Los Angeles County Municipal Code § 5704.2 Fire Code

Waste liquids shall be kept in a sump, tank, or receptacle approved for this purpose. The waste must be disposed of in accordance with the provisions of the California Health and Safety Code, Division 20, Chapter 6.5, Hazardous Waste Control.

Vaults shall be substantially liquid tight and there shall not be backfill around the tank or within the vault. The vault floor shall drain to a sump. For premanufactured vaults, liquid tightness shall be certified as part of the listing provided by a nationally recognized testing laboratory. For field-erected vaults, liquid tightness shall be certified in an approved manner. Secondary containment shall be provided for new installations of underground tanks and existing tanks with a breach in integrity.

The fire protection system shall be a deluge type foam system, which provides a minimum of 0.25 gpm (0.9463 L/m) over the entire vault area. The minimum duration of the foam supply shall be 10 minutes. If a manual system is provided, it must assume a maximum of 125 psi (861.85 kPa) at the fire department connection.

All existing aboveground tanks exceeding 1,500 square feet (139.3546 m 2 ) of liquid surface area used for the storage of Class I or Class II flammable liquids shall be provided with foam fire protection.

Exceptions:

Tanks with floating roofs for storage of crude oil exceeding 1,500 square feet (139.3546 m 2 ) of liquid surface area and less than 12,300 square feet (1142.7074 m 2 ) of liquid surface area shall have foam fire protection only for the seal area.

Floating roof tanks or pressure tanks operating at or above 1 pound per square inch gauge.

Above-ground tanks for storage of liquids with boilover characteristics shall be located in accordance with Table 22.4.1.4 of NFPA 30. Shell-to-shell spacing between tanks shall not be less than the diameter of the largest tank.