This calculation corrects hydrocarbon volumes metered under pressure to the corresponding volumes at the equilibrium pressure for the metered temperature. It contains compressibility factors related to the meter temperature and relative density (60%deg;F/60°F) of the metered material. The corresponding metric (SI) version is API MPMS Chpt. 11.2.2M:1986

References
API Manual of Petroleum Measurement Standards Chapter 11 – Physical Properties Data - Section 2 Part 2 – Compressibility Factors for Hydrocarbons: 0.350-0.637 Relative Density and -50°F to 140°F Metering Temperature, Second Edition 1986, Amended 1994