Pressurise a real-size separator and see what the code asks for. This lab works through ASME Section VIII Division 1 UG-27 live: required shell thickness, the plate you would order, the shell’s MAWP and the UG-99(b) hydrotest pressure. The 3-D shell changes colour as the pressure approaches MAWP.
| Required t, circumferential stress · UG-27(c)(1) | |
| Required t, longitudinal stress · UG-27(c)(2) | |
| t + corrosion allowance | |
| Plate to order (next standard size) | |
| Shell MAWP, corroded · inverted UG-27 | |
| Hoop stress at the gauge pressure (corroded) | |
| Hydrotest ≈ 1.3 × MAWP · UG-99(b) |
How to use the lab
- Start from V-100: a 1800 mm separator at 15 barg, SA-516-70, CA 3 mm, spot radiography (E = 0.85). Press Reset to V-100 any time.
- Change one input at a time and watch the required thickness, the ordered plate and the MAWP. The wall build-up bar shows how corrosion allowance, code thickness and round-up margin add up to the plate.
- Switch E from 0.85 to 1.00 to see how full radiography thins the shell from 16 mm to 14 mm.
- Run the hydrotest to take the shell to 1.3 × MAWP. The hoop stress rises above the design allowable, which UG-99 allows for the test.
Learn the calculation
Every step is worked by hand, with the static head and heads included, in Pressure Vessel Shell Thickness Calculation (UG-27): worked example. The whole vessel (shell, heads, nozzle reinforcement, external pressure, MDMT and hydrotest) is in the Pressure Vessel Design course, which starts with 5 free lessons. For thick shells beyond the UG-27 limits, use the thick-wall (Lamé) calculator. Next, cut a nozzle into this shell in the Nozzle Reinforcement Lab (UG-37). More tools: all Design Hub Labs · free calculators.
Teaching model, not a design tool. Allowable stresses are typical Section II Part D values: confirm them against your code edition and project specification.
