Class 300 Ball valve

About Class 300 Ball valve

A Class 300 ball valve is a quarter-turn isolation valve designed to handle higher pressure applications than Class 150 valves. It is manufactured in accordance with pressuretemperature ratings specified by the American Society of Mechanical Engineers (ASME), typically under ASME B16.34.

What Does Class 300 Mean?

Class 300 refers to the flange pressure rating of the valve.

For carbon steel materials (e.g., ASTM A216 WCB):

• Maximum pressure at 100F (38C): approx. 740 PSI (51 bar)

• Pressure rating decreases as temperature increases

• Flange dimensions generally follow ASME B16.5

This pressure class is suitable for medium to high-pressure systems.

Working Principle

A Class 300 ball valve works using a rotating ball with a central bore:

• Open Position Bore aligned with pipeline for full flow

• Closed Position Ball rotated 90 to stop flow completely

The quarter-turn design ensures fast operation and tight shut-off.

Main Components

• Body Cast or forged carbon steel, stainless steel, or alloy steel

• Ball Precision-machined stainless steel or alloy steel

• Stem Blow-out proof design

• Seats PTFE, RPTFE, PEEK, or metal seated (for high temperature)

• End Connections Flanged (most common), butt-weld, or socket weld

• Operator Lever (small sizes), gear operated (large sizes), or actuator