Depending on the plant location for a new project different Codes and Standards are applied for design and calculation of high pressure equipment. Many countries do not have a specific code for high pressure vessels and components, respectively the high pressure used in petrochemical plant is out of the code range. In this case the purchaser or the process licensor determines the code to be applied on the equipment for the new plant. This paper provides a technical analysis and comparison for high pressure components calculated according to the following codes: ASME VIII, AD 2000 and CODAP 95. Design and calculation results according to the different codes are verified on an example of a double pipe heat exchanger using identical mechanical properties of materials and the same operating conditions. The results are illustrated on figures for different low pressure and high pressure components. The literature does not define a limit between low pressure, high pressure and ultra high pressure. As the difference between steam pressure in the jacket (3,3MPa), pressure in the process tube (50 MPa, 160 MPa, 360 MPa) and autofrettage pressure (1000MPa) is very significant, this sequence is applied in the paper. Economic aspects are more and more important for new projects in order to minimize costs for high sophisticated equipment. For this reason also a cost analysis was performed for the calculation examples and the economic impact of application of different codes is indicated on a diagram. The technical–economical evaluation leads to an optimised product.