Water Distribution System Design...

General Design Criteria...

Design Approval...

The Department of Public Utilities shall approve all designs and shall alter the following design requirements as necessary to meet the City water sys tem plan. The Department of Public Utilities and the Transportation Engineering and Development Business Group shall review and comment on all designs. The City of Naperville’s standard details, as currently adopted by the Department of Public Utilities, should be used in all construction plans. Any modifications to these standard details require approval from the Director of Public Utilities.

IEPA Permit Required...

All public water main extensions require an IEPA Construction permit, prior to construction.

Differentiation Between Public and Private Water Mains...

When the water distribution system is complete and the improvements have been formally accepted by the City, the Department of Public Utilities shall be responsible for the repairs and maintenance of all service lines and water mains located in the public right-of-way and publicly dedicated water mains and loop systems. Maintenance and repairs for the portion of the system located on private property shall be the responsibility of the property owner, or property owner’s association or a property owner’s association depending upon the property owner’s covenants and guidelines. In such cases where the City performs maintenance or repairs on the private water distribution system, the City reserves the right to charge the property owner for necessary work. All engineering plans shall clearly differentiate between all portions of the public and private water distribution system.

Easements...

All public water mains and fire hydrants that are not located within a public right of way shall be placed in a public utility and drainage easement, minimum 15-feet wide or as directed by the Department of Public Utilities, to the City of Naperville. The easement shall be granted to the City either through a recorded plat of subdivision or a recorded plat of easement. The City shall be granted access to these easements if not directly adjacent to public right-of-way. At the discretion of the Director of Public Utilities, the City may require additional easements for future maintenance or repair of the system, even those portions which may be located within the public right-of-way.

Water Mains...

Basis of Design...

All water systems shall be designed using the Hazen-Williams method. The coefficient of roughness shall equal one hundred (c = 100).

Pipe Material...

Ductile iron pipe shall be cement-lined, have a minimum Class 52 thickness designation, and polyethylene encasement. For information regarding applicable ANSI, AWWA, and ASTM designations, refer to Section 502 of the City of Naperville Standard Specifications.

Location in the Public Right-Of-Way...

Water mains shall be generally be located on the north and west sides of the public right-of-way, or as directed by the Director of Public Utilities.

Sewer and Water Main Separation...

Water mains and water service lines shall be protected from sanitary sewers, storm sewers, combined sewers, house sewer service connections, drains, and sanitary sewer force main. In addition to the following guidelines, refer to Section 503 of the Standard Specifications.

Horizontal Separation...

Water mains shall be laid at least 10 feet horizontally from any existing or proposed drain, storm sewer, sanitary sewer, combined sewer or sewer service connection. Water mains may be laid closer tha n 10 feet to a sewer line when :

· Local conditions prevent a lateral separation of ten feet;
· The water main invert is at least 18 inches above the crown of the sewer; and
· The water main is either in a separate trench or in the same trench on an undisturbed earth shelf located to one side of the sewer.

When it is impossible to meet the conditions above, the drain or sewer shall be constructed of slip-on mechanical joint cast or ductile iron pipe, or PVC SDR 26 pipe meeting the requirements for water main. The drain or sewer shall be pressure tested to the maximum expected surcharge head before backfilling with no leakage allowed in the area of required water main protection. A City of Naperville representative shall witness this testing. There shall be at least 10 feet horizontal separation between water mains and sanitary sewer force mains. Water mains must be separated at least 25 feet from septic tanks, disposal fields, seepage beds, and sewage lift stations.

Vertical Separation...

A water main shall be laid so that its invert is 18 inches above the crown of the drain or sewer whenever water mains cross storm sewers or sewer service connections. The vertical separation shall be maintained for that portion of the water main located within 10 feet horizontally or any sewer or drain crossed. A length of water main pipe shall be centered over the sewer to be crossed with joints equidistant from the sewer or drain. The sewer shall be constructed of slip-on or mechanical joint cast or ductile iron pipe, or PVC SDR 26 pipe, meeting the requirements for water main when :

· It is impossible to obtain the proper vertical separation as described above; or
· The water main passes under a sewer or drain.

A vertical separation of 18 inches between the invert of the sewer or drain and the crown of the water main shall be maintained where a water main crosses under a sewer. Support the sewer or drain lines to prevent settling and breaking of the water main. If the invert of the water main is not 18 inches above the crown of the sewer when the pipes cross, a casing pipe can be installed around either the water main or sewer in lieu of constructing the sewer with water main equivalent pipe. The casing pipe must be a material that is approved for use as water main. The casing must extend on each side of the crossing at least 10 feet as measured at right angles from the outside edge of water main pipe to the outside edge of the sewer pipe. Pipe support shall be provided within the casing pipe and ends of the casing shall be filled with an approved non-shrink grout.

At crossings when the invert of the water main is not 18 inches above the crown of the storm sewer, and the sewer crossed the water main at right angles, the storm sewer can be constructed with reinforced concrete pipe using flexible gasket joints meeting ASTM C-361 or ASTM C-443 instead of providing a casing pipe or constructing the storm sewer with water main equivalent pipe. If gasketed storm sewer piping is proposed, it shall be installed between adjacent storm struc tures. The drain or sewer shall be pressure tested to the maximum expected surcharge head before backfilling with no leakage allowed in the area within 10 feet of the water main. A City of Naperville representative shall witness this testing.

Construction shall extend on each side of the crossing until the distance from the water main to the sewer or drain line is at least 10 feet as measured at right angles from the outside edge of the water main pipe to the outside edge of the sewer pipe. Where a water main passes over an existing or proposed forcemain, an 18- inch vertical separation shall be provided at the crossing. (Note: A forcemain shall not be allowed to be above the water main at the crossing.)

Depth of Pipe Cover...

All pipe shall be laid to a minimum depth of 5 feet measured from the proposed ground surface to the top of the pipe, unless specifically allowed otherwise in special circumstances by the Director of Public Utilities. If approved, the pipe shall be insulated with 2-inch exterior grade rigid insulation board. One 2-inch thick sheet of insulation shall be provided for each 6 inches of cover below the required 5-foot minimum depth and extend a minimum of 12 inches on each side of the water main. The insulation shall have a minimum R-value of R-9, and comply with ASTM C 578-92 Type 1X.

Water Main Sizing...

Water mains shall be constructed of 8-inch diameter or 12-inch diameter pipe, or as directed by the Department of Public Utilities.

Oversizing Requirements...

It may be determined that the water main be oversized in order to provide service to additional benefiting properties. Section 7-3-6 of the Municipal Code (City participation in construction of public improvements) outlines the City’s policy relative to cost sharing for oversizing.

Limits of Installation...

At a minimum, water main shall extend across the frontage of the property, at the developer’s cost, such that a connection could be made with minimal disturbance in the future. In some cases, the City may require that the water main be installed from one corner to the diagonally opposite corner, at the developer’s cost. All water main stubs for future extension shall terminate with a valve and hydrant. Restrained joints shall be located 40 feet from the capped end.

Gridiron or Looping...

Each 8- inch diameter water main shall be looped at a distance not to exceed 1,000 feet. Each 12-inch diameter and larger water main shall be looped at a distance not to exceed 3,000 feet. No dead-ended water mains shall be allowed.

Water Services...

No more than one building shall be supplied from one service pipe. Whenever possible, the service pipe shall enter the building in a direct line with the curb stop and tap. Said pipe shall be provided with a valve before and after the water meter, not less than 1- foot inside of the wall or above the foundation floor (main building shutoff valve). The property owner shall be responsible for the maintenance, repair or replacement of the main shutoff valves. Every building, except auxiliary buildings sha ll be individually metered. All valves shall be arranged so that each line can be shut off from the exterior of the building.

Pipe Material...

Service lines 2 inches or less (<= 2”), inside diameter, shall be copper pipe, “Type K”. All services 3 inches or greater (>= 3”), inside diameter, shall be Class 52 ductile iron pipe with cement lining.

Water Service Line Sizing...

The following guidelines shall be used to size water service lines :

Fire Protection...

Fire Protection Supplies...

Fire flow requirements will be approved by the Director of Public Utilities. The required fire flows may be computed at a residual pressure of 20 psi for Fire Department use. It should be recognized that higher residual pressures may be necessary for specific fire protection demands. The following flow requirements are guidelines which will be modified based upon construction types, size and height of the buildings :

Public Fire Flow Requirements...

Public fire flow requirements (Fire Department pumper supply) and domestic consumption demands are cumulative.

Private Fire Protection...

Private fire protection demands (standpipe systems, sprinkler systems, etc.) will not be considered cumulative with public fire flow demands. These requirements are based upon the building height, area, use and construction type.

Fire Hydrant Locations...

Fire hydrants shall be located 7.5 feet from the right-of-way within north or west parkways. All points of buildings shall be within 300 feet of all points of the building, as the hose lays (must be shown on engineering plans). The linear spacing of hydrants shall not exceed 350 feet in single-family areas or 300 feet elsewhere. Fire hydrants shall be situated in the parkway within 10 feet from a paved roadway and 50 feet from a Fire Department connection (Siamese). Access to hydrants shall be provided by paved roadways (minimum structural number = 2.5) routes adequate in width, clearance and strength to support all fire equipment. Such routes shall be maintained during all seasons of the year.

Valves...

Valve Boxes and Valve Vaults...

Valve boxes may only be used for fire lines that are less than 8 inches in size. The valve box shall be located in a grassy area; otherwise a valve vault must be used. Valves for water mains or fire lines 8 inches or larger shall be provided with a vault.

Valve Locations...

Valves shall be located such that no more than a maximum of 500 feet to 700 feet of main may be shut off at any given time. This spacing should be reduced, such that no more than 25 to 30 single- family homes, or 50 multi-family residences (excluding apartment buildings) would be shut off at any given time. Where a “tee” is installed, at least two (2) valves will be utilized. Where a “cross” is installed, at least three (3) valves will be utilized.

Pressure Taps...

Pressure taps shall be cast iron or ductile iron tapping sleeves for size-on-size taps, or taps on mains greater than 12 inches (> 12”). Stainless steel tapping sleeves can only be used for nonsize-on-size taps or taps on mains less than or equal to 12 inches (<= 12”).

Appurtenances...

Casing Pipes...

Manufactured non- metallic or non-corrosive casing spacers, adjustable runners, or cradles shall be used to support the pipe in the casing. A minimum of three supports shall be used per pipe, or per manufacturer’s recommendation. The annular space shall be filled with pea gravel or as required by the permitting agency, and provisions shall be made so that no voids are left. Water main installed within casing pipes shall have restrained joint construction the entire length of the casing pipe for future removal if necessary.

Casing Pipe Material...

The steel casing pipe shall be bituminous coated, minimum of 30 mils thickness inside and out, and shall be of leak proof construction, capable of withstanding the anticipated loadings. The steel casing pipe shall have a minimum yield strength of 35,000 psi and shall meet the requirements of ASTM A139, Grade B. Ring deflection shall not exceed 2% of the nominal diameter. The steel casing pipe shall be delivered to the jobsite with beveled ends to facilitate field welding.

Sizing of Casing Pipes...

The diameter of the casing pipe shall be a minimum of 12 inches greater than the outside nominal diameter of the water main.