Class 150 vs 300 vs 600 Valves
ASME Class 150, 300 and 600 identify pressure classes, not fixed pressure values; allowable pressure depends on the valve material and design temperature.
Higher classes generally increase flange thickness, bolting, wall sections, weight and operating loads, which can also change actuator or gearbox requirements.
Use the project design pressure and temperature with the selected material rating to choose the class, then confirm end connection, dimensions, testing and piping compatibility.