Final phase of Northumbrian Water contract

Citation

(2002), "Final phase of Northumbrian Water contract", Anti-Corrosion Methods and Materials, Vol. 49 No. 5. https://doi.org/10.1108/acmm.2002.12849eab.005

Final phase of Northumbrian Water contract

Final phase of Northumbrian Water contractKeywords: Water, Corrosion, Civil engineering

BAC Corrosion Control reports that it has begun the final phase of its Northumbrian Water Limited (NWL) refurbishment contract (see Plate 4). This entails minor civil works, testing, commissioning, interference testing and completion of technical documentary requirements.

The contract started some three years ago with a desktop study of buried steel water-mains from the Scottish border down to the River Tees in County Cleveland. Working closely with NWL asset managers and utility survey teams, buried steel mains were identified and assessed for refurbishment. The mains were prioritised utilising a custom-made criticality matrix: the major factors of the matrix being third-party interaction, SSSI (environmental considerations), leak history, soil corrosivity, industrial/domestic use, alternative supply route, access difficulties and, finally, expenditure.

Steel mains ranging from 200mm to 1,200mm diameter with a combined length of 450km were identified and cathodic protection (CP) requirements reassessed, designed and implemented.

Both impressed current (ICCP) and galvanic anode CP systems have been used to provide protection to the steel mains, dependent on factors pertinent to the specific main. Selection also involved assessment of third-party-owned facilities, whereby interaction had to be kept to an absolute minimum.

Transco have a vast array of HP gas mains in the industrial area along the River Tees, so BAC has kept in close contact throughout the construction phases to ensure inter-company harmony.

Railtrack's fears of electrical interference with signalling systems were alleviated after a full and detailed testing programme indicated that no adverse effects would occur to the train signalling systems at maximum CP system outputs.

The final test for interference is with Huntsman Chemicals and BP on the TSEP Ethylene pipeline.

BAC believes that, judging by the early cooperation between NWL/BAC and BP, then the same successful outcome is expected.

With continued monitoring and maintenance, the investment made over the last three years is likely to be paid back many times with diminishing costly leaks due to corrosion.

For further information contact: BAC Corrosion Control. Tel: +44 (0)1952 290321; Fax: +44 (0)1952 290325; E-mail: tony.gerrard@bacgroup.com; Web site: www. bacgroup.com