The inspection of pressure vessels is done for safety purpose and to avoid potential accidents on the floor. But do you have any idea how these intricate processes are executed by the NDT experts? Sometimes, inspections are also conducted at the very first stage of the vessels, that is, during the manufacturing process.
Usually, all kinds of inspection and testing on pressure vessels are done according to approved specifications, drawings and company standards. But they are executed while staying within the practices & rules applied by the governmental ordinances in a particular country or state.
The codes and specifications applied for a pressure vessel inspection include:
• Design code
• Approved drawings
• Purchaser’s standards
• Purchase order specification
Sometimes the applied codes and standard may match with the international standards too.
At first, the raw materials are inspected on the pressure vessel to learn its type. As per the ASME Code, providing reports on material test is mandatory. It is covering all the components of a pressure vessel like the nozzle pipes, lines, heads, fittings, etc.
The AICIP pressure vessel inspector examines all the required certificates for compliance with specifications using appropriate drawings. It includes:
• Heat or Cast Number
• Chemical Composition
• Certificate Number
• Heat Treated Condition
• Mechanical Properties
The junior inspector witnesses the plate material identification based on the certificates. Based on the requirement they can also check the identification with the pressure vessel datasheet, material list and other specifications as mentioned in the certificates.
After inspecting the materials, visual inspections are conducted on the surface to find out probable defects and dimensional obstacle & complications. At this stage, the process includes:
• Records of all non-conformities
• Confirmation of satisfactory document review
• Record of tests witnessed
The Inspection Of Fabrication
After the visual and raw material inspection, comes the fabrication. Remember, this will start only if the previous results are satisfactory and meet the codes. The NDT expert checks the crucial points on the pressure vessel, based on the previous inspection and test plan.
Some business owners prefer to have stringent controls on pressure vessels due to heavy duty services. In such cases the inspection naturally grows more intricate. However, this depends on the inspection budget, which purchasers assign for inspection.
One thing that has to be kept in mind is that AICIP pressure vessel inspection can be done only if the inspectors are verified and certified by a reputed legal firm or the AICIP itself.