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Riser Clamp Holding Plastic Pipe, Penetrating Through 2 Hour Fire Resistance Rated Concrete Floor Slab. The Copper Pipe Penetration Is Firestopped With Firestop Mortar.
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Riser clamp in use on a standpipe through-penetration firestop inside a fire hose cabinet that is under construction.

A Riser clamp is a device used by mechanical building trades to support vertical runs of piping at each floor level. The devices are placed around the pipe and integral fasteners are then tightened to clamp them onto the pipe. The friction between the pipe and riser transfers the weight of the pipe through the riser to the building structure. Risers are generally located at floor penetrations, particularly for continuous floor slabs such as concrete. They may also be located at some other interval as dictated by local building codes or at intermediate intervals to support plumbing which has been altered or repaired. Heavier piping types such as cast iron require more frequent support. Ordinarily, riser clamps are made of carbon steel and individually sized to fit certain pipe sizes. The term "riser" is typically used to refer to vertical runs of pipes, electrical conduit and tubes.