Standard flow rate is a correction applied to an actual flow measurement based on a given temperature and pressure. The correction is applied using the ideal gas law. The most widely used value is 1 atmosphere (101.3 kPa) or 14.696 psia at sea level and 59 0F (150C).
Normal flow rate is 1 atmosphere (101.3 kPa) or 14.696 psia at 32 0F (0 0C).
Actual flow rate is the actual volume of fluid that passes a given point based on given pressure and temperature of the process.
Engineering checks before conversion
Before using quoted standard or normal gas flow in valve sizing, record the reference temperature and absolute pressure, gas composition, and whether the basis is dry or wet because contract and standard definitions can differ. Start with the control-valve process-data checklist, retain the actual operating conditions used for selection, and then review the Cv calculator with the agreed reference basis.
