(a) Category 1 or 2 flammable liquids, or Category 3 flammable liquids with a flashpoint below 100oF (37.8oC) shall be stored in closed containers, or in storage tanks aboveground outside of buildings, or underground in accordance with Article 145.
(b) Category 3 flammable liquids with a flashpoint at or above 100oF (37.8oC), Category 4 flammable liquids and liquids with a flashpoint greater than 199.4oF (93oC) (formerly designated Class IIIB Combustible liquids) shall be stored in containers, or in tanks within buildings or aboveground outside of buildings, or underground in accordance with Article 145.
(c) Containers of flammable or combustible liquids when piled one upon the other shall be separated by dunnage sufficient to provide stability and to prevent excessive stress on container walls. The height of pile shall be consistent with stability and strength of containers.
(d) Piping systems shall be in accordance with Article 146.