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[MW:27273]

By Materials & Welding
Dear Experts can you advise me for the below clarifications (also refer the attached sketch):


Shell to bottom cutting for Tank bottom plate replacement as per API-653

As per API 653 section 9.10.3, it is recommended for removing existing tank bottom by cutting the shell parallel to tank bottom at a minimum of ½'' above the bottom to shell weld.

For shell plate having a thickness of 10mm, a minimum of 10mm height will be reduced from the existing shell height (if removal of heat affected zone is not considered) 

Alignment with existing piping connections can be made possible by increasing the eathen foundation level for 10mm, prior to laying of new bottom/ annular plate.

Still is a concern of decrease in minimum distance from bottom of Tank to centre of shell/ manhole Nozzles and reinforcement pads. After completion of repair/ replacement works, Tank needs to be certified for API 653.

Also would like to know any impact of above by use of gas cutting method for the above (pug cutting machine)


Thanks in advance
--
SANDEEP K SREEDHAR

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https://materials-welding.blogspot.com/
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