Section 173-360-820. Secondary containment of piping.

(1) Applicability. Piping installed or replaced after October 1, 2012, routinely containing regulated substances and in contact with the ground must be secondarily contained and monitored for releases in accordance with the requirements in this section. However, the requirements in this section do not apply to:

(a) Suction piping meeting the standards in WAC 173-360-350 (2)(b)(i) through (v); or

(b) Piping replacing less than fifty percent of a single-walled piping run.

(2) Replacement of piping. Unless otherwise approved or directed by the department, if fifty percent or more of a single-walled piping run is replaced after October 1, 2012, then the entire piping run must be replaced.

(3) Secondary containment. In addition to meeting the requirements in WAC 173-360-305(2), piping must meet the secondary containment requirements in this subsection.

(a) Performance standards. Piping must be double-walled. Containment sumps may also be used as part of the secondary containment and interstitial monitoring system for piping.

(i) Piping. Double-walled piping must be designed, constructed, and installed to:

(A) Contain any regulated substances leaking from the primary space (through the inner wall) within the piping's interstitial space or a containment sump until they are detected and removed;

(B) Prevent the release of regulated substances into the environment throughout the operational life of the UST system; and

(C) Allow for interstitial monitoring within either the piping's interstitial space or a containment sump.

(ii) Containment sumps. Containment sumps used as part of the secondary containment and interstitial monitoring system for piping must be designed, constructed, and installed to:

(A) Be liquid-tight on its sides, bottom, and at any penetrations;

(B) Allow for visual inspection and access to the components in the sump; and

(C) Allow for interstitial monitoring of the piping. The piping's interstitial space must be exposed within the sump. Sensors must be placed within the sump where they are able to detect any leak of regulated substances.

(b) Codes of practice. Double-walled piping must be designed and constructed in accordance with a code of practice developed by a nationally recognized association or independent testing laboratory. The following codes of practice may be used to meet this requirement:

(i) Underwriters Laboratories, Standard 971, "Standard for Non-metallic Underground Piping for Flammable Liquids"; or

(ii) Underwriters Laboratories, Standard 971A, "Outline of Investigation for Metallic Underground Fuel Pipe."

(4) Release detection. Double-walled piping must be monitored for releases using the methods specified in this subsection.

(a) Pressurized piping must be monitored interstitially for releases at least every thirty days in accordance with WAC 173-360-345 (6)(h)(i) and be equipped with an automatic line leak detector in accordance with WAC 173-360-350 (3)(a).

(b) Suction piping not meeting the standards in WAC 173-360-350 (2)(b)(i) through (v) must be monitored interstitially for releases at least every thirty days in accordance with WAC 173-360-345 (6)(h)(i).

(c) Methods that continuously monitor the interstitial space using a vacuum, pressure, or a liquid must be able to detect a breach in both the inner and outer walls.

[Statutory Authority: Chapter 90.76 RCW. WSR 12-17-041 (Order 08-08), § 173-360-820, filed 8/8/12, effective 10/1/12.]

Chapter 90.76 RCW. WSR 12-17-041 (Order 08-08), § 173-360-820, filed 8/8/12, effective 10/1/12.

Rules

173-360-350,173-360-305,173-360-345,173-360-350,173-360-350,173-360-345,