EN 13480-3 Pipe Wall Thickness Calcs

[SteMcG1984]

Hi All,

This is my first post so please be considerate I have spent some time searching existing threads but have been unable to find an answer to my query, if I have missed something feel free to point me in the right direction.

I am a graduate Materials and Pipe Stress Engineer, currently working on pipe wall thickness calcs using EN 13480-3. I have got my head around the formulas, but cannot find guidance on which figure to use for "Elongation, A", longitudinal or transverse, which then determines which set of formulas to use for the design stress calcs. E.g. for A >= 35%, f = ... and for 1.4404 stainless steel, A(l) = 40% and A(t) = 30%.

There are good arguments for either/worst case etc. but I would appreciate any guidance or reasoning that members here could offer.

Thanks, Steve

 

[XL83NL]

Could you point out the section/paragraph of 13480-3 youre dealing with? I suspect it's the long. elongation, but Id have to check.
I might be able to help, used the code for a recent job, and found some bumps we had to take ourselves too (one of which turned out to be a complete lack of market offer/supply of standard simple fittings, e.g. to type B in common grades like 1.4404, or absurd prices for other simple fittings).

Though 13480 is much more clear in some areas wrt formula's and specific requirements (e.g. supporting) than e.g. B31.3, there's still a (imo) vast area where the code is not consistent, and leaves a lot of interpretation/guessing to the designer.

 

[SteMcG1984]

Hi XL83NL, thanks for your response.

The part that gives the equation for design stress (f) for austenitic steels, which depends on the elongation (A) is EN 13480-3 Section 5.2.2.1. The design stress calculated from this is then used in the equations in section 6 for straight pipe and various components to calculate the minimum required wall thicknesses.

For safety's sake, I have been calculating the wall thickness for each case and using the worst case where there is a difference. If you have any experience of this to share it will be much appreciated.

Steve

 

[XL83NL]

Im pretty sure the elongation implied would be longitudinal, but I cant put my finger on any para in EN 13480.
To be sure, send a submission form with your question to the EN 13480 commiittee; see here (and find "Submission of questions")

 

[SteMcG1984]

Thanks for your input XL83NL. I'll continue to calculate it for both cases and use the 'worst' of the two for now and send the query to the EN 13480 committee.

Thanks, Steve