B31.1 Excessing flange ratings

[Seimen]

Hi Boys,

I read already several threads in here, but didn't find an answer for following issue:
Is there any possibility to excess the pressure/temperature ratings of B16.5 flanges under B31.1? Coming from EN 1591 Standards there is a way to calculate B16.5 flanges with higher values than mentioned.
Background is that several valve suppliers are giving me excess rated flanges: Valve flange is #600 but according 31.1 I shall use #900.

Many Thanks!

 

[LittleInch]

Please provide figures and data.

What pressures are involved here?

What section of 31.1 are you using to calculate #900

Is this a materials / temperature de-rating issue?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Seimen]

100 bar 60°C and for vessels 100 bar 110°C. What is for #900 not a problem but for #600. However, the spec says all vessel manufactured under PED what means they designed according to AD2000. With that the supplier of course says #600 is okay for us because they using EN 1591 for flange design.

 

[LittleInch]

It's all about material and de rating. I'm not familiar with 1591, but post some specifics.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[TGS4]

There is no route in B31.1 (or any of the B31 codes) to use EN1591 to demonstrate pressure/temperature ratings. You can use ASME Section VIII Division 1 Appendix 2 (which, of course, can't hold a candle to EN1591).

Sorry, but you're stuck, they way the rules are currently written.

If you want to change the rules, start attending the B31 Code Committee Meetings.

 

[Seimen]

There are no ratings within EN1591. It is a simple calculation standard which allows to design each flange according material standard for pressure, temperature and forces. I was thinking that it should be possible to calculate flange by the user on its own somehow.

 

[XL83NL]

Let me tell you, EN 1591 is not simple calculation work.

 

[Seimen]

Yes indeed. Simple is the wrong word for the calculation but simple in making flanges for higher rates available, especial when flange are B16.5 because they are massiv in comparison to PN flanges.

 

[TGS4]

I am fully aware that EN1591 has no ratings. And I know how complicated the calculations are - I have my own home-built set of calculations to it.

What I am telling you is that there is no route to use EN1591 calculations to DEMONSTRATE a temperature/pressure higher than the B16.5 ratings available in ASME B31.

You simply can't get there from where you are.

 

[LittleInch]

I just don't understand what your problem is.

100 bar at 60C and 100 bar at 110C is within the ratings for pressure for class 1.2 materials, which should be easily available, but may cost a fraction more than 1.1.

Or use materials listed in ANSI / MSS SP44. No de-rating below 121C

It's all about the material which you haven't specified.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Seimen]

Thanks for the material hints.
Another approach maybe. Reading through B31.1 104.7 Other Pressure-Containing Components and take 104.7.2 consideration would allow also flanges according EN 1759 with the calculation from EN 1591.
The interesting thing is that the customer spec also requiring the EN 1759 for flanges.

 

[Seimen]

Additional information it is nonboiler external piping.