Truck Company Ops: Ventilation From Above

By Mark van der Feyst

As discussed in previous articles, ventilation is an important fireground task when trying to suppress any fire. The need for ventilation will aid in removing hot gases and smoke; reducing the chances of flashover, smoke explosions, or backdraft; increasing the visibility of the environment; and providing fresh air for any victims inside. Every structure fire to which we respond will require some form of ventilation; choosing which method to use is hard part.

In a single-family residential structure, ventilation will be either horizontal (with the opening of windows and doors), by using mechanical devices such as positive pressure fans or natural air currents, vertical by cutting a hole in the roof, or by using hydraulic means. The bulk of our structural fire calls will be residential-type homes with a peak roof. So, let’s turn our attention away from single-family residential structures and focus on commercial, industrial, multiple residential structures, and high- and low-rise buildings.

Every building type listed above has two common features: a flat roof and height. Accompanying these two variations are some obstacles when ventilating a structure. The height for one may not allow for ground ladder access but may require aerial access, the roof type may not be easily cut such as concrete, or perhaps the fire is between two floors in a multiple-story building. Ventilating these types of structures will be limited by the options available.

One option is to ventilate the structure from above. If the building has windows near the top of the roof or above the location of the fire, then using those windows will be a great alternative. Getting to the roof or above the fire can sometimes be done by ground ladder, by aerial ladder, or by stairwell inside the building, with access to the roof or the floor required. If possible, establish a secondary means of escape before commencing any operation. Just as we establish two ways off on a residential building, we must establish the same for these types of structures.

Wearing proper personal protective equipment is also vital when conducting this type ventilation. Because you will be located above the fire and possibly blasted with smoke and hot gases when the window is broken, you must ensure that you are well protected with self-contained breathing apparatus and structural firefighting garments.    

Also ensure that it is safe to stand on the flat roof. As you walk across the roof, sound it to check for structural integrity. If the roof feels soft or has too much “bounce” in it, then it is probably not safe. Another way to check is by visual means; bubbling tar on a flat roof is never a good sign, so avoid the roof if you see this.

To complete this operation, always bring a good set of proper tools with you whenever you are conducting certain fireground functions. When ventilating on a flat roof, bring the following:

  • A roof hook or pike pole (preferably six-foot).
  • A bag of utility rope.
  • A flat-head ax.
  • A halligan bar.
  • A rotary or chain saw (rotary preferable).

If you bring an ax or a pike pole only, your ability to complete your assigned task will be limited.

There are three ways to complete venting from above. The first involves using a pike pole or a roof hook. Your tools need to be long enough to allow you to reach over the edge of the building and break the glass out below. A six-foot roof hook will be the minimum length required, but a longer length will only help. The firefighter breaking the glass must be secured by his partner so that he does not fall over the edge.

The firefighter must not lose his grip on the hand tool when attempting to break the glass; this action will also require good upper body strength. Repeat the striking action several times to ensure the window is broken and cleared out enough to warrant effective ventilation. This will be fatiguing if the firefighter needs to clear numerous windows.

The second method is to use a piece of rope and a hand tool such as a halligan. Secure the hand tool with the rope and then toss it over the edge like a pendulum to break the window. The first step is to secure the halligan with the rope in the same method as when you prep the tool to hoist it to the roof. This is a basic skill learned in firefighter I. 

In photo 1, the halligan is secured using a clove hitch and a half-hitch. Use a rope no larger than 12 mm (1/2-inch) in width, with a smaller diameter being optimal. This will allow you to ensure the hand tool is tightly secured and ready for deployment.

(1) Photos by author.

 

Once he secures the tool, the firefighter will lower the tool over the edge to measure and mark the location of the window. Once the hand tool is at the middle of the window, stop lowering it and mark off on the rope where that distance is with one of your hands. The firefighter will position this hand (left or right) at the spot where the rope is supposed to pendulum to break the window. This hand will also be the static or anchor hand; it will not move when tossing the tool over the edge.

Once the rope is marked, it can be retracted back up to the roof. When the firefighter is ready to toss the tool over, he will take that hand; grab the hand tool; toss it over the edge, making sure the other hand (the static/anchor hand) does not move at all; and holds the rope at the proper mark. As the hand tool is tossed out, it will swing like a pendulum and break the glass on contact.

The firefighter can repeat this action several times to clear out as much glass as possible. A downside to this option is the rope will be destroyed by glass pieces from the broken window; this is why a utility or other smaller diameter rope is best to use (instead of a life safety rope). A variation of this would be to use an ax, as shown in photo 2.   

(2)

 

The third method is to use a roof hook outfitted with a welded chain link at its bottom. In photo 3, the six-foot roof hook has a small link that allows you to hook in a small carabiner attached to a piece of rope or secure it with just rope and a “figure 8” follow-through knot.

(3)

 

The firefighter can conduct the same operation with a halligan bar or with the roof hook. The disadvantage with the roof hook is it is too lightweight in contrast to the halligan or ax. The halligan has more weight in the adze and spike end than the roof hook has at the hook end. Using the law of physics and gravity, the halligan is more effective and can also be outfitted with a small link welded to it near the fork end, allowing it to be used in the same manner.

If conducted properly, this technique of venting from above can be very effective. Practicing this type of ventilation is tough to coordinate, but it can be done if your community initiates the proper planning. Using abandoned buildings slated for demolition can be a great asset in practicing this technique. Getting permission will be the hard part.

 

Mark van der Feyst has been in the fire service since 1999 and is a full-time firefighter in Ontario, Canada. He is an international instructor teaching in Canada, the United States, and India, and at FDIC. Van der Feyst is a local level suppression instructor for the Pennsylvania State Fire Academy. He is also the lead author of Residential Fire Rescue (Pennwell).

 

MORE MARK VAN DER FEYST

Truck Company Ops: Rooftop Obstructions

Truck Company Ops: Horizontal Ventilation

Truck Company Ops: Louver Cut

Truck Company Ops: Vertical Ventilation

Truck Company Ops: Taking the Window

Truck Company Ops: Working the Ladder

 

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