FDC Caps and Plugs

Fire Department Connections (FDCs) are the access points for firefighters to supplement additional water to a building's fire sprinkler system during a fire.

FDC Plugs

Protect Fire Department Connections

1.5" and 2.5" diameters

StorzGuard® Caps

Protect Fire Department Connections and Hydrants

4" and 5" diameters

Why Are Fire Department Connections (FDCs) Important?

The fire department connects to FDCs on your building to supplement water to your sprinkler system.

Unprotected FDCs are vulnerable to vandalism and debris that can prevent the flow of water.

Knox FDC Caps and Plugs protect connections and keep pipes clean ensuring the maximum flow of water to sprinklers.

Which FDC Product is Right for My Building

Knox FDC Plug Series


Knox FDC Plugs lock securely in place to protect fire system pipes and enable delivery of high-pressure water flow to fire sprinkler systems.

2.5" Knox Locking FDC Plug with Swivel-Guard™ Enhanced Protection

Male Plug

Model #3041

Retail $177

2.5" Knox Locking FDC Plug

Male Plug

Model #3043

Retail $137

1.5 Knox Locking FDC Plug

NH Male Plug

Model #3050

Retail $103

Knox FDC Plug Features

Secure locking cap that can be accessed by Fire Department personnel

Swivel-Guard (Model #3041) provides enhanced security

Built Knox-Rugged

FDC plugs available in 2.5" and 1.5" NH sizes

Stainless steel construction to withstand all weather conditions

Knox FDC Plug Benefits

  • Eliminates costly services to back flush the pipes due to debris
  • Ensures ready and reliable connections to fire sprinkler systems
  • Protects FDC swivel from theft, damage and vandalism
  • Protects check valves from freezing in cold climate areas

Knox FDC Plug Applications

Keep it clean.

FDC are your building's lifeline to fire prevention. When FDCs are left unsecured, they are vulnerable to damage, debris and vandalism which can constrict the flow of water to:

  • Fire sprinkler protection systems
  • Standpipes located in parking garages and stairwells

Knox StorzGuard Cap Series


Knox StorzGuard locking caps protect Fire Department Connections (FDCs) to ensure reliable water connections and prevent fire hydrant water loss or theft.

5" Knox StorzGuard

Model #5002

Retail $313

4" Knox StorzGuard

Model #5001

Retail $293

Knox StorzGuard Cap Features

Large locking cap that can only be accessed by Fire Department personnel

Anodized aluminum, built Knox-Rugged

Knox StorzGuard available in 4" and 5" sizes

Available with straight or 30-degree elbow adaptors

Knox StorzGuard Cap Benefits

  • Eliminates costly services to back flush the system due to debris
  • Provides a ready and reliable connection to sprinkler systems
  • Protects large diameter Fire Department Connections
  • Keeps water connection clear of debris, animals, and vandalism
  • Ensures FDCs' operational integrity
  • Prevents water theft or loss in hydrant applications

Knox StorzGuard Cap Applications

Make an impact.

Fight fire with high-pressure water, every time. Knox StorzGuard cap protects large diameter FDCs from damage and vandalism on:

  • Fire hydrants
  • Fire sprinkler systems
  • Standpipes



View our case studies, specs and brochures below to learn more.

Case Study

Edina Case Study


Specs and Brochures

Knox FDC Plug Operating Instructions


Contact us to learn more about
Knox Rapid Access Solutions

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Contact your local Fire or Public Safety Department for Knox product recommendations.
Spec sheets are available on this page under the "Resources" section or can be found here.
Knox FDC Caps & Plugs are easily installed by anyone. Click here to see product installation instructions.
Knox locking FDC plugs protect fire department connections and are generally found on the exterior of buildings. Knox StorzGuard® caps protect fire hydrant and fire department connections which can be found in stairwells, parking garages and the exterior of buildings. More location and installation information can be found here.
Knox locking FDC plugs come in two sizes: 2.5" and 1.5" diameters. Knox StorzGuard® caps also come in two sizes: 4" and 5" diameters. Click here to view product spec sheets.
Click here to email us your questions.