Flange connections

A distinction is made between standard, non-standard and bad-actor flange connections


Standard flange connection:

This standard flange connection meets a number of requirements: the ASME B16.5, ASME B16.47 series B, an appliance partial flange or an air cooler header box cover that has good integrity (with no history of leakage).


Non standard flange connection:

Flange connections that fall outside the standard procedure will require an evaluation per connection to ensure that the correct gaskets, tightening torques, bolt materials and bolt tensions are applied. Non-standard flange connections are:

  • Non-metallic flange connections such as Glass Reinforced Epoxy (GRE) or High and Low-density PolyEthylene (LDPE or HDPE)
  • Non standard RTJ flange connections (converted to comb profile)
  • Flange connections connected to pumps and compressors
  • Flange connections that are not listed as standard flange connections
  • Body-bonnet flanges of valves and control valves
  • Manhole covers of storage tanks (API650)
  • Flange connections on RPAN in orthoxylene service or in brackish cooling water or acid service

Bad-actor flange connections:

The term bad-actor flange connections means a flange connection that is equipped with an engineered flange clamp, or is injected, equipped with special bolts such as Rotabolts, is not gastight or has leaked more than twice. To find out the cause of the varnish and take the correct action, an extensive inspection of the flange connection is carried out.