allowable nozzle load

[VigneshK]

Dear expertise,
we are designing API storage tank about 20m diameter,client required nozzle load calculation too but in API annex-p given as tank not less than 36m.What should i do for nozzle load calculation for 20m dia tank?if i get nozzle data from client can i do the analysis with WRC107?

Thanks all

 

[HTURKAK]

Pls read the code again...

API 650 Appendix P 'P.1 Introduction
This appendix shall be used (unless specified otherwise by the Purchaser on Line 29 of the Data Sheet) for tanks larger than 36 m
(120 ft) in diameter, and only when specified by the Purchaser for tanks 36 m (120 ft) in diameter and smaller. See W.2(5) for
additional requirements....'

Good luck..

 

[JStephen]

There are a couple of technical papers that are the basis of the Annex P approach. Long ago, I had looked into those papers some. If I remember right, to simplify the design, the authors assumed that shell thickness was proportional to pressure. In large tanks, that is true, in small tanks governed by minimum thickness requirements, it is not true. So if in your case, thickness is greater than the API minimum thickness, I'd consider using that approach anyway.

Also, read the procedure cited there- you're supposed to calculate the deflections due to product in the tank and the stiffness of the nozzle, and report that to the owner, who THEN calculates the pipe loads, which you then check the nozzle for. If those loads were derived assuming a "fixed" nozzle, they may be overly high. If it's just a standard load to be applied to all nozzles/tanks, it may be unreasonable for your particular tank. It's not uncommon to have nozzle loads specified just as an exercise with no real meaning for either party, too.

 

[VigneshK]

NOTED THANKS FOR YOU REPLIES.

 

[MJCronin]

This problem has been around for a long time ....

More information here:

https://asmedigitalcollection.asme....zles-in-API-650-Tanks?redirectedFrom=fulltext

http://forums.coade.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=46454

https://www.eng-tips.com/viewthread.cfm?qid=432126

MJCronin
Sr. Process Engineer