Maximum Length for LWN

[nashof]

Hello All,

Could someone confirm me if there is a maximum length for long weld necks?

The client is asking for a vessel in cyclic service to provide self-reinforced nozzles for those bigger than 2" and LWN nozzles for 2" and less. (Something quite usual).
The problem is this vessel will have 200mm of insulation, so minimum projection for 2" nozzles needs to be something like 300mm from vessel ouside wall.
I think this is not possible using LWN nozzles, as the maximum length for these is 228mm. Can someone please confirm?
If actually no LWN nozzles can be used, is it possible to use a WN self-reinforced nozzle of 2"?

Thank you very much in advance!

 

[yl0525]

Hi Nashof,

If that is the case, you could opt for self-reinforced nozzle eg H-neck etc.

yl0525

 

[doct9960]

FVC has 18" long LWN's in stock for 2" NPS. You can even order lengths longer than 18" but it will cost you.

http://www.ameriforgegroup.com/fvc/FVC Prices web effective 5-11-06.pdf

 

[vesselfab]

we have gotten them 24" long

If we are forced to use one longer....we buy two short ones and weld together.

 

[waskillywabbit]

You can order custom lengths, we got some that were 30" long on a recent project, but they are pricey.

 

[DG72]

We have found that 9" and 12" are standard off-the-shelf lengths,but custom lengths, ordered in 1" increments above 12" are also readily available, but they do get pricey. Word of advice, if you go with a long length, you will probably want to add gussets to the nozzle, since it will be long and slender.

 

[nashof]

Thank you for all the comments!
9" and 12", as DG72 is saying, I think are most common lengths.

Our LWN are stainless steel (SA-182 Gr. F304L) and they need to be LWN or self reinforced WN, as the vessel is in cyclic service.

Do you consider if the vendor considers difficult to find (or the client considers expensive...) LWN with a length of aproximately 14" the using of self reinforced WN nozzles of 2" is ok for this service?
I think it should be completely ok.

 

[SnTMan]

Assuming this is Sec VIII, Div 1 then:

2" nozzles are likely to be exempt from any reinforcement calculations.

If not, if they can be made to "make" w/o pad, they are "self reinforcing" a term I find somewhat ambiguous.

However, if the client requires LWN, the client requires LWN.

Regards,

Mike

 

[SnTMan]

nashof, I just read your other thread, so my previous post may not apply to your situation. Doh!

Regards,

Mike