#600 vessel nozzle Flange 1

[Lhenrique]

Dear Friends,
We have a #600 piping project that will connect to a vessel due to codes and standards this pressure class has to have sealing rings on pipe flanges but the vessel nozzle flange is not for sealing ring, it’s RF. My question: Is it correct?
Best Regards
Luiz Souza

 

[unclesyd]

Class 600 flanges can be either RF or RTJ depend on the piping design specifications. Is is usually based on the service like steam, hot gases, high pressure, etc.

Our piping specifications have a mix of RTJ's on Class 300 flanges and RF's on Class 2500 Flanges. Things like steam > 300 psig and thermal heating fluid all have RTJ's.

Can you comeback with a little more details.

 

[Lhenrique]

Thanks Unclesyd,

We are using this project for testing and measurement of on-shore oil well, max pressure 25 psig and max temp is 104° F.

We've contracted the designing and fabrications of these vessels and when they came up I figure out that nozzle flanges are RF, I ask contractors why, they told they had followed ASME code for the vessels and it was correct.

 

[Lhenrique]

Unclesyd

Concerning the pressure I mentioned above the correct is 355,584 psi

 

[unclesyd]

Please correct your pressure.

 

[Lhenrique]

pressure 356 psi

 

[waskillywabbit]

Generally the customer's specs dictate the type of flange to be used on the connections due to the process, at least this has been my experience. I work for a vessel fabricator and it is not w/in our scope to make flange decisions based on process, as we don't do process design, strictly fabrication.

Was the contractor not given specs that spelled out specifically what type of flanges needed to be used on the connections?

Brian

 

[Lhenrique]

waskillywabbit,

Thanks for your reply. The problem is if the contractor says he is correct what is the code I could check out?

We do process design but we do not do vessel design, we only give them at the time of bidding a data-sheet that doesn't specify the vessel it serves only as a guide for them to design.

 

[waskillywabbit]

UG-44 deals with flanged connections and pipe fittings.

I cannot ever recall a time where I've had to do anything more than pick the type specific appropriate class flange out of the standard acceptable flanges based on pressure and temperature according to the customer's specifications. It is really pretty cut and dry.

Sounds like there is a breakdown somewhere in the communication between you and the contractor over this RF flange issue.

Brian

 

[SnTMan]

Lhenrique, I doubt you will find any code reference as to selection of flange facings, that is more a matter of experience and preference, in my opinion.

Also my opinion, is at 356 psi and 104 F, a raised face is fine, especially if used with a sprial wound gasket. I don't think you'll have any problems.

Regards,

Mike

 

[Lhenrique]

Thanks All for your helpfull comments. That's why I read this forum everyday and learn a lot, I used to say here is my "real" graduation.
Thanks again

Luiz Souza
luizhenrique_99@yahoo.com

 

[PAN]

Lhenrique,
For your specific condition (365 psi @ 104 F), I do not know why do not you use flange class 300 instead of class 600.

RF flange is O.K. as SnTMan's post.

 

[Lhenrique]

PAN,

That's due our clients specs (our main client

http://www.petrobras.com.br)

concernig the site the equipment we've sold to them require.

 

[robsalv]

... ??

RTJ's are generally reserved for pretty harsh services, either in process fluids or pressure/temperature. Can't see the need for the conditions quoted... perhaps it's the product/process fluid? Perhaps the client is unduly conservative speccing an RTJ piping system [e.g. Our 600# steam system is an RF spiral wound system, whereas the Ammonia system is an RTJ 150# system...]


It seems that someone wasn't on the ball specifying a vessel with a 600# RF nozzle when it needs to connect into a 600# RTJ piping system.

If the piping spec is truly required to be RTJ [Client's directive or good practice] then the vessel nozzle ideally should be RTJ. The alternative would be to use a mating 600# RF spec for the pipe flange at the nozzle, then spec break back to the RTJ piping spec for the piping system... and have this reviewed and approved by the relevant owner engineer/project manager.

Cheers

Rob

 

[Lhenrique]

Rob,

Thanks for your explanation. You're pretty right the customer is unduly conservative, the fluid/process is not harsh, that's crude oil, natural gas, sand and water that comes from the wells, we have only cavitation to worry about, as you see, not a so dangerous product.

The alternative we've already take was exactly you suggests, but we have one problem two instruments to be connected on vessel were specified, and purchased as RTJ flanges.

What is, in your opinion, the unique way out? To change flanges to RTJ for these instruments? That's what we're thinking about.

 

[robsalv]

"All the way with RTJ"... sorry, bit of Aussie humour.

...somewhere down the line, a facilities engineer is going to curse the hodge podge of flange types that don't seem to have good reason.

IMO, and based on my limited understanding of all the competing demands, I'd make the vessel RTJ.

Cheers

Rob

 

[bsme3]

Check with Flexitallic before you start cutting flanges off. Ask them about a cross over gasket. They may be able to supply you with a gasket that will seal an RTJ to a RF. Believe it or not they work. I used them on my gassification project and was very skeptical when the supplier came out with this crossover gasket to seal our oxygen line. Guess what?, it worked and our pressure was around 600 psig.

Good luck,

LV

 

[Lhenrique]

LV

I've checked the site you mentioned I couldn't find this wonderfull gasket, may you tell me the name?

I('m still astonish if is there a gasket like that !!!