Set on nozzles in ASME VIII 1

[DefenderJ]

Please can anyone tell me if there is a limit to the maximum size of set-on nozzle you are allowed on to a vessel shell?
We need to put a 4" nozzle onto the shell of a heat exchanger and would find a set on preferable to a set through.
I've had a look but cannot find anything defining a limit - however I am not an experienced user of ASME VIII. If you could mention the relevant section it would be a help.

I know that API 650 sets limits on set on nozzles, so I am assuming ASME VIII might also.

Thanks

 

[gr2vessels]

There is no specific limitation on the set-on nozzles size per ASME VIII. And that applies for all pressure vessels, including heat exchangers, air coolers, etc. API 650 is the steel storage tanks standard, not for pressure equipment.
Cheers,
gr2vessels

 

[DefenderJ]

Thanks gr2vessels.
So the reason I couldn't find a limit is that there isn't one!
It's really helpful to get a quick answer instead of trawling through the standard looking for an answer.

Cheers
John

thinking slightly philosophically: if you are looking for something in a standard and don't find it - can you assume it isn't there? Perhaps you just haven't found it yet?

 

[rneill]

That said, many end users do implement there own limit in their specifications. I've seen specs that mandated Set-on nozzles be limited to 2", some that limit it to 4" and some that don't have a limit.

 

[jte]

And some that don't allow them at all.

 

[JStephen]

I think the API-650 restriction just reflects how things are normally done. API tanks always have access from both inside and out, so there's not a lot of motivation to do it from one side only. Note that hot-taps per API-653 use larger nozzles of different style than shown in API-650.

 

[LSThill]

Reference to ASME DIV. 1 PAGE 130-134, FIG US-16.1, SEE NOTES