Fire Department Connections

September 6, 2023

Most buildings have a sprinkler system intended to activate in the event of a fire. While effective at reducing the size of a fire until the fire department can respond, more pressure is required to boost the system and completely extinguish the flames. This is done with the use of fire department connections.

world trade center

Dixon's stainless steel FDCs blend seamlessly with the glass and steel construction of 3 World Trade Center, an 80-story, LEED-certified Gold office tower that includes a major concentration of retail.

What are FDCs?

Fire department connections, abbreviated as FDCs, are a connection through which the fire department can provide supplemental water to a building's sprinkler and/or standpipe system. Fire departments can connect one or more hose lines to the FDC, and this is the only way to provide water to manual dry standpipe systems that are not connected to a permanent water supply. FDCs are a part of all fire sprinkler and standpipe systems following NFPA 14.

Components of FDCs

FDCs have several components. There is piping to the sprinkler system riser along with check valves and plugs. The check valves stop water backflow, and the plugs cover the inlet valve to prevent foreign materials from clogging the pipes. Alternatively, some FDCs have clappers that act as a check valve allowing hose lines to be disconnected during and after use. During use the clappers allow a second supply line to be connected, and afterward, they prevent all the water from dumping into the street.

figure 5.1.4(a)

NFPA 13E, Chapter 5, pg. 11

Types of FDCs

There are two main types of FDCs: exposed and concealed. Exposed FDCs are located on the outside wall of a building with the body, inlet, and swivels exposed for easy access. Exposed FDCs can also be freestanding, meaning they stand apart from a building and are connected through a buried pipe.

Concealed FDCs are installed flush with the wall of a building. The swivels are exposed while the body and outlets sit behind the wall concealed by an ID plate.

FDC Placement

FDCs must be properly placed to ensure maximum accessibility for firefighters. The requirements for the use and installation of FDCs are outlined in NFPA 13, 14, and 15. Ultimately, the authority having jurisdiction (AHJ) has the final say at the local level, but they should be on the street side of a building and easily recognizable and accessible. FDCs should be placed reasonably close to the nearest fire hydrant. To be specific, they should be no more than 100 feet from the fire hydrant, but not too close to prevent fire trucks from having clearance. In addition, fire trucks and hoses should not obstruct access to the building.

Required Signage

NFPA compliance requires signage to identify the system served by an FDC. The sign should state automatic sprinklers, standpipes, standpipe, and automatic sprinklers, or a test connection. In addition, the signs can also identify the specific part(s) of the building to which the system supplies, as well as indicate pressures that vary from the standard operating range.

Dixon offers round identification plates to help quickly identify the connection.

Dixon FDCs

Dixon Fire, located in Winchester, Virginia, manufactures and supplies a diverse line of fire protection products including valves, fire hose, racks, reels, nozzles, Storz and large diameter hose (LDH) suction hose fittings, and fire department connections. The type of fire department connections Dixon offers include exposed, concealed, and single inlet.

Exposed FDCs


Single Clapper
Back Outlet and Bottom Outlet


  • Provides the required 500 GPM minimum to supplement the fire protection as an auxiliary inlet connection to the water supply (250 GPM minimum per inlet) at 250 PSI


  • Single swing clapper with (2) pin lug swivel inlet
  • The swing clapper design provides an unobstructed waterway
  • Exposed FDCs provide an economical method of satisfying local fire codes


  • UL listed
  • ULC listed



Double Clapper
Back Outlet and Bottom Outlet

  • Provides the required 500 GPM minimum to supplement the fire protection as an auxiliary inlet connection to the water supply (250 GPM minimum per inlet) at 175 PSI


  • Exposed FDCs provide an economical method of satisfying local fire codes


  • UL listed
  • ULC listed
  • Factory Mutual approved

Triple Clapper
Back Outlet and Bottom Outlet


  • Supplies 750 GPM to supplement the fire protection (250 GPM minimum per inlet)


  • Branding options include AutoSprinkler, StandPipe, and no branding
  • Replacement swivels are available


  • Maximum operating pressure 175 PSI at 70°F (21°C)




  • Fire suppression, fire department connection, standpipe at 250 PSI working pressure


  • Stainless steel screen
  • Aluminum body
  • Storz seal


  • UL listed


Sidewalk Assemblies


  • The complete unit consists of: (1) 21-133 90° Siamese body, double clapper, (2) 17-127 pin lug plugs with chains, (1) 23-404 sleeve, (1) 24-405 escutcheon plate


  • UL listed
  • Factory Mutual approved

Concealed FDC




  • The unique design of clappers is fully reversible with a perpendicular trunnion allowing one body to be installed for top and bottom connections


  • Cast brass
  • Dual female inlets x female NPT thread outlet
  • Maximum operating pressure 250 PSI


Single Inlet
Residential Sprinkler Connection


  • A complete single inlet connection, exposed type for residential automatic sprinkler systems


  • (1) 17-127 1-1/2" pin lug with chain
  • (1) 24-209 4-7/16" O.D. round escutcheon plate, with swivel


Single Inlet Connections


  • Used for sprinkler systems that do not require a large amount of water to supply the system


  • Provides a complete exposed single-inlet connection
  • The complete unit consists of (1) 24-209 round plate branded Auto Sprinkler, (1) 23-270 double female or 09-215 male and female connection, (1) 17-127 pin lug plug with chain
  • Swivel end


  • Rigid hexagon end of either connection is 2-1/2" NPT


Stainless Steel FDCs

The NFPA requires a minimum fire department connection rating of 175 PSI. Most brass FDCs are currently rated up to 300 PSI, but that only gets water to about 50 stories with the assistance of pumper trucks. The solution is Dixon's FM-approved, 600 PSI, stainless steel FDC designed and manufactured in the USA.


  • Provides water up to 90 stories


  • Uniquely designed clappers are fully reversible with a perpendicular trunnion, allowing one body to be installed for top or bottom connections
  • Concealed unit mounts behind a wall plate; escutcheon sold separately for exposed installation
  • 100% tested

Since we manufacture several of these FDCs at our facility here in the U.S., we offer special threads, branding, and finishes. Contact us for part numbers, pricing, and availability.


Although often overlooked in the overall function of a building, FDCs play a critical role in the event of a fire. Thus, they should be properly selected and maintained according to NFPA requirements. Dixon offers a wide selection of FDCs to ensure you always have The Right Connection®. For more information, visit or call 877.963.4966.