KOREA - Checking for contact with other buried services

- survey of buried pipeline ...

A steel pipeline replaced a cast iron line which had been abandoned but left in place. Two other cast iron lines crossed the steel line. There were also numerous power and street lighting cable lines buried close by. The location was under a well-used carriageway and the ‘cover’ was tarmacadam and concrete - up to 2 metres thick in places.

The cathodic protection (CP) potential was being ‘drained’ from the steel pipe and numerous attempts - using traditional survey methods and excavation - had been made to locate the source without success.

2 ‘current loss’ areas were identified by a leading pipeline survey company using the system. This was particularly difficult at one site where 12 buried services were uncovered during the excavation. At both these sites, cast iron lines - or sections of old cast iron pipes - were found to be in contact with the steel pipeline. The situation was rectified and a good level of cathodic protection achieved over the whole pipeline.