(A) Materials and design. Piping, valves, and fittings for flammable liquids shall be designed for the working pressures and structural stresses to which they may be subjected. They shall be of steel or other material suitable for use with the liquid being handled. Pipe wall thicknesses shall be determined in accordance with nationally recognized good practice; except that carbon steel pipe shall not be thinner than standard wall thickness pipe. Pipe wall thickness shall be determined according to the provisions of ASA B31.1-1955 “American Standard Code for Pressure Piping.” All threaded joints and connec-tions shall be made up tight and suitable lubricant or piping compound. These provisions shall apply to all piping for flammable liquids which falls within the scope of this chapter.
(B) Protection against corrosion. All piping for flammable liquids, both aboveground and under-ground, where subject to external corrosion, shall be painted or otherwise protected.
(C) Supports. Pipe systems shall be substantially supported and protected against physical damage and excessive stresses arising from settle-ment, vibration, expansion or contraction.
(D) Valves. Pipe systems shall contain a sufficient number of valves to operate the system properly and to protect the plant. Pipe systems in connection with pumps shall contain a sufficient number of valves to control properly the flow of liquid in normal operation and in the event of physical damage. Connections to pipelines, by which equipment such as tank cars or tank vehicles discharge flammable liquids by means of centrifugal pumps into aboveground storage tanks, shall be provided with check valves for automatic protection against backflow.
('81 Code, § 5.40.220) Penalty, see Ch. 13