Section 658-109-9 - Oil Supply and Return Piping1. Whenever a copper oil supply or return line is installed under cement, sub-floors, or earth surface, it shall be continuous from the burner to the tank without any splices.2. In order to avoid undetected oil leaks under floors, all copper oil supply and return lines installed under cement, sub floors, or beneath any surface, shall be encased in a continuous piece of non-metallic, liquid tight conduit such as PVC, ENT, or other approved material. The conduit shall be a minimum of one (1) pipe size larger than the oil supply and return lines. The ends of the conduit shall penetrate the cement or earth surface a minimum of two (2) inches above grade. All copper tubing, spliced within an oil supply line, shall be made above the surface of the cement, sub-floor or earth surface.3. Coated copper tubing must have an OSV valve or PRV valve installed at the tank when used underground.4. All copper fuel oil lines shall be encased in a continuous piece of non-metallic liquid tight conduit such as PVC, ENT, coated copper tubing, or other approved material and secured in order to prevent physical damage. The end of the conduit shall not exceed more than two (2) inches from any fitting, except the connection at the fuel tank and at the fuel pump located at the burner shall not exceed six (6) inches.5. No oil supply line may be concealed in a wall, ceiling, or partition unless access to the oil supply or return line can be had without cutting through existing walls, ceilings or partitions. This may be accomplished by providing removable panels.6. Oil supply lines, which penetrate a foundation wall, shall be encased in a non-metallic, liquid tight conduit such as PVC, ENT, or other approved material. The sleeve shall be sealed at the wall to prevent the entry of water, insects, or rodents.7. When an oil filter or other accessory equipment is connected to copper piping smaller than three-quarter (3/4) inch and is not located within the vicinity of the oil supply or burner connections, the filter or other devices shall be rigidly supported by a wall or floor mounted bracket or other means providing sufficient support for stability and servicing this type of accessory equipment.8. All oil supply and return lines of copper tubing shall be connected by flare fittings only. All fittings shall be accessible for service or replacement. No compression fittings shall be used on a supply or return oil line unless it is for the introduction of the lines at the top of the tank with a single or double tap bushing.9. All connections of supply or return oil lines located outside shall be made with flare frost fittings.10. No oil lines or oil devices which are disconnected from an oil supply tank, burner or unit, shall be left open. Any oil line or oil device which is disconnected or discontinued shall be sealed or closed with a plug, cap or other approved fitting.11. Unprotected supply lines that are buried and grouted must be removed from service.12. If underground or under-slab piping is connected to a tank of over 660 gallons capacity or to tanks with an aggregate capacity of over 1320 gallons, the installation of the underground piping must meet Department of Environmental Protection requirements. (See Appendix A)13. Oil spills must be reported to the Department of Environmental Protection in accordance with Appendix A.02-658 C.M.R. ch. 109, § 9