Wood Group – Innovation to improve flange management when decommissioning

Submitted by Wood Group

Use of Springlynn, a self-tapping saddle for draining and venting, adopted from the water industry.

Impact 

The system is very simple in design, and can be used by someone with no previous training Using a self-tapping saddle for draining and venting systems while decommissioning negates the need to break flanges whilst ensuring that re-energisation of the pipeline cannot occur.

Being simple to install and effective in design, the system removes potential risk of asbestos exposure from old compressed asbestos fibre (CAF) gaskets, and therefore does not require specialist asbestos operators to be present.

Where engineered valves are not installed or are difficult to access, the system may also be used to install vents and drains.

Spill risks are reduced by making it easier to divert potential liquid inventories through to a containment system prior to commencing separation scopes.

From the point of ‘Cessation of Production’ (COP) and the initiation of decommissioning work, the process of engineering down selected systems and pipelines begins.

Systems are physically isolated and de-energised with air gaps, and appropriate vents and drain points installed as further safeguards. Breaking flanges is a routine part of this process to prove it is safe before progressing with module and process separation. Similarly, breaking flanges is necessary when separating topsides for Single Lift Vessel (SLV) removal. All of these flange breaks take time to carry out safely as they may interrupt asbestos present in CAF gaskets of old flanges.

To solve the issue, our decommissioning services contract team proposed using a system adopted from the water industry. The Springlynn system avoids the need to break valves and may also be used to install vents and drains at low/high points if there are no engineered valves installed where required (or if they are difficult to access).