This Practice provides engineering guidance for the selection, design, and application of flow measurement systems. This Practice provides guidelines, performance considerations, and preliminary recommendations for the selection of flow meters and their general application. This guideline applies to devices used to measure the flow of single phase, homogeneous liquids, vapors, and gases. This Practice presents commonly accepted meter types but does not limit application choices. Unique or special requirements may require consideration of other meter types. Specific custody transfer guidelines are not provided and are only mentioned with reference to other industry practices.