The location of a nozzle on a vessel shell is determined by which pair of measurements?

• A. Elevation and degree of the center-line
• B. Nozzle diameter and length
• C. Shell diameter and thickness
• D. Pressure and temperature

Answer: (A)

The location on a vessel shell is defined by two coordinates: the elevation (vertical position) and the angular position around the circumference (degree of the centerline). Elevation tells you how high up the shell the nozzle centerline sits, while the degree around the centerline specifies where around the circumference the nozzle is placed relative to a reference line. Together, these two measurements uniquely identify where a nozzle attaches on the curved shell.

The other factors describe the nozzle or the vessel, not its position: diameter and length pertain to the nozzle size, shell diameter and thickness pertain to the shell’s dimensions, and pressure and temperature are process conditions.