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+Jason Hugo

#28 - FDC Caps or Plugs | What Are My Options?

Posted by on 10/29/2013 to Fire Sprinkler System Components
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
FDC without covers - Notice the crayon and other junk inside?

See the junk in the FDC above? If you look close there is even a crayon! When an FDC inlet is left uncovered 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.

So what happens to the caps? Every FDC, when initially installed, comes standard with "plate and plugs", industry lingo for the circular "Auto Spkr" plate identifying the FDC (see "Auto Spkr" in the image above) and brass plugs to protect the inlets. The most common reason for missing plugs is, sadly, thieves. We noticed a significant uptick in missing plugs following the recession. It's just too easy for brass thieves to remove them and get a quick pay day. Other less nefarious reasons are fairly common, too. For example, breakable caps (see the image below) can loosen over time and fall off or are never replaced during testing of the standpipe system. 

There is another reason for making sure your FDCs are covered. In most jurisdictions, an annual fire inspection is required. The most common citation received by our customers is for missing FDC caps. Usually, these citations come with a remedy period: fix it within 7 days and they'll lift the citation. Have experience with this? You're not alone. Scroll to the bottom to see your options, most of which are cheap enough to have a few extras on hand to avoid citations in the first place! 

FDC Inlets Properly Protected by FDC Caps
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 is made of brass or aluminum and requires the use of a wrench to remove. 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 by NFPA, 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. Their lower cost also makes keeping a few on hand in case of damage or theft a cost-effective addition to building safety.

Now you know your options and why it's important to keep your FDCs covered. Check out the table below to find the option that is best for you! All FDC caps and plugs are IN STOCK and ready for immediate shipment. 

Plastic Breakable Caps from QRFS!Plastic FDC Caps - 2 1/2 inch

  • Most Popular Option!
  • Fire engine red for easy identification
  • Easily breakable with the butt of an ax
Aluminum FDC Break Caps from QRFS!Aluminum FDC Caps - 2 1/2 or 3 inch

  • Won't Fade or Crack!
  • Easily breakable with the butt of an ax
  • Available in 3 inch for San Francisco and New York markets
Brass FDC Plug and ChainBrass FDC Plug and Chain - 1 1/2" or 2 1/2"

  • Durable Rough Brass Exterior 
  • Thread types to meet your local requirements
  • Includes chain to avoid loss during emergency
Aluminum Plug and ChainNEW! Aluminum FDC Plug and Chain - 2 1/2"
  • Stop Brass Thieves in Their Tracks! 
  • Lightweight, durable aluminum build
  • Includes chain to avoid loss during emergency


Date 5/20/2014
Paul delgado
Can Aluminum 3 1/2" caps be used on Auto SPKR
Date 9/29/2016
Bob Baker
Brass FDC Plug and Chain 2-1/2"

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