ISO 12473:2017

Overview

ISO 12473:2017 - General principles of cathodic protection in seawater provides the foundational guidance for employing cathodic protection in marine environments, including seawater, brackish waters, and marine mud. Published by the International Organization for Standardization (ISO), this standard serves as an introductory document that bridges the theoretical concepts and practical implementation of cathodic protection systems.

The standard outlines key protection criteria, explains the use of reference electrodes for monitoring, and details design considerations to optimize system performance and longevity. It is intended to support more specific standards related to protecting various marine steel structures such as offshore platforms, pipelines, and ship hulls.

Key Topics

• Cathodic Protection Methods

  • Galvanic anode systems - Use of metals like aluminium, zinc, or magnesium as sacrificial anodes.
  • Impressed current systems - Application of an electrical current using inert anodes and external power sources.
  • Hybrid systems - Combination of galvanic and impressed current approaches for flexible protection and redundancy.

• Protection Criteria

  • Potentials and criteria required for effective cathodic protection of steel and other metallic materials.
  • Guidelines to prevent overprotection, which can lead to coating disbondment or material embrittlement.

• Reference Electrodes

  • Selection and use of field-robust reference electrodes such as silver/silver chloride for accurate potential measurement.
  • Verification procedures for maintaining calibration and ensuring reliable monitoring in marine environments.

• Design Considerations

  • Factors influencing the system design, such as design life, materials, required protection current, and effects of environmental conditions (temperature, salinity, oxygen, and marine fouling).
  • Integration of protective coatings and maintenance procedures to extend structural service life.

• Secondary Effects and Monitoring

  • Identifying and managing side-effects like alkalinity shifts, hydrogen embrittlement, corrosion fatigue, and stray electrical currents.
  • Recommendations for regular inspection, maintenance, and use of appropriate instrumentation.

Applications

ISO 12473:2017 is essential for industries and professionals involved in:

• Marine and Offshore Engineering Protecting fixed and floating offshore structures, harbor installations, and submarine pipelines from corrosion to ensure safety and structural integrity.
• Shipbuilding and Maintenance Designing cathodic protection systems for ship hulls and submerged parts, reducing maintenance costs and extending operational life.
• Oil, Gas, and Petrochemical Sectors Safeguarding offshore pipelines and facilities operating in aggressive seawater environments.
• Civil Infrastructure Implementing corrosion protection for submerged steel reinforced concrete and waterfront installations.

Its guidelines help ensure that structures exposed to marine environments meet stringent durability and reliability standards, benefitting asset owners, engineers, and maintenance teams.

Related Standards

ISO 12473 forms the foundational basis for several other standards focusing on practical applications of cathodic protection in seawater, including:

• EN 12495 - Cathodic protection for fixed steel offshore structures
• ISO 13174 - Cathodic protection of harbour installations
• 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 - Offshore pipeline cathodic protection
• ISO 12696 - Cathodic protection of steel in concrete

For comprehensive and effective corrosion management in marine and offshore environments, ISO 12473:2017 provides the general framework while these related standards address specific applications and detailed methodologies.

Keywords: ISO 12473, cathodic protection, seawater, marine corrosion, galvanic anode, impressed current, corrosion prevention, offshore structures, reference electrodes, marine engineering standards.