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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This new window has been cut into an existing wall. No steel lintel was installed. The window frame is now a structural element supporting the brick wall. If the frame burns out, the bricks are hanging upside-down held only by mortar, which is a bedding agent without the necessary tensile strength. Once one brick falls, a major collapse may result. (BCFS3, 158)
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The building industry calls these cross braces firestopping. In fact, their purpose is to brace the stud (which is a column receiving compressive loads) at about midpoint, thus greatly increasing its load-carrying capacity. Their firestopping value is incidental-firestopping should cut off the wall voids from the floor voids. (BCFS3, 65)
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Note the wood stud bearing wall against the concrete block firewall. The code applicable to this building permits no penetration of the firewall. Other codes permit the firewall to be used structurally, thus providing fire penetrations. Know your buildings! (BCFS3, 234)
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For economy, apartment kitchens are built back-to-back. If the connection is not adequately firestopped (practically impossible), expect early extension of a kitchen fire to the next unit.
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A fire in one kitchen will be in the next kitchen by the time you arrive. Chapter 5 of BCFS3 contains a full discussion of the deficiencies in fire containment in garden apartments and similar commercial structures.
FRANCIS L. BRANNIGAN, SFPE (Fellow), the recipient of Fire Engineering’s first Lifetime Achievement Award, has devoted more than half of his 59-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.
