B31.1, 102.2.4 Ratings: Allowance for Variation from Normal Operation

[hansenhanh]

Hi

I learnt that this B31.1 ASME clause is only applicable for ASME valves/piping and etc.

Is there any equivalent European Standard for EN1092 flanges / valves?

Thank you

Regards
Hansenhanh

 

[XL83NL]

I don’t think you can make this comparison. EN 1092 is a component standard, product standard, fitting standard, whatever you want to call it. It is used by e.g. EN 13480, which is a construction code. Construction codes may set additional (usually more stringent) requirements on top of a product standard.
I’m not overly familiar with B31.1, but 102.2.4 refers to ratings of a.o. piping components and fittings which have an established rating. B31.1 then deals with that with additional measures on top of that. So it’s apples and bananas here.
I don’t think there’s any code that allows you to exceed the rating of a flange, except maybe for a hydrotest.
Does that answer your question?

Huub

 

[hansenhanh]

Hi Huub

Thank you for the response. Maybe I will illustration with an example.

I have right now a pipe manifold uses PN160 rated flanges tied into a PN160 ball valve. however, the maximum operating pressure is expected to be 165bar. so in B31.1, 102.2.4 Ratings: Allowance for Variation from Normal Operation, this clause allows exceeding the system design pressure by 15% or 20% depends on the frequency of usage. so both the PN160 rated pipe manifold and ball valve are within this clause as its maximum operating pressure is only 165bar.

however, the only problem now is that ASME do not accept the DIN standard/ EN1092-1 standard use here. They are classified as Unlisted Component in ASME.

Therefore, I wish to check if there is any similar clause for EN/PED standard that addresses this Allowance for Variation from Normal Operation in ASME B31.1.

Hansenhanh

 

[IdanPV]

Hansenhanh,

Maybe paragraphs 104.7.2 and 126.2 will help you.

 

[hansenhanh]

Hi IdanPV, thank you for your response.

I have gone through 104.7.2 and it seems like I need to conduct a proof test to determine its MAWP.

It brings me to another question.
when determine it MAWP, can the MAWP be set as the system maximum operating pressure of 165bar and maximum operating time of 2 min? In this case, the proof test will be conducted at 165bar and in 2min to redefine the new MAWP of this system?

For 126.2, i see that dimensions should follow ASME/ANSI standard as much as possible. therefore,EN1092-1 flange is generally smaller and thinner than ASME ones

Thank you

Regards
Hansenhanh

 

[IdanPV]

104.7.2(c): Proof Test shall be made in accordance with ASME B16.9;MSS SP-97 OR Section I A-22. You have to follow the requirements as they appears in one of these Standards

 

[XL83NL]

Did you read 102.2.4 in that it allows B16.5 flanges to be used beyond their rating?
Again, I’m not overly familiar with B31.1, but that’s something I’ve never heard before. That’s probably not written in that paragraph.

To provide an answer to your original question, and let’s say B31.1 allows B16.5 flanges you be used above theIt rating; afaik there’s no similarity in EN 13480.

Huub

 

[hansenhanh]

Thank you IdanPV for the Clarifications.

Hi Huub

I have attached an image below abstract from the clause.

Thank you for confirmation on the similarity clause from EN13480.

I guess I have to exercise the proof test as highlighted by IdanPV for the pipe manifold and valves.

 

[IdanPV]

Hi,
Refer to 104.7.2, you have 4 options, proof test is one of them.
104.7.2(a) - Based on service experience.
104.7.2(b) or 104.7.2(d) - stress analysis based on ASME BPVC VIII-2.

Consider to use one of the options above, before you going to destroy an item.