API 650 Nozzle through Floor and Shell

[uncletank]

Hi all,

We are currently designing a small anchored sulfuric acid tank (D = 4.2m, H = 4.8m )and have been requested by our client to allow for a "Gullet Drain" That is basically a pipe with centreline intersecting the floor to shell joint (see attached sketch). Legislation in New Zealand requires that we comply strictly with API 650.

This type of nozzle does not appear to be covered in API 650 - it is between a flush nozzle and a underfloor connection.

I have the following questions:

1) Can this type of nozzle comply with API 650?
2) If yes to above, would heat treatment be required as we penetrate the floor to shell joint?

 

[MJCronin]

Uncle....

I have seen this special type of "flush/cleanout" nozzle contained within company mechanical standards. Yes, you are right, it is not contained within API-650.

You would most typically find this design where there is dirty liquid contained (slity or ash service). I do not see the purpose of this nozzle on a sulfuric acid tank. (I know, I know....the client wants it)

Some comments:

If the nozzle is to be used for a hose attachment, then support the end of the nozzle (near the flange) with a post that goes to concrete. This will protect the tank when the hose gets twisted/pulled and otherwise abused.

Is there any leak detection grooves in the foundation ? If so, they should be considered in the design.

IMHO API-650 should have a detail for this type of nozzle, just like they do for manways.

Best Regards

-MJC

 

[JStephen]

The simplest detail that would comply with API-650 would be a bottom opening with a short-radius ell and pipe running out under the tank.

The problem here is that API-650 is intended for oil storage tanks, not general industrial tanks, so there's a lot of stuff that isn't covered.

 

[IFRs]

You could of course use an API flush nozzle detail. The detail you have shown is not that uncommon, even for tanks otherwise built to conform with API.