API MPMS Chapter 12.1.1 :2019

This document guides the user through the steps necessary to calculate static liquid quantities, at atmospheric conditions, in upright cylindrical tanks and marine tank vessels. It defines terms employed in the calculation of static petroleum quantities.
This document also specifies equations that allow the values of some correction factors to be computed. Fundamental to this process is the understanding that, in order for different parties to be able to reconcile volumes, they must start with the same basic information (tank capacity table, levels, temperatures, and so forth) regardless of whether the information is gathered automatically or manually.
This document does not address the calculation of clingage, nonliquid material, small quantities (such as onboard quantities, quantities remaining on board, and wedge formula, where material is not touching all bulkheads on marine vessels), and vapor space calculations.