A heavy fuel oil leak was detected on the insulated overhead part of a pipeline supplying the boilers of the Berre petrochemical unit from the ‘La Pointe’ port facility. The product released was collected in the retention structure underneath the pipeline. The fuel thickened nearly instantaneously upon exiting the pipe, which limited its spread. No pollution was observed by the operator or on the Salins du Midi side or Etang de Berre side. The spilt fuel was pumped, and the retention basin cleaned up.

Three holes measuring 1 to 2 mm in diameter

External corrosion under the thermal insulation was responsible for the release, as a result of the structure being routed through a humid and saline environment. The leak zones consisted of 3 perforations located close to one another and ranging from 1 to 2 mm in diameter. The perforations were located on a rectilinear portion of the pipeline.

In-service monitoring of the structure

The structure is corrosion protected:

• the aerial portion is protected by a coat of paint and waterproof thermal insulation. Visual inspections are performed regularly;
• the underground portion is protected by a tri-layer polypropylene covering and cathodic protection.

A fault-finding inspection focussing on the covering of the underground portions (DCVG) and a hydraulic test are conducted every two and six years, respectively. Visual inspections of singular points, in addition to ground-based monitoring systems (overhead parts and structures under roadways), complete the system every 24 to 30 months.

Corrosion defects were detected while the thermal insulation was being repaired. An inspection with an intelligent pig was also scheduled, for the 1st quarter of 2016, as part of the Pipeline Monitoring and Maintenance Program (PSM, Programme de Surveillance et de Maintenance). The pig inspection is scheduled to take place in January 2016.

Measures taken

Temporary repair with repair clamps was undertaken to seal off leaky zones. The pipe was filled with water after shutdown and installation of the repair clamps. The operator intends to fully remove the thermal insulation.

The replacement of damaged sections and the use of a suitable external protective covering are also scheduled (epoxy coating/glass fibre cloth, but without thermal insulation). The required repair operations were undertaken (surfacing, installation of sleeves, replacement of sections, etc.) before putting the pipeline back into service.