Flange do not required de-rating upto 120C as per B31.3 2

[Spoonful]

Dear all,

Reading from Australian standard, AS2885.1 point 3.4.3(see below), it stating that no need to de-rating flanges(eg, B16.5) under 120C, which means design pressure at 90C of 5110KPA, class 300 flange can be still used. And it saying it is refereed from to B31.3, I couldn't find the exact point in B31.3 saying about this. Dose any of you have knowledge about this? Thanks.


AS2885.1
3.4.3 Strength de-rating
Carbon steel and carbon manganese steel flanges and valves complying with nominated
Standards may be used without derating at design temperatures not exceeding 120°C.
NOTES:
1 Reference ASME B31.3, ASME VIII, and MSS SP44 – At temperatures up to 120°C flange
designs are based on (a constant) ultimate tensile strength resulting in no strength derating
requirement.
2 The temperature limit for flanged valves applies only to the flanges. Assurance should be
sought from the valve manufacturer that the valve body and seals are suitable for the required
service conditions.
3 The adoption of a higher design temperature for flanges requires that the pipeline and the
piping each satisfy the stress limits required by the design standard.
4 This permission does not currently apply to vessels designed in accordance with AS 1210
(e.g. filter vessels). AS 1210 currently requires strict compliance with the temperature
derating requirements of B16.5 flanges – although it does permit the use of MSS SP44
Where the pipeline design temperature is above 65°C the yield strength of the pipe steel
shall be derated. The reduction in yield strength shall be 0.07%/°C by which the design
temperature exceeds 23°C.
NOTE: The use of 65°C as a boundary below which no de-rating needs to be applied covers
common gas pipeline compressor discharge temperatures. This exemption results in a step change
in de-rating above 65°C.
[/b]

 

[TWP]

I have used all of the mentioned ASME standards for more than 30 years now and I have never encountered a similar statement on ratings in the references ASME's.

 

[Spoonful]

Hi TWP,

If you are right, that could explain why couldn't I find any reference in B31.3 for this, but I wonder where dose these Australia standard people get the reference from?

 

[TWP]

Dear spoonful

I work with a lot of american standards/ codes and standards/ codes in Europe.
Also used AS's to some extent (AS 1210).
No idea where 120 C is coming from.
Perhaps from a standard valid in the good old days.
But I'm already as well (nearly 62).
So, no idea, sorry.
Certain local standards here in Europe allow us to use Room temp. allow. stresses up to incl. 50 C.
Still not 120 C.
Regards,
TWP (piping & vessel engin. Netherlands)

 

[786392]

Dear Spoonful Hello/good Morning,

In all fairness "TWP" seems to be correct.

If you are so sure/confident about 120C temperature issue.

Why don't you quote/share applicable current code's specific clause(s) reference for our awareness and knowledge update

Best Regards
Qalander(Chem)

 

[Spoonful]

Hi All,
Thanks for all the response, I couldn't find any reference code clause to support what is stated in AS2885.1, hence I am here seeking advise on where these supporting clause could be. Please don't get me wrong, I am not trying say this statement is correct, I am just trying to understand where it coming from.

 

[bernoullies123]

Permission to not derating the flange was proposed by the Committee ME-038, Petroleum Pipelines and ultimately approved by the Council Standard of Australia. The permission has nothing to do with any other standard or code.

I am not a member of this committee, but if I were to speculate, I would think it has to do with the fact that they have had successful operations and track records of these flanges without any issues in leaking etc. therefore they allowed permission. They probably realized that all pipelines would easily exceed 60 deg just in the sun in Australia, which would push the flange into then next class which would have significant economic impacts.