A ‘flow factor’ is to multiply the flow transmitter signal measured on a 0-10 square root or 0-100 linear scale to get the flow calculated by flow metering. This is used due to the standardization of the transmitters signals, to 20-100 kPa or 4-20mA.

The following points are considered for flow calculation and in deriving the flow factor:

D = pipe diameter,

Small d = orifice diameter

Service = gas or liquid

PI = operating pressure

DP = Transmitter differential pressure

T =operating temperature

Small p= density or molecular weight

Small v= viscosity