BY BY JAMIE C. MORELOCK
Rising concern about heating costs nationwide has led property owners to search for ways to reduce their monthly heating bills. Cellulose insulation is one of the quickest, easiest, and cheapest ways to accomplish this goal, by increasing insulation in the structure. Installation requires a blower unit, a hose, and bags of cellulose. All can be picked up at most local home centers.
What is cellulose insulation? In simple terms, it is finely ground, recycled newspaper with a chemical additive to make it “fire resistant.” When installed properly, cellulose presents no more of a fire hazard than any other insulating product. However, with the “do-it-yourself” trend and inexperienced contractors trying to make a fast dollar, my fire department has seen a large number of attic fires caused by improper cellulose-insulating techniques.
(1) Open up all adjacent bays to check for extension. (Photos by author.)
Attic fires involving cellulose require different overhaul tactics than the routine attic fire. Most cellulose fires start when the insulation is applied around a heat source that requires open air space to dissipate heat. Normally, chimneys, canister lights, and old wiring (such as knob and tube) are the biggest culprits. Heat builds in the insulation and starts a smoldering fire. The smoldering fire works a snake-like pattern through the insulation in multiple directions until it reaches an unprotected combustible, like a structural wood member. Here, it continues to smolder until the fire is exposed to sufficient air to support free burning. Building occupants often mention smelling a burning odor for hours and even days before the fire has broken out. Next time you respond to an odor of smoke call, be sure to check for the presence of cellulose insulation.
Once the main body of fire has been extinguished, start the overhaul process by deploying salvage covers. Salvage covers should be used in case a firefighter accidentally steps down through the ceiling. The covers should be deployed to protect the contents and floor coverings in any rooms over which you will be working. If your department does not have sufficient covers to protect multiple rooms, move the covers from room to room. Work only in the attic areas directly above the rooms that are protected by covers. Avoid using positive-pressure fans when cellulose is involved. First, it causes the smoldering fires to travel faster; second, it creates an extreme amount of airborne insulation particles, which can cause a “flash” fire or possibly a dust explosion. As in all overhaul operations, proper protective clothing and SCBA must be worn.
Expect overhaul to take several hours because of the extra work that will be involved to ensure complete fire extinguishment. This can be accomplished only by removing all of the insulation around any area that has been “touched” by flames. This may be an entire attic full of insulation.
A DIFFERENT APPROACH
Let’s look at a different approach to removing the insulation. If the living areas of the structure have not been affected by the fire other than by light smoke and minor water damage, do not pull the ceilings. Instead, remove sections of the roof decking for access to overhaul the attic space. Use a power saw to remove the decking in the same fashion that you would when performing normal ventilation. However, you are not venting for fire, so take the extra time to carefully and neatly cut the roof. If the roof pitch is too steep to operate on or is unsafe because of fire damage or weather conditions, work from an aerial device or cut a “door” into a gable end of the attic space. Working through the roof prevents large amounts of dust from spreading throughout the structure. It will also be less expensive for the building owner to repair. When the decking is removed, it facilitates a cooler atmosphere, allows more room for firefighters to work, and may be the only way to reach some areas.
(2) Older-style wire requires an air space to dissipate heat.
The roof cut should start out as a four-foot by eight-foot opening and be expanded as necessary. If experience tells you that it is safe, you can remove one or two rafters to facilitate debris removal. Never cut or remove any component of a truss system; doing so may cause collapse of the roof assembly. Trusses do not need to be removed, since they are normally spaced wider than rafters.
(3) Smoldering cellulose insulation can cause severe structural damage.
Some attics have wood floors for storage purposes. Remove this flooring to expose the insulation. After removing the attic contents, one of the easiest ways to remove the flooring is to cut it into manageable lengths with a power saw. Only experienced saw operators should be allowed to perform this function, since it is critical not to cut into any of the ceiling joists. If there is no flooring or after it has been removed, inspect the ceiling joists for damage. Smoldering fires can burn completely through a joist. Also, any joist that has been involved in the fire should be checked for possible smoldering between the joist and the ceiling. Use extreme caution whenever negotiating ceiling joists, and always make sure of what you are stepping onto before putting your weight down.
REMOVING THE INSULATION
After the roof opening is complete, the tools of choice are the flat shovel, a five-gallon pail, and debris bags. A firefighter chain is the most efficient method for removing the insulation. This reduces fatigue, speeds operations, and decreases the chances of breaching the ceiling into the living areas. The safest way to perform the chain is to have firefighters lie across several joists or use a section of the roof decking, distributed over several joists, as a work platform.
Avoid trying to balance yourself on the ceiling joists. Passing debris from one person to another could cause a loss of balance that could result in a breach of the ceiling or, even worse, an injury.
(4) Smoldering cellulose insulation can breach structural components and enter other void spaces, like the top plate of this wall.
Pile the debris on the ground several feet from the structure. Position a hoseline so that the materials can be wet down frequently. When removing insulation, work in a systematic pattern, focusing on one area at a time. The easiest way to remove the insulation is to place the shovel flat on the ceiling and scrape the insulation onto the shovel with a gloved hand. A similar method would be to lay the pail on its side between the joists and scrape the insulation into it with a gloved hand. Remove all of the burned insulation from each area, and then remove an additional one to three feet of material to ensure there was no further fire extension.
A thermal imaging camera is a useful tool when overhauling cellulose insulation fires. The large roof opening allows the attic area to cool quickly, making a camera very effective. Using a camera can reduce the time it takes to locate hidden pockets of fire still smoldering. If using a camera, scan the entire area, and then physically inspect each suspect area. When overhaul is complete, make one final scan of the entire attic.
PROTECTING THE STRUCTURE
With overhaul completed, the roof opening should be covered. Depending on the time of day, the building owner may want to contact a contractor to secure the building. Other options would be to cover the opening with heavy-weight tar paper or inexpensive poly tarps, or you could lend a salvage cover to the owner. Consider the weather when selecting a covering. Regardless of which method you choose, be sure to adequately secure the covering to the roof surface.
Also, consider obtaining permission for a fire company to return several hours later to quickly, but thoroughly, recheck the attic area.
Attic fires involving cellulose insulation can be labor and time intensive, but a thorough overhaul can ensure that the job will be done right the first time. ■
■ JAMIE C. MORELOCK is a firefighter with the Fremont (OH) Fire Department. An Ohio-certified instructor, he teaches fire tactics in Bowling Green State University’s continuing education program and engine and ladder company operations for Vanguard-Sentinel Career Center in Fremont.