Issuing body
ISO
Latest edition
Parts 1–6, 2003–2022
Region
Global
Equipment items
1
Scope
Orifice plates, nozzles, Venturi tubes, cone meters, wedge meters — flow measurement using DP.
Key requirements (8)
- Differential pressure flow measurement: orifice, nozzle, Venturi.
- Orifice: square-edged; β ratio (d/D): 0.10–0.75 typical; thickness ≤ 0.05·D.
- Pressure tap configurations: corner, D and D/2, flange.
- Discharge coefficient C: Reader-Harris/Gallagher equation for orifice.
- Expansibility ε ≤ 1.0 for compressible flow correction.
- Uncertainty: ~0.5–1.0% of rate for properly installed orifice.
- Upstream straight length: 10–80×D depending on β and disturbance type.
- Reynolds number range: typically Re_D > 5000 for orifice validity.
Related standards (1)
Applied to 1 equipment item
Instrumentation & Control
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