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Zinc Stand Off/Harbour Anode
Coatings are the first barriers to protect offshore structures such as jackets or Harbour sheet piles from corrosion. Due to microscopic pinhole defects in the coating and damage to it whilst in service localised pitting will occur. Stand off anodes are used to complement the coating at areas of exposed steel prolonging the life of the coating.
MCPS Limited Stand-off anodes are designed so that they have a minimum distance from the steel surface they are protecting of 300mm, to ensure uniform current distribution to the surface. The life period of a system is not less than five years. The anode core will support the anode to maintain the anode shape during later stages of the anode's life.
Zinc is the only material that has an official specification, the American MIL-A-18001 K spec. Zinc is a well-proven anode material and its capacity is virtually unaffected by the operating current density, although the driving voltage diminishes with increasing temperature therefore it has limited application. If zinc is not to this specification i.e. commercial purity zinc, it will have a limited use as an anode material because of excessive polarisation due to iron present as an impurity.
Systems can be designed to protect uncoated steel such as installations that have been in operation for many years
Aluminium Stand Off/Harbour Anode
Aluminium alloy anodes are now mostly preferred due to their higher electrochemical efficiency which enables them to operate at different temperature co-efficient. The anodes are less dense than zinc making them lighter and easier for handling when fitting. Systems can be designed to protect uncoated steel such as installations that have been in operation for many years.
Cathodic Protection Systems shall be designed to deliver sufficient protective current to polarise the steel structure in the submerged zone and maintain that potential. For steel susceptible to hydrogen induced stress cracking (HISC), the potential value is targeted between -0.770V and -0.830 V verses the Ag/AgCl seawater reference electrode
Platform Anode M400AP
Material : Aluminium
Weight (kilogram) : 40
Length (millimeter) : 1300
Breadth (millimeter) : 100
Height (millimeter) : 100
Comments : C/W 20mm Core Diameter Extending 152mm Either Side
Platform Anode M720AP
Material : Aluminium
Weight (kilogram) : 72
Length (millimeter) : 1515
Breadth (millimeter) : 133
Height (millimeter) : 127
Comments : C/W 20mm Core Diameter Extending 152mm Either Side
Platform Anode M1250AP
Material :Aluminium
Weight (kilogram) : 125
Length (millimeter) : 1525
Breadth (millimeter) : 185
Height (millimeter) : 160
Comments : C/W 25mm Core Diameter Extending 152mm Either Side
Platform Anode M1680AP
Material : Aluminium
Weight (kilogram) : 168
Length (millimeter) : 2373
Breadth (millimeter) : 160
Height (millimeter) : 162
Comments : C/W 60mm Core Diameter Extending 152mm Either Side
