PREPLANNING BUILDING HAZARDS
BY FRANCIS L. BRANNIGAN, SFPE
Editor`s note: For further reference, consult Building Construction for the Fire Service, Third Edition. Page numbers are included after each caption for your convenience.
(Top) This building, on New York`s Houston Street, presents many indications of possible collapse in a fire. I believe that tactically it should be attacked on the initial response with identified collapse zones and flanking location of streams as shown in FDNY Deputy Chief Vincent Dunn`s videotape Wall Collapse.1
This is a combination of two buildings facing on two streets. The right-hand building apparently started as a very early New York “Knickerbocker” building with the roof sloping sharply downward to the street. At some point, the roof was raised in the front to give a complete top floor. The left-hand building was probably built later. Note the different color bricks where the buildings join. Joining two brick walls is rarely successful due to differences in the brick and mortar in reaction to weather.
Note the many star-shaped spreaders on the wall, indicating the wall has been tied up to the floor structure for stability. The heavy cooling tower on the roof obviously was an addition; note the two vertical channel steel sections bracing the wall against the added load.
In the 1870s, a fatal collapse occurred in New York City when a water tank supported on interior columns collapsed. The code was changed to require subsequent tanks to be located on exterior masonry walls. Since the water tank seen is on interior columns, we know the building is about 120 years old. Very probably, it is of water-soluble sand lime mortar.
(Middle) An interior inspection might show wooden lintels (a beam over an opening in a wall) similar to those found in this Annapolis, Maryland, building. The burnout of the wooden lintel can precipitate a collapse. (Ref. p. 158)
Look carefully at the top of the slide. Note that the wooden floor beams rest on a wooden leveling beam inserted into the wall to provide a level surface for setting floor beams. If such a beam burns out, a “Plane of Weakness,” like the score on a sheet of gypsum board, will result, and the wall will crack in a horizontal line. (Ref. p. 164)
(Bottom) Check the gas service in apartments. The meters are grouped together for convenience in reading the meters. A separate gas line leads to each stove. Grouped together, the lines are a heavy load. The support is often poor and can and has failed in a fire. In a Silver Spring, Maryland, fire, the entire 20 gas lines fell–fortunately ahead of, rather than behind, units advancing lines down the narrow corridor. Some gas lines broke, increasing the body of fire that could not safely be extinguished before the gas supply was cut off. (Ref. p. 221)
References
1. Dunn, Vincent. “Wall Collapse,” Fire Engineering Books & Videos, 1988.
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FRANCIS L. BRANNIGAN, SFPE, a 52-year veteran of the fire service, began his fire service career as a naval firefighting officer in World War II. He`s best known for his seminars and writing on firefighter safety and for his book Building Construction for the Fire Service, Third Edition, published by the National Fire Protection Association. Brannigan is an editorial advisory board member of Fire Engineering.
