Secondary containment systems required in accordance with § 74:56:03:04 for existing AST systems located at facilities with a total capacity of 250,000 gallons or more shall consist of the following:

1. (1) Construction of a retaining structure surrounding the AST systems capable of containing 110 percent of the volume of the largest tank in the facility;

2. (2) Construction beneath any aboveground piping of containment system which meets the following requirements;

   1. (a) Such a containment system may consist of native soils, clays, bentonite, or artificially constructed materials equivalent to 60 mil high density polyethlene or greater. An impermeability of at least 10^-6 centimeter per second is required to permit containment;
   2. (b) The containment system must be constructed and maintained so that the required impermeability is met for the operational life of the AST system;
   3. (c) The containment system must be compatible with the regulated substance stored;

   4. (d) Construction of the containment system must be in accordance with professional engineering practices;

      Plans and specifications for the secondary containment system must be submitted for approval by the department at least 30 days before construction of the system.

      Aboveground and underground piping from the AST is exempt from these requirements provided that pressure tests are performed every five years to demonstrate the piping's integrity.

Source: 14 SDR 76, effective November 29, 1987; 18 SDR 62, effective October 10, 1991; transferred from § 74:03:30:12, July 1, 1996.

General Authority: SDCL 34A-2-93 , 34A-2-101.

Law Implemented: SDCL 34A-2-100 , 34A-2-101.