Knox Box FDC Lock 1 1/2" Male NH/NST Locking Cap

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. The Knox FDC Lock is available in 1 1/2" configuration and is operated with a Knox FDC wrench controlled by the Fire Department. Ensures ready and reliable connections to fire sprinkler systems Protects check valves from freezing in cold climate areas Eliminates costly services to back flush the pipes due to debris The 3190 model with 1½" NH threads (9.0 TPI x 1.999 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. WarningThis product must be installed by Authorized Fire Department representative or Fire Department-Authorized Contractor only. This is a security product that requires a special fire department keywrench to lock the cap in place. Unauthorized installation may result in improper locking of the cap. An improperly locked cap may be subject to removal by unauthorized personnel. What is the Knox FDC Lock 1½" NH/NST Male Locking Cap?The Knox 1½" FDC Lock is a locking cap that protects fire department connections from vandalism and keeps them free of debris. It features stainless steel construction and is operated with a Knox Keywrench. The thread specification is 1½" Male (1.99" x 9 TPI). NH (National Hose Thread) and NST (National Standard Thread) refer to the same thread standard, so these terms are interchangeable when ordering or specifying this product. What does the "Male" designation mean for this cap?The "Male" designation refers to the thread orientation of the cap itself. The 1½" NH/NST Male Locking Cap threads onto a female FDC inlet, acting as a plug that seals and secures the connection opening. This is the standard configuration for protecting FDC inlets on the exterior of buildings where firefighters would connect a hose during an emergency. What are the key features of the Knox FDC Lock 1½" cap?Key features include stainless steel construction, availability in the 1.5" NH size, and a locking mechanism that secures and protects FDCs. It is authorized by 2018 IFC and IBC (Chapter 912.4.1) and 2018 NFPA 1 (Chapter 13.1.13). The cap is engineered to withstand all weather conditions and is built to the Knox-Rugged standard, ensuring long-term reliability in outdoor environments. What are the primary benefits of installing this cap?Benefits include ensuring ready and reliable connections to fire sprinkler systems, protecting check valves from freezing in cold climate areas, and eliminating costly services to back flush the pipes due to debris. Beyond debris protection, a fire sprinkler system is subject to malfunction and malicious attack when foreign matter such as debris, trash, or animal nests enters the system through an unprotected FDC connection. The Knox cap eliminates all of these risks. How is the Knox FDC Lock 1½" cap removed during an emergency?Knox FDC Lock removal is quickly and easily accomplished with a Knox Keywrench. The Knox FDC Protection Program provides fire department control over FDC equipment, and when a department adopts the program, Knox Keywrenches are provided to the department at no charge. This ensures firefighters can rapidly remove the cap during an emergency, preventing any delay in water delivery.