The FDC: What Does it Stand for and What Does it Do?

Posted May 28, 2020 by Koorsen Fire & Security

fire department connection

FDC stands for Fire Department Connection. It is part of a fire sprinkler system or standpipe system.

Though easily overlooked by most, the FDC’s role in ensuring the effectiveness and success of a fire sprinkler system to suppress a fire is pivotal.

What is a Fire Department Connection and What Does it Do?

A fire department connection is an inlet and pipe system that enables a responding fire department to supplement a fire sprinkler system’s water supply.

In the event of a fire, the emergency responders can connect a hose line from their pumper truck to the FDC and pump additional water into the fire sprinkler system to ensure sufficient water and pressure to suppress the fire in the building effectively.

The FDC is not intended to provide a specific amount of water, nor to provide the sprinkler system’s full demand. Fire sprinkler systems that are designed to be NFPA 13 compliant typically get their water from the facility’s domestic water supply.

However, supplementation from a pumper truck via the FDC will help ensure a sufficient supply and will also act as a backup in the instance that:

  • The domestic water supply delivers an inadequate amount of water

  • A valve is erroneously closed between the domestic water supply and the sprinkler system preventing water from reaching the system during a fire

  • A change to the facility’s occupancy since the fire sprinkler was installed poses a more significant hazard than the original sprinkler system was designed to handle

In any of the above scenarios, the availability and use of the FDC can make the difference between a successfully suppressed fire that does little damage and a total loss of the facility.

FDCs are required for all fire sprinkler systems and standpipe systems (the pipes which enable firefighters to connect and use their hoses within a structure) according to NFPA 13 and NFPA 14.

Where Would an FDC be Located?  

Fire department connections are usually located on the outside of the building they protect. Though some FDCs are placed apart from the building. FDCs that are placed away from the structure they protect are called freestanding or sidewalk FDCs.

According to NFPA 13, the FDC should be located on the street side of a facility. It is not uncommon for state and/or local jurisdictions to further require that the connection be located on the building’s address side.

However, this placement is not possible with all buildings, such as shopping centers or malls. In these instances, the local AHJ and governing officials will need to be involved during the development and construction processes to ensure the best location of the FDC.

Regardless of its location, the FDC must also be marked by a sign that indicates what type of system it supplies (fire sprinkler system or standpipe), the necessary water pressure required by the FDC, and whether it only supplies a portion of the building complex.

FDC Components and Operation

Most fire department connections are pipes protruding from the side of a building in a Y shape. This is commonly known as the Siamese valve or inlet body. The Y portion of the valve is composed of two, swiveling female fittings that are 2.5 inches in diameter and is the only visible component of the FDC.

The inlet valve connects to a pipe called the outlet that runs behind the wall. This pipe is typically 4 or 6 inches in diameter and is the part of the fire department connection that links up with the sprinkler system riser or main.

In addition to the inlet body (on the exterior of the wall) and the outlet piping, an FDC also has a check valve, which prevents water backflow, and caps or plugs that cover the inlet valves to prevent debris from clogging the pipes.  

According to NFPA 13, the FDC should be installed on the fire sprinkler system’s side of its water supply check valve.

When responding to a fire, firefighters hook the female end of their hose to a pumper truck and connect the male end of the hose to one of the FDC’s female swivel connections. The water then flows through the Siamese inlet valve into the outlet pipe on the inside of the wall and onto the fire sprinkler main, supplementing the system’s water supply.

FDC Inspection and Service Requirements

As with other fire protection systems, the NFPA does require some regular maintenance and testing of the FDC.

First, NFPA 13 recommends that the piping connecting the exterior FDC and its check valve should be hydrostatically tested just as the balance of the system is tested. This testing ensures proper installation of the piping to prevent leaking or bursting.

The NFPA also recommends that the FDC be flushed every five years to ensure that it is free of materials and blockages that could prevent water from reaching the sprinkler system.

In addition to the above servicing steps, the NFPA also has the following requirements that the FDC:

  • Must undergo quarterly inspections
  • Be accessible and visible
  • Swivels or couplings must be able to rotate smoothly and be free of damage
  • Caps/plugs must be properly installed and undamaged
  • Identification signs must be correctly placed and readable
  • Check valves must be operational and free of leaks
  • Automatic drain valve is correctly placed and operating properly

The above quarterly inspections and requirements can be performed by the building owner or a designated individual.

Choosing and Caring for Your FDC

Because the fire department connection is so far removed from the purpose and operations of those within the building, it can be very easily overlooked. However, the difference an effectively operating and properly maintained FDC can make in the event of a fire can be huge.

As with all things, there are a host of options for the types of FDCs you could choose, as well as a variety of component options and placement. Between that and the host of both federal and local codes and requirements, it can be overwhelming to determine the best FDC options for your facility and to properly maintain it and keep it up to code.

Working with a fire protection agency like Koorsen Fire & Security, which has over 70 years in the business and is an industry leader, will go a long way in answering your questions and ensuring the best protection for your building and your people.

Give the experts at Koorsen a call today.

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Topics: General, Fire Sprinkler Systems

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Disclaimer: The information in this article is for informational purposes only. It is believed to be reliable, but Koorsen Fire & Security assumes no responsibility or liability for any errors or omissions in the content of this article. It does not constitute professional advice. The user of this article or the product(s) is responsible for verifying the information's accuracy from all available sources, including the product manufacturer. The authority having jurisdiction should be contacted for code interpretations.