For containers undergoing pressure testing, are Class C and Class D welds also required to undergo 100% non-destructive testing?

It should be 100% MT or PT... Of course, if the space does not allow it, VT can be added (with the help of relevant equipment) along with airtightness.

There is no mandatory requirement for surface inspection of Class C and D welds on containers that undergo pressure testing.

Why must welds of categories A/B be tested at 100% RT during pressure testing? Isn’t pressure testing dangerous anyway... Is it only when there are defects in welds of categories A/B that it’s dangerous, while defects in categories C/D aren’t a problem? Internal pressure failure is equally dangerous whether it occurs in categories A/B or C/D.

In other words, as long as containers of types A and B are 100% inspected, surface inspection is required for welds of types C and D. Every weld is important; there are no mandatory requirements in the standards for conducting inspections. The designer can decide based on the specific operating conditions – there is no fixed rule.

As long as 100% testing is carried out for containers of types A and B, there are no specific requirements for welds of types C and D; in other words, 100% testing is not necessary for them. However, as a designer, it is possible to specify on the drawings what type of inspection should be carried out on welds C and D, depending on the design conditions.

For containers undergoing pressure testing, are Class C and Class D welds also required to undergo 100% non-destructive testing? If not specified in the drawings, there is no requirement for surface non-destructive testing of Class C and D welds. Generally, the design drawings specify such requirements, which are related to the properties of the medium and the strength of the material. Materials with a tensile strength greater than 540 MPa, as well as those with poor weldability, and media that are highly toxic, flammable, or explosive, usually require surface non-destructive testing. The pneumatic testing, the requirements regarding the volume of support structures, as well as any trace residues of water are all factors that come into play. As for minimizing risks, this is ensured through proper control during the testing process, such as increasing pressure gradually and implementing on-site safeguards. Under the same pressure levels, the stress on Class C and D welds is also less than that on Class A and B welds. The process is ensured by type test specimens.

According to Article 10.8.3 of GB150-1998, for vessels subjected to pressure testing, Class C and Class D welds must undergo 100% non-destructive testing in accordance with the methods specified in the drawings.

Does Article 10.8.3 of GB150-1998 state that for containers subjected to pressure testing, Class C and Class D welds must undergo 100% non-destructive testing in accordance with the methods specified in the drawings? Only those that meet several conditions shall proceed

I don’t remember any standard specifying what kind of testing is required for welds in pressure tests! However, C and D welds are generally subject to 100% inspection using MT or PT.

If you don’t mind the costs, it’s of course best to do it, but based solely on standards, no one will blame you if you don’t. It must only be done if it truly meets the requirements of 10.8.3.