The third edition of API MPMS Chapter 4.8 "Operation of Verification System" was published in July 2021.

The third edition of API MPMS Chapter 4.8 "Operation of Verification System" was published in July 2021. This standard provides operating information for the verification of single-phase liquid hydrocarbons. This standard can be used as a reference manual for the operation of the verification system.

The requirements of this standard are based on the customary practice of single-phase liquids. Mainly applies to hydrocarbons, but most of the information may apply to other liquids. The special requirements for other liquids shall meet the requirements of the parties concerned.