1 Comparative Study: EN – ASME VIII Workshop on the Pressure Equipment Directive Warsaw, June, 2004 Dr. Reinhard Preiss TÜV Austria Krugerstrasse 16 A-1015 Vienna, Austria Tel

2 Introduction This study compares the economic and non-economic implications arising from the application of (a) EN and, (b) the internationally used ASME Boiler & Pressure Vessel Code plus major related codes when appropriate (TEMA, WRC Bulletins), for the design, manufacture, inspection and acceptance testing of 9 benchmark examples of unfired pressure vessels.

3 Introduction The consortium which carried out the study, based on a contact with the EC / DG Enterprise, consists of TUV Austria - a Notified Body acc. to the PED in Austria -, and of Consorzio Europeo di Certificazione (CEC) - a Notified Body acc. to the PED in Italy. The detailed design of the benchmark examples was performed by the consortium. To evaluate the economic factors concerning individual and/or serial production of the benchmark vessels, pressure equipment manufacturers from Italy, France, Germany and Austria took part as subcontractors.

4 Benchmark Examples - Overview

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7 Benchmark Examples – CNG Storage Tank

8 Benchmark Examples – Stirring Vessel

9 Benchmark Examples - Aircooler

10 Conformity Assessment For estimation of the costs the following combinations of codes and conformity assessment routes were considered: EN and conformity assessment according to the PED (CE- marking).· ASME Section VIII (Division 1, Division 2 if applied) and conformity assessment according to ASME (U-stamp, or U2-stamp). ASME Section VIII (Division 1, Division 2 if applied) and conformity assessment according to the PED (CE-marking).

11 Conformity Assessment The exercise is based on compliance with the corresponding requirements in a situation where there are no pre-existing qualifications or supplementary data which could be used from other similar equipment. In the case of application ASME Section VIII (Division 1, Division 2 if applied) and conformity assessment according to the PED the following additional requirements were made (these are based on an agreement between the members of the consortium on the general approach within their organisations to such matters, but they cannot be taken as generally valid for PED conformity assessment for vessels designed according to the ASME code) for Materials Hydrostatic test Pressure Permanent joining and NDT Fatigue design

12 Overall Summary

13 Overall Summary Material costs are frequently greater using the ASME code. In some cases, savings attributable to lower material costs with EN are partly offset by additional costs of weld testing and NDT when compared with ASME requirements. For standard refinery heat exchangers no notable costs differences are reported (if TEMA requirements are considered). In some cases the reported costs differences for different manufacturers are larger than the cost differences resulting from the application of the various code routes. PWHT costs are frequently higher for ASME design, since the PWHT requirements depend on the wall thicknesses.

14 Overall Summary Material costs using EN Design-by-Analysis techniques are lower in some cases (e.g. special and/or advanced design or materials), but design costs are higher as for DBF. According to the cost estimations of the manufacturers, the extra costs for ASME designs to meet the PED requirements are in general small for the approach used in the study.

15 Overall Summary Based upon the design results, fatigue design according to ASME Div. VIII Sec. 2 Appendix 5 for welded regions is considered to be non-conservative in comparison with fatigue analysis procedures in major European pressure vessel codes (e.g. EN 13445, AD- Merkblatt, PD 5500) and the underlying experimental results. Thus, ASME fatigue design for these regions is not considered to meet the requirements of PED Annex I. Concerning the necessity for improvement of the present ASME fatigue rules see the current proposal for revision of ASME VIII Div. 2.