Preferred wall thickness for fittings

What are preferred wall thicknesses for particular fittings diameters?

EN 10253-2 Standard in table 17 stipulates preferred diameters and wall thicknesses so that they fit pipe dimensions stipulated in EN 102020. Here is the table for diameter from 26.9 fi – 88.9 fi:

This means that it is advised e.g. to produce and deliver elbows 26.9 fi with thickness s=2.3, s=3.2, s=4.0, s=5.6, s=8.0.

26.9 x 2.9 elbows are to be purchased. The investor does not allow any changes in required products. What to do in such situation?

The standard, apart from preferred wall thicknesses, allows to agree sizes which are different from those stipulated in a table. The deliverer may not have such an elbow on stock and it needs a few or even more than a few weeks to be produced. In addition such product will definitely cost much more than a standard solution.

It is worthwhile to think and agree with an investor to buy elbows with standard wall thickness, bearing in mind that EN 10253-2 allows wall thickness tolerance -12,5% / +20%.

Required elbows: 26.9 x 2.9
Tolerance -12,5% / +20%.

Calculation of allowed thicknesses:
2.9 – 12,5% = 2.5375
2.9 + 20% = 3.48

Scope of allowed thicknesses: from 2.53 to 3.48

On agreeing with the investor you may change thickness s=2.9 to e.g. s=3.2 provided that upon exact taking all measurements will show size not bigger than allowed s=3.48.