Orifice Diameter (d)
β
Pipe Diameter (D)
β
Orifice Area
β
π‘ Recommendations
- Enter values to see recommendations
Beta Ratio Calculator
Orifice plate sizing validation per ISO 5167 / ASME MFC-3M
Calculation Mode
Enter your orifice and pipe dimensions to check if the beta ratio is within acceptable limits.
Enter your pipe size and desired beta ratio to find the optimal orifice diameter.
d/D
Recommended: 0.50β0.70
Enter your orifice size and desired beta ratio to find the minimum pipe diameter.
d/D
Max recommended: 0.75
Flow Parameters (Optional - for advanced analysis)
Β°C
β
0.62 sharp β’ 0.75 rounded β’ 0.95 nozzle
Results
β
Beta Ratio (Ξ² = d/D)
β
0.0
0.2
0.4
0.6
0.75
1.0
Too small
ISO 5167 Standard Range (0.20 β 0.75)
Too large
π Basic Results
βΌπ¬ Advanced Analysis
βΌCd Stability
β
Discharge coefficient reliability
ΞP Ratio (Permanent Loss)
β
Pressure recovery estimate
Reynolds Number Range
β
Enter flow rate to calculate
Orifice Velocity
β
Enter flow rate to calculate
Estimated Flow Capacity
β
Enter ΞP to calculate
Area Ratio (Ξ²Β²)
β
Orifice/Pipe area ratio
Key Equations:
Ξ² = d / D | Q = Cd Γ A Γ β(2ΞP/Ο) | Re = (V Γ d) / Ξ½
Ξ² = d / D | Q = Cd Γ A Γ β(2ΞP/Ο) | Re = (V Γ d) / Ξ½
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Beta Ratio Reference
| Beta Range | Status | Notes |
|---|---|---|
| 0.10 β 0.19 | Usable | Very high ΞP, limited turndown |
| 0.20 β 0.50 | Optimal | Best Cd stability, good ΞP signal |
| 0.50 β 0.70 | Good | Standard range, reliable |
| 0.70 β 0.75 | Acceptable | Upper standard limit |
| 0.75 β 0.80 | Marginal | Some standards permit, reduced accuracy |
| > 0.80 | Not Recommended | Cd unstable, poor ΞP signal |
Common Pipe Internal Diameters
| Nominal Size | Sch 40 ID (mm) | Optimal Orifice (Ξ²=0.65) |
|---|---|---|
| DN50 / 2" | 52.5 | 34 mm |
| DN65 / 2Β½" | 62.7 | 41 mm |
| DN80 / 3" | 77.9 | 51 mm |
| DN100 / 4" | 102.3 | 66 mm |
| DN150 / 6" | 154.1 | 100 mm |
| DN200 / 8" | 202.7 | 132 mm |
Standards Reference
ISO 5167-1:2022 β Measurement of fluid flow by means of pressure differential devices
ASME MFC-3M β Measurement of fluid flow in pipes using orifice, nozzle, and venturi
AS 2419.1 β Fire hydrant installations (Australian)
We provide no warranty or guarantee for the use of this tool or its accuracy. In no event will we be liable for any loss or damage, including, without limitation, indirect or consequential loss or damage, or any loss or damage arising from loss of data or profits arising out of, or in connection with, the use of this tool.