DANSK DSF/ISO/FDIS 21903 PDF

This document describes the metrological and technical requirements for flowmeters intended to be used in the dynamic measurement of Liquefied Natural Gas (LNG) and other refrigerated hydrocarbon fluids. This document sets the best practice for the proper selection and installation of flowmeters in cryogenic applications and identifies the specific issues that can affect the performance of the flowmeter in use. Moreover, it offers a calibration guideline for laboratory and on-site conditions (mass or volume) by either using LNG or other reference fluids. The choice of calibration fluid will depend on the capabilities of available flow calibration facilities and the ability to achieve the overall uncertainty demanded by the intended application. It is applicable, but is not limited to, the usage of Coriolis and ultrasonic flowmeters for dynamic measurements of LNG. In principle, LNG and other refrigerated liquid hydrocarbons are considered in the standard. Recommendations in this standard are based on available test results with LNG. These results are probably applicable to other cryogenic fluids.