Valves, Fittings, and Pipe Materials Flashcards

Which valve type uses a rotating disc perpendicular to flow to achieve shut-off?

Answer: Butterfly valve

A butterfly valve uses a disc that rotates 90° within the pipe bore to open or close flow.

What is the primary purpose of a swing check valve?

Answer: Prevent backflow

A swing check valve allows flow in one direction and automatically closes to prevent reverse flow.

Schedule 80 pipe compared to Schedule 40 pipe of the same nominal size has:

Answer: Thicker wall and smaller bore

Schedule 80 has a thicker wall than Schedule 40, resulting in a smaller inside diameter and higher pressure rating.

A 45-degree elbow is used instead of a 90-degree elbow primarily to:

Answer: Reduce friction loss and turbulence

A 45° elbow creates less turbulence and pressure drop than a 90° elbow by making a gradual direction change.

Which material is most commonly used for high-pressure steam piping above 750°F?

Answer: Chrome-moly alloy steel

Chrome-moly alloy steel (such as P11 or P22) retains strength at elevated temperatures required for high-pressure steam service.

A weld neck flange is preferred over a slip-on flange in high-pressure, high-temperature applications because:

Answer: It provides a stronger, more fatigue-resistant connection

The weld neck flange's tapered hub distributes stress and provides superior strength for demanding service conditions.

What does the term 'CWP' stamped on a valve indicate?

Answer: Cold Working Pressure

CWP stands for Cold Working Pressure, indicating the maximum allowable pressure rating at ambient temperature.