Using a RJT union or hygienic ferrule on a pressure vessel nozzle 1

[Arron_]

Is it acceptable to use either an RJT hygienic union or a hygienic ferrule on the nozzle of a ASME VIII vessel whose connecting pipe work consists of the same unions/ferrules?
If no, why? And if yes, what requirements must they meet?

ASME B31.3 is being used for the design of the pipe work connecting to the vessel which are both low pressure and low temp (5barg, 75deg c) and I am planning to use the same connections on the nozzles as detailed in ASME B31.3 - Fig. U335.8C.
I have been told that my colleges have done this in the past but the design verifier has not accepted it and requested it be changed to B16.5 flanges. This has later proved to have pretty severe impacts on the function and process design that I wont go into here. So I would like to try my best to get a suitable design across the line using these fittings.

 

[BJI]

It isn't the place of the verifier to insist on such a change, it is the responsibility of the designer to demonstrate that the custom flange meets the code requirements. Alternatively, the vessel scope could end at a butt welded nozzle and the flange could fall under the piping scope.

 

[Arron_]

it is the responsibility of the designer to demonstrate that the custom flange meets the code requirements

Yes, hence my post.
Since posting I re-read my notes. Am I right in thinking that UG-44 prohibits the use of any pipe fittings that are not among the listed ASME standards?

 

[SnTMan]

It does not. Manufacturers standard parts are permitted. This subject has been discussed before. As I recall some manufacturers certify their fittings to Sec VIII, Div 1. Try a search.

Regards

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[EdStainless]

Read the ASME BPE, since they do this all of the time.
Typically the vessel rules stop before these flanges.

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P.E. Metallurgy, consulting work welcomed

 

[XL83NL]

Agreed with Ed. Read BPE. Also, purchase a copy of "W.M. Huitt - Bioprocessing Piping and Equipment Design (A Companion Guide for the ASME BPE Standard - ASME Press)". Highly recommended.

Where is this vessel located? Weve had this discussion before as well, and Im quite sure there are older discussions on it on ET as well (

https://www.eng-tips.com/viewthread.cfm?qid=477298,

https://www.eng-tips.com/viewthread.cfm?qid=460032,

https://www.eng-tips.com/viewthread.cfm?qid=423427).

Long story short, Its very tricky to buy hygienic clamps that meet VIIII-1 requirements, though (iirc) there are companies who sell these from stock (

https://www.ljstar.com/

/

https://pveng.com/wp-content/uploads/2016/06/PVEfea-4472.0.pdf)

or tackled this issue before.
EU companies, where U-stamp isnt mandatory may be more flexible in accpeting a vessel with such unions, even when those unions dont exactly meet code requirements.

Huub
- You never get what you expect, you only get what you inspect.

 

[Arron_]

Thankyou for the great replies, I will grab a copy of the W.M Huitt book and read through BPE.

Cheers

 

[CuMo]

We have used these on U-stamped filters for the pharmaceutical industry in the past.

https://advanced-couplings.com/product-category/safety-clamps/

https://ibb.co/GQ8d7WM

Also look for BS 4825-3

You might need to back up your calcs with a check of the fittings - it's been very long time since then but it might help you. See attached.

 

[EdStainless]

One thing to remember with sanitary clamp fittings is that brands are not interchangeable.
the two faces, spacer ring, and clam all have to be of the same make.
There are enough subtle differences to ruin your day otherwise.

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P.E. Metallurgy, consulting work welcomed