scope:

Part 3 of this European Standard specifies the requirements andtests for the construction, performance, safety and conformity offlow computers (FCs) used to meet the metrological and technicalrequirements of a high accuracy volume conversion device. They areused to determine volume of fuel gases, including those of thefirst and second families according to EN 437. For the purpose ofthis European Standard, only flow computers that are intended tooperate with ultrasonic meters according to ISO 17089-1 or gasturbine meters conforming to EN 12261 are considered. For thepurpose of this European Standard only classification classes E2and M1 are considered for the flow computer calculator. FCs areequipped with external separate transducers for pressure andtemperature which may be approved separately. The provisionsconcerning pressure and temperature transducers are given in AnnexB and C. Requirements and tests are given for energy calculator inEN 12405-2.