This API MPMS chapter is intended to be a standardized guideline to determine and document the fidelity of implementation of the API MPMS calculations standards. As with all standards developed under Chapter 22.1, this standard includes a listing of parameters affecting the performance of the devices, a description of the tests required, requirements for the test facility, a data reporting format, and an uncertainty determination methodology. The field of application for this testing protocol is limited to devices that are used in the orifice-based measurement of hydrocarbon fluids in the petroleum, energy, and petrochemical industries.