FD ISO/TR 12767, X10-151 (10/2023)

This document provides guidance for estimating flow with primary pressure devices constructed or operated outside the scope of the ISO 5167 series. Additional tolerances or corrections do not necessarily compensate for the effects of deviation from the ISO 5167 series. This information is provided, primarily, to indicate the level of care necessary in the manufacture, installation and maintenance of pressure-generating devices, describing some of the effects that non-compliance may have requirements and, secondly, to enable users who cannot fully comply with the requirements to assess, albeit approximately, the magnitude and direction of the resulting throughput error. Each affected variation is treated as if it were the only error present. When it is known that there are multiple errors, unpredictable interactions can potentially occur and the combined evaluation of these errors requires special precautions. If there are a significant number of errors, consider a way to eliminate some of them. The variations included herein are by no means complete and refer largely to diaphragm examples. An example with Venturi tubes was introduced at the end of this section. This document does not apply to measuring cones or wedge flow meters. There are, undoubtedly, many similar examples of installations not complying with the ISO 5167 series for which no comparable data has been published. This additional information from users, manufacturers and others may be taken into account in future revisions of this document.
(Automatic translation from French)