The history of the compact flange

The Swedish engineer Jan Webjörn developed in the early 1960’s compact flanged connections (CFC), without gaskets, which could withstand higher pressure and bending moments than the adjoining pipe without leakage. Mr. Webjörn was invited to present his ideas at several conferences worldwide including annual ASME PVP Summer conferences. He claimed that flanges found in ASME flange standards constitute a “mis-concept”, because his high strength connections could be designed to weigh less than 1/10th of a corresponding ASME flange connection.

Probably due to an uncompromising attitude to established standards for valves and pipes etc, the Verax Compact Flange designed by Mr. Webjörn, became no great sales success, but a few connections went into service where severe vibrations made conventional gasket based flanged connections unreliable.

A breakthrough for the compact flange technology was achieved in 1989 when a temporary dynamic riser was assembled with several pairs of compact flanges designed by Mr. Webjörn and the Norwegian company Steel Products Offshore. The riser was made for an emergency operation to prevent a serious blow-out from an oil and gas reservoir at Block 2/4-14 in the North Sea. The operator, Saga Petroleum was so satisfied that this type of bolted joints was used for more than 500 flange pairs in the dynamic pipeline risers of the floating Snorre A tensioned legs platform, which has been in successful service through numerous storms with heavy seas since 1991.

The first major application in process piping appeared in the turret area of the Norne FPSO, which has been in service since 1998, and system weight of flowlines and manifolds was reduced by 20% just because of the compact flanges.

After successful use in process piping without any leakages or problems during construction at both Norne and Snorre B, an agreement to release this technology for standardization was signed between Statoil, Hydro Oil and Gas and Steel Products Offshore in 2001, and the NORSOK standard L-005 was issued first time in 2003. An international standard, ISO 27509 (3) based on this NORSOK standard was issued in 2012.