CEN/TC 219/WG 3 - Cathodic protection of steel structures in sea-water

This document specifies the requirements for the external and internal cathodic protection for offshore wind farm structures. It is applicable for structures and appurtenances in contact with seawater or seabed environments. This document addresses:
—    design and implementation of cathodic protection systems for new steel structures;
—    assessment of residual life of existing cathodic protection systems;
—    design and implementation of retrofit cathodic protection systems for improvement of the protection level or for life extension of the protection;
—    inspection and performance monitoring of cathodic protection systems installed on existing structures, and
—    guidance on cathodic protection of reinforced concrete structures.

This document specifies the requirements and recommendations for cathodic protection systems applied to the internal surfaces of metallic tanks, structures, equipment and piping containing natural or treated seawater or brackish waters to provide an efficient protection from corrosion.
Cathodic protection inside fresh water systems is excluded from this document. This is covered by EN 12499.
NOTE   EN 12499 covers internal cathodic protection for any kind of waters, including general aspects for seawater but excluding industrial cooling water systems. This document specifically details applications in seawater and brackish waters.

This European Standard covers the general principles of cathodic protection when applied in seawater, brackish waters and marine mud. It is intended to be an introduction, to provide a link between the theoretical aspects and the practical applications, and to constitute a support to the other European Standards devoted to cathodic protection of steel structures in seawater.
This European Standard specifies the criteria required for cathodic protection. It provides recommendations and information on reference electrodes, design considerations and prevention of the secondary effects of cathodic protection.
The practical applications of cathodic protection in seawater are covered by the following standards:
-   EN 12495, Cathodic protection for fixed steel offshore structures;
-   EN ISO 13174, Cathodic protection of harbour installations (ISO 13174);
-   EN 12496, Galvanic anodes for cathodic protection in seawater and saline mud;
-   EN 13173, Cathodic protection for steel offshore floating structures;
-   EN 16222, Cathodic protection of ship hulls;
-   EN 12474, Cathodic protection of submarine pipelines;
-   ISO 15589 2, Petroleum, petrochemical and natural gas industries - Cathodic protection of pipeline transportation systems - Part 2: Offshore pipelines.
For cathodic protection of steel reinforced concrete whether exposed to seawater or to the atmosphere, EN ISO 12696 applies.

This European Standard specifies the minimum requirements and gives recommendations for the chemical composition, the electrochemical properties, the physical tolerances, and the test and inspection procedures for cast galvanic anodes of aluminium, magnesium and zinc based alloys for cathodic protection in sea water and saline mud.
This European Standard is applicable to the majority of galvanic anodes used for seawater and saline mud applications, i.e. cast anodes of trapezoidal, "D", or circular cross section and bracelet type anodes.
The general requirements and recommendations of this European Standard may also be applied to other anode shapes, e.g. half-spherical, button, etc., which are sometimes used for seawater applications.

ISO 13174:2012 defines the means to be used to ensure that cathodic protection is efficiently applied to the immersed and driven/buried metallic external surfaces of steel port, harbour, coastal and flood defence installations and appurtenances in seawater and saline mud to provide protection from corrosion.
ISO 13174:2012 specifies cathodic protection of fixed and floating port and harbour structures. This includes piers, jetties, dolphins (mooring and berthing), sheet or tubular piling, pontoons, buoys, floating docks, lock and sluice gates. It also specifies cathodic protection of the submerged areas of appurtenances, such as chains attached to the structure, when these are not electrically isolated from the structure.
ISO 13174:2012 is to be used in respect of cathodic protection systems where the anodes are exposed to water or saline mud. For buried areas, typically in soil or sand filled areas behind piled walls or within filled caissons, which may be significantly affected by corrosion, specific cathodic protection design and operation requirements are defined in EN 12954, the anodes being exposed to soils.
ISO 13174:2012 does not cover the cathodic protection of fixed or floating offshore structures (including offshore loading buoys), submarine pipelines or ships.
ISO 13174:2012 does not include the internal protection of surfaces of any components such as ballast tanks, internals of floating structures flooded compartments of lock and sluice gates or the internals of tubular steel piles.
ISO 13174:2012 covers the cathodic protection of structures fabricated principally from bare or coated carbon and carbon manganese steels.
As some parts of the structure may be made of metallic materials other than carbon steels, the cathodic protection system should be designed to ensure that there is a complete control over any galvanic coupling and minimize risks due to hydrogen embrittlement or hydrogen-induced cracking (see ISO 12473 ).
ISO 13174:2012 does not address steel reinforced concrete structures (see EN 12696).
ISO 13174:2012 is applicable to the whole submerged zone in seawater, brackish waters and saline mud and related buried areas which can normally be found in port, harbour, coastal and flood defence installations wherever these structures are fixed or floating.
For surfaces which are alternately immersed and exposed to the atmosphere, the cathodic protection is only effective when the immersion time is long enough for the steel to become polarized. Typically, effective cathodic protection is achieved for all surfaces below mid tide.
For structures such as sheet steel and tubular steel piles that are driven into the sea bed or those that are partially buried or covered in mud, ISO 13174:2012 is also applicable to the surfaces buried, driven and exposed to mud which are intended to receive cathodic protection along with surfaces immersed in water.
Cathodic protection may also be applied to the rear faces of sheet steel piled walls and the internal surfaces of filled caissons. Cathodic protection of such surfaces is specified by EN 12954.

1.1   General
This European Standard defines the general criteria and recommendations for cathodic protection of immersed external ship hulls and appurtenances.
This European Standard does not cover safety and environmental protection aspects associated with cathodic protection. Relevant national or international regulations and classification society requirements apply.
1.2   Structures
This European Standard covers the cathodic protection of the underwater hulls of ships, boats and other self propelled floating vessels generally used in seawater together with their appurtenances such as rudders, propellers, shafts and stabilisers.
It also covers the cathodic protection of thrusters, sea chests and water intakes (up to the first valve).
It does not cover the protection of internal surfaces such as ballast tanks.
It does not cover steel offshore floating structures which are covered in EN 13173.
1.3   Materials
This European Standard covers the cathodic protection of ship hulls fabricated principally from carbon manganese steels including appurtenances of other ferrous or non-ferrous alloys such as stainless steels and copper alloys, etc.
This European Standard applies to both coated and bare hulls; most hulls are coated.
The cathodic protection system should be designed to ensure that there is a complete control over any galvanic coupling.
This European Standard does not cover the cathodic protection of hulls principally made of other materials such as aluminium alloys, stainless steels or concrete.
1.4   Environment
This European Standard is applicable to the hull and appurtenances in seawater and all waters which could be found during a ship’s world-wide deployment.

This EN defines the means to be used to cathodically protect the submerged metallic surfaces of steel offshore floating structures and appurtenances in sea water and saline mud.

This european standard defines the means to be used to cathodically protect the submerged areas of fixed steel offshore structures and appurtenances.

The proposed Standard, based upon a revised and updated EN 12496: 2013 will specify the minimum requirements and give recommendations for the chemical composition, the electrochemical properties, the physical tolerances, and the test and inspection procedures for cast galvanic anodes of aluminium, magnesium and zinc alloys for cathodic protection in sea water and saline mud.
The Standard will be applicable to the majority of galvanic anodes used for seawater and saline mud applications, i.e. cast anodes of trapezoidal, "D", or circular cross section and bracelet type anodes.
The general requirements and recommendations of this proposed Standard may also be applied to other anode shapes, e.g. half-spherical, button, etc., which are sometimes used for seawater applications.
Applications for this Standard are in offshore renewables, flood defences, offshore oil and gas, offshore or submarine pipelines, ports and harbours, ships and all applications in which galvanic anodes are used for cathodic protection in sea water and saline muds.
Work is proposed to be undertaken in parallel between ISO TC 156 WG 10 and CEN TC 219 WG3, under ISO lead in accordance with the Vienna Convention. This scope is agreed in principle by both parties.

This European Standard establishes the general criteria and recommendations for the design, installation, monitoring and commissioning of the cathodic protection systems for submarine pipelines.
This standard is applicable to all grades of carbon manganese steel and to stainless steel pipelines; it covers all types of sea water and seabed environments encountered in submerged conditions.
The cathodic protection of short lengths of submarine pipelines and their branches, which are directly connected to cathodically protected onshore pipelines, are outside of the scope of this standard (see EN 12954:2001).
The cathodic protection of risers is included in this standard only if they are insulated from the supporting structure. The cathodic protection of the risers in direct electrical contact with the supporting structure is included in EN 12495.

This European Standard covers the general principles of cathodic protection including the criteria for protection, environmental and design consideration and secondary effects of cathodic protection and is intended as an introduction to other European standards in the general series "Cathodic Protection of Steel Structures in Sea Water". This European Standard provides a link between the theoretical aspects and the practical applications of cathodic protection as contained in the European Standards, as for example prEN 12474:1997, "Cathodic protection for submarine pipelines".

This EN defines the means to be used to cathodically protect the immersed and buried metallic external surfaces of steel harbour installations and appurtenances in sea water and saline mud.