WAC 296-307-48039. Painting and marking service piping systems

(1) Underground pipe and tubing and outdoor ferrous pipe and tubing must be covered or painted with a suitable material for protection against corrosion. (2) Aboveground piping systems must be marked according to the American National Standard Scheme for the Identification of Piping Systems, ANSI A 13.1-1956. (3) Station outlets must be marked to indicate the name of the gas.