Shop Fabricated Tanks

Quality, field fabricated tanks are nothing new.

API-650 applies to both partially and complete field fabrication.

Discuss details of the degree of field fabrication with your contractor. Ask about the success of other jobs that he has done in this manner. Get references and talk with them.

Review the specific differences of installation, inspection and testing of API-650 field fabricated versus shop fabricated tanks.

Hydotesting and liquid disposal is a big issue

This will be a decision made by the customer and his insurance carrier.

My advice is to go with the code. But, I'm not there, not part of that culture nor never been in that part of the world, and never want to go.

Either follow the controlling documents, or throw them away.

There are several issues to analyze here:

1.- If the tanks are pre fabricated then transported, and then assembled and welded, the different QA/QC steps in between have to be carefully monitored, since damage to welds, over stressing welds, etc., may affect the final quality of the tanks.

2.- If the tanks are pre fabricated, what is the size of the sections, since there are transport, damages, etc., and other considerations to be reviewed.

3.- Generally a pre fabricated tank like what you are mentioning, require Post Weld Heat Treatment to relieve the stresses caused on the metal.

4.- The client and their insurance carrier need to address the cost of the transport hazards.

5.- Review the contractor who will perform the work and have a group of inspectors there to assure that all the steps and tests are performed prior to shipment and that the contractor will repair any and all issues that may arise on the job site.

If all of these steps can be resolved then you can almost surely do it that way.

Thanks a lot for all your valuable replies.

Say, Tank Contractor situated inside the free zone itself near to the site. Hence, transportation won't take much distance (But have to transported through road).

Tank Contractor agreed to follow Appendix-J -Shop assembled storage tanks.

And if all your above points agreed by Contractor, Shall we still indicate API 650 as design code?

Is this not violating API 650 requirements?

If we accept Tank contractor for shop assembly, Do we have to face any other complications?

Need your expert advice...