What two measurements define the position of a nozzle on a vessel shell?

• A. Elevation and degree of the center-line
• B. Diameter and wall thickness
• C. Material and coating
• D. Temperature and pressure

Answer: (A)

On a cylindrical vessel shell, the nozzle’s location is described by two coordinates: elevation and its angular position around the circumference (the degree around the centerline). Elevation tells you how high the nozzle sits along the shell, while the degree around the centerline specifies where around the circle the nozzle is placed. Together, these two measurements pin down the exact outdoor position on the shell.

Diameter and wall thickness describe the vessel’s size and material, not where a nozzle attaches. Material and coating are about what the shell is made of and its surface treatment. Temperature and pressure relate to the operating conditions, not the physical location on the shell.