USAFA HTHW Isolation Valves Basewide

SEC designed the replacement of over 90 HTHW isolation valves throughout the utility tunnel system at the US Air Force Academy. The existing Class 300 and 600 cast steel gate valves were replaced with Triple Offset Rotary (TOR) valves with gear drive actuators and butt weld connections. Construction cost was $1,792,233, completed in 2019.

The replacement valves are rated for a minimum of 454 degrees Fahrenheit at 450 PSI gauge pressure with 8,600 GPM peak flow capacity. Major valve locations include 14-inch main isolation valves in the tunnel southeast of Fairchild Hall, 12-inch main isolation valves north of Fairchild Hall, 8-inch main isolation valves at the tunnel intersection, and 6-inch isolation valves at the Cadet Gymnasium Building 2170 tunnel.

The design incorporated five temporary boiler tie-in locations with mobile temporary HTHW generators rated at 8,369 MBH input and 6,695 MBH output. This approach allowed valve replacement work to proceed while maintaining heating service to mission-critical facilities throughout the campus.