Calculator
Example data table
| Case | Head (m) | Surge (%) | Diameter (mm) | Allowable (MPa) | E | SF | CA (mm) | Tol (%) | Recommended thickness (mm) |
|---|---|---|---|---|---|---|---|---|---|
| Hydropower penstock | 120 | 20 | 2000 | 150 | 1.00 | 1.50 | 2.0 | 12.5 | 18 |
| Higher head line | 250 | 25 | 1800 | 200 | 0.85 | 1.60 | 3.0 | 12.5 | 26 |
Example values are illustrative; verify with your governing design code.
Formula used
- Static pressure from head: (Pstatic = ρ g H)
- Surge allowance: (Pdesign = Pstatic(1 + surge%/100))
- Effective allowable stress: (Seff = S × E / SF)
- Thin-wall hoop thickness: (t = P D / (2 Seff))
- Nominal thickness with allowances: (tnom = (t + CA) / (1 − tol/100))
- Check stresses: (σh = P D / (2 teff)), (σl = P D / (4 teff))
This tool uses the thin-cylinder approach. If your D/t ratio is low, consult a thick-wall method and your project specifications.
How to use this calculator
- Choose a pressure method: head-based or direct pressure.
- Enter diameter and select a material preset or custom stress.
- Set joint efficiency, safety factor, corrosion, and tolerance.
- Click Calculate to view results above the form.
- Download CSV/PDF to attach design notes and approvals.
Always confirm inputs, units, and code requirements before final design.