Hi,

I have to make some pipe stress calculations, E235N material acc. EN10305-4.
Is it allowed to calculate pipe stress with Re values from a suppliers material certificate (which are higher values, 310 N/mm2 instead of 235 N/mm2) instead of Re values from EN10305-4?

Thanks in advance
Edwin

What is an Re Value?

Re = Yield strength

It is entirely acceptable to use values determined from actual testing of said certified material in your pipe stress check.
You need to be satified that the chemical composition and mechanical properties meet or exceed the material specification/standard and that the material certification is to the required standard as well.
I usually go for certification DIN 50049/EN 10204/3.1B and then personally check materials and certificates match when arrives to our workshop.
generally, the code stated values are minimums that must be met to qualify the material.
I would normally use the default library code values used by my pipe stress software and only revert to using actual strength values if stresses to the limit and design marginal.

That's totally clear. Thanks!