Fire Department Connection (FDC) caps or plugs are used to cover the inlets on an FDC, which is the fitting that your fire department uses to connect their fire hose(s) when on-scene at a fire. They can be located both inside and outside a building, and are used to provide delivery of water to the fire via either a sprinkler or fire hose. If your building is equipped with these connections they have to be covered to prevent debris accumulated inside the inlet from impeding the delivery of the water, while still providing the easiest possible access for the fire department.
FDC without covers – Notice the crayon and other junk inside?
As demonstrated by the image above, when an FDC inlet is not covered it is prone to collecting junk. In a fire emergency, the fire department will connect hose between a pumper truck full of fire-impeding water and the FDC and actually pump water into the building, supplementing the building’s water supply and pressurizing the sprinkler or standpipe system. If debris is inside the FDC inlet and the water is pumped in, that junk ultimately moves its way through the system and can disrupt a sprinkler’s operation.
FDC inlets properly protected by aluminum FDC caps
Are all FDC covers the same? No, they differ in size and type of material. FDC covers come in two main styles, commonly referred to as breakable caps or plug and chain. The plug style cover requires the use of a wrench to remove, while the FDC breakable caps are designed to be removed by breaking the caps, usually with the butt of a fireman’s ax. Since FDC fittings are female threaded, as called for in NFPA 13, FDC plugs are designed to fit those threads. Always check with your local fire department or inspector to be sure your FDC connections will match up with their equipment. FDC caps, in comparison, use eye-bolts to connect to the FDC inlet’s swivel as demonstrated in the image above.
The materials used in these covers include brass, aluminum and plastic. Plugs are almost always made of brass though recently aluminum alternatives have been introduced into the market. Plastic FDC caps are the most common and the least likely to be stolen by thieves looking for recyclable metals, a phenomenon that has increased due to the recent recession. Their lower cost also makes keeping a few on hand in case of damage or theft a cost-effective addition to building safety.