BY FRANCIS L. BRANNIGAN,SFPE (FELLOW)
Editor’s note: For further reference, consult Building Construction for the Fire Service (BCFS3), Third Edition. Page numbers, where applicable, are included after the caption.
This looks like an excellent exit, open to the atmosphere. However, it could collapse very early in the fire. The builder was allowed to use a continuous wood truss across the stairway landing to the opposite apartment. An untested piece of gypsum board “stops” a fire in the truss void in an apartment from spreading to the stairway void. This void is an ideal path for a cable from one side to the other. In your experience, will the hole broken into the already inadequate gypsum board be closed tightly? (See the sketch in BCFS3, 544-546)
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This single line of studs in an interior bearing wall is supporting the floor joists above. Fire damage to this wall can cause interior collapse. Look at buildings under construction. Removing part of such a wall in renovation sets up a collapse hazard. (BCFS3, 169)
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This “undress the building” view shows interior voids interconnected by piping chases to make one big void through which fire moves freely. Think piercing nozzles. Pulling ceiling allows in air, which can spread fire beyond the reach of hose streams. In the concern about collapse, the fact that a “truss loft” is created in every floor void is often overlooked. (BCFS3, 542-543)
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I was at this stable fire in 1938. The skylights were off, and there was horizontal ventilation, but there was a three-foot-deep cockloft. An hour and a half into the fire, heavy smoke caused a knowledgeable buff to exclaim, “This thing is going to blow!” In about a minute, there was a great explosion. A falling wall killed a fire officer and injured others. The review board (not on the scene at the time) determined that there was no explosion; the wall simply fell, a known hazard of firefighting. There is a myth that backdrafts will occur only early in a fire. This is just not true. (BCFS3, 422)
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.
