Questions regarding pressure testing of vertical containers
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A Class II stainless steel vessel requires a hydrostatic test at 3.03 MPa and non-destructive testing; Class A welds need 100% RT inspection. What requirements then apply to Class C, D, and E welds?
Regarding surface non-destructive testing, omissions often occur. GB/T150-2011 is based on TSG R0004-2009, and the new revised standard TSG 21-2016 introduces certain requirements that are not present in GB150. For example: 1. If the medium is extremely hazardous, 100% surface inspection is required. 2. When pressure or gas-liquid combination tests are used, 100% surface inspection is necessary. 3. Surface inspection is mandatory for Cr-Mo steel. These three points are where defects are most likely to occur; there are other requirements as well. For details, see the partial non-destructive testing section of TSG 21-2016
The risks associated with pneumatic testing are much greater than those of hydraulic testing; therefore, stringent non-destructive testing requirements are necessary to prevent defects from causing tearing failures.
Large-scale codes require surface inspection of all welds. For categories A and B, in addition to RT inspection, surface inspection is also necessary, as surface and near-surface defects cannot be detected by RT; PT/MT inspections are required instead
The pressure is still quite high; surface non-destructive testing is required for the fillet welds
Do A/B class welded joints require surface inspection?
For pressure testing, are surface inspections required for Class A/B weld joints?