(a) Tanks shall rest on the ground or on foundations made of concrete, masonry, piling of steel. Tank foundations shall be designed to minimize the possibility of uneven settling of the tank and to minimize corrosion in any part of the tank resting on the foundation.
(b) When tanks are supported above from the foundations, tank supports shall be installed on firm foundations. Supports for tanks storing Category 1, 2, 3, and 4 flammable liquids shall be of concrete, masonry or protected steel. Single wood timber supports (not cribbing) laid horizontally may be used for outside aboveground tanks if not more than 12 inches high at their lowest point.
(c) Steel supports or exposed piling for tanks storing Category 1, 2, 3, and 4 flammable liquids shall be protected by materials having a fire resistant rating of not less than two hours, except that steel saddles need not be protected if less than 12 inches high at their lowest point. Water spray protection or its equivalent may be used in lieu of fire-resistive materials to protect supports.
(d) The design of the supporting structure for tanks such as spheres shall requires special engineering consideration.
(e) Every tank shall be so supported as to prevent the excessive concentration of loads on the supporting portion of the shell.
(f) In areas subject to earthquakes, the tank supports and connections shall be designed to resist damage as a result of such shocks.