BY FRANCIS L. BRANNIGAN, SFPE (FELLOW)
President George Washington was ex officio mayor of the City of Washington, one of three cities in the 10-mile-square District of Columbia donated to the Federal Government by the states of Maryland and Virginia. About 1830 the Federal Government retroceded the Virginia portion to Virginia, and it became Arlington County.
As mayor of the city, President Washington was concerned about the spread of fire from wooden structure to wooden structure. He knew that a brick wall could help stop the spread of fire from building to building. He also knew that developers would be very unhappy about the cost, so he signed a law that said that side walls must be half built on the owner’s property and half on the adjacent property. When the adjacent owner built, he would be required to reimburse the wall builder for the cost of half the wall.
The requirement that half the wall was to be built on the neighboring property was unique. In fact, it applied only to the city of Washington, which at that time ended at what is now Florida Avenue. Today, the city is coterminous with the District of Columbia. When builders outside the city limits followed the rule, lawsuits ensued.
A party wall is structurally part of two buildings. It is usually a matter of contract between the adjoining owners; but in some jurisdictions, required fire walls may be permitted to serve as party walls. Thus, a party wall may or may not be a complete fire barrier.
(1) Two girders are installed in the same opening, providing the fire with a path through the firewall. (Photos by author.)
When girders (a beam that supports other beams) are inserted in the wall, it is most convenient to insert the girders of both buildings into the same opening. This provides a path for fire extension. Some codes require that the girders be offset one from another. This is not popular with builders, as it interferes with repetitive design. Know your local codes and practices.
When there are openings in firewalls, get units into the exposure immediately to catch any fire coming through. Ceilings should be opened to look for signs of fire spread; thermal imaging cameras, the firefighter’s radar, should be used. If the fire building is heavily involved and resources are limited, consider giving priority to the exposures.
“Fire Limits” is a term used in many municipal building codes to define an area within which the outer walls of structures must be of masonry. The idea, of course, is to assist the fire department in confining a fire to the building of origin. Some have fought the concept of fire limits, saying they are outdated since the buildings will be brick veneered and sprinklered. A serious hazard exists when a huge wooden building is under construction in a closely developed area. Preplans should recognize the conflagration hazard.
In Los Angeles, a wooden apartment house under construction burned. It severely damaged an adjacent senior residence, and embers started major fires over a wide area. It required the largest commitment of fire department resources for a structural fire in the city’s history, more than for the library or the First Interstate high-rise fire.
Recently, Richmond, Virginia, suffered a conflagration that started in a wooden college dormitory under construction and came to involve a large number of buildings. The previous chief, Jack McElfish, had made the department an all-quint operation, a step both praised and derided. The quints were most useful in getting water on the roofs of buildings attacked by flying embers. Even after completion, the building may still be a hazard. Typically, the sprinkler system would be a partial NFPA 13 D system, designed to prevent flashover in the occupied space before the tenants evacuate. Void spaces are not covered.1
In Solomons, Maryland, a mulch fire penetrated the exterior and entered the unsprinklered floor void of a five-story apartment house and spread rapidly throughout the building, unhampered by the sprinkler system. The building was destroyed.
When under construction, the big wooden buildings are prime targets for arsonists. It might be well to require the builder to provide a watchman service, although I am aware of one fire that started from a kerosene heater provided for the watchman’s comfort. At the very least, the police should be asked to give the building special attention.
(2) This would be described as a “brick building.”
(3) In fact, when we “undress it,” we see that it is a brick-veneered wooden building—a menace to the area when under construction and if a fire starts in or extends into the void spaces where the sprinklers cannot reach.
The builder should be impressed with the necessity for calling the fire department immediately if a fire occurs. Construction tradespeople using torches, such as plumbers, are prone to attempting to extinguish the fire themselves. In discussing the matter, it would not be out of line to point out that their failure to establish the “call the fire department procedure” will leave them in a very poor position when the insurance company subrogation experts start looking for reimbursement of the losses the company suffered as a result of fires caused by embers. A subrogation clause is included in all insurance policies. The policyholder assigns to the insurance company the right to sue anybody the policyholder might sue for negligence. The fire department plan should include a maximum commitment of available resources and a study of the area to determine a favorable point from which to make a stand against a spreading fire.
A freestanding firewall, independent of the building and unpierced, is the best protection. However, during construction and demolition or fire, it may become unstable and collapse.
At the U.S. Navy Yard in Norfolk, Virginia, a firewall in a warehouse containing millions of dollars of war reserve equipment collapsed because of poor foundations. We pressed for its replacement. A contract was let. Our inspector found that the ingenious contactor had erected a structure within the building to hold a drum of gasoline for gravity feed to the compressor feeding air to the jackhammers. The drum was removed. We set up procedures that included fire department participation in precontract information discussions and a daily inspection of all construction sites.
A similar setup for diesel fuel was a key factor in the disastrous multifatality fire on the carrier USS Constellation at the Brooklyn Navy Yard in 1960.
KNOW YOUR BUILDINGS, AND PLAN ACCORDINGLY.
1. See Building Construction for the Fire Service, Third Edition, 580.
FRANCIS L. BRANNIGAN, SFPE (Fellow), the recipient of Fire Engineering’s first Lifetime Achievement Award, has devoted more than half of his 63-year career to the safety of firefighters in building fires. He is well known as the author of Building Construction for the Fire Service, Third Edition (National Fire Protection Association, 1992) and for his lectures and videotapes. Brannigan is an editorial advisory board member of Fire Engineering.
Carbon Fiber Tensile Reinforcement
Do you have any knowledge of the use of carbon fibers to increase the load-carrying capacity of wooden beams? Please contact me at Fbrannigan@comcast.net.