An owner and an operator of a UST system shall comply with the installation requirements of this regulation. Install piping in accordance with the requirements of this regulation. Place underground piping on a 6-inch bedding of appropriate backfill material as described in Regulation .04 of this chapter. Maintain the following clearances when installing piping: Twice the nominal diameter of the pipe but at least 4 inches between all piping; At least 6 inches between piping and electrical conduits related to the UST system; At least 6 inches between piping and excavation zone sidewalls; and At least 18 inches between piping and the surface of the ground. Unless otherwise approved by the Department, ensure piping rises 1/8 of an inch for each lateral foot from the UST to the piping endpoint. Follow the manufacturer specifications and installation requirements when installing piping. In accordance with manufacturer specifications, use a UL listed flexible connector to connect piping as follows: Except for a direct fill line, to connect a pipe carrying a regulated substance to a UST at the end of a piping run; and To connect a pipe carrying a regulated substance to a dispenser system. Unless otherwise approved by the Department, an owner and an operator of a UST system may not use a flexible connector to connect piping carrying petroleum vapor or a regulated substance at any other point in the piping system not listed in §G of this regulation. Place a UL listed shear valve on pressurized product piping dispensing motor fuel, and properly anchor the shear valve at the dispenser. Install appurtenances such as water or air piping in a separate piping trench; Ensure vent lines above the ground surface are: Constructed with at least schedule 40 steel; Protected from traffic; Properly anchored; and Protected from weather and debris. Ensure the vents of a UST system storing a flammable or combustible liquid meet the following conditions: If the UST system stores a flammable liquid, the vents terminate 12 feet above the ground surface and 2 feet above an attached building; and If the UST system stores a combustible liquid, the vents terminate at least 3 feet above the ground surface.