Making an aggressive interior attack on a well-involved structure will require a considerable effort from the initial arriving companies. Any time that the suppression forces have to deal with a significant fire in an overhead space, there will be some monumental obstacles to overcome. This month, we will look at some characteristics that the on-scene companies will have to identify in order to efficiently handle fires in these spaces.
First, it is imperative that the incident commander (IC) determine what type of overhead space they are dealing with. For our discussion, we will stick to attic spaces, and point out some similarities when dealing with cocklofts and overhead void spaces. When we discuss an Attic, we are referring to an upper-floor space, usually built with a steep-pitched roof to shed snow and rain water, usually high enough for storage and can be used as a living space (photo 1). Conversely, a Cockloft is a top-floor area, but is not large enough to incorporate occupied living space. It is a structural space above the top-floor ceiling and below the roof rafters, connecting similar occupancies at the roof line. These spaces are usually unfinished, with nothing more than roof joists or trusses, with a floor that is constructed from the top-floor ceiling and insulation (photo 2). From time to time, one may come across plywood that is set on the ceiling rafters to allow for storage and mobility around the floor area. Access to these spaces is usually by means of a spring-loaded, pull-down stairwell. Most of these carry weight ratings topping out at 250 pounds; this is not recommended for firefighter use. Crews are much better served opening these spaces up and utilizing fire service ladders for access instead.
Once the space has been identified, consider the usage that the space is providing in the building. Many residential dwellings maximize living space by renovating the available attic space into a top-floor bedroom or living area (i.e., office, playroom, etc…). These spaces can be identified during the 360-degree size-up process. Decorative window treatments and dressings, window decals and pictures, and flower boxes around window areas can be sure signs of upper-floor occupancy. Furthermore, many of these top-floor bedrooms will have an exterior means of access/egress for emergency evacuation (photo 3). These stairways are not recommended for use during fire suppression operations. Compounding this problem will be the location and accessibility of the top-floor stairs; many times these stairs are located in somewhat unorthodox places, such as behind pocket doors and hallway closets.
The IC must also consider the construction methods and alterations that may exist in these areas. Older residential wood-frame dwellings were constructed utilizing Balloon Framing, where the wall joists run from the sill plate of the foundation all the way up to the top attic/void space. This allows for an unimpeded vertical shaft for fire extension. Newer wood frame structures have made changes that limit the vertical travel of products of combustion within the wall studs; however, many of these “starter castles” will have additional voids built in the structure that allow for vertical fire spread to these areas. Overhead spaces that traverse over multiple occupancies may or may not have inherent fire stops in place. Even in those with fire stops, utilities and other breaches between the walls will provide an avenue for heat and smoke to travel horizontally throughout the space, involving multiple structures.
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.
In the event the fire is in a much larger void space, such as a strip mall, multiple dwelling, or any other large building, it may be possible to utilize an Inverted Trench Cut to stop the fire. This can be advantageous for a few reasons; first, it takes less effort to pull ceilings from below than it takes to open up a three-foot trench the entire depth of the structure in a multi-layered roof assembly. Secondly, accessibility is much easier from the inside than to set up companies on the roof. Also, there may be a considerable amount of time that passes before a sufficient amount of personnel arrive to trench the roof. The inverted trench cut is performed in two steps. Operating under the assumption that conditions are such that the evolution can be done safely and from the most advantageous location, the best location to perform this cut is in a common area of the building, such as a hallway or other suitable space, which may provide a bit more structural stability. Pull the ceiling area along the wall closest to the advancing fire. This will provide the best protection for firefighters if there is a partial collapse of the roof assembly.
To make an inverted trench cut, first open up a three-foot section of ceiling along the wall in the hallway (or suitable space) closest to the advancing fire. This opening should be from wall to wall as much as possible. Second, position a 2½-inch handline in the hall to darken any advancing fire in the attic/void space area. The application of water on the underside of the roof area will slow or stop the fire and the spread of convection currents. This line should only be operated if fire is evident or imminent. This cut can be used on two sides of the spreading fire in an effort to squeeze off the extension and extinguish the fire.
Should the attic space become fully involved, the operation of large-caliber streams may be the only option; however, without a route to the underside of the roof assembly, this tactic may be ineffective, and may only result in additional water damage to the rest of the structure (photo 9). If the attic gets opened up, and the stream can get a good shot into the attic void, then the operation may be successful. If not, then the roof assemblies will most likely burn off, and the attack can be from above the fire.
Fires in attics and void spaces will be difficult to handle without proper coordination between ventilation and suppression forces. Underestimating the amount of energy that can be present during operations will tax even the most seasoned firefighters. Be sure to have the right resources on scene to mount the attack to ensure the best results for your personnel. Know your buildings; picture the hidden vertical and horizontal voids that travel through the building. If the fire gets hold of the voids and the attic, plan for early collapse and keep a safe distance.
Until next time, stay focused and stay safe.
MICHAEL P. DALEY is a lieutenant and training officer with the Monroe Township, NJ, Fire District No. 3, and is an instructor with the Middlesex County Fire Academy, where he is responsible for rescue training curriculum development. Mike has an extensive background in fire service operations and holds degrees in business management and public safety administration. Mike serves as a rescue officer with the New Jersey Urban Search and Rescue Task Force 1 and is a managing member for Fire Service Performance Concepts, a consultant group that provides assistance and support to fire departments with their training programs and course development. Mike has been guest on several Firehouse.com podcasts including:Successful Rescue Operations in Today's Fire Service, Preparing for Tomorrow's RIT Deployment Today and Basement Fire Tactics Roundtable podcasts. View all of Michael's articles and podcasts here. You can reach Michael by e-mail at: FSEducator@aol.com.