API MPMS 12.2.3:1998(R2002) pdf download.Manual of Petroleum Measurement Standards Chapter 12- Calculation of Petroleum Quantities
When most of the older standards for the calculation of petroleum quantities were written, mechanical desk calcula- tors were widely used for calculating the measurement docu- ments. Tabulated values were used more widely than is the case today. Rules for rounding and the choice of how many figures to enter in each calculation step were often made by individual operators at the time of the calculation. As a result, different operators obtained different results from the same data. This multi-part publication consolidates and standardizes the calculations pertaining to metering petroleum liquids using turbine or displacement meters and clarifies terms and expressio_ns by eliminating local variations of such terms. The of standardizing the calculations is to produce identi- cal answers from given data. For different operators to obtain identical results from the same data, the rules for sequence, rounding, and discrimination of figures (or decimal places) must be defined.
1 This provides standardized calculation methods for the determination of meter factors under defined conditions, regardless of the point of origin or destination or units of measure by governmental customs or statute. The criteria contained here will allow different entities using vari- ous computer languages on different computer hardware (or by manual calculations) to at results using the standardized input data. This document also specifies the equations for computing correction factors, including the calculation sequence, dis- crimination levels, and rules for rounding to the calculations. No deviations from these specified equations are permitted, since the intent of this document is to establish a rigorous standard.
2.4 PART &CALCULATION OF BASE PROVER VOLUMES BY WATERDRAW METHOD
2.4.1 The waterdraw method uses the displacement (or drawing) of water from a prover into certified volumetric field standard test measures. Alternatively, for open tank provers, the waterdraw method may also use the displacement (or drawing) of water from field standard test measures into the open tank prover. Certification of the field standard test mea- sures must be traceable to an appropriate national weights and measures organization. 2.4.2 Recording of field data, rules for rounding, calcula- tion sequence, and discrimination levels are specified, along with a set of example calculations. The examples are designed to aid in checkout procedures for any routines that are developed using the requirements stated in this part.