Increased life and fewer replacements due to the manufacturing process are the major benefits of BAC Corrosion Control’s new Isoline magnesium sacrificial anodes. Extruding the magnesium, rather than casting, gives a smooth surface finish resulting in uniform anode consumption and increased operational efficiency leading to a greatly improved cathodic protection system.
BAC has two magnesium anode types, BAC Isomag, with an electrical potential of 1.7 volts, for older and less well coated pipelines and buried structures and BAC Isorod, with an EP of 1.5 volts, for well coated pipelines and soils with a low resistivity. For application in high resistivity soils, Isomag 1.7 volt anodes are recommended as they provide a higher driving voltage. Both types are manufactured from virgin magnesium alloys and are supplied in 18 standard sizes, ranging in weight from 1.3 to 27.3 kg to cater for today’s most commonly used sizes. Integral electrical cables are either 6mm² or 10mm² XLPE/PVC.
All the anodes are supplied in readily identifiable cotton bags - Isomag in red and Isorod in grey - which are backfilled with a mixture of 75% gypsum, 20% bentonite and 5% sodium sulphate. The advantage of supplying with a ‘built-in’ backfill is that as soon as the anodes are placed in the ground and electrically connected to whatever they are protecting, they begin to work.
For applications where flexible anodes are required Isomag and Isorod anodes are available in ribbon form. Ribbon anodes are for specialised applications such as the protection of external tank bases and pipelines inside sleeved crossings.