ARM 17.56.204. SECONDARY CONTAINMENT, UNDER-DISPENSER CONTAINMENT, AND INTERSTITIAL MONITORING

(1) Any UST that is replaced or installed must employ: (a) secondary containment and approved continuous interstitial monitoring, as described in ARM 17.56.407(1)(g) and (2), as a monthly leak detection method; (b) under-dispenser containment that provides access; and (c) a liquid-tight tank top sump where the product piping exits the tank. (2) Any pressurized product piping regulated under this chapter that is installed or replaced must: (a) employ secondary containment; (b) terminate in a liquid tight sump at each end. The sumps must: (i) be liquid-tight on their sides, bottom, and at any penetrations; (ii) be compatible with the substance conveyed by the piping; and (iii) allow for visual inspection and access to the components in the containment system and/or otherwise allow the system to be monitored; and (c) employ approved continuous interstitial monitoring, as described in ARM 17.56.407(1)(g) and (2), as a monthly leak detection method. (3) If over 50% of the length (measured from the piping terminus at the tank to the nearest point where the product is dispensed or otherwise used) or a pressurized product pipe regulated under this chapter is replaced, then the entire length of product piping must be replaced with secondarily-contained piping. The replacement of a line of product piping from a particular UST does not require the replacement of product pipes connected to other USTs. (4) Under-dispenser containment must be installed under dispensers when: (a) a new UST system is installed; (b) dispensers and any associated hardware used to attach the dispenser to the product piping are replaced; (c) product piping is repaired or replaced at an associated dispenser island; (d) significant modifications are made to the concrete at a dispenser island; or (e) the department determines under-dispenser containment is necessary to meet the requirements of this rule. (5) If under-dispenser containment is required pursuant to (1) or (4), the containment must: (a) employ approved interstitial monitoring, as described in ARM 17.56.407(1)(g) and (2), as a monthly leak detection method; (b) be liquid-tight on its sides, bottom, and at any penetrations; (c) be compatible with the substance conveyed by the piping; and (d) allow for visual inspection and access to the components in the containment system and/or allow the system to be monitored.