§ 15.01.740. Ductile iron pipe.

A.

General requirements. Ductile iron pipe shall be Class 50 for slip-on or mechanical joint piping (Class 51 for eight-inch size and under) and Class 53 for flanged joint piping unless otherwise required by the city engineer due to loadings, site conditions, etc.

B.

Materials. Ductile iron pipe for the transmission and distribution of water shall be manufactured in accordance with AWWA C151 and ANSI A-21.51 "American Standard for Ductile-Iron Pipe, Centrifugally Cast in Metal Molds or Sand-Lined Molds, for Water or Other Liquids."

All pipe shall be made of good quality ductile cast iron and of such chemical composition and structure as is required to meet the physical and mechanical property requirements of the standard.

C.

Joints. Ductile iron pipe shall be of the following types, as indicated on the approved plans.

1.

Mechanical joints and the rubber gaskets and lubricant for ductile iron pipe, shall comply with the requirements and be dimensioned in accordance with AWWA C-151 and C-111. All gasket surfaces shall be smooth and free from imperfections. All mechanical joint gaskets shall be armor guard type gaskets and shall conform to tests in accordance with construction specifications and shall be less than one year old. Lubricant shall be non-toxic and have no deteriorating effects on gasket materials. Lubricants shall not impart taste, odor, or flavor to water in the pipe.

2.

Rubber gasket push-on joints, and the rubber gaskets and lubricant for ductile iron pipe shall comply with the general requirements of AWWA C- 111 of latest revision. Gaskets shall be free from defects and not over one year old. Lubricant shall be non-toxic and have no deteriorating effects on gasket materials. Lubricants shall not impart taste, odor, or flavor to water in the pipe.

3.

Cast iron pipe flanges, and bolts and nuts therefore, shall be dimensioned in accordance with ASA B16.2 for Class 150, and ANSI A21.10. Threads for screwed on flange pipe shall comply with ASA B-2.1. Flange joints shall be bolted firmly with machine, stud or cap bolts of proper size. Flange shall be faced and drilled in accordance with ANSI A21.10.

D.

Fittings.

1.

Mechanical joint fittings. Mechanical joint fittings shall conform to the provisions of ANSI/AWWA C110/A21.10-82 or C153/A21.53-58.

2.

Push-on fittings. Push-on fittings shall conform to ANSI A 21.10 with bells, sockets, and plain ends per ANSI A 21.11.

3.

Flanged fittings. Flanged fittings shall conform to ANSI/AWWA "American Standard for Cast Iron Fittings."

All flanges shall be faced and drilled. Where cap screws or stud bolts are needed, flanges shall be tapped to support cap screws or stud bolts.

E.

Lining and coating. The waterway surfaces of all ductile iron water pipe and fittings shall be completely covered with a uniform thickness of cement-mortar or covered with a bituminous seal coat, all in accordance with AWWA C-104, and AWWA C-151. Ductile iron pipe or fittings lined in the field will not be accepted as conforming to AWWA C-104.

The outside surface of all "buried" ductile iron pipe shall be coated with a bituminous coating in accordance with AWWA C-151 requirements.

F.

Corrosion protection and soil tests. When a public works engineer determines that a corrosive conditions exists such as poor drainage or reactive soils, pipe and fittings shall be encased in polyethylene wrap as described in subsection G.

G.

Polyethylene encasement. The outside surface of all ductile iron pipe and fittings shall be encased with polyethylene film in tube or sheet form unless otherwise approved by the city engineer.

The polyethylene film shall be manufactured of virgin polyethylene material conforming to the requirements of ASTM Standard Specification D-1248-68-Polyethylene Plastics Molding and Extrusion Materials. The film shall have a minimum nominal thickness of 0.008" (8 mils) with a minus tolerance not exceeding ten percent of the nominal thickness.

The polyethylene encasement shall prevent contact between the pipe and the surrounding backfill and bedding material but is not intended to be a completely air and watertight enclosure. Overlaps shall be secured by the use of polyethylene plastic tape, plastic string, or other materials capable of holding the polyethylene encasement in place under light tension until backfilling operations are completed.

Repair any rips, punctures, or other damage to the polyethylene with polyethylene plastic tape or with a short length of polyethylene tube cut open, wrapped around the pipe, and secured in place.

Cover bends, reducers, offsets, and other pipe-shaped appurtenances with polyethylene in the same manner as the pipe.

When valves, tees, crosses, and other odd-shaped pieces cannot be wrapped practically in a tube, wrap with a flat sheet or split length of polyethylene tube by passing the sheet under the appurtenance and bringing it up around the body. Make seams by bringing the edges together, folding over twice, and taping down. Tape polyethylene securely in place at valve stem and other penetrations.

Provide openings for branches, service taps, blow-offs, air valves, and similar appurtenances by making an X-shaped cut in the polyethylene and temporarily folding back the film. After the appurtenance is installed, tape the slack securely to the appurtenance and repair the cut, as well as any other damaged areas in the polyethylene, with tape.

Where polyethylene-wrapped pipe joins an adjacent pipe that is not wrapped, extend the polyethylene wrap to cover the adjacent pipe for a distance of at least two feet. Secure the end with circumferential turns of tape.

All polyethylene-wrapped pipe, fittings, and valves shall be inspected for proper wrapping by the city engineer or public works director before backfilling operations.

H.

Pipe installation. All pipe shall be laid as specified in AWWA Standard for "Installation of Water Mains" C-600, except as modified herein and in special conditions approved by the city engineer.

Tees, elbows, crosses, and reducers shall be used for changes in direction and outlets, unless otherwise specified on the approved detail drawings.

Anchors, thrust bolts and thrust blocks shall be placed at valves, elbows, tees, etc., as shown on the approved detail drawings or as directed by the city engineer.

All ductile iron pipe installation shall proceed on a stable foundation, with joints closely and accurately fitted. Joints shall be clean and dry, and a non-toxic joint lubricant, as recommended by the pipe supplier, shall be applied uniformly to the mating joint and gasket surfaces to facilitate easy, positive joint closure. All push-on joints shall-have brass wedges as supplied by the pipe manufacturer, and installed as per standard push-on joint specifications unless otherwise directed by the city engineer.

All pipe shall be installed with uniform bearing under the full length of the barrel, with suitable excavations being made to receive pipe bells and fittings.

Select bedding material shall be compacted around the pipe to firmly bed the pipe in position. If adjustment of position of a pipe length is required after being laid, it shall be removed and rejoined as for new pipe installation. In addition to the above requirements, all pipe installation shall comply with the specific requirements of the pipe manufacturer.

Each pipe shall be laid true to line and grade and in such a manner as to form a close concentric joint with adjoining pipe and to prevent sudden offsets to the flow line. All joint offsets shall be made as specified in AWWA Standard for "Installation of Water Mains" C-600, except as modified herein and in special conditions approved by the city engineer. As work progresses, the interior of the pipe shall be cleared of dirt and superfluous materials. Where cleaning after laying is difficult because of small pipe size, a suitable swab or drag shall be kept in the pipe and pulled forward past each joint immediately after jointing has set, and pipe shall not be laid when conditions of the trench or weather is unsuitable for such work. At all times when work is in progress, all open ends of the pipe and fittings shall be securely closed to the satisfaction of the city engineer, so that no water, earth, or other substance will enter the pipe or fittings.

I.

Gravel foundation for pipe used. Wherever the subgrade material does not afford a sufficiently solid foundation to support the pipe, the superimposed load, and where groundwater must be drained, the subgrade shall be excavated to such depth as may be necessary and replaced with crushed rock, gravel or other suitable material as approved by city engineer, all such material shall be compacted into place.

Gravel for ductile iron pipe foundations shall be clean gravel with one hundred percent passing a one-and-one-half-inch screen and five percent passing a three-fourths-inch sieve.

J.

Pipe bedding. All pipes shall be protected from lateral displacement and possible damage resulting from impact or unbalanced loading during backfilling operations by being adequately bedded. A groove shall be excavated in the bottom of the trench to receive the bottom quadrant of the pipe. Before preparing the groove, the trench bottom shall be excavated or filled, with approved bedding material, and compacted to an elevation sufficiently above the grade of the pipe so that, when completed, the pipe will be true to line and grade. Bell holes and pipe fitting holes shall be excavated so that only the barrel of the pipe and bottom quadrant of the fitting receive bearing from the trench bottom.

Pipe bedding materials placed at any point below the midpoint of the pipe shall be deposited and compacted in layers not to exceed eight inches in uncompacted depth. Deposition and compaction of bedding materials shall be done simultaneously and uniformly on both sides of the pipe. Compaction shall be accomplished with hand or mechanical compactors. All bedding materials shall be placed into the trench with hand tools or other approved method in such a manner that they will be scattered alongside the pipe and not dropped or pushed into the trench in compact masses. Bedding materials shall be loose earth, free from lumps, boulders or other debris; sand materials free from roots, sod, or other vegetable matter. All bedding materials shall be approved by the city engineer.

In the event trench materials are not satisfactory for pipe bedding, modified bedding materials will be required. Modified bedding shall consist of placing compacted granular material on each side of and to the level of twelve inches above the top of the pipe.

Modified bedding materials shall be graded as follows: one hundred passing a one-inch screen and five percent passing a No. 4 sieve. All modified bedding materials shall be approved by the city engineer.

K.

Cleaning and flushing. The contractor shall take every precaution to remove dirt, grease and all other foreign matter from each length of piping before making connections in the field. After each section of piping is installed, it shall be thoroughly cleaned to remove rocks, dirt, and other foreign matter by washing, sweeping, scraping, or other method that will not harm the lining, or pipe.

Water required for flushing shall be furnished by the contractor. All temporary connections for flushing and drainage shall be furnished, installed, and subsequently removed by the contractor.

All open ends of pipes shall be bullheaded or plugged when workmen are not on the job or in the immediate area to prevent rocks or other foreign matter from entering the pipe.

All new water systems or extensions to existing systems shall be thoroughly flushed before being placed in service. Flushing shall be accomplished through hydrants, or end of the line blow-off assemblies.

(Ord. No. 2007-07-31, §§ 9.4—9.4.11, 7-10-2007; Ord. No. 2010-11-24, § 2, 11-23-2010; Ord. No. 2012-05-15, § 1, 5-8-2012)