self reinforced nozzle
self reinforced nozzle
(OP)
Is LWN flange self reinforced nozzle?
If it is, is there any reference in the code?
Thank you
If it is, is there any reference in the code?
Thank you
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RE: self reinforced nozzle
But not always is
calcs prove it is or isn't
RE: self reinforced nozzle
If the calc's show that there is adequate reinforcement with a LWN and its welds (i.e. no repad), then the construction would be considered "integrally reinforced."
jt
RE: self reinforced nozzle
On the other hand, if your area calculations are not satisfied, you have some choices:
1. Add a reinforcement pad (your nozzle will not be considered self-reinforced).
2. Increase your cylinder thickness. (this can be costly, especially if you are dealing with long segments; but, if you are dealing with short segments, as on a channel for a heat exchanger, it can be a very desirable option).
3. Increase your nozzle neck thickness. You have several options here: FVC has several standard heavy wall nozzles (ie. HB, V1, V2, ...). Also, you can design a custom bottleneck forging.
Dan
RE: self reinforced nozzle
My problem is not as simple. I have multiple openings on flat head (b 16.5 blind flange) with LWN flanges.
Minimum distance is 3/16” less than required by UG 36 (2.5*(d1 +d2)). As UG 36 is mentioning unreinforced opening (it maybe worded differently, I do not have code at home) I was hoping that I may be exempted.
As nozzles are 2”, normally, they would be exempted from area calculation, however being 4 nozzles closer than required by UG 36, they are not reinforced adequately.
My question is (as nozzles are already welded): do I have any alternative?
RE: self reinforced nozzle
You should be referring to the rules of UG-39 for reinforcement in flat heads.
RE: self reinforced nozzle
I can not agree with your definition of self-reinforced. In ASME VIII, any nozzle greater than 2NPS must be reinforced. Whether the reinforcement comes from a repad, excess shell plate or excess nozzle thickness... it's a reinforced nozzle. I think the term "self reinforced" is a non-code term that most of us understand anyway.
Joe Tank
RE: self reinforced nozzle
and sometimes 3" openings do not need to be looked at for reinforcement in ASME Sect VIII
the common vernacular, may not be professional engineerspeak, is that if a nozzle does not require additional reinforcing elements add, it is self reinforcing.
RE: self reinforced nozzle
Not a narrow view at all. It's just what the Code means. And, yes, sometimes a 3NPS is also an unreinforced nozzle. Isn't a thickened nozzle neck added reinforcement too? I'm not trying to change anybody's mind about the lingo we use among friends. I sometimes just get worried about proper terms as it's important to vessel maintenace and terms used by NBIC and API-510.
Joe Tank
RE: self reinforced nozzle
Really interested in new things
RE: self reinforced nozzle
Enjoying the Christmas holiday at this point, but I will find it in ASME and API-510 later. I don't have a copy of NBIC available. Have a graet holiday time.
Joe Tank
RE: self reinforced nozzle
Joe- That's not entirely true... The available vs. required reinforcement does not have to be checked for all nozzles greater than 2" NPS. At least for ASME VIII Div. 1 (I haven't checked the new Div. 2):
See also the rest of UG-36(c).
So, if I have a vessel not subject to rapid fluctuations in pressure with a shell which has a minimum thickness before adding CA of 0.374" I can add a stub-on (i.e. the right hand side of Fig. UG-37.1) 4" Sch 160 nozzle and not have to even consider calculating the areas of reinforcement. Alternatively, I can take a 3" NPS pipe and use it for a stub-in (left hand side of Fig. UG-37.1) design and not be concerned with opening reinforcement calculations - even if I'm using a weaker nozzle neck material than the shell such as SA-106B in a SA516-70 shell.
On shells of any required thickness, I can take a 3" NPS XXS (2.30" ID) pipe and use it for a stub-on nozzle without considering reinforcement.
The "anything larger than 2" NPS needs calc's" rule of thumb is just that: A rule of thumb which may safely (in terms of VIII-1 compliance) be applied to any construction. In my experience, most of the designs I check verify area replacement requirements for nozzles larger than 2" NPS - but if they don't I can't call them on a code violation. On the other hand, stub-in nozzles are against my current employer's standards so I'd have to exclude stub-in construction or allow an exception.
jt
RE: self reinforced nozzle
RE: self reinforced nozzle
I agree with you both pointing out that a 3NPS nozzle can also unreinforced under some instances. My point was that that a "reinforced" nozzle is any nozzle greater than 2 NPS (and also 3 NPS sometimes). That said, I also wanted to make a point that a thickened neck nozzle, although called "self-reinforced" in this forum is in fact a reinforced nozzle. Perhaps I was nit-picking the terms, but I just wanted to point out that a the presence of a repad is not what defines a reinforced nozzle. Rather, it's the size that defines an "unreinforced" nozzle. When ASME VIII, Div 1 refers to an "unreinforced: nozzle, it is referencing these smaller nozzles.
Joe Tank
RE: self reinforced nozzle
no one said "unreinforced"
what was being said was "self reinforced"
expounding.....it reinforces the opening with itself...
without any additional reinforcing elements added.
I do not ever recall seeing the code refer to an opening as a non-reinforced opening.
RE: self reinforced nozzle
I can see you lost in the jungle of arguments, with your question still unanswered..
Yes, you have a problem, because with the close proximity of your nozzles, the material between the nozzles cannot be counted for reinforcement any longer and either the nozzles will have to pick-up the required reinforcement or you have to add more thickness to the blind cover, or both.
The question is;- if you are designing, then pick the thickest 2" NB forging available, perhaps that will cover your requirement for "self-reinforced" nozzle also. If your nozzles have already been installed in the cover and the reinforcement is short due to nozzles proximity, all I can see is additional reo plate joining all your nozzles, with split between nozzles. Full pen weld and fillet weld on the perimeter. But this will cancel the self-reinforcing nozzles requirement. Is it acceptable? Please keep us posted..
cheers,
gr2vessels
RE: self reinforced nozzle
I guess I stuck my nose in and made a comment that was not really necessary. Let's not drag this out any further.
Joe Tank