Weld Spacing Issue

[edmiester]

I found out that none of the nozzles have been stressed-relieved on the tank I am currently working on. So if I am going to install an annular ring (to fix a corrosion issue, not because it needs one) then I would like to know if I need to make any modifications to existing nozzles. The existing weld spacing between the reinforcing pads and cornerweld does not meet current API 650 weld spacing of 10". Most of the nozzle spacing ranges from 2"-4". Further, some repads have about 2"-3" that I can trim, while others have none. So even if did trim them, I still wouldn't meet current weld spacing requirements. Can I leave the nozzles alone after installing a new bottom annular ring?

 

[Duwe6]

The 'Code' answer is NOPE.

Look at API-653 for replacing a floor - which is more or less what you are doing. The approved answer is that, for nozzles that will be too close to the shell-to-new floor weld, the entire repad-nozz assembly is cut out and 'pulled up'.

 

[fegenbush]

The common practice in bottom replacements is to increase the height of the nozzles accordingly, just as Duwe6 says. Regardless of existing construction, you could be liable (negligent) in the event of a failure if you notice a non-compliance component and fail to act.