Joist Hangers with Steel Joists

Another method uses an option that formerly was limited to wood framing: the use of sheet-metal joist hangers to support steel joists from other steel joists or girders, as shown in photo 2.

(1)

(2)

The joist hanger manufacturers advertise that these hangers have the approval of one or more of the model building codes and of some of the state codes for the type of structure shown in photo 2. The joist hangers for supporting cold-formed steel joists are listed by the manufacturers with different model and approval numbers from the hangers for sawn lumber or manufactured wood joists. In this application, the joist hangers can be attached with welds, self-drilling screws, or steel pins driven by powder charges or compressed air.

However, since the cold-formed steel joist has dimensions similar to those for sawn lumber and manufactured wood components, it is possible that a hanger for lumber or manufactured wood could be substituted for supporting steel joists and that structural strength could be compromised. 

Since steel-stud and steel-joist construction have been tested and approved for use as the framing inside fire-rated wall and floor-ceiling assemblies by Underwriters Laboratories (UL®), FM Global (FM®), and other independent testing agencies, it is possible that we already have in our response areas fire-rated wall assemblies attached to fire-rated floor-ceiling assemblies using this type of connection. Even though the connection is usually considered to be the weak point in construction, it should perform acceptably under fire conditions as long as the fire and products of combustion are outside and not inside the assembly.

For more information on this connection method from manufacturers, trade associations, and code developers, conduct an Internet search for “steel joist hangers” and search specific Web sites for “steel to steel joist hangers.”

Download a printable PDF version of this article HERE.

Gregory Havel is a member of the Town of Burlington (WI) Fire Department; retired as deputy chief and training officer; and is 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; has more than 30 years of experience in facilities management and building construction; and has presented classes at FDIC.  

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Subjects: Building construction for firefighters