255.476 Internal corrosion control: design and construction of transmission line.

Except as provided in subdivision (b) of this section, each new transmission line and each replacement of line pipe, valve, fitting, or other line component in a transmission line must have features incorporated into its design and construction to reduce the risk of internal corrosion. At a minimum, unless it is impracticable or unnecessary to do so, each new transmission line or replacement of line pipe, valve, fitting, or other line component in a transmission line must:#

(1)be configured to reduce the risk that liquids will collect in the line;#

(2)have effective liquid removal features whenever the configuration would allow liquids to collect; and#

(3)allow use of devices for monitoring internal corrosion at locations with significant potential for internal corrosion.#

The design and construction requirements of subdivision (a) of this section do not apply to pipeline installed or line pipe, valve, fitting or other line component replaced before May 23, 2007.#

When an operator changes the configuration of a transmission line, the operator must evaluate the impact of the change on internal corrosion risk to the downstream portion of an existing onshore transmission line and provide for removal of liquids and monitoring of internal corrosion as appropriate.#

An operator must maintain records demonstrating compliance with this section. Provided the records show why incorporating design features addressing paragraph (a)(1), (2), or (3) of this section is impracticable or unnecessary, an operator may fulfill this requirement through written procedures supported by as-built drawings or other construction records.#