ISO 21903-2020 pdf free.Refrigerated hydrocarbon fluids — Dynamic measurement —Requirements and guidelines forthe calibration and installation offlowmeters used for liquefied naturalgas (LNG) and other refrigerated hydrocarbon fluids.
1.This document specifies the metrological and technical requirements for flowmeters intended to beused for the dynamic measurement of liquefied natural gas (LNG) and other refrigerated hydrocarbonfluids. For LNG static volume measurement used in custody transfer, see ISO 10976.
This document sets the best practice for the proper selection and installation of flowmeters in cryogenicapplications 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) byeither using LNG or other reference fluids.The choice of calibration fluid will depend on the capabilitiesof the available flow calibration facilities and the ability to achieve the required overall measurementuncertainty demanded by the intended application.
This document is applicable, but is not limited, to the use of Coriolis and ultrasonic flowmeters fordynamic measurements of LNG.
ln principle,LNG and other refrigerated liquid hydrocarbons are considered in this document.Recommendations in this document are based on the available test results with LNG.These results areprobably applicable to other cryogenic fluids.
2.Normative references:The following documents are referred to in the text in such a way that some or all of their contentconstitutes requirements of this document. For dated references,only the edition cited applies. Forundated references, the latest edition of the referenced document(including any amendments) applies.
3.1.Terms and definitions:For the purposes of this document, the following terms and definitions apply.
3.2measurement error:measured quantity value (3.1.3) minus a reference quantity value.
3.3.measured quantity value:quantity value representing a measurement result
3.4.measurement uncertainty:non-negative parameter characterizing the dispersion of the quantity values being attributed to ameasurand, based on the information used.Note 1 to entry: A list of metrological definitions can be found in ISO/1EC Guide 99.ISO 21903 pdf download.