
Calculate internal pipe diameter at flow temperature:

Calculate correction factor for steam quality (for liquid, water, and gas FS=1);

Calculate orifice diameter at flow temperature.

For LoLoss tube, nozzles,and Venturi tubes:

For other orifices:


Calculate b ratio.

For all Flow meters except Segmental orifices:

Segmental orifices.

Calculate segmental radius:

Calculate b ratio.
HS is calculated with the help of HS0 in accordance with step 3b.



Calculate gas expansion factor (for liquid and water, EPS=1).

For square edge orifice with 2½D and 8D pipe taps:

For LoLoss tube, nozzles,and Venturi tubes:

For eccentric orifices:

For squareedge orifices specified in ISO 51672003 (flange tappings, corner tappings, and radius tappings):

For other Flow meters:


Calculate first estimate for flow rate:
*W0 [kg/s]

Calculate Pipe Reynolds number:
*W0 [kg/s]

Calculate discharge coefficient.For more information see the Appendix.

Calculate new flow rate:
*W[kg/s]

For quarter of circle (Quadrant Edge) orifice, Loloss tube, Venturi tubes, and Segmental orifices go to step 13.

Calculate the relative change in Flow rate:

Repeat steps 7 to 11 until the relative change in the flow rate is less than 0.0001.

For quarter of circle (Quadrant Edge) orifice, calculate radius of upstream profile: