Roof Ventilation

One of the most difficult tasks any fire company can face is opening a flat roof. Multiple layers of building materials and successive coats of tar make removal, even with the aid of a power saw, time consuming and labor intensive. Add to this the necessity for the roof crew to work directly over the hostile fire area and operate close to the cut, making the operation as dangerous as it is difficult.

Photo by David Young
Firefighters prepare to leave a roof as fire vents skyward.

If, however, the time spent working directly over the fire could be shortened or if the need to work in close proximity to the hole could be eliminated, the operation could be made safer.

When faced with the task of providing a ventilation hole which may require the removal of an eight-by-10-foot section, the roof crew is often forced to cut and remove decking in sections. The size of the sections being removed is often limited by the use of pike poles and pick-head axes to pry up and strip back sections of decking. The operation requires two or three firefighters working in an already fire-weakened area.

An alternative method for removing the decking would be with the use of a 12- or 16-foot roof ladder. With the roof crew in position and the site for the ventilation hole selected, the operation proceeds as follows:

  1. A power saw is used to make an eight-foot-long cut in the decking.
  2. A second cut, 10 feet long, is made with the saw at a 90-degree angle to first cut.
  3. The firefighter returns to the point where the two cuts meet and completes a triangle cut two feet into the 90-degree angle.
  4. Using a pick-head axe, the firefighter removes the decking from the small triangle-cut area. This permits a quick inspection of any void area, such as a cockloft, under the roof. In addition, this hole may expose a roof rafter that will indicate the direction the rafters run under the decking. This hole will also serve as the starting point to insert a roof ladder for deck removal.
  5. With the direction of the roof rafters determined, the last power saw cut can be made in the direction of the rafters. This cut will be eight or 10 feet in length.
  6. The hooks on the roof ladder are set (opened). With one firefighter on each beam of the ladder or two on each beam, the hooks are set into the triangle inspection hole. Once the hooks are set under the decking, force for pulling the deck is applied by the firefighters on the ladder. The decking is stripped back in the direction of the roof rafters (this is important because you would not want to dislocate the rafters that support the roof).

Photo by Jack Haley/Action Photography
A firefighter uses a chain saw to open the roof of a fire building. Regardless of the type of roof flat or peaked the same safety precautions need to be followed.

The use of the roof ladder to pull the decking offers a number of advantages over the use of pike poles and axes:

  • Firefighters involved in the deck removal are no longer required to work in close proximity to the hole. The length of the roof ladder used for pulling determines how far the firefighters can be from the opening.
  • The use of the roof ladder makes for better coordination of the removal effort. Far more force can be applied against the decking by teams of two or four firefighters using one tool (the roof ladder) than four individuals with pike poles.
  • Moving the firefighters away from the opening reduces the problem of heavy smoke conditions and fire emitting from the opening.
  • If necessary, this operation would allow room to bring a second ladder and team of firefighters to assist when removing decking is too difficult for a single roof ladder operation.
  • The roof ladder works well on metal decking and offers protection to the firefighters from hinging-in, which can occur when removing metal decking with pike poles.
  • Sheets of plywood are easier to handle with the roof ladder and in some instances can be removed as an entire sheet.
  • Trench cuts can be made quicker and safer with this method of deck removal.

Weighing The Costs

Caution must be used anytime a standard fire service roof ladder is used for removing roof deck material, since the ladder was not intended for this type of stress but there is a solution to this. For most departments, flat roof ventilation is not an everyday occurrence but when it is necessary to perform this operation, the advantages of using the roof ladder make it reasonable to over-stress one ladder and remove it from service until it can be inspected and tested for safety.

If deemed necessary, certain roof ladders could be designated and strengthened for use in this operation and there would be no need to use standard fire service roof ladders.

Richard Courtright, a 25-year fire service veteran, is a captain in the Rochester, NY, Fire Department.