This manual describes methods of cathodic protection. Cathodic protection is a method to reduce corrosion by minimizing the difference in potential between anode and cathode. This is achieved by applying a current to the structure to be protected (such as a pipeline) from some outside source. When enough current is applied, the whole structure will be at one potential; thus, anode and cathode sites will not exist. Cathodic protection is commonly used on many types of structures, such as pipelines, underground storage tanks, locks, and ship hulls.
This manual provides guidance for the selection, design, installation, operation, and maintenance of cathodic protection systems (CPS’s) used to supplement paint systems for corrosion control on civil works hydraulic structures. It also discusses possible solutions to some of the problems with CPS’s that may be encountered at existing projects.
The Corps uses CPS’s in combination with protective coatings to mitigate corrosion of hydraulic structures immersed in fresh, brackish, or salt water. Protective coatings are rarely completely effective because, even on application, they contain pinholes, scratches, and connected porosity. As coatings degrade with time, these imperfections, commonly known as holidays, have a profound effect on overall coating integrity because of underfilm corrosion. CPS’s, when used in conjunction with protective coatings, have been effective in controlling corrosion. CPS’s consist of anodes that pass a protective current to the structure through the electrolyte environment. CPS’s can be one of two types, sacrificial anode or impressed current anode. Hybrid CPS’s installed on structures can contain both types of anodes to provide protective current.
Unified Facilities Criteria UFC 3-570-06
31 January 2003
This handbook provides guidance for inspection and maintenance of cathodic protection (CP) systems. It should be used by field personnel to perform scheduled inspections and preventive maintenance, and to troubleshoot and repair defects. Information on non-routine field measurements is also included to enable technical assistance personnel to troubleshoot problems beyond the capability of field personnel to isolate or correct.
Cathodic protection is an electrochemical method used to prevent or control corrosion of buried or submerged metallic structures. CP systems are active systems that rely on the application of electric current to control corrosion. If current is interrupted, corrosion will progress at a normal rate for the material/environment combination; if supplied current is inadequate for complete protection, corrosion will progress at a reduced rate. After a CP system is installed and adjusted to provide adequate protection, currents and potentials should remain relatively stable; changes in currents or potentials indicate a problem
The purpose of this manual is to serve as a technical guide for both Naval and civilian personnel in identifying existing or potential corrosion problems, determining the proper corrective actions, and implementing the corrective actions. As corrosion and corrosion control are affected by both original design and construction and maintenance, information is presented regarding all methods for reducing corrosion even though the information is primarily oriented toward maintenance and repair.
This manual describes the mechanisms of corrosion, the types of corrosion commonly experienced in naval shore facilities and waterfront structures, the methods that can be used to control corrosion and methods for implementing an effective corrosion control program. This manual emphasizes methods for determining the most cost effective means of controlling corrosion and practical application of corrosion control to typical problems encountered in the Naval shore establishment.
U.S. Department of Commerce
National Bureau of Standards Monograph 58
Steel pilings have been used for many years as structural members of dams, flood walls. bulkheads, and as load-bearing foundations. While its use is presumably satisfactory, no evaluation of the material after long service has been made.
In cooperation with the American Iron and Steel Institute and the U.S. Corps of Engineers, the National Bureau of Standards has undertaken a project to investigate the extent of corrosion on steel piles after many years of service. Results of inspections made on steel pilings which have been in service in various underground structures under a wide variety of soil conditions for periods of exposure up to 40 years are presented.
In general, no appreciable corrosion of steel piling was found in undisturbed soil below the water table regardless of the soil types or soil properties encountered. Above the water table and in fill soils corrosion was found to be variable but not serious.
It is indicated that corrosion data previously published by the National Bureau of Standards on specimens exposed under disturbed soil conditions do not apply to pilings which are driven in undisturbed soils.
This manual is intended for use in the design and construction of cathodic protection systems for the mitigation of corrosion of buried or submerged metallic structures. Design of cathodic protection systems is somewhat different than design of other electrical or mechanical systems because it must be based upon local environmental conditions such as soil resistivity. This manual presents criteria for cathodic protection, methodologies for the determination of required environmental conditions, methodologies for design of cathodic protection systems, examples of typical systems and design calculations, installation and construction practices, recommended initial system checkout procedures, and system maintenance requirements.
Supersedes MIL-HDBK-1110, 17 January 1995 (this book is contained in the present document in its entirety.)
This handbook presents information on the effective use of paint-type coatings to protect metal, concrete, and wooden structures at military activities from deterioration. In this handbook, the words “paint” and “coating” are used interchangeably. Sometimes, the word “paint” is used to describe an architectural rather than protective material, but this is not the case in this handbook.