Minimum distance between welds API 650 (non-reinforcement nozzle and vertical fillet weld)

[trolex]

I have been working on the design of a small API650 Tank and I'm having some issues with the spacing that between nozzles and welds.

To be more specific, if we look at Figure 5.6 and 5.7.3 I have something close to the requirement for distance E.
Also, NOTE 2, specifies the following: "Weld spacings are measured to the toe of a fillet-weld, the centerline of an insert or thickened insert plate butt-weld, or the centerline of a shell butt-weld". But as per what I see, I have a "S-N" Nozzle (no reinforcement plate) close to an overlapped plate welded to the tank shell (vertical fillet welding).

Here is an image with the detail

I want to know if:

* Figure 5.6 (spacing E) is what applies here.
* If the previous answer is no. Is 50 mm (2 in) ok? Otherwise,where I can find in the norm the minimum spacing requirement
* If the answer is positive and 75 mm is the minimum. What other options do I have to solve the issue?

Any comments you may have is well appreciated.

Regards

 

[JStephen]

I don't have a copy of the code in front of me, but...
-The "Weld spacings are measured" clause is specifically telling you how the nozzle spacing requirements are to be measured, not just fillet welds in general. So I would say the yellow doohingy doesn't fall under that category.
-There is a clause elsewhere in the standard for "shell attachments" that would include the yellow doohingy. It gives minimum spacing for Group IV and above shell, but NOT for Group I/II, as I recall, meaning, no minimum spacing in that requirement. (Edit: Section 5.8.1.2.)
-Annex A has reduced spacing requirements for nozzles. (Edit: A.5.2.) That looks like a VERY small tank, and in that case, Annex A and J should be used for it. Note that Annex A is referenced for design by Annex J, although it is not clear if that means all Annex A is applicable.
-For that specific situation, one alternative would be to extend the pad on the yellow doohingy to encompass the nozzle, serving as a repad for both. Or make the whole shell thicker where the yellow repad isn't required.