API510 - par 3.1.5.7 size of shell-to-bottom fillet welds 1

[aldocigna]

The rule is this

3.1.5.7 Shell-to-Bottom Fillet Welds

a. For bottom and annular plates with a nominal thickness 12.5 mm (½ in.), and less, the attachment
between the bottom edge of the lowest course shell plate and the bottom plate shall be a continuous fillet
weld laid on each side of the shell plate. The size of each weld shall not be more than 12.5 mm (½ in.)
and shall not be less than the nominal thickness of the thinner of the two plates joined (that is, the shell
plate or the bottom plate immediately under the shell) or less than the following values:

Nominal Thickness Minimum Size of
of Shell Plate Fillet Weld
(mm) (in.) (mm) (in.)
5 0.1875 5 3/16
>5 to 20 >0.1875 to 0.75 6 ¼
>20 to 32 >0.75 to 1.25 8 5/16
>32 to 45 >1.25 to 1.75 10 3/8

My question is this:

If anular plate size is 12mm and shell plate size is 11mm what is the minimum size of each shell-to-bottom welds?
I think correct 11mm minimum but the constructor (external company) used a 6mm weld size. It's incorrect?
If incorrect what repair is possible to do if already realizzed?

Eng. Aldo Cigna
Mantinance Engineering
ERG Priolo (Syracuse-Italy) Refinery

 

[JStephen]

From the info above, it should be 11 mm- the lesser of the two plate thicknesses. A weld that size would normally be a multi-pass weld anyway, so it should be possible to add additionl passes to bring it up to size.

 

[aldocigna]

Sorry for my mistake but the standard is API 650 (not API 510)