(a) Pipe, valves, faucets, fittings and other pressure containing parts as covered in Section 5606(b) shall meet the material specifications and pressure and temperature limitations of the applicable sections of ANSI B31, American National Standard Code for Pressure Piping, except as provided by Section 5607(b), (c) and (d). Plastic or similar materials, as permitted by Section 5607(d), shall be designed to specifications embodying recognized engineering principles and shall be compatible with the fluid service.
(b) Nodular iron shall conform to ASTM A-445-70, Ferritic Ductile Iron Castings for Valves, Flanges, Pipe Fittings and Other Piping Components. Malleable iron shall conform to ASTM A-47-68, Malleable Iron Castings.
(c) Valves at storage tanks, as required by Sections 5596(b) and 5601(b), and their connections to the tank shall be of steel or nodular iron, or malleable iron except as provided in (1) or (2).
(1) Valves at storage tanks may be other than steel, malleable or nodular iron when the chemical characteristics of the liquid stored are not compatible with steel or when installed internally to the tank. When installed externally to the tank, the material shall have a ductility and melting point comparable to steel or nodular iron so as to withstand reasonable stresses and temperatures involved in fire exposure, or otherwise be protected such as by materials having a fire resistance rating of not less than two hours.
(2) Cast iron, brass, copper, aluminum, and similar materials may be used on tanks described in Section 5590(c) or for tanks storing liquids with a flashpoint greater than 199.4oF (93oC) (formerly designated Class IIIB Combustible liquids) when the tank is located outdoors and not within a diked area or drainage path of a tank storing a Category 1, 2, 3 or 4 flammable liquid.
(d) Low melting point materials, such as aluminum, copper and brass; or materials which soften on fire exposure, such as plastics; or non-ductile material, such as cast iron, may be used underground for all flammable and combustible liquids within the pressure and temperature limits of the ANSI B31, American National Standard Code for Pressure Piping, if such materials are used outdoors in aboveground piping systems handling Category 1, 2, 3 or 4 flammable liquids or within buildings handling any flammable or combustible liquid, they shall be either suitably protected against fire exposure, or so located that any leakage resulting from the failure would not unduly expose persons, important buildings or structures or located where leakage can readily be controlled by operation of an accessible remotely located valve or valves.