API RP 14E · Engineering Tool
API RP 14E Erosional Velocity
Ve = C / √ρm
Screening erosional velocity and minimum line ID for two-phase oil & gas flow per API RP 14E, with an actual-velocity check.
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Ve — erosional velocity
44.7ft/s
- C factor
- 100
- Mixture density ρm
- 5lb/ft³
How it works
API RP 14E sets a maximum (erosional) velocity for two-phase production lines to limit high-velocity impingement and sand-driven metal loss at pipe bends, restrictions, and fittings. The limit scales inversely with the square root of the gas–liquid mixture density, so dense fluids tolerate lower velocities and light gas systems tolerate higher ones.
The empirical constant C reflects the service class. Continuous service uses C = 100 (field units) / 122 (SI); intermittent service allows a higher value; corrosive or sand-bearing service forces a lower value. The standard is explicit that these are screening values, not a substitute for a sand-erosion study where solids are present (see API RP 14E §2 and DNV-RP-O501).
Line sizing typically targets an actual velocity well below Ve. This tool reports Ve and flags when a supplied actual velocity approaches or exceeds it; Ve is the upper bound to design against.
Assumptions & limitations
- Ve is a screening limit, not a design velocity — sand-erosion analysis (e.g. DNV-RP-O501) governs when solids are present.
- Mixture density ρm is the in-situ gas–liquid mixture density at line pressure and temperature, not standard conditions.
- C factors and units follow API RP 14E field (ft/s, lb/ft³) and SI (m/s, kg/m³) conventions as commonly applied.
- Does not account for corrosion-erosion synergy, inhibition, or cladding.
Related Reading
Companion Articles
Process · Subsea
API 14E Erosion Velocity and Sand Management in Early Production
API 14E gives a one-line correlation that has sized offshore piping for forty years — and is now the most argued-about equation in subsea engineering. Here's what the C-factor really represents, when the conservative limit is right, and where modern guidance moves it.
Jose CampinsProcess · Subsea
Sand Erosion Management Beyond API 14E — DNV-RP-O501 in Practice
API 14E's C-factor is a screening tool, not a sand model. When solids are in the stream, the controlling component is the choke or the first elbow downstream — and DNV-RP-O501 is the framework that actually sizes them.
Jose CampinsNeed line-sizing or erosional-velocity support for a production or injection system?
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