Greencastle pipe condition inspection, Belfast
A 587mm diameter spun iron pumping sewer, laid in 1949, is located along the foreshore of Belfast Lough. It is laid in a trench approximately 2m deep and running parallel to the railway line. It extends from Greencastle Waste Water Treatment plant at Shore Road, Newtownabbey to Fortwilliam/Duncrue Link, Belfast where it crosses the railway and beneath Translink’s Train Cleaning Shed.
Amphora Consulting were appointed to carry out a value weighted iron pipe corrosion risk assessment and determine the overall condition of the pipeline and remaining service life prediction. A number of inspection sites were excavated along the route and a scan grid established on the pipe. Ultra-sonic scanning of the pipe was carried out at each inspection site.
The ground around the pipe was made up of predominately clay. Soil pH was in the normal range as was chloride content, redox potential and soil resistivity. However, sulphate content was slightly elevated. The data collected from the ultra-sonic scanning was analysed and a 3-D image of the pipe wall was created.
A general wall loss of the pipe in the region of 3mm was identified due mainly to abrasion and corrosion and a further 11mm due to localized pitting.
Considering the remaining service life analyses, together with the pipe material type and severe corrosion risk score, Amphora concluded that preventative measures such as a Cathodic Protection System, be installed along the pipeline to preserve its service life.