FieldEngineersKitEngineering Reference & ASME Code Basis
1. Core Formula & Variable Definitions
API Recommended Practice 14E (erosional velocity screening) · Norsok P-002 / ISO 13703 (CRA C-factor guidance — reference) · ASME B36.10M (CS schedules) / ASME B36.19M (SS schedules)
v = QA · vc = C√ρ [API RP 14E, ρ in lb/ft³ → convert to m/s]
Status: Safe if v < 0.8 vc and liquid v ≤ cap · Warning ≥ 0.8 vc or liquid cap · Erosion Risk if v ≥ vc
Liquid warning cap: CS 3.5 m/s (11.5 ft/s) · SS/CRA 5.0 m/s (16.4 ft/s)
API RP 14E erosional velocity screening (this app)
Hero is mean velocity v = Q/A using schedule ID (B36.10M for CS, B36.19M for SS). Erosion limit vc follows API RP 14E with user density converted to lb/ft³ inside the engine. Default C = 100 (CS) or 150 (SS). Liquid services also apply a practical warning cap (CS 3.5 m/s, SS 5.0 m/s). Multiphase mixture-density formulas are out of scope — enter ρ directly. Sand-laden slurries need dedicated erosion models.
- v (Mean Velocity) — Hero output — Q / A through the schedule ID bore (m/s or ft/s).
- vc (Erosional Velocity Limit) — API RP 14E limit from C / √ρ (ρ in lb/ft³), converted to the active unit system.
- C (Empirical Factor) — Default 100 (CS continuous) or 150 (SS/CRA). Override in Advanced 1.2.
- ρ (Fluid Density) — User density (kg/m³ or lb/ft³). Converted to lb/ft³ for the RP 14E formula.
- Q (Volumetric Flow) — m³/h or GPM.
- A (Flow Area) — π ID² / 4 from the selected NPS/schedule.
- v / vc (Utilization Ratio) — Safe < 80%; Warning 80–100% (or liquid cap); Erosion Risk ≥ 100%.
2. Allowances, Tolerances & Standards
Screening only. Confirm project velocity standards and sand content before PO.
Normal continuous operation band for this calculator.
CS liquid cap 3.5 m/s; SS/CRA liquid cap 5.0 m/s. Consider larger NPS.
At or above the RP 14E erosional limit for the entered C and ρ.
If sand ≫ ~1 lb/1000 bbl, do not rely on RP 14E — use particulate erosion models.
Quick Reference Lookup Table
| Q (m³/h) | v (m/s) | v / vc | Status |
|---|---|---|---|
| 20 | 0.68 | 18% | Safe |
| 40 | 1.35 | 35% | Safe |
| 50 | 1.69 | 44% | Safe |
| 80 | 2.71 | 70% | Safe |
| 100 | 3.38 | 88% | Warning |
| 130 | 4.40 | 114% | Erosion Risk |
Matches this app’s rules: Warning if v ≥ 0.8·vc or liquid v > 3.5 m/s (CS); Erosion Risk if v ≥ vc. Default Q = 40 m³/h is Safe (~35% of vc).
3. Material & Code Limitations
Material family selects schedule set (B36.10M vs B36.19M), default C, and liquid warning cap.
| Material Group | Temperature Range | Allowable Stress / Limit | Engineering Notes |
|---|---|---|---|
| Carbon & Alloy Steel | Liquid warning cap 3.5 m/s (11.5 ft/s) | Default C = 100 | B36.10M schedules. Continuous solids-free screening. |
| Stainless / CRA | Liquid warning cap 5.0 m/s (16.4 ft/s) | Default C = 150 | B36.19M S schedules. Higher C reflects tougher passive films. |
| Gas service | Typical band ~10–25 m/s (screening note) | Still compare v to vc | Liquid cap does not apply when ρ < 400 kg/m³ in this app. |
| Two-phase / sand | Enter mixture ρ if screening | RP 14E clean-fluid assumption | Formal multiphase / sand erosion analysis is outside this tool. |
Code Applicability & Safety Boundaries
- Calculator scope: v = Q/A, vc = C/√ρ (RP 14E), CS/SS liquid caps, and Safe/Warning/Erosion Risk.
- Does not replace particulate erosion models (DNV-RP-O501 / Tulsa) for sand service.
- Does not check AIV/FIV acoustic limits on high-velocity gas lines.
4. Step-by-Step Worked Example
Field VerificationShowHide
Reproduce the app default: CS NPS 4 Sch 40, Q = 40 m³/h, ρ = 998 kg/m³, C = 100.
Flow area A
From pipeSchedule.json Sch 40 ID.
Mean velocity v
Hero output for the default case.
API RP 14E limit vc
Same conversion used in the engine.
Ratio and liquid cap
Both Safe criteria satisfied.
Status
Matches the calculator default screening result.
5. Frequently Asked Questions & Technical References
ShowHide
API RP 14E sets an erosional velocity limit from empirical factor C and density ρ in lb/ft³. This app converts your density input, computes vc, and compares it to v = Q/A.
C = 100 is the CS continuous solids-free default. C = 150 is the SS/CRA default here (Norsok / ISO style guidance). Intermittent CS service is often 125–150 — follow site standards.
Even when RP 14E allows a higher vc, this app flags Warning for CS liquids above 3.5 m/s (SS 5.0 m/s) for FAC / film-stripping and plant hydraulic practice.
No. RP 14E assumes relatively clean fluids. High sand loadings need dedicated particulate erosion models — not this screening tool.