In Offshore West Africa permanently non-weather vaning, spread moored FPSO is located.

 During a shut down, it was observed that two cracks separately developed on a flare.

At this time there was no mean to determine or not the impact on the flare. The flare is a self supporting triangular-shaped structure, of about 80m in length. 

It became necessary to evaluate the root cause of these cracks and any consequences which could happen to the flare.

Global Oceon Engineers Nigeria Limited has been requested to investigate the root cause of this crack and determine the necessary actions.

At the beginning of this project a plan has been put in place to identify each potential cause of the crack and started to eliminate one by one each of them, (Vortex Induced Vibration, Fatigue Analyses, Thermal Loading etc …). All our analyses have been done using StruCAD software and no cause of the crack has been found at the end of this stage.

The second stage was more based on thermal loading and to understand and evaluate the importance of the flame direction regarding different parameter like wind and distance from flare.

Impact on structural members has been investigated and we found out that the flame direction was having a significant impact on our thermal calculations. Finally we decided to confirm this founding by having more sensitivity analyses and this sensitivity analyses confirmed that crack was occurring exactly were it has been found. At this stage cause of the crack was determined.

 The last stage was to determine whether or not this crack will be impacting the entire flare and at the end it has been concluded that this crack will have no other impact on the entire flare and solutions like grounding or adding grating (to protect against radiation) has been proposed to our client.

Finally Global Oceon Engineers provided to her client the solution to this problem and presented the results at the OWA in Ghana in 2011.