scope:

General 

This standard presents accepted methods and practices for the control of external corrosion on buried or submerged steel, stainless steel, cast iron, ductile iron, copper, and aluminum piping systems. 

This standard is intended to serve as a guide for establishing requirements for control of external corrosion on the following systems: 

New piping systems: A proven method of corrosion control (e.g., coating supplemented with CP) should be provided in the initial design and maintained during the service life of the piping system, unless investigations indicate that corrosion control is not required. Consideration should be given to the construction of piping in a manner that facilitates the use of inline inspection (ILI) tools. 

Existing coated piping systems: CP should be provided and maintained (which includes the maintenance of coating as necessary), unless investigations indicate that CP is not required. 

Existing uncoated piping systems: Studies can be made to determine the extent and rate of corrosion on existing uncoated piping systems. When these studies indicate that corrosion affects the safe or economic operation of the system, adequate corrosion control measures shall be taken. 

The provisions of this standard are intended to be applied under the direction of competent persons who, by reason of knowledge of the physical sciences and the principles of engineering and mathematics, acquired by education and related practical experience, are qualified to engage in the practice of corrosion control on underground or submerged metallic piping systems.

Note: Such persons might be, but are not limited to, registered professional engineers or persons recognized as Corrosion Specialists or CP Specialists by NACE, if their professional activities include suitable experience in external corrosion control of underground or submerged metallic piping systems. 

Special conditions in which CP is ineffective or only partially effective sometimes exist (see Paragraph 6.2.1.4for examples). Deviation from this standard might be warranted in specific situations provided that corrosion control personnel in responsible charge are able to demonstrate that the objectives expressed in this standard have been achieved.

This standard is not intended for use in the control of internal corrosion.