Section 6-77-102 - Installation of plastic pipe(a) Plastic pipe must be installed below ground level.(b) Plastic pipe that is installed in a vault or any other below grade enclosure must be completely encased in gas-tight metal pipe and fittings that are adequately protected from corrosion.(c) Plastic pipe must be installed so as to minimize shear or tensile stresses.(d) Thermoplastic pipe that is not encased must have a minimum wall thickness of 0.090 inches, except that pipe with an outside diameter of 0.875 inches or less may have a minimum wall thickness of 0.062 inches.(e) Plastic pipe that is not encased must have an electrically conductive wire or other means of locating the pipe while it is underground.(f) Plastic pipe that is being encased must be inserted into the casing pipe in a manner that will protect the plastic. The leading end of the plastic must be closed before insertion.[Eff ] (Auth: HRS § 269-6) (Imp: 49 C.F.R. §192.321, OCT 1, 1990)