SPED Equipment Piping (Pumps, Exchangers, Vessels & Control Stations) 5

Question 1

What is the standard arrangement of a control valve station?

Accepted Answer

Block valves upstream and downstream with a globe bypass

Answer

Blocks and bypass allow isolating the control valve for maintenance while operating manually.

Question 2

Which orifice tap orientation is typical for gas lines to avoid liquid in impulse lines?

Accepted Answer

Top

Answer

Top taps prevent condensate from collecting in the impulse tubing.

Question 3

Why is straight pipe required upstream and downstream of an orifice meter?

Accepted Answer

To develop a stable flow profile for accurate measurement

Answer

Fittings and valves distort velocity profiles, so required run lengths depend on beta ratio.

Question 4

What clearance is commonly maintained between the bottom of a control valve and grade?

Accepted Answer

Enough for removal of bottom flange or plug, typically at least about 12 inches

Answer

Maintenance access to the valve bottom and actuator requires working space.

Question 5

Where should a flashing-service control valve be placed?

Accepted Answer

As close as practical to the downstream vessel, with downstream line sized for two-phase flow

Answer

Flashing generates vapor, so the downstream line must be larger and short to limit erosion and noise.

(SPED) Society of Piping Engineers and Designers Certification Practice Test