Tool · ANSI/ISA-75.01.01-2012 (IEC 60534-2-1 MOD)

Control valve sizing.

Enter the service conditions and the valve data. The flow coefficient is computed as Kv and Cv, with choked flow, attached reducers and non-turbulent flow handled by the equations of the standard. Everything runs in this page; nothing is sent to the server.

Service conditions

Flow rate Inlet pressure P₁ Outlet pressure P₂ kPa P₁ and P₂ are gauge pressures (atmosphere 101.325 kPa) Inlet temperature T₁ Viscosity μ cP Density ρ₁ kg/m³ Vapour pressure P_v, abs kPa Critical pressure P_c, abs kPa

Critical pressure sets F_F through Eq. (4). 22 120 kPa is water.

Valve and piping

Valve style, Table D.2 Valve size d Upstream pipe ID D₁ mm Downstream pipe ID D₂ mm Pressure recovery F_L Valve style modifier F_d Rated coefficient, optional

Leave D₁ and D₂ empty for a line-size valve. Short concentric reducers are estimated with Eq. (15) to (22). Table D.2 values are typical; use the manufacturer's F_L, x_T and F_d when you have them.

Manufacturer travel data, optional

One row per travel point: travel, C, F_L, x_T. Separate with commas, tabs or spaces; x_T may be left out for liquids. Coefficient column is

With a table, F_L and x_T are read from it at every trial value of C, as Annex C.2 asks, instead of being held fixed. The last row is taken as the rated coefficient. The result then also reports the travel and the percentage of rated C.

What the calculation does

Clause numbers and equations refer to ANSI/ISA-75.01.01-2012.

Step	Liquid	Gas or vapour
Choking limit	F_F from Eq. (4), ΔP_choked from Eq. (3), ΔP_sizing from Eq. (2).	F_γ from Eq. (11), x_choked from Eq. (10), x_sizing from Eq. (8), Y from Eq. (12).
Flow model	Eq. (1).	Eq. (6) for kg/h, Eq. (7) for standard volume.
Reducers	F_P Eq. (15), F_LP Eq. (21), ζ from Eq. (16) to (19).	F_P Eq. (15), x_TP Eq. (22).
Solving for C	F_P, F_LP and x_TP depend on C, so C is found by bisection as in Annex C.2, with the upper limit of Eq. (C.4) and (C.5).
Travel data	With a manufacturer table, F_L and x_T are interpolated against C at every trial value, as Annex C.2 Steps 2, 3 and 5 require, and the travel and percentage of rated C are reported. Without one, the fixed F_L and x_T above are used at every travel.
Reynolds check	Re_v from Eq. (23). Below 10 000 the line-size equations of Annex A are solved as well (F_R from Eq. (A.6) to (A.8), Y from Eq. (A.5)), and the larger C is reported.
Scope	C/(N₁₈d²) < 0.047 for the ±5 % accuracy of clause 1. Flashing liquids, multiphase flow, non-Newtonian fluids and the multistage valves of Annex B are not covered.

Cv is Kv divided by 0.865, the ratio of the N₁ constants in Table 1. Results are for sizing studies; confirm the final selection with the valve manufacturer's data.