Knox Box FDC Lock 2 1/2" NH/NST Male Locking Cap (Swivel-Guard)
Item Number: 3111
Description
Knox FDC Locks protect fire department connections (FDCs), keeping pipes clean of debris to ensure the delivery of high-pressure water flow to fire sprinkler systems. Swivel-Guard versions also enhance security against vandalism. Operated with Knox Keywrench.
- Ensures ready and reliable connections to fire sprinkler systems
- FDC Swivel-Guard brings added protection against vandalism
- Protects check valves from freezing in cold climate areas
- Eliminates costly services to back flush the pipes due to debris
The 3111 model with 2½" NH threads (7.5 TPI x 3.068 OD) is the most widely used configuration — however, thread patterns and sizes vary by jurisdiction, so always verify the correct specifications with your local fire department before ordering.
What is a Knox FDC locking cap with Swivel-Guard?
The Knox FDC Lock with Swivel-Guard is an enhanced version that covers the entire swivel connection and minimizes the potential for theft. It is designed specifically to address the growing problem of brass and copper theft from FDC connections.
Why was the Swivel-Guard version developed?
In recent years, communities have seen an increase in stolen copper and brass, including siamese brass FDC swivel connections. A stolen FDC connection places a building, its occupants, and responders at risk. Knox's Swivel-Guard version directly combated this threat.
What is the main physical difference between the two caps?
The standard locking cap secures the opening of the FDC inlet but leaves the brass swivel connection exposed. With Swivel-Guard, the set screw is inaccessible, making the brass connection difficult to remove. The Swivel-Guard essentially wraps around and covers the entire swivel assembly, adding a second layer of physical protection.
Do both versions lock the same way?
Yes. Both versions are locked and unlocked using the same proprietary Knox Keywrench, which is controlled by the local fire department. This ensures that only authorized fire department personnel can remove the cap during an emergency.
Which version should I choose?
If your primary concern is keeping the FDC free of debris and preventing vandalism, the standard locking cap is sufficient. However, if your area has experienced theft of brass or copper FDC components, the Swivel-Guard version provides significantly stronger protection. The Swivel-Guard version protects the FDC swivel from theft, damage, and vandalism, making it the better choice for high-risk locations.
