Pressure/Vacuum Relief Valve with Pipe-Away Feature - Model 1220A is used for pressure and vacuum relief where vapors must be piped away. Special pallets in the Model 1220A housing virtually eliminate the intake of air and the escape of vapors except during normal tank breathing, thus reducing the loss of product. These special pallets are engineered to allow only the intake or outlet relief necessary to maintain the proper working pressure, thereby protecting the tank from possible damage. Escaping vapors are piped away through a flanged outlet connection. This helps to provide increased fire protection and safety.