Code and standard: EN 10253-4

Butt-welding pipe fittings – Part 4: Wrought austenitic and austenitic-ferritic (duplex) stainless steels with specific inspection requirements;

EN 10253-4 specifies the technical delivery conditions for seamless and welded fittings for welding-in (elbows, concentric and eccentric reducers, tees with the same branch and with reduced branch, caps) made of austenitic and austenitic-ferritic (duplex) stainless steel in two test categories, intended for pressure loads at room temperature, low temperature or at elevated temperature and for the transfer and distribution of fluids and gases.

This standard specifies two type of fittings:
Type A: fittings for welding-in, reduced degree of utilisation;
Type B: fittings for welding-in, full degree of utilisation;