This document contains the basis for the calculation of seamless pipes and elbow pipes made of carbon and stainless steel for oil- and water-hydraulic systems. It is valid for pipings where all of the three following terms are fulfilled: 1. For installation in machines according to Directive on Machinery 2006/42/EC. 2. For operation i. with fluids of Group 2 acc. Directive for Pressure Equipment 2014/68/EU (PED) for DN 200 at any pressure and for DN 200 and a maximum permissible pressure PS 50 MPa (500 bar) or ii. with gases of Group 2 acc. PED for DN 100 or PS·DN 350 MPa (3500 bar). 3. For operation with a maximum permissible temperature TS up to 120°C. It does not apply for pipings that fall in the scope of the Directive for Pressure Equipment.