4.3.1.2. (1) Except as required in Sentences (2), (4), (6) and (8) and permitted in Sentences (3), (5) and (7) and in Section 4.9, atmospheric storage tanks shall be built in conformance with (a) API 12B, “Bolted Tanks for Storage of Production Liquids”, (b) API 12D, “Field Welded Tanks for Storage of Production Liquids”, (c) API 12F, “Shop Welded Tanks for Storage of Production Liquids”, (d) API 650, “Welded Steel Tanks for Oil Storage”, (e) ULC-S601, “Shop Fabricated Steel Aboveground Horizontal Tanks for Flammable and Combustible Liquids”, (f) CAN/ULC-S602, “Aboveground Steel Tanks for Fuel Oil and Lubricating Oil”, (g) CAN/ULC-S603, “Steel Underground Tanks for Flammable and Combustible Liquids”, (h) CAN/ULC-S603.1, “Galvanic Corrosion Protection Systems for Steel Underground Tanks for Flammable and Combustible Liquids,” (i) CAN4-S615, “Reinforced Plastic Underground Tanks for Petroleum Products”, (j) ULC-S630, “Shop Fabricated Steel Aboveground Vertical Tanks for Flammable and Combustible Liquids”, (k) CAN/ULC-S643, “Shop Fabricated Steel Aboveground Utility Tanks for Flammable and Combustible Liquids”, (l) ULC-S652, “Tank Assemblies for Collection of Used Oil”, (m) ULC-S653, “Aboveground Steel Contained Tank Assemblies for Flammable and Combustible Liquids”, (n) ULC/ORD-C58.10, “Jacketed Steel Underground Tanks for Flammable and Combustible Liquids”, (o) ULC/ORD-C142.5, “Concrete Encased Steel Aboveground Tank Assemblies for Flammable and Combustible Liquids”, (p) ULC-S655, “Aboveground Protected Tank Assemblies for Flammable and Combustible Liquids”, or (q) ULC/ORD-C142.23, “Aboveground Waste Oil Tanks”. (2) Tanks built in conformance with Clauses (1)(a), (b) and (c) shall be used only for the storage of crude petroleum at oil fields. (3) When necessitated by possible contamination of the liquid to be stored or possible rapid corrosion of the tank, storage tanks need not conform to Sentence (1), provided that they are designed and built in conformance with good engineering practice for the material being used. (4) Atmospheric storage tanks shall not be used for the storage of flammable or combustible liquids at temperatures at or above their boiling points. (5) Existing aboveground atmospheric storage tanks in service that do not comply with Sentence (1) are permitted to remain in service provided that the tank (a) is not leaking, (b) has no dents in the tank greater than 30 degrees or 35 mm in depth from the normal configuration, (c) has no pitting in excess of 3 mm, and (d) has metal thickness of at least 50 per cent of the minimum permissible thickness specified in an applicable standard referenced in Sentence (1). (6) Existing aboveground atmospheric storage tanks that do not comply with Sentence (1), (3), (5) or (9) shall be refurbished in conformance with Sentence 4.10.4.2.(3) or be replaced. (7) Existing underground storage tanks in service that do not comply with Sentence (1) are permitted to remain in service provided that the tanks are not leaking and steel storage tanks and associated piping are protected from external corrosion in conformance with Subsection 4.3.9. (8) Existing underground storage tanks that do not comply with Sentence (1), (3) or (7) shall be refurbished in conformance with Sentence 4.10.4.2.(3) or be replaced. (9) Existing aboveground atmospheric storage tanks that comply to ULC/ORD-C142.16-1994, “Protected Aboveground Tank Assemblies for Flammable and Combustible Liquids” shall be deemed to comply with Clause (1)(p). Low pressure storage tanks and pressure vessels