Owners and operators must ensure partially exempt UST systems identified in WAC 173-360A-0110 (2)(a)(i) through (iii) meet the performance standards of this section. This section does not apply to aboveground storage tanks associated with previously deferred UST systems and any partially exempt UST systems for which installation commenced on or before December 22, 1988.

(1) Performance standards. Partially exempt UST systems must:

(a) Prevent releases due to corrosion or structural failure for the operational life of the system;

(b) Be cathodically protected against corrosion, constructed of noncorrodible material, metal-clad with a noncorrodible material, determined by a corrosion expert to be located within a noncorrosive environment under WAC 173-360A-0310 (3)(c), or designed in a manner to prevent the release or threatened release of any regulated substance stored in the system; and

(c) Be constructed or lined with material that is compatible with the regulated substance stored in the system.

(2) Guidance. The performance standards in WAC 173-360A-0310 for new UST systems and the following codes of practice may be used as guidance for complying with this section:

(a) National Association of Corrosion Engineers International, Standard Practice 0285, "External Corrosion Control of Underground Storage Tank Systems by Cathodic Protection";

(b) National Association of Corrosion Engineers International, Standard Practice 0169, "Control of External Corrosion on Underground or Submerged Metallic Piping Systems";

(c) American Petroleum Institute, Recommended Practice 1632, "Cathodic Protection of Underground Petroleum Storage Tanks and Piping Systems"; or

(d) Steel Tank Institute, Recommended Practice R892, "Recommended Practice for Corrosion Protection of Underground Piping Networks Associated with Liquid Storage and Dispensing Systems."