Pressure Vessel Thickness Calculator report

Example vessel · Rev A

2026-07-26 23:42:54 UTC

SI (mm · MPa · °C)

ASME BPVC Section VIII, Division 1 (2025)

Design basis

Construction route

ASME BPVC Section VIII, Division 1 (2025)

Design pressure

1.500 MPa

Static head

0.000 MPa

External pressure / vacuum differential

0.000 MPa

Hydrotest-fluid head

0.000 MPa

Design / test temperature

200.0 °C / 20.0 °C

Material basis

SA-516-70 · curated ASME II-D Table 1A subset

Design / test allowable or nominal stress

138.00 MPa / 138.00 MPa

Design / test yield or proof strength

260.0 MPa / 260.0 MPa

Design / test elastic modulus

190000.0 MPa / 200000.0 MPa

Hydrotest stress-ratio basis

Automatic selected-material ratio = 1.0000

Joint coefficient

spot radiography preset · E/η = 0.850

Corrosion / tolerance treatment

Component-specific corrosion allowance and percentage mill undertolerance

Schematic

Governing summary

Governing check

Maximum allowable working pressure — Cylindrical shell

Utilisation

0.860 (86.0%)

Overall status

pass

FEA recommended

Yes

Checks

Check	Demand	Capacity	U	Status
Internal-pressure thickness — Cylindrical shell	7.73 mm	9.00 mm	0.859 (85.9%)	Pass
Governing component mode: circumferential stress.
Equations used $t = \frac{P R}{S E - 0.6 P}$ (asme-viii-1)
Minimum code thickness — Cylindrical shell	1.50 mm	9.00 mm	0.167 (16.7%)	Pass
Maximum allowable working pressure — Cylindrical shell	1.50 MPa	1.74 MPa	0.860 (86.0%)	Pass
MAWP is the lowest component pressure rating at design temperature in the corroded condition.
Hydrostatic test pressure	2.27 MPa	—	—	Info
Reported test pressure is a minimum pressure basis; include elevation/static-head effects at the gauge and high point.
External-pressure stability	0.00 MPa	—	0.000 (0.0%)	Pass
No external-pressure differential was entered.

Pressure component schedule

Required nominal thickness includes corrosion allowance and mill undertolerance.

Component	Type / governing mode	Selected nominal	Required nominal	Available pressure t	Utilization	MAWP	MAP new/cold (fixed geometry)
Cylindrical shell	circumferential stress	12.0 mm	10.6 mm	9.0 mm	85.9%	1.744 MPa	2.031 MPa
2:1 ellipsoidal head	ellipsoidal crown	12.0 mm	10.5 mm	9.0 mm	85.4%	1.757 MPa	2.049 MPa

Component	Inside diameter	Geometry	Corrosion allowance	Mill tolerance	External-shape inputs
Cylindrical shell	1200.0 mm	Unsupported L 2400.0 mm	1.5 mm	12.500%	—
2:1 ellipsoidal head	1200.0 mm	Inside depth 300.0 mm	1.5 mm	12.500%	—

Vessel MAWP

1.744 MPa

Vessel MAP, new and cold (fixed entered geometry)

2.031 MPa

Hydrotest pressure basis

2.267 MPa

Hydrotest pressure at entered component elevation

2.267 MPa

External-pressure differential

0.000 MPa

Warnings & scope flags

Minimum pressure at the top/reference point; include test-fluid static head at lower components.
Governing utilization is 86.0%; independent verification is recommended.

Assumptions

The implemented equations address static internal- and external-pressure thickness. Local loads, fatigue, creep, wind, seismic, piping reactions, support loads, and nozzle effects require separate assessments.
Except for the curated ASME Division 1 subset, material properties and allowable stresses are user inputs and must be confirmed for the governing product form, thickness, temperature, heat treatment, and edition.
Entered inside diameters, depths, and radii are the calculation geometry in the corroded condition. The calculator deducts corrosion allowance from thickness but does not automatically enlarge an entered diameter or radius.
The new-and-cold pressure rating restores corrosion allowance to available thickness and uses test-temperature material properties, while holding the entered inside geometry fixed. This is conservative for uniform internal corrosion; use a separate as-built-geometry run when an exact new-condition rating is required.
The entered joint efficiency or testing group must be verified against the governing weld category, joint detail, examination extent, material, and standard table. Convenience presets do not determine code eligibility.
Corrosion allowance is treated as a uniform loss from the pressure-resisting thickness.
Mill undertolerance is applied as a percentage deduction from nominal thickness.
The calculation assumes an unpierced pressure boundary; openings, reinforcement, attachments, and discontinuities require separate checks.
Shell and head thicknesses are evaluated as individual pressure-boundary components. Cone-to-cylinder, head-to-shell, and flat-end attachment stresses or reinforcement must be checked from the actual junction geometry.
The curated allowable-stress subset is transcribed from ASME Section II, Part D (2021 metric edition) and is used with the supplied 2025 Section VIII editions; verify edition alignment for an issued design.

Source traceability

ASME BPVC Section VIII, Division 1 · 2025 · UG-27
Internal-pressure rules for cylindrical and spherical shells.
ASME BPVC Section VIII, Division 1 · 2025 · UG-16
Minimum vessel thickness and plate undertolerance requirements.
ASME BPVC Section II, Part D · 2021 · Table 1A
Allowable stress values for the curated Division 1 material subset.
ASME BPVC Section VIII, Division 1 · 2025 · UG-99
Hydrostatic test-pressure basis.
ASME BPVC Section VIII, Division 1 · 2025 · UG-32
Internal-pressure rules for formed heads and conical sections.
ASME BPVC Section VIII, Division 1 · 2025 · Mandatory Appendix 1
Supplementary internal-pressure equations for nonstandard head geometry.

Pressure-thickness calculation only, not whole-vessel certification. A qualified pressure-equipment engineer must verify material/product-form data, fabrication and examination categories, all load combinations, junctions, openings, flanges, fatigue/creep/impact requirements, supports and attachments, test execution, jurisdictional requirements, and the exact governing edition.