Evidence-controlled arithmetic · not code sizing
Controlled Pressure-Vessel Thickness Record Comparator
Compare a thickness already established by an approved licensed-code calculation, plus only its explicitly authorized additive allowances, with a minimum credited thickness on the same documented basis.
Arithmetic comparison
Same-basis record comparison
margin = tcredit − tdocumented,total
ratio = tcredit / tdocumented,total
All three thickness inputs must refer to the same physical component location and compatible thickness definition. The worksheet converts inches to millimetres internally with exactly 1 in = 25.4 mm, performs addition/subtraction/division, and returns the selected display unit.
A positive margin means only that the entered credited value is numerically above the entered arithmetic total; zero means equal; a negative margin means below. No safety factor, allowable stress, joint coefficient, head coefficient, pressure formula or code acceptance rule is applied.
The former page claimed minimum shell and head thicknesses to EN 13445 and ASME Section VIII from pressure, outside diameter, a fixed material value, a generic weld factor and corrosion allowance. That claim was not supportable.
| Former component | Confirmed problem |
|---|---|
| Design temperature | Collected but never used. Hard-coded allowable stresses therefore did not change with temperature. |
| Material presets | Fixed values were shown without a verified edition, product form, temperature row, notes or code-source traceability; ASME SA material labels were also offered under the EN route. |
| Joint / weld factors | Generic 1.0, 0.85 and 0.7 choices were applied to both code systems without verified joint category, examination scope or licensed rule. |
| Cylindrical formula | The displayed ASME inner-radius equation differed from the outside-diameter equation executed by JavaScript. The worked example used another radius approximation while the default route was EN. |
| Heads | Hemispherical and ellipsoidal equations were labelled code formulas while runtime comments called them approximations or simplifications. Flat-head coefficients 0.33 and 0.35 were hard-coded as “typical” without geometry/attachment scope. |
| Corrosion and plate recommendation | Universal service allowances and “use 12 mm plate minimum” ignored the controlled corrosion basis, negative tolerance, forming, other loads and code-specific requirements. |
Changing one coefficient would conceal rather than fix these root causes. The unsupported formula engine, presets, automatic results and code-compliance language were removed.
This list is a scope reminder, not a substitute for either code. The responsible approved calculation must determine what applies, including:
- jurisdiction, exact governing code/edition/addenda and component scope;
- design, operating, test and external pressures; temperatures and coincident load cases;
- component geometry, diameter/thickness convention, heads, openings, nozzles, supports and discontinuities;
- material specification, product form, temperature-dependent allowable basis and degradation mechanisms;
- joint category, weld details, examination extent, applicable coefficient and fabrication route;
- corrosion/erosion allowance, design life, negative material tolerance, forming thinning and credited minimum thickness;
- external-pressure stability, local loads, wind/seismic/dead weight, thermal effects, fatigue, creep, fracture and cyclic service as applicable;
- reinforcement, inspection, nondestructive examination, pressure testing, overpressure protection, documentation and authorized approval.
ASME BPVC Section VIII, Division 1
The official ASME BPVC.VIII.1-2025 product page describes requirements for design, fabrication, inspection, testing and certification of vessels within its scope, with material/fabrication requirements and mandatory and nonmandatory appendices. This public scope confirms why a few generic equations cannot establish conformity; detailed rules require authorized access.
EN 13445-3
The official national-standards-body page for NBN EN 13445-3:2026 identifies it as active from 2 July 2026, replacing NBN EN 13445-3:2021+A1:2026. Its scope is design of unfired pressure vessels covered by EN 13445-1:2026 and constructed of steels under EN 13445-2:2026. Detailed rules remain licensed, and the applicable national adoption/jurisdiction must be confirmed.
Length conversion
NIST SP 811 Appendix B.8 lists 1 inch = 0.0254 metre and marks exact factors in bold. Therefore 1 in = 25.4 mm and the official unit check 0.5 in = 12.7 mm is exact.
Sources and lifecycle status accessed 13 July 2026. No ASME/EN clause number, table value or formula is asserted without the licensed text.
Nikolai Shelkovenko
Nikolai Shelkovenko is a vibration analysis engineer and the founder and CEO of Vibromera. For more than 15 years he has balanced rotating equipment in the field rather than on a test bench: mulchers, industrial fans, crushers, centrifuges, shafts and spindles. That work is what the Balanset instruments grew out of — they were designed as a tool a specialist can carry to the machine and use alone, on site, not as laboratory equipment. Vibromera was founded in 2017 and has been based in Porto, Portugal, since 2023. Development, assembly and support of the Balanset line all happen here. The flagship instrument is the Balanset-1A, a portable analyser for single- and two-plane balancing and for vibration diagnostics. Nikolai is personally involved in customer support, in working through difficult balancing cases and in the development of the software. He works with customers worldwide, in any language.
