scope:

This document describes and discusses the characteristics of displacement flowmeters. Attention is given to the factors to be considered in the application of positive displacement meters to liquid metering. These include the properties and nature of the liquid to be metered, the correct installation and operation of the meter, environmental effects, and the wide choice of secondary and ancillary equipment. Aspects of meter proving and maintenance are also discussed.

This document is applicable to the metering of any appropriate liquid. Guidance is given on the use of positive displacement meters in the metering of two-component mixtures of the same phase such as water and oil.

It is not applicable to two-phase flow when gases or solids are present under metering conditions (i.e. two-phase flow). It can be applied to the many and varied liquids encountered in industry for liquid metering only. It is not restricted to hydrocarbons.

Guidance on the performance expected for fiscal/custody transfer applications for hydrocarbons is outlined. This document is not applicable to cryogenic liquids such as liquefied natural gas (LNG) and refrigerated petroleum gas. It does not cover potable water and fuel dispenser applications