The Pressure Vessel Inspections article provides you information about the inspection of pressure vessels and pressure vessel tests in a manufacturing shop. You may want to review the pressure vessel inspection procedure and corresponding inspection and test plan.

Pressure Vessel Definition – Based on the ASME Code Section VIII, pressure vessels are containers for the containment of pressure, either internal or external.

This pressure may be obtained from an external source, or by the application of heat from a direct or indirect source, or any combination thereof.

Click on the above link for detailed information about pressure vessel definition, scope, and boundaries based on ASME and API codes which specifically focus on pressure vessel inspections.

ASME Code Section 8 – ASME Code Section 8 is the construction code for Pressure Vessels.

This Code section addresses mandatory requirements, specific prohibitions, and non-mandatory guidance for pressure vessel materials, design, fabrication, examination, inspection, testing, certification, and pressure relief.

You may know that ASME Code Section 8 has three divisions. Division 1 covers pressure up to 3,000 psi, Division 2 has an alternative rule and covers up to 10,000 psi, and Division 3 can be used for pressure higher than 10,000 psi.

This section is divided into three parts: subsections, mandatory appendices, and non-mandatory appendices.

Subsection A consists of Part UG, covering the general requirements applicable to all pressure vessels.

Subsection B covers specific requirements that are applicable to the various methods used in the fabrication of pressure vessels. It consists of Parts UW, UF, and UB, and deals with welded, forged, and brazed methods, respectively.

Subsection C covers specific requirements applicable to the several classes of materials used in pressure vessel construction.

It consists of Parts UCS, UNF, UHA, UCI, UCL, UCD, UHT, ULW, and ULT dealing with carbon and low alloy steels, nonferrous metals, high alloy steels, cast iron, clad and lined material, cast ductile iron, ferritic steels with properties enhanced by heat treatment, layered construction, and low temperature materials, respectively.

Click on the above link for detailed information about ASME code section 8, which specifically focuses on pressure vessel inspections. 

Pressure Vessel Plate Material – You have to be careful when choosing Pressure Vessel Plate Materials; there are lots of requirements and specific prohibitions in the ASME code.

Some of these requirements are ASME and Non ASME plate material, plate specification, inspection requirement and material test report.

ASME Code Sec VIII DIV 1 requires that materials that used for pressure containing parts are one of the materials specified in ASME section II, but with some restrictions which are stated in ASME Code Sec VIII Div 1 in subsection C e.g. UCS, UHF, UNF.

For example, SA 283 plate material is listed in ASME Sec II, but when you refer to subsection C in Sec VIII Div 1, you see it is not allowed to be used for lethal substance services as well as for unfired steam boilers. Also, you cannot use this material when you need your thickness to be greater than 5/8 of an inch.

Click on the above link for detailed information about pressure vessel plate materials which are specifically focused on pressure vessel inspections. 

ASME Pressure Vessel Joint Efficiencies – You may know ASME Pressure Vessel Joint Efficiencies are linked to the radiography testing grades, and there is concession for full radiography testing per the UW-11(a) (5) (b) clause, which it is a little bit confusing.

Based on ASME Code requirements, manufacturers have to mark the type of RT, e.g. RT1, RT2, RT3 and RT4, in the pressure vessel name plate and state the same in the Pressure Vessel Data Report.

We have seen many professionals including inspectors and quality control engineers who are confused between RT1 and RT2, specifically when they see that the ASME Pressure Vessel Joint Efficiencies for both RT1 and RT2 is the same and is equal to 1(E=1);

They say both RT1 and RT2 are categorized in the “Full Radiography” part in UW-11 clause. So why are some joints in RT2 radiographed in spot? We are doing spot radiography, but it is categorized in full radiography!!!

Click on the above link to answer to this question, which specifically focuses on pressure vessel inspections.

ASME Impact Test Requirement – You need to take care about ASME Impact Test Requirement. Suggest you have pressure vessel in the design process and construction has not started yet.

Based on ASME impact test requirements, you need to make an assessment to see that either your pressure vessel is exempted from impact testing or you need to carry out the test.

There are 4 steps for impact test exemption assessment. You need to go through these steps, and you might be exempted in the first, second or third steps, and might not be exempted in step 4;

So if you are in step 4 and you have not exempted, then you need to carry out the test. This article explains you this assessment process.

First, you have to keep your pressure vessel design data available and then refer to UG-20 (f), if you are exempted from this clause, you do not need proceed anymore.

But if you are not exempted by UG-20 (f), you have to proceed to UCS-66(a). Again if you are exempted, there is no need for more assessment.

But if not, you have to proceed to UCS-66(b). If you are exempted now, no need for more assessment, otherwise you have to proceed to UCS-68(c). Again, if you are still not exempted; you have to carry out impact testing.

It means for some cases we might be exempted from ASME impact test requirement in first stage in UG-20 (f), in others in UCS-66(a) or UCS-66(b) or UCS-68(c) or might not be exempted and must prepare for doing this costly test.

This test would be more costly out of the US because of the Laboratory Accreditation requirement. The Accredited Laboratory based US accreditation system is not used too much in Europe, the Middle East and other locations.

Click on the above link for detailed information about the ASME Impact Test Requirement, which specifically focuses on pressure vessel inspections.

Pressure Vessel Dimension Inspection – Do you know what the Pressure Vessel Dimension Inspection requirement is? You may know some fabrication tolerances have not been addressed in ASME Code Section VIII.

So you need to refer to other sources for inspection. Most dimensional controls of Pressure Vessels are either addressed or not addressed in the ASME Code. They consists of the following items:

Pressure Vessel Inspections – Dimension

• Mill Undertolerance of Plates and Pipes
• Tolerances for Formed Heads
• Out of Roundness of Shell
• Nozzles and Attachments Orientation
• Nozzles and Attachments Projection
• Nozzles and Attachments elevation
• Nozzles and Attachments levelness
• Weld Mismatch
• Weld Reinforcement