Cathodic Protection of Offshore Structures/Катодная защита морских сооружений

Издание на английском языке
Cathodic protection, when used in conjunction with protective coatings, is a common method used to protect immersed parts of steel surfaces from corrosion. This text on Cathodic Protection of Offshore Structures offers detailed recommendations on cathodic protection for offshore structures. Traditional seagoing vessels dock at regular intervals, but offshore structures such as Floating Production Storage and Offloading structures (FPSOs) are stationary and are in continuous operation for prolonged periods of time. Therefore, the design of the corrosion protection for a 15-year or longer service life of a floating offshore structure requires special consideration. Some Floating Production Installations (FPIs) have hull designs similar to oil tankers, especially those converted from oil tankers. Others are designed and built as floating production platforms. Cathodic protection systems are to consider the structure to be protected as a whole as well as individual components which are attached to the structure.
The information presented in text is intended solely to assist the reader in the methodologies and/or techniques discussed. This text does not and cannot replace the analysis and/or advice of a qualified professional.

Contents
1 General
1.1 Scope
1.2 Materials
1.3 Offshore Corrosion Zones
1.3.1 General
1.3.2 Atmospheric Zone
1.3.3 Splash Zone
1.3.4 Submerged Zone (External Areas)
1.3.5 Submerged Zone (Internal Areas)
1.4 Corrosion Control Considerations
1.4.1 Structure Design Considerations
1.4.2 Piping System
1.4.3 Mooring Lines
1.5 Personnel
1.6 Normative References
1.7 Definitions and Acronyms
1.7.1 Definitions
1.7.2 Acronyms
2 Design Criteria and Recommendations
2.1 General
2.2 Design Life
2.3 Environment
2.4 Potential Criteria of Cathodic Protection
2.4.1 Protection Potential
2.4.2 Cathodic Protection Evaluation
2.5 Coatings in Combination with Cathodic Protection
2.6 Design Current
2.6.1 General
2.6.2 Cathodic Protection Zones
2.6.3 Surface Area Calculation
2.6.4 Current Demand
2.7 Circuit Resistance
2.7.1 General
2.7.2 Anode Resistance Calculations
3 Cathodic Protection Systems
3.1 General
3.2 Cathodic Protection System Selection
3.2.1 Comparison of SACP and ICCP Systems
3.2.2 Information for Cathodic Protection System Design
3.3 Electrical Continuity and Current Drain
3.3.1 Cable Connection
3.3.2 Electrical Bonding
3.3.3 Connection to Other Structures
3.4 Stray Current
3.5 Galvanic Anode Cathodic Protection
3.5.1 General
3.5.2 Design Considerations
3.5.3 Anode Material Properties
3.5.4 Anode Arrangement for External Hulls
3.5.5 Cathodic Protection of Flooded Compartments and Ballast Tanks
3.6 Impressed Current Cathodic Protection
3.6.1 General
3.6.2 ICCP System Components
3.6.3 ICCP Design Considerations
3.6.4 ICCP Installation Considerations
3.6.5 Cathodic Protection in Service Monitoring
4 Commissioning, Operation, and Maintenance
4.1 General
4.2 Potential Measurement
4.3 Commissioning: Galvanic Systems
4.4 Commissioning: Impressed Current Systems
4.4.1 Visual Inspection
4.4.2 Pre-energising Measurements
4.4.3 Initial Energising
4.4.4 Performance Assessment
4.5 Operation and Maintenance
4.5.1 General
4.5.2 Galvanic Anode Systems
4.5.3 Impressed Current Cathodic Protection Systems
4.6 Planned Drydocking or Underwater Survey Period
4.7 Fitting Out and Lay-Up
4.7.1 General
4.7.2 Fitting-Out Period
4.7.3 Lay-Up Period
4.7.4 Stray Current
5 Retrofit of a Cathodic Protection System
5.1 General
5.2 Cathodic Protection Retrofit Systems
5.2.1 General
5.2.2 Hanging Impressed-Current Anode Systems
5.2.3 Gravity Anode Sled
5.2.4 Anode Pod and Anode Mat
5.2.5 Anode Link
5.2.6 Buoyant Sled
6 Documentation
6.1 General
6.2 Galvanic Anode Systems
6.3 Impressed Current Systems
6.4 Combination System