BY FRANCIS L. BRANNIGAN,SFPE (FELLOW)
EDITOR’S NOTE: For further reference, consult Building Construction for the Fire Service, Third Edition (BCFS3). Page numbers, where applicable, are included after the caption.
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A balloon frame was invented to enable unskilled workers to erect a building, replacing the skilled craftsmen who built heavy-post, sand-frame buildings. Heavy timber proponents called them “balloon,” alleging they would blow away in a wind. As seen here, balloon frame provides one big interconnected void from the basement to the attic with crossovers through the floor voids. (BCFS3, 96-100)
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This fire was set with a few sheets of newspaper stuffed in the wall cavity. The fire developed rapidly. Bear in mind that the wood in the void has been dry for possibly a hundred years.
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If there is fire in the voids, you might try the technique of not opening the interior walls. Open the outside wall instead to hit the fire.
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George Washington (ex officio mayor of Washington, D.C.) invented the tradeoff. To provide fire barriers, a builder who built a brick party wall (half on each lot) would be reimbursed for half the cost of the wall by the person who built the adjacent building. Floor joists of each building were fitted into the same opening. Fire spread through such openings is subtle. Often, the exposure is well involved before the problem is discovered. (BCFS3, 197-199, 233-234)
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One of these row houses was rehabilitated to an expensive townhouse. However, like Siamese twins, they are bound together by floor joists set in a common opening.
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That was then. This is now, but not necessarily better. Note the recently built joists in a common opening in a fire wall.
FRANCIS L. BRANNIGAN, SFPE (Fellow), recipient of Fire Engineering’s first Lifetime Achievement Award, has devoted more than half of his 57-year career to the safety of firefighters in building fires. He is well known for his lectures and videotapes and as the author of 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.
