Locking FDC Caps

Fire Department Connections (FDCs) are the access points for firefighters to supplement additional water to a building's fire sprinkler system during a fire. Protect these vital protection systems with Knox locking FDC caps: FDC Locks and Storz Locks.

FDC Locks

Protect Fire Department Connections

1.5" and 2.5" diameters

Storz Locks

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 Locks and Storz Locks protect connections and keep pipes clean ensuring the maximum flow of water to sprinklers.

Which FDC Product is Right for My Building

Knox FDC Lock Series


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

2.5" Knox FDC Lock with Swivel-Guard™ Enhanced Protection

Male Locking FDC Cap

2.5" Knox FDC Lock

Male Locking FDC Cap

1.5" Knox FDC Lock

NH Male Locking FDC Cap

Knox FDC Lock Features

Secure locking FDC cap that can be accessed by Fire Department personnel

Swivel-Guard (Model #3041) provides enhanced security

Built Knox-Rugged

FDC Locks available in 2.5" and 1.5" NH sizes

Stainless steel construction to withstand all weather conditions

Knox FDC Lock 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 Lock Applications

Keep it clean.

Fire Department Connections (FDCs) 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 Storz Lock Series


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

5" Knox Storz Lock

Model #5002

4" Knox Storz Lock

Model #5001

Knox Storz Lock Features

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

Anodized aluminum, built Knox-Rugged

Knox Storz Lock available in 4" and 5" sizes

Available with straight or 30-degree elbow adaptors

Knox Storz Lock 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 Storz Lock Applications

Make an impact.

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

  • Fire hydrants
  • Fire sprinkler systems
  • Standpipes



Image Gallery


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

Case Study

The "Weakest Link" in Fire Sprinkler Systems


Obstructed FDCs Block Fire Attack


Increasing Campus Safety at ASU


Brochures and Specs

FDC Protection Solutions


Knox FDC Property Owner Brochure


Knox FDC Fire Dept Brochure


Knox FDC Lock Specs


Knox FDC Lock Operating Instructions


Knox Storz Lock Specs


Knox Storz Lock Operating Instructions


Knox Storz Lock Adapter Installation Guide


Contact us to learn more about
Knox Rapid Access Solutions

Fill out my online form.


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.
After receiving your Knox locking FDC caps, call your responding Fire Department to schedule an inspection and help install and lock the caps.
Knox locking FDC caps protect fire department connections and are generally found on the exterior of buildings. Knox Storz Lock 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 FDC Locks come in two sizes: 2.5" and 1.5" diameters. Knox Storz Locks also come in two sizes: 4" and 5" diameters. Click here to view product spec sheets.
Click here to email us your questions.