Every underground storage tank installed after December 31, 1983, shall meet the following requirements:
(a) Be designed and constructed to provide primary and secondary levels of containment of the hazardous substances stored in them in accordance with the following performance standards:
(1) Primary containment shall be product-tight.
(2) Secondary containment shall be constructed to prevent structural weakening as a result of contact with any released hazardous substances, and also shall be capable of storing, for the maximum anticipated period of time necessary for the recovery of any released hazardous substance.
(3) In the case of an installation with one primary container, the secondary containment shall be large enough to contain at least one hundred percent of the volume of the primary tank
(4) In the case of multiple primary tanks, the secondary container shall be large enough to contain one hundred fifty percent of the volume of the largest primary tank placed in it, or ten percent of the aggregate internal volume of all primary tanks, whichever is greater.
(5) If the facility is open to rainfall, then the secondary containment must be able to additionally accommodate the volume of a twenty-four hour rainfall as determined by a one hundred year storm history.
(6) Single-walled containers do not fulfill the requirement of an underground storage tank providing both a primary and a secondary containment.
(b) Be designed and constructed with a monitoring system capable of detecting the entry of the hazardous material stored in the primary containment into the secondary containment. If water should intrude into the secondary containment, a means of monitoring for water intrusion and for safely removing the water shall also be provided.
(c) When required by the local agency, a means of overfill protection for any primary tank, including an overfill prevention device or an attention-getting higher level alarm or both. Primary tank filling operations of underground storage tanks containing motor vehicle fuels which are visually monitored and controlled by a facility operator satisfy the requirements of this paragraph.
(d) Different substances that in combination may cause a fire or explosion, or the production of flammable, toxic, or poisonous gas, or the deterioration of a primary or secondary container, shall be separated in both the primary and secondary containment so as to avoid potential intermixing.
(e) If water could enter into the secondary containment by precipitation of infiltration, the facility shall contain a means of removing the water by the owner or operator. This removal system shall also provide for a means of analyzing the removed water for hazardous substance contamination and a means of disposing of the water, if so contaminated, at an authorized disposal facility. (Ord. No. 944, § 3.)
