Why vessels need more than a final inspection
By the time a vessel is painted, most of what matters is hidden: weld quality, repairs, heat treatment and material traceability. Our inspection plan puts visits at the points where defects can still be seen and fixed, then uses the hydrotest and data book review to confirm the record.
Equipment covered
Drums, separators, columns, reactors, storage spheres, air receivers, shell-and-tube heat exchangers, air coolers and plate heat exchangers, in carbon steel, low-alloy steel, stainless steel, duplex and clad plate.
Where vessels are fabricated in China
Fabricators of process vessels are concentrated in Jiangsu (Zhangjiagang, Wuxi, Nanjing), Zhejiang, Shanghai and Shandong, with heavy-wall reactor shops in Liaoning and Sichuan. Send us the fabricator’s name and city and we will confirm inspector availability.
Non-conformances we find most often
- Welder working outside the positions or thickness range of the qualification.
- Weld repairs visible on radiographs that are not recorded in the repair log.
- PWHT chart with too few thermocouples or a soak time shorter than the procedure.
- Nozzle orientation or projection different from the approved drawing.
- Material identification not transferred before plates are cut.
- Hydrotest gauge range or calibration not acceptable.
Questions buyers ask
What is the hydrostatic test pressure for an ASME VIII Div. 1 vessel?
Under UG-99 the standard hydrostatic test pressure is at least 1.3 times the maximum allowable working pressure, multiplied by the ratio of allowable stress at test temperature to allowable stress at design temperature. The inspector checks the calculated value on the test procedure before the test starts.
Do you replace the ASME Authorized Inspector?
No. The Authorized Inspector works for the fabricator's insurance or inspection agency and certifies code compliance for the U stamp. We act for the buyer, checking your specification, drawings and quality requirements, which go beyond the code.
How many visits does a pressure vessel need?
A typical vessel needs four to six visits, set by the hold and witness points in your ITP, such as document review, fit-up, NDE review, hydrotest and final inspection. Large or critical equipment may justify a resident inspector instead.