How will check api 650 tank plumbness of shell plate?

To check the plumbness of a shell plate in an API 650 tank, a plumb bob or laser level is typically used to measure the vertical alignment of the tank shell. Measurements are taken at multiple points around the circumference of the tank to ensure consistency and identify any deviations from vertical. If the shell plate is found to be out of plumb beyond acceptable tolerances specified in API 650, corrective measures may be required to realign the structure. Regular monitoring during construction can help maintain the integrity of the tank's design.