Orifice Sizing Calculator
Calculate required orifice diameter from flow and pressure
Design Requirements
0.62 sharp β’ 0.75 rounded β’ 0.95 nozzle
Required Orifice Size
Diameter (mm)
β
Diameter (inch)
β
Orifice Area
β
Formula: d = β(Q / (Cd Γ C Γ βP))
Where C is the unit conversion constant
Where C is the unit conversion constant
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Standard Orifice Sizes
| Nominal (mm) | Actual (mm) | Inch | Area (mmΒ²) |
|---|---|---|---|
| 10 | 10.0 | 3/8" | 78.5 |
| 15 | 15.0 | 1/2" | 176.7 |
| 20 | 20.0 | 3/4" | 314.2 |
| 25 | 25.0 | 1" | 490.9 |
| 32 | 32.0 | 1ΒΌ" | 804.2 |
| 40 | 40.0 | 1Β½" | 1256.6 |
| 50 | 50.0 | 2" | 1963.5 |
Standards Reference
AS 2419.1 β Fire hydrant installations
ISO 5167 β Measurement of fluid flow by means of pressure differential devices
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