AASF 1 OS and Y Gate Valve Replacement - Cecil Field

Existing 14" OS&Y Gate Valves were installed in 1975 and are a major component of the aircraft hangar AFFF Fire Suppression System. Both valves have developed intermittent leaks and the Pump Room Pit has periodic flooding with water levels up to 12 inches deep. Although the valves have an internal packing that can be tightened as part of maintenance, the facility was advised that there is no longer any adjustment remaining in the outside packing adjustment screw. Bolts holding the packing retaining yoke have rusted to the main body of the valve and are not likely to be removed without causing further damage. Failure of any of these components will result in large internal pressure drop in the AFFF Fire Suppression System and possibly cause the AFFF System to either inadvertently discharge or fail to properly operate in the event of a fire emergency. Project Scope of Work consists of replacing two (2) existing 14" OS&Y Gate Valves, dated 1975, with two (2) new NIBCO 14" OS&Y Flanged Gate Valves. The system pressure will be taken to 0.0 psi during this construction phase and the AFFF Fire Suppression System will be placed in an inoperable status until repair and replacement is completed. The Fire Pump Supply and AFFF Foam Concentrate Supply will be isolated and locked-out while work is being performed. Remove and replace the existing dated OS&Y Gate Valves with (2) NIBCO 14" OS&Y Flanged Gate Valves. The Spool Piece between the OS&Y and Flange Tee will be removed and replaced with 14" Ductile Iron Pipe and a 14" STAR Flange. The lock-out of the AFFF Fire Suppression System will be removed, then the system will be pressurized, checked for leaks and verified for proper system operation.

Division 21 -	Fire Suppression.
Division 28 -	Electronic Safety and Security, Fire Detection and Alarm.