AGF's PURGEnVENT Model 7900 Automatic Air Vent (AAV) is a 1" isolation ball valve, barrel strainer, air vent, and purge valve that helps prevent corrosion by automatically releasing trapped air in wet fire sprinkler systems. It meets NFPA 13 code that requires a single air vent on each wet pipe sprinkler system utilizing metallic pipe. The patented design automatically vents air without leaking, eliminating the need for drip pans or drain lines. The unique purge valve with hose thread can be used for rapid air purging as the system is filling and doubles as a vacuum breaker when draining the system. The purge valve is also designed to facilitate and accelerate required NFPA 13 and NFPA 25 strainer maintenance. AGF recommends installing Model 7900AAV near the high point of the system, at the end of branch lines, and on top of supply risers.