NAC459.9935. Marina storage tanks: Secondary containment.

     1. A marina storage tank must have a secondary containment area for the fuel stored in the tank.

     2. Multiple products stored within the same containment area must be compatible with each other.

     3. If the secondary containment area is open to precipitation, it must be capable of containing 110 percent of the capacity of the largest tank plus the volume displaced by the other tanks within the containment area.

     4. The secondary containment area must be made of concrete or steel and be compatible with and impermeable to the products stored in the tank.

     5. Liquid discharges to the environment from the secondary containment area are prohibited if contamination of the liquid by a regulated substance is suspected or detected.

     6. The secondary containment area must not include any uncapped drain that extends outside of the containment area.

     7. A double-walled tank does not require additional containment if:

     (a) All piping connections to the tank are made above the normal maximum liquid level;

     (b) A mechanism is provided to prevent the release of liquid from the tank by siphon flow;

     (c) A mechanism, accessible to a delivery operator, is provided for determining the level of liquid in the tank;

     (d) A mechanism which does not restrict or interfere with the proper functioning of the normal vent or emergency vent is provided to prevent overfilling by sounding an alarm when the liquid level in the tank reaches 90 percent of capacity and by automatically stopping the delivery of liquid to the tank when the level in the tank reaches 95 percent of capacity;

     (e) The interstitial space is enclosed and the space has emergency venting; and

     (f) A means is provided to verify the integrity of the double wall.

     (Added to NAC by Environmental Comm’n by R083-05, eff. 10-31-2005)