SFRC factor for 250000 h - problem in finding the design stress

[Dan Codrut]

Hello,

How can i find the design stress in the creep range for a superheated steam pipeline that exceeded 200000h of operation?

I have the mean value of creep rupture strength (SRTt)at 250000h operating time (given by the material norm), but EN 13480 gives no factor for finding the design stress for pipelines that worked over 200000h.

Thanks,
Codrut

 

[Raaden]

Since the code doesn't give you a safety factor for 250000h, then I don't think you have any other choice than to use the factor for 200000h which is 1.25

 

[Dan Codrut]

I think that is what I'm going to do, since i couldn't find any other design code that could give any info on how one may verify/ design pipelines that worked/should work for that huge amount of time.
US standards (ASME, API) only go as far as 100000h of lifetime. I think that says allot about equipment working over 200000h (in my case).
Thanks Raaden