ASME MFC-1 pdf download Glossary of Terms Used in the Measurement of Fluid Flow in Pipes
This Standard consists of a collection of definitionsof those terms that pertain to the measurement of fluidflow in pipes. The definitions provided also give guidance for recommended usage in the application of flowmeasurement devices.
This Standard is organized alphabeticlly. Symbols normally applied to various quantities are tabulated insection 3.
This Standard was compiled from many sourcesincluding various reports and standards from TheAmerican Society of Mechanical Engineers (ASME) theAmerican Gas Association (AGA).the AmericarPetroleum Institute (API)the nternational Society oAutomation (ISA) the British Standards Institute (BSI)the International Organization for Standardization(ISO) the National Institute for Standards andTechnology(NIST), and the International Organizationof Legal Metrology (OIML)
2 GLOSSARY OF TERMSabsolute pressure: algebraic sum of the atmospheric pressure and gauge pressure.absolute static pressure of a fluid: static pressure of a fluidmeasured with reference to a perfect vacuum.
acceptance test: the evaluating action(s) to determine if arinstrument satisfactorily meets its performance criteriapermitting the owner/purchaser to formally accept itfrom the supplier.
Accuracy of measurement: the extent to which a given measurement agrees with a reference for that measurementoften used by manufacturers to express the performancecharacteristics of a device.
NOTE:“Accuracy”is not the same as “uncertainty” (see “uncer-tainty of measurement”).
Acoustic matching layer: material comprising one or morelayers, selected to maximize the acoustic coupling coeffi-cient between two media.
acoustic path: the path that the acoustic signals follow asthey propagate through the measurement sectionbetween the transducer elements.
acoustic ratio: the differential pressure ratio divided bythe isentropic exponent (compressible fluid).air: mixture of gases and associated water vapor sur-rounding the earth; dry air plus its associated watervapor. The term is used synonymously with atmosphere.air, dry: mixture of dry gases present in the atmosphere.ambient temperature: temperature of the atmosphere measured in the immediate vicinity of the point of measurement and unaffected by wind or other atmosphericphenomena.
annular chamber: piezometer ring integral with the pipeor the primary device that simplifies the constructionof annular pressure taps.
annular space: area between the tapered tube and thefloat that normally increases as the float rises.
area meters: flowmeter in which a variation in the crosssection of the fluid stream under constant head is usedas an indication of the rate of flow, e.g, a float is sus-pended in a vertical tapered tube and as the fluid flowrate changes, the position of the float in the tube changes.arithmetic mean: the sum of values divided by the numberof values, also called “average.