My initial column in the June 2010 issue began a discussion about buildings called "mixed multiple occupancies," or "taxpayers," as they are known in some places. We noted that they have plenty of internal void spaces, which means a fire can travel quickly beyond its room or area of origin. With...
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Wood-frame construction using balloon-framing methods.
My initial column in the June 2010 issue began a discussion about buildings called "mixed multiple occupancies," or "taxpayers," as they are known in some places. We noted that they have plenty of internal void spaces, which means a fire can travel quickly beyond its room or area of origin. With that in mind, the potential is great for a tough firefight and an extreme life-safety problem when the building is occupied. Basic engine and truck work is the order of the day. Fire departments confronted with a working fire in a mixed multiple occupancy must perform their duties in a methodical manner with coordination and communication.
• Construction — Most of these structures were built of Type V wood-frame construction methods in the late 1800s or early 1900s. Everything used to build them is made of wood or other combustible materials. This also means there will be balloon framing in place — expect plenty of void spaces for fire to travel in. Exterior walls for wood-frame buildings may be covered with wood, aluminum or vinyl siding or even old asphalt shingles.
Many other mixed multiple structures were built using Type III "brick-and-joist" methods. This means the outer walls are of masonry construction. Floor joists that support each floor rest on an exterior wall shelf while the other end of the joist spans the distance to the other side of the building. In wider buildings, floor joists span from the exterior walls inward to a girder supported by a column or a bearing wall in the middle of the structure. A joist from the opposite exterior wall spans inward the same way. The joist ends meet at a common support beam, hence the term "brick-and-joist" construction. (Note: In many Type III buildings, the joist ends have been built into the outer walls creating a joist "pocket." This condition creates a very unstable wall if there is any movement in a joist or where a joist may rotate or give way, as the other end of the joist moving will destroy the masonry wall at the connection area and cause collapse. Also, this type of construction creates both vertical and horizontal void spaces like balloon-framing.)
• Apartment layouts — Usually, access to an apartment is through an ordinary entry door from a common hallway. The apartment areas generally have room enough for a small family; however, there is no guarantee about how many people may be living in one unit!
Once inside an apartment, a single unit can have a kitchen-dining area, a single full bath, two bedrooms and a living room. As you pass through the kitchen-dining area, the bathroom and bedrooms will be to the other side of the suite. There will likely be a living room at the end of the rooms. There may also be a narrow hallway that separates the living room from the bedrooms. In heavy smoke, this will create a maze-like problem for firefighters trying to conduct a search operation. There may be only one suite or as many as four units per floor.
In general, there can be several different floor layouts. There may even be a front entry door at street level leading up to an apartment over the store. In any case, firefighters should expect a confusing situation in heavy smoke and heat conditions.
• Inside the mixed multiple — Interior walls will be plaster over wooden lath strips. In many buildings, remodeling has seen sheetrock or drywall placed over old walls, but in some cases, the old plaster and lath has been removed and replaced with drywall. Some remodeling has seen new walls covering over the old walls, creating double wall cavities. (A note of caution: In some remodeled structures, polycarbonate-coated drywall has been used to prevent wall damage. This is a problem for forcible entry because of its resistance to damage. This can create an operating hazard to firefighters who may have to perform a survival move such as opening a wall to get through to a safe area. Firefighters using forcible entry tools during drills have found this wall nearly impossible to break through, a situation made much worse under a stressful fire condition.)
Ceilings in apartments above the main floor are usually eight feet high and made from plaster and lath, unless they have been altered. They can be handled the same as ceilings in a house would be. In some instances, top-floor ceilings have an attic floor above them. In the case of flat-roofed structures, that space above is a "cockloft" — the open space between the top-floor ceiling and the under-side of the flat roof deck.
Original ceilings in the first floor or store area are of plaster and lath or they may be made of impressed tin. Tin ceilings are nailed directly to the underside of the floor joists to the floor above. Sometimes, furring strips are attached to the joists first, then the tin panels are attached to them. In either case, this creates a horizontal void space for fire to travel through.
Ceilings in these areas are going to be higher, maybe 10 or 12 feet high from the floor. In many cases, owners or occupants have installed suspended ceilings below the original one. In any event, firefighters will need longer hooks to reach the original ceilings during overhaul operations. If drywall has been placed over old ceilings, it will be extremely labor intensive to open during fire attack and overhaul. If any fire is detected in a ceiling space, firefighters must get above that location quickly to determine whether fire has made it beyond the ceiling space. A good tactical consideration is to send a hoseline to investigate.
• Floors — Floors will most likely be of wood. In first-floor business areas, wood floors are heavy because there are sub-floors over the floor joists and finish tongue-and-groove planking of at least two inches thick laid on top. These buildings were designed and built to support the weight for a specific kind of occupancy back in their time. It was determined then that wood floors were the material of choice to support the loads of meat counters, coolers, shelving and stock. Many stores had or have linoleum covering or other material added over time.
Floors found in upper floor apartments will most likely be sub-floors over joists and perhaps a lighter weight wood floor. In some cases, hardwood floors are found. Today, you may find carpeting over a hardwood floor. If this floor must be "opened up" during fire operations, it may be preferable to cut away the carpet first, then use a power saw or other tool to complete the opening.
Concrete floors have also been used in these structures, but in older buildings they were not installed originally. Some buildings have had terrazzo-style finishes added. In any case, an unplanned-for floor load creates a serious concern, especially if no additional support has been added to carry the weight.
A serious operating concern comes from basement fires, because of their location, especially if a gas meter is involved. Add any stock or other combustible materials stored there and you have a recipe for a very well-fueled fire that will create a dangerous, smoky condition. This may lead to weakened flooring. Also, there probably will not be any fire suppression system down there to help you!
• Roofs — Roofs to typical "mom-and-pop" buildings will usually be of two types — peaked or flat. Peaked roofs sit over attic spaces. In some buildings the attics are unfinished and unoccupied, but in others the attic is a tall space designed for apartment use and presents another floor level.
A peaked roof is made from wooden structural pieces perhaps as small as two by four inches. There should be a ridge board to tie all the rafter ends together or unify them. However, in some cases there is no ridge board — the ends of the rafters abut each other, thus making a very unstable roof condition, especially if fire involves the attic space. The roof sheeting boards will likely be one-by-six-inch sheeting boards with an air space between them.
In many older roofs this method or style was finished with cedar shingles. Over time, as roofs began to leak and fail, the original roofs have been left in place and covered with asphalt shingles — sometimes on a few occasions. You may see a heavier-than-expected roof covering system. This is, or should be, a concern to firefighters if there is an appreciable amount of fire in the attic space. Flames in an unfinished attic will quickly penetrate roof boards and burrow into cedar shingles and into asphalt shingles.
The other common roof style is the flat roof. It creates the space between the top floor ceiling and the underside of the roof deck and is known as the "cockloft." It provides an easily accessible horizontal space for fire to access. If the roof is not opened up early, flames will spread over the top of the building and destroy it.
These roofs may have a little pitch to shed rain, but they are susceptible to environmental damage, especially rain and snow. Sometimes, a new "rain roof" or "inverted roof" is laid over the original roof. Whatever repair work that takes place does not take away from the fact that the original flat roof is still there and spans the entire top floor of the structure.
If it is necessary to open the roof for ventilation or to channel fire out of the structure, it is preferable for firefighters to access the roof with ladders for safety. Ladder or platform trucks on the scene should have priority positioning on the fireground so their ladders or buckets can be used. If ground ladders are to be used, check the roof pitch for a safe operating angle.
Buildings with flat roofs have parapet walls. Firefighters, remember that a parapet wall is a free-standing wall above the roof line. These walls have a bad history of collapse!
JEFF SHUPE has been a firefighter for the Cleveland, OH, Fire Department since 1981. He also serves as an acting lieutenant and a fire training instructor. In addition, Shupe is an Ohio Fire Academy field training officer and was the developer and lead instructor for the Cleveland Fire Department's "Back to Basics" program. He has an associate of applied science degree in fire technology from Cuyahoga Community College and holds State of Ohio certifications as a Hazardous Materials Technician, Emergency Medical Technician and Firefighter Instructor. Shupe was Cleveland's "Firefighter of the Year" in 2007.