11.2　Vacuum Tank

Ⅰ　Dominant Items

11.2.1　In case of welding for vacuum tank assembly，the WPQ shall be carried out with report，based on which the welding procedure and the operation instruction for welding shall be determined or prepared.

Quantity to be checked:100%.

Inspection method:Check WPQ report and the operation instruction for welding.

11.2.2　The internal quality of butt welds from the assembly of vacuum tank shall comply with the requirement of the design technical document，or that of Grade II of weld quality grading criteria of Construction and Acceptance Code for Welding Work of Field Equipment and Industrial Pipeline（GB 50236）in case of no requirement in the above document.Quantity to be checked:Randomly check 20%.Inspection method:Check the ultrasonic or radiographic inspection records.

11.2.3　The appearance quality of butt welds in case of vacuum tank assembly shall meet the requirement of the design technical document，or that of Appendix E of the Code in case of no requirement in the above document.

Quantity to be checked:Randomly check 20%.

Inspection method:Observe or check with a magnifier.

Ⅱ　General Items

11.2.4　The upper mouths for assembly of tank body shall be at the same horizontal plane with the height deviation of not larger than 5.0mm.

Quantity to be checked:100%.

Inspection method:Check with a level.

11.2.5　The allowable deviation for installation of vacuum tank shall comply with the requirements in Table 11.2.5.

Quantity to be checked:100%.

Inspection method:See Table 11.2.5.