API MPMS 14.12:2017

This Standard addresses the following: a) provides generic information on full-bore vortex shedding flowmeters, including glossary, and sets of engineering equations useful in specifying performance; b) describes vortex shedding flowmeters in which alternating vortices are shed from one or more bluff bodies installed in a closed conduit; c) describes how the vortex shedding frequency is used to determine the velocity to infer the volume, mass, and/or energy flow rate and the total gas flow through the meter over a specific time interval; d) applies only to single phase gas flows in closed conduit that are steady or vary slowly in time. For fiscal measurement, the output of the flow rate shall be within the acceptable limits of steady state flow rate; e) describes the physical components of vortex shedding flowmeters and identifies need for inspection, certification, and material traceability; f) addresses the effect of gas properties, installation, and process conditions that may affect the measurement uncertainty and describes guidelines for reducing or eliminating their influences; g) defines the method for calculating uncertainty of the flow rate measurement; h) defines the meter output requirements and necessary information pertaining to the meter output for the purpose of fiscal measurement of gas; and i) provides calibration and/or performance verification guidance for the field application.