02-658-8 Me. Code R. § 8
Wherever a copper oil supply or return line is installed under cement, sub-floors, or earth surface, it must be continuous without any splices from the burner to the tank.
All copper oil supply and return lines must be encased in a continuous piece of non-metallic liquid-tight conduit such as PVC, ENT, coated copper tubing, or other approved material and must be 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 6".
In order to avoid undetected oil leaks under floors, the conduit must be a minimum of one pipe size larger than the oil supply and return lines. The ends of the conduit must penetrate the cement or earth surface a minimum of two (2) inches above grade.
An oil supply or return line that penetrates a foundation wall must be sealed at the wall to prevent the entry of water, insects or rodents.
Coated copper tubing must have an OSV valve or PRV valve installed at the tank when used underground.
Wherever an outlet of an oil supply tank is located more than four (4) feet above the burner, an OSV valve or PRV valve is required.
No oil supply or return line shall be concealed in a wall, ceiling, or partition unless access to the oil supply or return line can be made without cutting through existing walls, ceilings or partitions. This may be accomplished by providing removable panels.
Coated copper tubing must be approved by the manufacturer for the intended use.
When an oil filter or other accessory equipment is connected to copper piping smaller than 3/4 inches and is not directly connected to the oil tank or oil burner, the filter or other devices must be rigidly supported by a wall- or floor-mounted bracket or other means that provides sufficient support and stability for servicing this type of accessory equipment.
All oil supply and return lines of copper tubing must be connected by flare fittings only. All fittings must 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.
All connections of supply or return oil lines located outside must be made with flare frost fittings.
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 must be sealed or closed with a plug, cap or other approved fitting.
Unprotected supply lines that are buried or grouted must be removed from service.
As set forth in the Appendix to this Chapter, 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 be installed by a certified underground oil tank installer and otherwise meet Maine Department of Environmental Protection requirements.
Oil spills, regardless of the amount spilled, must be reported within two (2) hours to the Maine Department of Environmental Protection in accordance with the Appendix to this Chapter.
02-658 C.M.R. ch. 8, § 8