(1) Application.

(a) WAC 296-24-47505 applies to installations made in accordance with the requirements of WAC 296-24-47507 through 296-24-47511, 296-24-47515 and 296-24-47517, except as noted in each of those sections.

(b) WAC 296-24-47507 through 296-24-47517 apply as provided in each of those sections.

(2) Inapplicability. These sections do not apply to:

(a) Marine and pipeline terminals, natural gas processing plants, refineries, or tank farms other than those at industrial sites.

(b) LP-gas refrigerated storage systems;

(c) LP-gas when used with oxygen. The requirements of WAC 296-24-680 through 296-24-722 must apply to such use;

(d) LP-gas when used in utility gas plants. The National Fire Protection Association Standard for the Storage and Handling of Liquefied Petroleum Gases at Utility Gas Plants, NFPA No. 59-1968, must apply to such use;

(e) Low-pressure (not in excess of one-half pound per square inch or 14 inches water column) LP-gas piping systems, and the installation and operation of residential and commercial appliances including their inlet connections, supplied through such systems. For such systems, the National Fire Protection Association Standard for the Installation of Gas Appliances and Gas Piping, NFPA 54-1969 must apply.

(3) Retroactivity. Unless otherwise stated, it is not intended that the provisions of these sections be retroactive.

(a) Existing plants, appliances, equipment, buildings, structures, and installations for the storage, handling or use of LP-gas, which were in compliance with the current provisions of the National Fire Protection Association Standard for the Storage and Handling of Liquefied Petroleum Gases NFPA No. 58-1972, 1973 at the time of manufacture or installation may be continued in use, if such continued use does not constitute a recognized hazard that is causing or is likely to cause death or serious physical harm to employees.

(b) Stocks of equipment and appliances on hand in such locations as manufacturers' storage, distribution warehouses, and dealers' storage and showrooms, which were in compliance with the current provisions of the National Fire Protection Association Standard for the Storage and Handling of Liquefied Petroleum Gases, NFPA No. 58-1972, 1973, at the time of manufacture, may be placed in service, if such use does not constitute a recognized hazard that is causing or is likely to cause death or serious physical harm to employees.