Comparative Analysis of ASME B16.5 and EN 1092-1 Welding Neck Flanges

The most widely used flange standards in the global pressure vessel and piping industry are ASME B16.5 and EN 1092-1. However, the lack of comprehensive information comparing these standards and their geometry difference has created hesitation in enabling their seamless functionality and interchangeability. ASME B16.5 has been in use since its initial approval and publication in 1927, while EN 1092-1, formalized by CEN in 2001, is based on the DIN (Deutsches Institut für Normung) flange standard established in 1928. Despite their evolution over the years, no detailed comparative study of their current forms has been made to help design engineers understand the differences and make informed decisions of standard selection for adoption in pressure vessel and piping projects worldwide based on certain criteria such as structural resistance and leakage performance. This paper examines the structural resistance and leak tightness of these two standards, focusing on flange sizes from 15 mm to 600 mm (NPS ½ to 24) and pressure ratings from PN10 to PN400 and Classes 150 to 2500. In particular, the compared parameters include flange rotation, maximum flange and shell stresses, gasket contact stresses, bolt loads, and tightness levels. The analysis employs the analytical model outlined in paper reference (Deutsches Institut für Normung (DIN), 2024, “History—Deutsches Institut für Normung (DIN),” DIN, https://www.din.de/en/din-and-our-partners/din-e-v/history), using SA105 flange material and spiral wound gaskets under bolt-up and pressure conditions at room temperature.