§ 15.01.600. Subsurface drain pipe.

A.

General requirements. Buried drainpipe with open joints or perforated pipe shall be provided for the drains in the locations shown on the drawings and as approved by the city engineer. The contractor shall furnish and lay the drainpipe.

B.

Material. Drainpipe may be perforated PVC pipe (ASTM D-178), perforated or non-perforated concrete pipe. Corrugated polyethylene piping per ASTM F-405-77a may also be used if installed with direct burial laser grade control equipment Perforated pipe shall be PVC, extra-strength non-reinforced concrete pipe (ASTM C-14) or reinforced concrete pipe (ASTM C-76). All of which shall have one-fourth-inch diameter perforations or as approved by the city engineer. Concrete pipe shall be furnished with bell-and-spigot.

C.

Laying pipe. When an open joint or perforated drainage system is utilized, a gravel backfill shall be placed under and over the pipe to the minimum depth as shown on the drawings. Approved filter fabric shall be used to separate the gravel liner from the native material. This fabric must entirely enclose the gravel and provide a complete overlap at the top of the pipe section. The pipe shall be laid carefully on the gravel in a workmanlike manner and to the lines and grades shown on the drawings or established by the city engineer.

The maximum allowable departure from grade shall not exceed one-tenth of a foot. The finished bed for all pipe shall be made smooth, including removal of material under the bell, so that the full length of pipe will be evenly and uniformly supported. The pipe shall be laid and completed with adjacent ends closely abutted and with the bell ends upgrade. Any pipe that is broken, cracked, or otherwise unsuitable, as determined by the city engineer, shall be removed and replaced at the contractor's expense. The water level in the trench area where the pipe is being laid shall be held to a minimum. During placement of the pipe the water level in the trench shall not exceed fifty percent of the diameter of the pipe above the invert of the pipe. Water may be removed by permitting the water in the trench to flow down the previously installed drain pipe, provided that a screen cover is kept continuously in place over the exposed end of the pipe at all times, except when additional pipe is actually being placed. The screen used for this purpose shall be approved by the city engineer and shall have maximum mesh openings of one-eighth inch. The pipe shall not be covered with backfill until it has been inspected and approved by the city engineer. After approval, the trench shall be backfilled as prescribed in Section 15.01.430.

The contractor shall keep the pipe drain and manholes free from deposits of mud, sand, gravel, or other foreign matter and in good working condition until the construction is complete and accepted. Any methods used by the contractor to remove deposits of mud, sand, gravel, or other foreign matter from the drains, such as use of water or air pressure, shall be subject to the approval of the city engineer.

(Ord. No. 2007-07-31, §§ 6.9—6.9.3, 7-10-2007; Ord. No. 2010-11-24, § 2, 11-23-2010)