All industrialized nations have developed their own code for the construction of pressure equipment. Among all codes or directives regulating this sector, the ASME Boiler and Pressure Vessel Code (BPVC) and the European Community Pressure Equipment Directive (PED: originally 97/23/EC, currently 2014/68/EU) are the most known and applied.
The PED and the ASME BPVC are not really directly comparable, since the European Directive enunciates only the general principles and the Essential Safety Requirements to be fulfilled by the pressure equipment in order to be allowed for free movement in the European market.
The Directive 2014/68/EC, which enetred in force on 19 July 2016 replacing the Directive 97/23/CE, doesn’t provide any detail rule or specification, as it is by the ASME BPVC that provides them. Under the content point of view is, therefore, more suitable to compare the ASME BPVC to the various European Norms (EN) in this sector, or to the national standards (e.g.: PD 5500 for the United Kingdom, AD-2000 for the German Federal Republic, CODAP for France or the VSR and VSG Rules in Italy).
Pressure equipment construction and design involve many technical disciplines and asks for multidisciplinary knowledge and skills. The manufacturing of a pressure vessel implies the development of complex design activities, in terms of calculation and drafting, in addition to the adoption of a specific control quality plan having the scope that the Manufacturer may take full control of the processes involved, i.e. purchasing of materials, the instruments used for examinations and tests, the welders' and welding procedures' qualification, the non-destructive examinations, and the execution of the final test.
As a confirmation of the complexity of this activity and the high technical skills necessary to carry it out in the correct way, ASME allows the Manufacturers to affix its certification mark and the relevant designator (in the past referred as "stamp") only upon a specific and tough process of qualification, requiring the preparation of the Quality Control Manual and the proof that it is correctly and fully implemented in all construction phases.
In order a pressure equipment may safely operate, it is required:
1) Using of suitable materials according to stringent specifications;
2) Accurate and rigorous design;
3) Welders and the welding joints qualification;
4) Carrying out accurate controls and test.
Under the design standpoint, the codes can be classified in two families: the ones adopting the design by rules (DBR), and the others adopting the design by analysis (DBA). To the first category belong: the Division 1 of the section VIII of the BPVC, the Italian regulations VSR and VSG, the BSI PD 5500, the German AD-2000, the EN 13445. To the second category belong: the Divisions 2 and 3 of the section VIII and the section III of the BPVC, the Annexes B and C of EN 13445-3, the Annex A of the PD 5500, the section S4 of AD-2000.