Building Construction: Warning Signs For Firefighters

Every day, firefighters across this country respond to structure fires. Sadly, many of them don't fully understand the problem to which they are responding. Photo by Michael L. Smith These old buildings differ in height but are...


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Every day, firefighters across this country respond to structure fires. Sadly, many of them don't fully understand the problem to which they are responding.

5_01_building1.jpg
Photo by Michael L. Smith
These old buildings differ in height but are commonly located in most main streets of America.

Many have been instructed to fight a fire by pulling a certain line, taking it to the seat of the fire and applying water. In certain books you will read that a 1 1/2-inch line will put out 1,200 square feet of fire when properly applied. That may be true for a class B spill on the tarmac, but we deal in cubic feet of fire.

Some people will contend that the time span for trusses to fail (collapse) when exposed to flame impingement ranges from three to 10 minutes. That may also be true, but to me a more important fact is that you can no longer determine from the outside of a building how it was constructed because more builders are constructing a structure to mimic another type.

The following article provides basic cues to help you identify the type of construction you are facing. It will also give some strategic and tactical considerations.

The facets of buildings and their construction should always be the topic for drills for all, from the new firefighter to the most experienced chief, because every day the building industry is striving to build them cheaper and quicker.

Ordinary Construction

In many parts of the country there are stretches of buildings with parapet walls (unsupported masonry above the roof line), intricate cornices and elaborate masonry work with arches on the exterior walls, and these buildings are joined together to form rows.

Inhabitants of cities and towns 100 years ago grew tired of rebuilding their communities every time there was a fire. The old-style wood-frame row buildings contributed to the conflagrations, and people wanted an alternative. The builders gave them a structure with a row configuration. The structures had multiple wythe vertical masonry walls with horizontal wooden members (serving as floor joists) embedded in the masonry. The front and rear walls are non-bearing.

The buildings usually are 12 to 20 feet wide and can be up to 100 feet long. The structures can be three or more floors, although I have seen buildings like these 10 stories tall and 150 feet wide. The wood floors are embedded into the vertical masonry at the side walls only; the intermediate connections are often found to be cast iron columns. The elaborate front facades were the outlets for the creativity of the builders, who created intricate patterns of masonry using brick or stone, often using arches over windows and doors. The cornices (horizontal projections at the roof line) were made of metal, masonry or wood.

The roofs of these buildings are usually flat and most contain skylights and penthouses for roof access. The framing for the roofs runs front to back to provide the pitch needed for rain control. The cockloft (the area between the ceiling of the top floor and the underside of the roof) is framed similar to the floor assemblies. The common use for these structures calls for a firewall to extend up through the roofline. Builders used mansard framing or some other trick to create a more aesthetically pleasing roofline. Many end units of the row have turrets or domes, or both. It is similar to the wooden framing of townhouses today.

By design a fire can occur in one of these buildings and be severe, but the fire will be contained within the building of origin by the masonry walls that form impervious barriers. However, if there is a common roof, all of the buildings in the row are in jeopardy, but this is more of an anomaly than a standard. These buildings can contain mercantile, residential or industrial tenants or a combination of any of these known as a "taxpayer." A taxpayer has a commercial venture on the first floor and renters, or "taxpayers," on the upper floors.

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