To locate a nozzle installed on a vessel shell, which information is required?

• A. The elevation and degree of the center-line of the nozzle
• B. The nozzle diameter and wall thickness
• C. The material grade and corrosion allowance
• D. The operating pressure and temperature

Answer: (A)

To locate a nozzle on a vessel shell, you need its position and orientation. Elevation tells you how high or low the nozzle center is on the shell, giving the vertical placement. The degree of the centerline describes the direction the nozzle bore runs as it penetrates the shell, which defines its angular placement around the circumference. Together, these two pieces of information pin down the exact spot and entry direction of the nozzle on the shell.

The other details describe the nozzle’s size, wall thickness, material, corrosion allowance, and operating conditions. While important for fabrication, strength, and service life, they don’t specify where the nozzle is located on the shell.