We offer comprehensive calculations of pressure vessels subject to the requirements of Directive 97/23/EC. Projects include in particular three-dimensional modeling, creation of full technical documentation, develop a list of materials, manuals and analyze collision. Developed by our comprehensive technical documentation allows for obtaining the certificate of conformity and CE marking. The proposed standard pressure vessels meet the requirements of the Directive 97/23/EC. The calculations are based on standard analytical formulas based on the method of DBF (Design by Formulas). For the design of complex pressure equipment, calculations are made based on DBA (Design by Analysis). DBA method allows for calculations that are not included in the standards, with the help of computer simulations. Moreover, this method allows the DBA to change the characteristics of the pressure vessels, including functionality optimization of the materials required to manufacture the unit, manufacturing costs, or related to the strength of materials.