How flow measurement standard ISO-5167 compares with AGA Report No. 3

Abstract

For U.S. companies that conduct business internationally, one most confusing problem that can occur is the presence of two different standards (one international and one national). In the area of flow measurement, is the national standard, ANSI/API-2530, ''Orifice Metering of Natural Gas,'' as well as an international document, ISO-5167, ''Measurement of Fluid Flow by Means of Orifice Plates, Nozzles and Venturi Tubes Inserted in Circular Cross-section Conduits Running Full.'' These two documents have many significant differences relevant to both the user and the supplier/designer. Since the international document is known in the U.S., the user (e.g., gas company) could be questioned by either the buyer or seller as to why the document or parts of the document are not being used. This article examines these differences along with some of the background and current research being conducted to resolve these differences. Although the ISO document is newer, it is, for the most part, based on the same data as the ANSI document and thus does not necessarily ensure a better flow measurement.