Lokring – Retaining Non-Hazardous Areas without Welding

Submitted by Tom Brown, Technical Sales Manager.

Problem statement

  • A Northern North Sea asset had to replace a 2’’ stainless steel fuel gas system which ran through both hazardous and non-hazardous areas.
  • The system therefore had to be ‘fully welded’.
  • The only way they could do this under traditional methods was to weld the pipe on the platform.
  • This was not possible due to the spacing restrictions in this instance.

Aims

  • To replace the system as a fully welded one so the non-hazardous areas could remain this way, without actually welding on site.

Method

  • The operator had used Lokring before on fuel gas, but was not sure if it could be used on a fully welded system in a non-hazardous area without reclassifying the area as hazardous, as would have to be done when installing a flange.
  • To get confirmation, the operator contracted Xodus to carry out a study on whether a Lokring coupling could be used in this situation while maintaining the non-hazardous area classification.

Impact

  • The findings of the report confirm that;
  • ‘There is strong, well-supported justification for the use of LOKRING fittings in place of welded connections on the fuel gas system located in a non-hazardous area. The work completed for this study is judged to have suitably justified weld-equivalence for LOKRING fittings in non-hazardous areas, which by inference facilitates the support of their use in hazardous areas also.’

How does this relate to the Oil and Gas industry?

  • Traditionally, when installing fully welded pipework, the only option in non hazardous areas of a platform have been to weld on site.
  • This takes time, involves hot work permits, welders, habitats, fire watch and there is always the safety risk welding on site
  • This study has now provided another option to welding fully welded systems, while at the same time being quicker, safer and more cost effective.

Click on the image above to download the case study.