Minimum weld spacing requirement
Minimum weld spacing requirement
(OP)
Good afternoon all,
API 650 figure 5-6 states the fillet weld spacing requirement for shell nozzles.
Column C in this table state 75 mm minimum distance from the edge of pad plate (toe weld) to the corner weld (toe weld).
Is there any technical problem if we are not following this requirement ? Let say the actual distance is only 30 mm.
Many thanks for your respond.
API 650 figure 5-6 states the fillet weld spacing requirement for shell nozzles.
Column C in this table state 75 mm minimum distance from the edge of pad plate (toe weld) to the corner weld (toe weld).
Is there any technical problem if we are not following this requirement ? Let say the actual distance is only 30 mm.
Many thanks for your respond.





RE: Minimum weld spacing requirement
RE: Minimum weld spacing requirement
Note that in Appendix A, some of these weld clearances are reduced dramatically, and in API-12D, they aren't required in the first place, although it may be the same materials, same weld, and at the same stress level.
RE: Minimum weld spacing requirement
Thanks for the comments.
Yes we did use low type RF pad. Tombstone = Low type ?
The problem was there was fabrication error. So there is about 30 mm gap from the bottom of this low type RF pad to the corner weld.
The tank had been hydrotested. I do not know why this issue was not caught during fit up inspection nor visual inspection nor release for hydrotesting.
So far we do not see any un-usual appearance on this area.
RE: Minimum weld spacing requirement
RE: Minimum weld spacing requirement
It is impossible to modify this RF pad at this stage.
Yes, it is 30 mm above the annular plate.
Hydrotest at ambient temperature.
Shell and RF pad A516-60 9 mm thickness. Neck is A53B pipe. Full penetration weld.
CA for shell 3 mm.
Visually, there is no something strange in this area.
RE: Minimum weld spacing requirement
RE: Minimum weld spacing requirement
Thanks for your comments.
At present nothing we can do. No one will allow me to do such modification.
The maximum operating temperature is 60 deg C.
In this area the minimum ambient temperature during winter is about 2 to 5 C. deg.
The tank diameter is 18 M. Dome roof tank.