What the result helps you understand
Pressure thickness, joint efficiency, future metal loss and manufacturing tolerance affect the answer in different ways. Keeping them separate makes the screening calculation traceable and easier to review.
Vessels & Tanks
AS 1210 Vessel Shell Thickness & MAWP Calculator
Screen cylindrical or spherical shell internal-pressure thickness, nominal wall after allowances and under-tolerance, and MAWP from an entered wall.
“I have the vessel diameter, pressure, material design strength and joint efficiency. What shell wall does the pressure equation require, and what MAWP does the entered nominal wall screen to?”
Core formulae
AS 1210 shell pressure-thickness screen
Cylindrical shell — circumferential stress
t = P D / (2 f ηL − P)Cylindrical shell — longitudinal stress
t = P D / (4 f ηC − P)Spherical shell
t = P D / (4 f η − P)Required nominal wall
t_nom = (t_pressure + allowances) / (1 − under-tolerance)Expressions shown are the inside-diameter forms. The calculator also supports the corresponding outside-diameter forms.
The inverse MAWP screen uses the effective entered wall after the under-tolerance and allowances entered by the user.
Simple arrangement sketch
Shell diameter, wall and pressure
1
Shell pressure basis
Use the approved design pressure, design tensile strength and joint-efficiency basis for the actual vessel.
2
Allowances and entered wall
Keep pressure thickness, future loss allowance and manufacturing under-tolerance visible as separate inputs.
Results
Internal-pressure shell screen
Circumferential-stress thickness5.91 mm
Longitudinal-stress thickness2.95 mm
Governing calculated pressure thickness5.91 mm
Thickness including allowances7.41 mm
Required nominal wall incl. under-tolerance8.47 mm
Effective entered wall for pressure screen9 mm
After entered under-tolerance and allowances.
MAWP screen from entered nominal wall1.519 MPa
MAWP — circumferential stress1.519 MPa
MAWP — longitudinal stress3.037 MPa
Entered nominal wall is above this simplified pressure-thickness screen
This only means the entered wall exceeds the calculated internal-pressure thickness plus the allowances and under-tolerance entered here. It is not vessel approval.
Pressure-equation thickness may not govern the nominal vessel wall
AS 1210 also has separate minimum nominal thickness and construction requirements. A lower pressure-equation result does not by itself permit a thinner vessel wall.
High-consequence pressure equipment — full AS 1210 design remains required
Not checked: external pressure and buckling, heads and transitions, openings and reinforcement, nozzles, local loads, supports, fatigue, thermal gradients, minimum construction thickness, forming thinning, corrosion mechanisms, material temperature limits, testing, inspection, registration or jurisdictional requirements.
Design-basis boundary
This calculator applies only the selected cylindrical or spherical shell internal-pressure relationship. Confirm the current AS 1210 edition and amendments, the full clause context, material properties, joint efficiencies and all other applicable design checks.
Job-file record
Save the calculation, not just the number.
Copy a permalink that reloads these inputs, or download a PDF record with inputs, visible results, assumptions, a sensitivity note, date and disclaimer.
Know where the quick calculation stops
Internal pressure in a simple cylindrical or spherical shell only. It does not check external pressure, heads and transitions, openings, nozzles, local loads, supports, fatigue, thermal effects, minimum construction thickness, forming thinning, inspection, testing or registration.
Important boundary
A calculator can show the arithmetic. It cannot establish every requirement that applies.
Confirm the actual equipment, loading, materials, condition, jurisdiction, contractual requirements, standard edition and current project documentation before using the result for design, repair, testing or lifting decisions.
Ask an engineer about this calculation →