Earthquake demands remedial work
Only months after completing a contract with Thames Water to design and install a corrosion protection system for a 140km water pipeline between the Yuvacik dam and Istanbul, engineers from BAC Corrosion Control found themselves back in Turkey surveying the damage following last August's Izmit earthquake.The 2.2m diameter steel pipeline, constructed under Turkey's first BOT contract, follows the northern coastline of the Marmara sea from Izmit towards Istanbul. The facility feeds 24 reservoirs and has six pumping stations.
BAC's impressed current cathodic protection (ICCP) system, as used on the Izmit pipeline, is based on silicon iron anodes in conventional coke breeze backfilled groundbeds, of which there are nine along the pipe's route.
The pipeline has been laid virtually at sea level and at one point constitutes the local sea defences.
BAC has been working on the Izmit Domestic and Industrial Water Supply project since 1996. Following the earthquake, the company was called in to conduct an audit on the ICCP system and the pipeline itself.
Apart from a major defect where the fault line crossed the pipeline, there was no serious damage. BAC undertook the necessary minor remedial work using local Turkish labour.
ICCP systems are considered to be highly efficient as cathodic protection for long distance cross-country pipelines. ICCP systems used on installations like the Turkish project feature monitoring stations at regular intervals along the pipe's length. These can be linked to a telemetry scheme, allowing pipe condition to be checked from a central monitoring station.