Description
Morrison Bros. 748A Pressure Vacuum Vent is designed for installation on top of the vent pipe of an aboveground or underground storage tank. The brass poppets seal vapors in the tank when pressure is equalized. The vent allows the tank to “breathe” during filling and dispensing operations.
This vent must be used in conjunction with an emergency vent. It is recommended that the opening pressure setting is set below that of the emergency vent so the normal vent operates first. Settings are approximate.
Note: Normal vents such as pressure vacuum and updraft vents for aboveground storage tanks should be sized according to NFPA 30 (2012) 21.4.3.
