(1) If required by the properties of the liquid stored. In case of doubt, the supplier, producer of the flammable or combustible liquid, or other competent authority should be consulted as to the suitability of the material of construction to be used;
(2) For installation underground;
(3) If used for the storage of combustible liquids (as defined in Section 5415) aboveground in areas not exposed to a spill or leak of a Category 1, 2 or 3 flammable liquid. If tanks storing combustible liquids are located where they are exposed to a spill or leak of a Category 1, 2 or 3 flammable liquid, they shall be constructed in accordance with Section 5585; or
(4) If used for the storage of combustible liquids inside a building protected by an approved automatic fire extinguishing system.