Illinois Administrative Code
Title 41 - FIRE PROTECTION
Part 175 - TECHNICAL REQUIREMENTS FOR UNDERGROUND STORAGE TANKS AND THE STORAGE, TRANSPORTATION, SALE AND USE OF PETROLEUM AND OTHER REGULATED SUBSTANCES
Subpart D - DESIGN, INSTALLATION AND CONSTRUCTION REQUIREMENTS
Section 175.465 - Additional Requirements for Installation and Upgrade of USTs

a) Excavation for USTs shall be made with due care to avoid undermining of foundations of existing structures.

b) The UST site shall be prepared to ensure safe movement and installation of equipment and materials. Sloping, benching, stepping or shoring the sides of excavations shall be performed in compliance with OSHA requirements under 29 CFR 1926.

c) Upon delivery at the installation site, tanks and piping shall be inspected to detect any evidence of damage to coatings or structure.

d) Upon discovery of any damage to tanks or piping, repairs shall be made in accordance with 41 Ill. Adm. Code 172, 174, 175, 176, and 177 and manufacturer's instructions.

e) Equipment shall be provided with sufficient lifting capacity to unload and place USTs into the tank excavation. The tank shall be placed in the excavation with care, since dropping or rolling the tank into the excavation can break a weld, puncture or damage the tank, or scrape off the protective coating of coated tanks. Tanks shall not be rolled, dropped or dragged.

f) Tanks shall be set on firm foundations and surrounded with at least 12 inches of noncorrosive inert material such as clean sand or gravel, well-tamped in place.

g) USTs shall be installed to safeguard against movement by anchoring in accordance with manufacturer's instructions.

h) Unless otherwise prescribed by the manufacturer's recommended installation procedures, steel tanks shall be covered with a minimum of 3 feet of approved backfill material. USTs existing on October 1, 1985 shall be buried so that the tops of the tanks will not be less than 2 feet below the surface of the ground or shall be under at least 12 inches of approved backfill material and a slab of reinforced concrete not less than 4 inches in thickness; the slab shall be set on a firm, well-tamped earth foundation and shall extend at least one foot beyond the outline of the tank in all directions. When asphaltic or reinforced paving is used as part of the protection, it shall extend at least one foot horizontally beyond the outline of the tank in all directions.

i) Tank to tank separation distance shall be a minimum of 24 inches for all tanks installed after May 1, 2003.

j) There shall be a minimum of 2 manufactured slotted or perforated observation wells of at least 4" diameter installed in each new tank field of tanks larger than 1,000 gallons and one well for 1,000 gallon tanks or less and shall have 2 wells for fields with more than one tank. They shall be placed at opposite ends or opposite corners one foot below the invert elevation of the lowest UST. Lids shall be securely protected against unauthorized activities. Only one well will be required if groundwater flow direction can be proven and that proof is supplied at the time of permitting and the well is then installed in the downstream location.

k) Metallic tanks and metallic piping shall not be backfilled with cinders or other material of corrosive effect. Corrosion protection shall be provided in accordance with Section 175.510.

l) Before the final inspection, but after the UST system has been installed, connected, backfilled and covered, tank and line precision testing shall be done on the entire UST system. Passing test results from the tank and line precision tests shall be available for the inspector to verify at the time of the final inspection.

m) Any work performed in or around the excavation area must stop at sunset unless adequate lighting is provided.