already set everything up to make access to the roof – and the vent saw was already running.
The crew grabbed the saw from the chauffeur and climbed the ladder. The crew cut a nice-sized hole on the pitched roof, and heavy smoke began pumping out. As the crew left the roof, heavy fire began showing from the hole.
The ladder company then re-entered the residence. As the company walked through the house – yes, walked – they could see clear as day, that is, until they made it to the kitchen. The entire stove, sink, cabinet and pantry area was free-burning, and all the products of combustion were exiting directly through the ventilation hole the crew had just cut.
The company officer and crew finished the primary search and exited the residence to retrieve some pump cans to initiate extinguishment, while at the same time, the first engine company arrived on scene. The ladder company officer directed the engine company officer to the kitchen and the fire was quickly extinguished.
Vertical Ventilation
Vertical ventilation is the removal of super-heated toxic gases and smoke by allowing it to take its natural traveling path – UP!
Fire companies make this possible by accessing the roof with a ladder, saws and other tools, and making an opening on the roof’s exterior, then punching the ceiling out with another tool. The final outcome of this tactic is that the super-heated smoke and toxic gases exit the building on their own. Vent crews simply provide the path of least resistance by cutting a hole in the roof decking large enough to release any products of combustion under pressure while confined within the structure.
Company officer
Most members will receive minimal training, including hands-on training, before going to the roof for their first time. Let’s train them to be safe. Let’s train them for that experience right here.
Training at this level is the company officer’s responsibility. The company officer needs to start by explaining every aspect of when, how and why the crew will perform vertical ventilation.
The company officer leads the way on this tactic, and they are responsible for training their crew to the level needed to complete the task safely. Every action must be explained and practiced over and over until there is complete understanding. It starts with the training, but once on scene, the company officer should assume the position of a formal roof safety officer.
The officer decides how the roof will be accessed and where the ladder will go, the path the crew will travel when walking on the roof, and where the hole will be cut. The company officer then supervises the crew doing the actual cutting, making sure they do not walk on their cuts, that they do not step off the roof, and that they do not walk anywhere that has not been checked for weakness.
Sounding the roof
Sounding the roof should not be accomplished with a size 10 boot. If your boot goes through, you are already in trouble. Sounding the roof is also not accomplished by simply tapping an axe head inches in front of each step taken.
Sounding should be accomplished with a 6-, 8- or 10-foot roofhook or other tool with some length to it. The idea is to drive the tool head through the roof as you walk to the location where ventilation is to take place. Again, you want to strike the surface of the roof, not tap it.
When the tool that is 6, 8 or 10 feet out in front of you goes through the roof decking, STOP. Maybe even take a step back and then have the crew start cutting.
Walking on the roof
When walking on a pitched roof, we want to walk on the strongest areas as much as possible. The strongest areas of a roof are the ridges and valleys. This is where the lumber is reinforced with beams. However, keep in mind that many of today’s modern peaked roofs do not have a ridge board at all. It is important that every crewmember follows the officer sounding the roof and that they not stray from the path.
When the officer decides where to cut, they will also sound out a safe working area on the decking that the fire crew should not go beyond. The officer will then observe and ensure the safety of the crew as they work on opening the roof.
Roof ladders
Roof ladders make working on the roof much safer. Even on sketchy or questionable roofs, vertical ventilation can still be accomplished because the roof ladder will support the entirety of the firefighter’s weight and spread it evenly between the ridge and load-bearing exterior wall.
If staffing allows, a second roof ladder is better. This allows two members to cut a single, but bigger, ventilation hole without ever stepping foot onto the roof.
Roof ladders are not always an option, though, sometimes due to roof design. Proper sounding techniques become imperative in these situations.
Working from an aerial device
Working from an aerial device is also a good option, if available. This method requires even more training, however, to be efficient and effective. It requires coordination between the firefighter doing the actual cutting and the operator at the turntable. I have seen good outcomes from crews that train regularly; unfortunately, I have also seen fine examples of a complete waste of time and resources.
Cutting the hole
There are many ways to cut a hole in the roof decking. My advice is to keep it simple. Avoid the new techniques you might find on random YouTube channels directing you to reposition your feet or walk around a lot or even techniques that require you to pull the saw out of the decking more times than you would actually cut.
Always shoot for a bigger hole. A 4 x 4-foot hole gets you a 16-square-foot hole, whereas a 6 x 6 gets you a 36-square-foot hole.
There’s a saying among firefighters regarding ventilation holes. In one’s head and in the textbooks, a hole should start of at 4 x 4 minimum. Well, the higher the roof and the steeper the pitch of that roof, combined with actual fire conditions, the smaller the ventilation hole gets. This is due to lack of proper training and experience, plus a real presence of fear or discomfort.
When cutting, you want to watch the depth of your bar or blade for two reasons: 1) We do not want to cut through any supporting members under the decking, and 2) we do not want to pick up or draw in any wiring or ductwork that may be fastened to the underside of the decking in a low-pitched roof. Picking up the wiring inside ductwork will put a complete stop to what should have been an otherwise quick operation. You will now be forced to use that pick-head axe we all hope someone remembered to bring in cases like this.
A little trick to save some time or make the vent hole bigger: If you see a ridge vent installed on a peaked roof, do not waste time in making a top cut. Your vertical cuts will be enough. The top of the decking is no longer attached to the ridge board, only to the rafters. Instead, add that top cut to your vertical cuts for a larger hole with the same number of cuts.
Punching through
Ventilation is not complete until you punch through the ceiling. The ceiling must be opened to allow the smoke and heat to enter the attic space then exit the vent hole.
Proper tool selection is important here. You need a tool heavy enough to make easy work of the job and with a big enough surface area to remove large sections at a time. A simple pike pole would not be my first choice for this function. A roofhook or trash hook would be a good choice.
Also, sizing-up the roof comes into play with the tool selection for this function.
The steeper the pitch of the roof, the longer your tool selection will need to be. You do not want to be on the roof with your favorite 6-foot roofhook when you need a 10-foot roofhook.
Some roof pitches will require the ceiling to be opened from the inside to allow for venting.
Coordinated attack
Today’s definition of coordinated attack is a little different than in years past.
In the past, the idea of vertical ventilation was to allow the pressurized smoke and heated air to escape before sending in the attack crew, making conditions safer by providing visibility and even preventing a backdraft. This also allowed for a more rapid advance to the seat of the fire.
Research coordinated by both NIST and UL has provided firefighters evidence to guide flow path management decisions. Vertical ventilation is part and parcel to this discussion. The timing for the decision to provide vertical ventilation does need to be carefully coordinated with the engine company. In locales with close-in companies, or where robust engine and truck crews arrive together, early vertical ventilation is a great strategy to improve conditions for the rapidly advancing engine crew, who will immediately apply water.
In locales where staffing is at a premium, early vertical ventilation in the absence of a ready hoseline could mean the difference between salvaging part of the building or ending up with a parking lot.
Experience and training along with crew size and crew integrity will be critical to the ventilate/not-ventilate decision and/or the decision on whether to go to the roof.
Tactically aware, means safe
Vertical ventilation has been one of the fundamental tactics since the dawn of modern firefighting.
It is as simplistic in use as a smoothbore nozzle. If you open a smoothbore nozzle, the water comes out based on the size of the tip and pressure at the pump. It’s that basic.
If you ventilate the roof, the smoke and heat come out at a rate equivalent to the size of the opening and pressure inside the house.
The only reason to fear vertical ventilation is for lack of training and understanding. Our members must be trained for complete understanding – understanding when vertical ventilation is needed, determining if the roof is safe to operate on, understanding the method of access, knowing the methods that are going to be used to actually cut the ventilation hole and looking for ways to make vertical ventilation safer.
Let’s train our members to be safe, comfortable and tactically aware of vertical ventilation operations.
