This standard provides guidance for the effective use of electronic liquid measurement systems for custody transfer measurement of liquid hydrocarbons under the following conditions: Use of the measurement systems must fall within the scope and field of application of API MPMS Chapter 12.2. Guidance applies to systems using turbine or positive displacement meters. Guifdance applies to systems using on-line CTL and CPL compensation. The procedures anmd techniques in MPMS Chapter 21.2 are recommended for new measurement applications. This standard provides custody transfer measurement procedures for pipeline and other electronic liquid metering systems including design, selection, use, auditing, reporting, calibration, verification and security.