Complete Annular Plate Replacement. Jacking?. Hydro Required?
Complete Annular Plate Replacement. Jacking?. Hydro Required?
(OP)
Hi All,
I have a 24m diameter tank that requires replacement of all annular plates. First question do I jack the entire tank or replace the plates 1 by 1. I am thinking that jacking the tank will allow a better job of replacing the plates and that it will ultimatly be quicker as I can have multiple welders working at once.
Secondly. If I jack the entire tank does this force me to undergo hydrostatic testing? I believe that I would be able to exempt myself from hydro if I replace 1 by 1.
Obviously everything I do needs to comply with API 653. Ultimatly my goal is to get my tank back online as quickly as possible.
I have a 24m diameter tank that requires replacement of all annular plates. First question do I jack the entire tank or replace the plates 1 by 1. I am thinking that jacking the tank will allow a better job of replacing the plates and that it will ultimatly be quicker as I can have multiple welders working at once.
Secondly. If I jack the entire tank does this force me to undergo hydrostatic testing? I believe that I would be able to exempt myself from hydro if I replace 1 by 1.
Obviously everything I do needs to comply with API 653. Ultimatly my goal is to get my tank back online as quickly as possible.





RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
Are you able to slot and insert when only replacing the annular? I can just picture that the annular plates would need to angle down to meet the exiting floor plates and I would be nervous of overstressing at this critical area. I can see that if you installed a completely new floor above the old one this would be possible.
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
I have left my copy of the standards in the work place. If im not getting it I would really like a diagram of how to weld this !!. Or is it like this? pack up the difference with oil sand?
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
TANKO and Chicago Bridge & Iron are my favorite large firms. They ALL know what to do and how to replace an annular ring. They should ask you what NDT you want on the new ring section-to-section welds, and how far in you want to make the intersection of the new floor plate to existing floor plate joint.
When you try to specify construction details to professionals that have [several orders of magnitude] more knowledge and experience than you do, you are making a huge mistake. And yes, I've made that mistake.
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
I need the tank back in service yesterday so time is more important than $ although that is a factor. Also I want the repair to be compliant and not give me problems down the track. If it makes any difference the tank is also an elevated temperature tank (200 deg C / 392 deg F)
RE: Complete Annular Plate Replacement. Jacking?. Hydro Required?
Jacking is becoming more common in building new tanks - fab a ring, jack it up, fab another ring [under the first one], repeat. The fitters & welders can stay on the ground. If that is in the resume of the experienced folks, I'd sign a contract for them FAST. And unless you can hire an experienced tank erection/repair superintendent to run your job, don't hire the local folks. When you are out of time, you are out of room for repairs and mistakes.
I don't see that your hot liquid will cause any differences in the repair method. But I would require the floor-to-shell 'corner welds' be made using a low-hydrogen process, like FCAW. Preferably gas-shielded; FCAW-G [vs. FCAW-SS]. The gas-shielded wires tend to be more ductile, emit less smoke [makes for happier welders], and is easier to make good-looking big welds [happier inspectors].