Article and photos by Gregory Havel
Fire-rated wall assemblies are built to separate building areas with higher hazards from those with lower hazards, to separate people from hazards and storage areas, to divide a building into smaller areas to slow the spread of fire, and to help confine fire to the area of origin.
Fire-rated door and frame assemblies are used in fire-rated walls. Fire-rated dampers are used in ducts that pass through fire-rated walls. Openings in these walls for pipes and cables must also be protected.
Photo 1 (below) shows a pipe and an electrical conduit that penetrate this two-hour-rated wall. The space between the concrete block and pipe or conduit has been stuffed with the proper brand and weight of mineral wool insulation from both sides of the wall, and covered with a "fire-caulk" (heat and flame-resistant) material on both sides of the wall. This brand of fire caulk is red, applied in the proper thickness, and laps over the proper distance onto both the concrete block wall and the pipe or conduit. Most paints will not stick well to many brands of fire caulk. Also visible at the left is the flange of a fire damper box for a duct that also passes through the wall. None of these details will be visible once the suspended ceiling tiles are installed. Similar fire-resistive systems have been designed and tested for use on fire division walls of other materials, as concrete and gypsum drywall board. See Underwriters Laboratories' Online Certifications Directory at www.ul.com for details on this and other systems to protect penetrations of fire-rated wall, floor, and ceiling assemblies
Photo 2 shows numerous pipes and sleeves (at lower left, for data and communication cables to pass through the wall) that have been properly insulated and fire-caulked.
To the right of center is a pipe passing through the wall that was not part of the original design. The workers were in a hurry and simply hammered a hole through the wall. This hole will be patched with masonry, mineral wool insulation, and fire-caulk before it will be acceptable to the building inspector in this city.
Unfortunately, both in the past and at present, unprotected openings like this one are sometimes missed by inspectors (or added by building occupants years later, without permits or inspectors). After the suspended ceiling tiles are installed, this type of defect will be invisible until discovered during a major renovation project, or by firefighters who open the ceiling on the "cold" side of a fire division wall while trying to contain a fire.
Any brands or brand names noted above are used only as examples, and the Web sites only as sources of additional information. Reference to them is not an endorsement of either product or manufacturer.
Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired deputy chief and training officer; and a 30-year veteran of the fire service. He is a Wisconsin-certified fire instructor II and fire officer II, an adjunct instructor in fire service programs at Gateway Technical College, and safety director for Scherrer Construction Co., Inc. Havel has a bachelor's degree from St. Norbert College and has more than 30 years of experience in facilities management and building construction.