Many of these newer buildings will also contain lightweight-engineered structural components throughout the structure, and the attic space is not immune to them (photo 4). Triangular peaked roof trusses are used consistently in attic spaces. This author has witnessed the removal of the King Post in the center of the truss in order for the resident to maximize the attic space for storage. Fires in these spaces (or originating in these spaces) will do significant damage to the structural integrity of the building, and it is not recommended to launch an aggressive interior attack when these components are present. Lastly, ceilings for the upper floors may be suspended from the roof area with the use of vertical tension rods. These rods may be hidden in the structure, and since they have less mass, they have less fire resistance. An attic fire that has been attacking the support system can drop the ceiling of the attack floor on the advancing suppression teams.
Another significant concern that the suppression team may encounter is the presence of Knee Walls. Attic living spaces will have non-load-bearing partition walls that are constructed from the underside of the roof area down to the attic floor. The space that is created within the partition walls is what makes up the living spaces. Many of these knee-wall spaces provide added storage capabilities for seasonal items, decorations, clutter, and other possessions (photo 5). A great amount of fuel can be found in these spaces, and can lead to a significant dynamic event in the entire floor. Access into these wall spaces may have a door, or may only be accessible through a small access trapdoor consisting of plywood or plasterboard. Stretching handlines into these spaces is not a wise decision; there is a safer way to handle this situation.
One of the primary factors to consider when dealing with an upper-area fire condition is to determine how the fire got into that space. Did the fire originate there, or did it spread there from a lower floor? Crews must make sure that they are not starting their attack over the fire floor. Many injuries and fatalities have been documented when companies have been located over the seat of the fire and experienced a catastrophic failure of the floor below, or a dynamic fire event within the lower floors. Be sure to send suppression companies into all of the floors below the space to confirm that there are no surprises waiting below for the attack teams.
Handling this fire will require effective coordination of both ventilation and suppression. Fire that reaches the attic will find a large lumber yard of fuel and unlimited air supply, based on the exchange of air within the structure. Consider the wood stove; if you want the fire to get bigger, open the damper (horizontal vent). Close the damper and the flames dissipate. As long as there is fuel and heat, there will be significant growth by air supply. Open the flue (roof) to the stove, and smoke is allowed to exit, being replaced with fresh air. So the bottom line is simple: control strategic ventilation and you control the fire. This strategic ventilation, coupled with sufficient fire flow, will knock out any fire. Insufficient flow rate, whether through limited pump capabilities or lack of adequate personnel to position ample handlines, will compound fire conditions and heat release rates (HRR). Bringing the right amount of water for BTU consumption and steam conversion is what tackles HRR in its tracks (photos 6, 7, & 8). Getting the water up there may be an arduous task, considering the amount of floors the crew has to climb and then locate the access path to the attic space. As a rule of thumb for hoseline length, figure on one length to the door, one per floor, and one length to cover the top space.
Be sure to have the vertical vent team in place to open up the attic space prior to pulling any ceiling/floor area from below. Consider the amount of heat and fire under the roof; if there are enough of both to require ventilation, the roof is probably unsafe, and supporting firefighters from an elevated aerial device should be considered. Accumulation of heat and smoke can result in a significant dynamic event in the space, including a backdraft or flashover. If there is a potential event, venting out the roof first will direct these products up and away from the suppression teams that are going to open up from below. Depending on the size and construction of the roof area, it may be necessary to perform a Trench Cut on the roof to stop the horizontal spread of fire (refer to my Trench Cut article in September of 2011 regarding this type of operation). As the fire vents, crews can begin pulling ceilings from below. Be ready for anything; this author has been surprised when pushing through a plasterboard ceiling only to find thick plywood flooring directly above the plasterboard. This will allow the fire to gain a considerable amount of energy ahead of the suppression teams.