Editor’s note: For further reference, consult Building Construction for the Fire Service (BCFS3), Third Edition.
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(1) When describing row buildings such as town houses, we describe the units on either side of the fire unit as “exposures.” I believe that unless the units are separated by unpierced, parapetted masonry fire walls, the whole group should be considered and described as the fire building. The fire knows nothing of addresses or ownership. It simply understands where fuel is available. Note that in this town house, a wood stud bearing wall is adjacent to the unpierced fire wall. By contrast
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(2), note the horizontal black line. It is a steel beam supported on the fire wall in the same socket as its counterpart in the next unit. (The vertical black line is not a column but a drainpipe). This fire path will be concealed when the owners finish off their ceilings-a nasty surprise for the firefighters and the owners.
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(3) Note the mansards.
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(4) A look up into the mansards shows that the fire wall does not extend to the mansard, permitting the fire an end run around the wall.
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(5) This extension of the fire wall into the mansards was required by Howard Sommers, former Virginia state fire marshal.
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(6) The sheathing is gypsum board, but the plywood mansard extends around the building. Fire penetrating the ordinary wood window casings would spread around the building. Your attack position is at an angle to the flaming void, directing solid streams upward. Preplan to get ahead of the fire on both ends and “prewet” the structure.
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(7) Arrow indicates the protruding two-inch gypsum fire wall. This fire wall was exposed to rain and snow all winter. Is it dependable?
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.
