min distance of adjacent welds
min distance of adjacent welds
(OP)
Hi all,
Got a question here,
On the body of the vessel, a nozzle and a tube-sheet need to be welded on opposite side of the body, (regardless of the reinforcement of the nozzle opening), is there a requirement of how close of these weld can be located?
The idea is, for a vertical vessel, the tube-sheet divide the vessel into upper and lower chamber. To drain the upper chamber, theoretically the bottom of the ID of a nozzle should be welded flush with the top face of the tube-sheet, but this will result weld on each side of the vessel wall too close or even overlap.
Is there an requirement in ASME stating about this issue? In AS1210 there is a requirement of adjacent weld min distance of 40mm or 3 times of thicknees of vessel wall, but for weld on the same side of the vessel wall, not sure if this apply to this case.
Any suggestion?
Thanks in advance
Got a question here,
On the body of the vessel, a nozzle and a tube-sheet need to be welded on opposite side of the body, (regardless of the reinforcement of the nozzle opening), is there a requirement of how close of these weld can be located?
The idea is, for a vertical vessel, the tube-sheet divide the vessel into upper and lower chamber. To drain the upper chamber, theoretically the bottom of the ID of a nozzle should be welded flush with the top face of the tube-sheet, but this will result weld on each side of the vessel wall too close or even overlap.
Is there an requirement in ASME stating about this issue? In AS1210 there is a requirement of adjacent weld min distance of 40mm or 3 times of thicknees of vessel wall, but for weld on the same side of the vessel wall, not sure if this apply to this case.
Any suggestion?
Thanks in advance





RE: min distance of adjacent welds
When you need to drain the shell side of a vertical HX, is an standard to drill a radial hole in the tube sheet , drill a distance till you save the gasket face, then you drill a vertical one so you connect both holes and then you have a path to outside.
On the tubesheet you can weld on the external face of the tubesheet, a nozzle and a socket valve.(about 1").
This job is done before you weld the tubesheet or the tube bundle.
RE: min distance of adjacent welds
RE: min distance of adjacent welds
However, if you HAVE to weld the dreaded nozzle flush with the tubesheet, the code doesn't stop you to weld them next to each other, provided you follow up the approved welding procedure for this particular weld and perform all the required NDE's.
The mentioned 1 1/2" or 3 times the shell thickness is only recommended by the code to avoid special welding conditions.
Cheers,
gr2vessels
RE: min distance of adjacent welds
from what I understand is instead of using a nozzle, just tab a hole on the tubesheet and use a plug? Well, in that case why can't it be just a tab on the vessel wall?( provided that the vessel wall is thick enough) What about say vessel 600NB, use a 1 inch plug or 2 inch plug will still take forever to complete drain it.
Thanks for all the comments.
RE: min distance of adjacent welds
RE: min distance of adjacent welds
In PD 5500 a doubler pad cannot be within minimum of 40mm or twice the shell thickness.
And a nozzles weld must be atleast 12mm from a main seam or the nozzle must pass through the centre of the main seam.
RE: min distance of adjacent welds