Expose all underground utilities which may be in conflict with proposed water lines prior to installing new lines.
(Ordinance 2007-106, App. B, adopted 3/20/07)
A.
General:
All pipe shall have a cover of at least 42 inches from finished grade unless shown otherwise on Plans. The pipe depth of cover shall not exceed 48 inches from finished grade unless approved by Engineer. No pipe shall be laid in water or when trench condition or weather is unsuitable for such work and pipe shall be kept clean before, during and after laying. Sanitary precautions shall be taken during water line installation as called for by AWWA Standards. Do not install pipe with radius of curvature less than the minimum recommended by pipe manufacturer. All buried iron or steel pipe, valves, fire hydrants, and appurtenances shall be poly wrapped.
1.
PVC Pipe:
PVC pipe shall be uniformly and continuously supported by stable soil. Bedding in the pipe zone from 4 inches below bottom of pipe up to 12 inches above top of pipe shall be hand placed select material free from rocks, organic refuse, or lumps greater than 1-1/2 inches, which will not break down readily when compacted. Bedding shall be placed in thin (approximately 4-inch) layers, moistened if necessary, and thoroughly compacted under and on each side of the pipe to provide support that is free from voids. The balance of the ditch may be machine backfilled unless otherwise shown on Plans.
2.
Ductile Iron and Steel Pipe:
Lay pipe on firm earth foundation and carefully backfill to 6" over pipe with acceptable material free from clods, rocks, or other sharp debris which may damage protective coating or cause pipe to shift. The balance of the trench may be machine backfilled unless otherwise shown on Plans.
3.
Valves, Valve Boxes and Fire Hydrants:
Install valves, valve boxes and fire hydrants plumb. Place valve boxes directly over valve stem. Before installation of valves or fire hydrants, clean all foreign material from interior and open and close valves to insure that they are in good working order. Hand tamp backfill around valve boxes and fire hydrants out to undisturbed trench face. For all nut operated valves below ground, provide and install a valve operator extension on any valve that is installed where the operating nut is more than 30 inches below surrounding finished grade.
B.
Conductive Trace Wire:
Install conductive trace wire with all nonmetallic main water lines and with all service lines.
C.
Separation of Water and Sewer Lines:
The following criteria from Texas Commission on Environmental Quality regulations (See 30 TAC sec. 290.44(e) in TCEQ regulations) shall be followed for water and sewer line separations:
When water mains and sanitary sewers are installed, they shall be installed no closer to each other than nine feet in all directions and parallel lines must be installed in separate trenches. Where the nine feet separation distance cannot be achieved, the TCEQ guidelines in the paragraphs below shall apply.
1.
New water line installation - parallel lines.
a.
Where a new potable water line parallels an existing, non-pressure or pressure rated wastewater main or lateral and the licensed professional engineer licensed in the State of Texas is able to determine that the existing wastewater main or lateral is not leaking, the new potable water line shall be located at least two feet above the existing wastewater main or lateral, measured vertically, and at least four feet away, measured horizontally, from the existing wastewater main or lateral. Every effort shall be exerted not to disturb the bedding and backfill of the existing wastewater main or lateral.
b.
Where a new potable water line parallels an existing pressure rated wastewater main or lateral and it cannot be determined by the licensed professional engineer if the existing line is leaking, the existing wastewater main or lateral shall be replaced with at least 150 psi pressure rated pipe. The new potable water line shall be located at least two feet above the new wastewater line, measured vertically, and at least four feet away, measured horizontally, from the replaced wastewater main or lateral.
c.
Where a new potable water line parallels a new wastewater main, the wastewater main or lateral shall be constructed of at least 150 psi pressure rated pipe. The new potable water line shall be located at least two feet above the wastewater main or lateral, measured vertically, and at least four feet away, measured horizontally, from the wastewater main or lateral.
2.
New water line installation - crossing lines.
a.
Where a new potable water line crosses an existing, non-pressure rated wastewater main or lateral, one segment of the water line pipe shall be centered over the wastewater main or lateral such that the joints of the water line pipe are equidistant and at least nine feet horizontally from the centerline of the wastewater main or lateral. The potable water line shall be at least two feet above the wastewater main or lateral. Whenever possible, the crossing shall be centered between the joints of the wastewater main or lateral. If the existing wastewater main or lateral is disturbed or shows signs of leaking, it shall be replaced for at least nine feet in both directions (18 feet total) with at least 150 psi pressure rated pipe.
b.
Where a new potable water line crosses an existing, pressure rated wastewater main or lateral, one segment of the water line pipe shall be centered over the wastewater main or lateral such that the joints of the water line pipe are equidistant and at least nine feet horizontally from the centerline of the wastewater main or lateral. The potable water line shall be at least six inches above the wastewater main or lateral. Whenever possible, the crossing shall be centered between the joints of the wastewater main or lateral. If the existing wastewater main or lateral shows signs of leaking, it shall be replaced for at least nine feet in both directions (18 feet total) with at least 150 psi pressure rated pipe.
c.
Where a new potable water line crosses a new, non-pressure rated wastewater main or lateral and the standard pipe segment length of the wastewater main or lateral is at least 18 feet, one segment of the water line pipe shall be centered over the wastewater main or lateral such that the joints of the water line pipe are equidistant and at least nine feet horizontally from the centerline of the wastewater main or lateral. The potable water line shall be at least two feet above the wastewater main or lateral. Whenever possible, the crossing shall be centered between the joints of the wastewater main or lateral. The wastewater pipe shall have a minimum pipe stiffness of 115 psi at 5.0% deflection. The wastewater main or lateral shall be embedded in cement stabilized sand (see clause (f) of this subparagraph) for the total length of one pipe segment plus 12 inches beyond the joint on each end.
d.
Where a new potable water line crosses a new, non-pressure rated wastewater main or lateral and a standard length of the wastewater pipe is less than 18 feet in length, the potable water pipe segment shall be centered over the wastewater line. The materials and method of installation shall conform with one of the following options.
(1)
Within nine feet horizontally of either side of the water line, the wastewater pipe and joints shall be constructed with pipe material having a minimum pressure rating of at least 150 psi. An absolute minimum vertical separation distance of two feet shall be provided. The wastewater main or lateral shall be located below the water line.
(2)
All sections of wastewater main or lateral within nine feet horizontally of the water line shall be encased in an 18-foot (or longer) section of pipe. Flexible encasing pipe shall have a minimum pipe stiffness of 115 psi at 5.0% deflection. The encasing pipe shall be centered on the water line and shall be at least two nominal pipe diameters larger than the wastewater main or lateral. The space around the carrier pipe shall be supported at five-foot (or less) intervals with spacers or be filled to the springline with washed sand. Each end of the casing shall be sealed with watertight non-shrink cement grout or a manufactured watertight seal. An absolute minimum separation distance of six inches between the encasement pipe and the water line shall be provided. The wastewater line shall be located below the water line.
(3)
When a new water line crosses under a wastewater main or lateral, the water line shall be encased as described for wastewater mains or laterals in subclause (2) of this clause (above) or constructed of ductile iron or steel pipe with mechanical or welded joints as appropriate. An absolute minimum separation distance of one foot between the water line and the wastewater main or lateral shall be provided. Both the water line and wastewater main or lateral must pass a pressure and leakage test as specified in AWWA C600 standards.
e.
Where a new potable water line crosses a new, pressure rated wastewater main or lateral, one segment of the water line pipe shall be centered over the wastewater line such that the joints of the water line pipe are equidistant and at least nine feet horizontally from the center line of the wastewater main or lateral. The potable water line shall be at least six inches above the wastewater main or lateral. Whenever possible, the crossing shall be centered between the joints of the wastewater main or lateral. The wastewater pipe shall have a minimum pressure rating of at least 150 psi. The wastewater main or lateral shall be embedded in cement stabilized sand (see clause (f) of this subparagraph) for the total length of one pipe segment plus 12 inches beyond the joint on each end.
f.
Where cement stabilized sand bedding is required, the cement stabilized sand shall have a minimum of 10% cement per cubic yard of cement stabilized sand mixture, based on loose dry weight volume (at least 2.5 bags of cement per cubic yard of mixture). The cement stabilized sand bedding shall be a minimum of six inches above and four inches below the wastewater main or lateral. The use of brown coloring in cement stabilized sand for wastewater main or lateral bedding is recommended for the identification of pressure rated wastewater mains during future construction.
3.
Water line and wastewater main or lateral manhole or cleanout separation.
The separation distance from a potable water line to a wastewater main or lateral manhole or cleanout shall be a minimum of nine feet. Where the nine-foot separation distance cannot be achieved, the potable water line shall be encased in a joint of at least 150 psi pressure class pipe at least 18 feet long and two nominal sizes larger than the new conveyance. The space around the carrier pipe shall be supported at five-foot intervals with spacers or be filled to the springline with washed sand. The encasement pipe shall be centered on the crossing and both ends sealed with cement grout or manufactured sealant.
4.
Location of fire hydrants.
Fire hydrants shall not be installed within nine feet vertically or horizontally of any wastewater main, wastewater lateral, or wastewater service line regardless of construction.
5.
Location of potable or raw water supply or suction lines.
Suction mains to pumping equipment shall not cross wastewater mains, wastewater laterals, or wastewater service lines. Raw water supply lines shall not be installed within five feet of any tile or concrete wastewater main, wastewater lateral, or wastewater service line.
6.
Proximity of septic tank drainfields.
Water lines shall not be installed closer than ten feet to septic tank drainfields.
D.
Thrust Blocking and Joint Restraint:
Concrete blocking and joint restraints shall be installed at all bends, tees, points where reducers or changes in pipe diameter occur, fire hydrants or valves and all plugged openings. Use concrete having compressive strength not less than 2,000 pounds per square inch. Place blocking against undisturbed solid ground, with area of bearing on pipe and on ground as required by manufacturer’s recommendation for the type of soil encountered. Place blocking so that pipe and fitting joints will be accessible for repair. See detail sheet for minimum sizing.
E.
Insulation:
4" diameter or smaller water lines and fittings and all sizes of valves installed above ground, shall be insulated to provide protection from freezing temperatures. The installation shall consist of a minimum 2 inch thick layer of Rigid-Wrap fiberglass insulation as manufactured by E.O. Wood Co., Fort Worth, Texas or a preapproved equal. All installation shall be weather proofed with Childers’ aluminum jacketing or preapproved equal. The jacketing is to be manufactured from 1100, 3003, 3105, 5005 or 5010 aluminum alloy and have a minimum thickness of 0.016 inches. All jacketing shall have an integrally bonded moisture barrier over the entire surface in contact with the insulation.
Encapsulation of insulation around fittings shall be accomplished utilizing a two coat vinyl-acrylic mastic coating system, Vi-Cryl CP-11, as manufactured by Childers or a preapproved equal. A glass cloth membrane, Chil-Glas #10, shall be embedded on to the first coat. The minimum dry film thickness of the vinyl-acrylic mastic shall be 1/16 inch. There shall be no voids or holidays and the mastic shall be trowelled, sprayed or wet brushed to a smooth even finish.
All of the above specified insulation, jacketing and encapsulation shall be installed in strict accordance with manufacturer’s recommendations to provide a waterproof membrane around the insulation.
F.
Casing Spacers:
Casing spacers shall be installed on all carrier pipe which is installed inside a casing. Casing spacers shall be installed such that the distance between spacers does not exceed the maximum distance recommended by the manufacturer of the carrier pipe and by the spacer manufacturer dependent on potential weight of the carrier pipe full of water, except the distance between spacers shall not exceed seven (7) feet. A casing spacer shall be installed within one (1) foot of the end of each joint of nonwelded carrier pipe, and two adjacent spacers shall be installed on the carrier pipe at each end of the casing such that the last spacer is within one (1) foot of the end of the casing.
G.
Hose Bibbs and Vacuum Breakers:
Install hose bibs at the locations shown on the plans. Install vacuum breakers at all hose bib location on the supply side of the hose bib to prevent backflow of contaminated water into the water supply system.
H.
Testing of Backflow Preventers:
After installation, backflow preventers shall be tested by a backflow prevention assembly tester licensed in the State. Testing shall be in accordance with the Manual of Cross-Connection Control, latest edition, published by Foundation for Cross-Connection Control and Hydraulic Research, University of Southern California; with the American Water Works Association - Recommended Practice for Backflow Prevention and Cross-Connection Control (Manual M14); and with local codes and requirements. Backflow preventers shall not be put into service until after passing the required testing.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Sections of water line determined to be defective either prior to or during hydrostatic pressure test shall be replaced with sound materials at no expense to the Owner. No repair clamps will be allowed on new construction.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Prior to final acceptance, hydrostatic pressure test and sterilize water lines according to the applicable sections.
(Ordinance 2007-106, App. B, adopted 3/20/07)
Adjust all fire hydrants, valve boxes and meter boxes to proposed or existing grade as applicable. Upon completion of water line construction, all debris and surplus materials resulting from the work shall be removed from the project site.
(Ordinance 2007-106, App. B, adopted 3/20/07)