SECTION 6.00
WATER DISTRIBUTION
1. Location
In accordance with Policy Statement Number 23, water lines shall be extended along the roadway to the adjacent property line. All public water mains shall be located within dedicated right of way or dedicated easements with a minimum width of 20 feet. See Section 2.10 for allowable landscape plantings within a Town easement.
2. Sizing
Major transmission lines shall be sized in accordance with the "Master Water Plan of the Town of Cary" or as directed by the Town. Six (6) inch mains may be used only when a good grid exists. The total maximum length of 6 inch and 8 inch lines, without connecting to a larger main, is 1200 feet and 2000 feet, respectively. Four (4) inch water mains are permitted on residential cul-de-sacs less than 400 feet long. Where a good grid does not exist, lines shall be upsized to provide adequate fire flow as directed by the Town Engineer.
3. Installation
All utility extension permits must be obtained prior to construction. Refer to General Provisions in Section 2 for further requirements.
All water mains shall have a minimum cover of 4 feet measured from the top of the pipe to the finished grade. When water lines are installed along a roadway which does not have curb and gutter, the water line shall be installed at sufficient depth to prevent conflict with future road improvements or vertical alignment changes.
4. Relation to Sanitary and Storm Sewers
Water mains shall be laid at least 10 feet from existing or proposed sanitary or storm sewers, measured laterally edge to edge, unless the elevation of the bottom of the water main is at least 18 inches above the top of the sewer with a horizontal separation of at least 3 feet.
Where a water main and a sanitary sewer cross, and the vertical separation is less than 18 inches or the water line passes under the sanitary sewer, the entire leg of the sewer line shall be ductile iron pipe equivalent to water main standards.
Water mains should only cross sanitary sewer mains at an approximate 90 degree angle.
Water mains and storm sewer mains shall have a minimum vertical separation of 12 inches when horizontal separation is less than 3 feet unless otherwise approved by the Town Engineer.
1. Material
All water main distribution pipe shall be ductile iron. The Department of Development Services will maintain a list of approved manufacturers for all water distribution products. New manufacturers must submit requests for approval to the Department of Development Services. Additional information such as catalogs, list of installations in the area or material samples may be required. A written response will be mailed to the applicant accepting or rejecting the product within 90 days of the receipt of all necessary information.
2. Ductile Iron Pipe
Ductile Iron Pipe shall be designed and manufactured in accordance with AWWA C150 and C151 for a laying condition Type 2 and a working pressure as follows:
3"-12" 350 psi. 14"-20" 250 psi. 24" 200 psi. 30"-54" 150 psi. Pipe joints shall be of the push-on type as per AWWA C111. Pipe lining shall be cement mortar with a seal coat of bituminous material in accordance with AWWA C104. Galvanized steel pipe will not be allowed as a material for water mains or water service lines.
1. Location
All fire hydrants shall be installed on a minimum 6 inch water line. Only one fire hydrant may be installed when the line is served by a 6 inch tap and is not looped to another main. There shall be at least one fire hydrant at each street intersection. The minimum acceptable flow for fire hydrants is 1000 gpm in residential areas and 1500 gpm in other districts. Hydrants at intersections shall be located in accordance with Standard Detail 6.06 & 6.07. Valves associated with fire hydrant assemblies shall be located within 15 feet of the fire hydrant.
In residential districts the maximum distance between hydrants, measured along street centerlines, shall be 500 feet. When residential intersections are less than 700 feet apart, a hydrant is required between the intersections.
In business, office and institutional, and industrial zoning the maximum distance between hydrants, measured along street centerline, shall be 300 feet. When business, office and institutional, and industrial intersections are less than 450 feet apart, a hydrant is not required between intersections
On major thoroughfares and collector streets with access points only at street intersections, hydrants shall be located at each street intersection and at 1000 foot intervals along the street. Where these intersections are less than 1200 feet apart, no hydrant is required between the intersections. Fire hydrants shall be placed in a staggered arrangement on both sides of any roadway classified as a major or minor thoroughfare with the hydrant spacing as referenced above. New buildings, or additions which result in a total building area of 10,000 square feet, require hydrants to be installed at 300 foot intervals along all sides of the building that are accessible to fire pumpers. These hydrants shall be at least 40 feet away from the building. The total number of hydrants shall not exceed one hydrant per separation of buildings plus one hydrant per 10,000 square feet of floor space.
Where sprinkler systems are used, a fire department connection shall be within 50 feet of an accessible fire hydrant. See Section 6.02B for other sprinkler system requirements.
2. Specifications
Hydrants shall conform to AWWA C502 with a minimum valve opening of 4 1/2 inches. Hydrants shall be furnished with a 4 1/2 inch steamer and double 2 1/2 inch hose connections with caps and chains, National Standard Threads, mechanical joint, 1 1/2 inch pentagon operating nut, open left, painted fire hydrant red, bronze to bronze seating, a minimum 4 foot bury depth with a break away ground line flange and break away rod coupling. The hydrant bonnet will be designed with a sealed oil or grease reservoir with O-ring seals and a Teflon thrust bearing. Fire hydrant caps shall be attached to the body of the hydrant with a minimum 2/0 twist link, heavy duty, non-kinking, machine chain. The Mueller "Centurion" (A-421), Clow "Medalion", or American Darling (MK-73) fire hydrants are approved for use.
3. Installation
Hydrants shall be set plumb, properly located with the pumper nozzle facing the closest curb of a fire lane or street, but not a parking space. The back of the hydrant opposite the pipe connection shall be firmly blocked against the vertical face of the trench with 1/3 cubic yard of concrete. Double bridle rods and collars shall be connected from the tee to the hydrant. Rods shall not be less than 3/4 inch diameter stock and coated with bituminous paint. A minimum of 8 cubic feet of stone shall be placed around the drains. The backfill around the hydrants shall be thoroughly compacted. Hydrant installation shall be in accordance with the Details. Hydrant Tees and mechanical restraints may be used upon approval of the Director of Development Services.
B. Automatic Fire Sprinkler Systems
1. General
Four (4) complete sets of working plans and calculations for all fire sprinkler systems and standpipe systems shall be submitted to the Development Services Department for review and approval. If 20 sprinkler heads or more are modified or added to an existing sprinkler system, complete plans and calculations will be required. All fire sprinkler systems shall be installed with an alarm check valve installed in each riser with all the trimmings (example: retard chamber, water motor gong, pressure gauges, etc.). Exception: NFPA 13 D and 13 R residential sprinklers when approved by a fire official. All installations, minor repairs, or minor replacements shall be performed by a licensed fire sprinkler contractor. Contact the Development Services Department for a permit application.
2. Design
Approved working plans shall be in complete compliance with NFPA No. 13, 13D, 13R, 14, 231, 231C, 231D, 231F and Town Specifications. An NFPA above ground material and test certificate and NFPA underground material and test certificate are required after completion of designated, approved work.
3. Hydraulic Design
If a system is hydraulically designed, the following design criteria must be followed:
a. Safety Margin
A 10% safety margin must be included in all hydraulic calculations. System supply must equal or exceed 1.1 times that of the system demand. (Example: Demand = 50 psi, Supply ³ 55 psi)
b. Hose Allowances
A minimum of 500 gpm outside hose allowance must be calculated on all sprinkler systems. Interior hose allowances are to follow NFPA 13 requirements.
4. Backflow Prevention
When a fire protection system is proposed, a double check valve assembly including 2 check valves, 2 OS & Y gate valves, and 4 test cocks shall be installed on the supply side of the sprinkler fire protection line. These backflow prevention devices must be UL listed and/or listed by Factory Mutual Research Corporation.
5. Post Indicator Valve
A post indicator valve shall be provided at the right of way or edge of easement (preference: listed indicating valves at each connection into the building at least 40 feet from building if space permits). The top of the PIV shall be 36 inches above finished grade. The Town shall maintain up to and including the post indicator valve but not beyond.
6. Fire Department Connection
Where automatic fire sprinkler systems are used, a fire department connection shall be provided. The fire department connection shall be located within 50 feet of a fire hydrant. When a sprinkler system serves only part of a large structure, the fire department connection shall be labeled, with minimum 2 inch letters on a permanent sign, as to which section of the structure that sprinkler riser serves
7. Dedicated Riser Room
A dedicated sprinkler riser room is required providing an entry door to the room from the exterior of the building.
8. Alarm Communication
All sprinkler systems are to have alarm communication equipment to fully comply with NFPA 72. Equipment must be fully functional and reporting to a UL listed central receiving station before a Certificate of Occupancy is issued for the facility.
9. Access
All buildings which have a fire alarm system monitored by a central receiving station or a fire sprinkler protection system shall provide a "Knox Box" key entry system. This "Knox Box" shall be mounted on the exterior entrance to the dedicated riser room. Mount "Knox Box" on wall at 5 feet A.F.F. on door handle side of dedicated riser room door. This "Knox Box" shall be ordered through the Town Fire Department and shall be in place before a Certificate of Occupancy is issued. Forms are available from the Fire Department. Average delivery time is 5 to 6 weeks. Keys to access the facility shall be provided to the Fire Department by the owner/manager.
10. Identification
The exterior door leading to the dedicated sprinkler riser room shall be labeled with minimum 2 inch lettering designating "SPRINKLER RISER ROOM" in a contrasting color. Durable vinyl lettering is suggested.
11. Fire Alarm Panel Location
When a building is protected by an automatic sprinkler system and has a fire alarm system, the fire alarm control panel or a remote annunciation of the fire alarm control panel shall be placed in the sprinkler riser room. This control panel shall have the capacity of silencing and resetting. Adjacent to the fire alarm control panel shall be a framed zone map. Nomenclature shall correspond with the zone map. Submit two complete sets of plans and specifications to the Department of Development Services, Inspections and Permits Division for approval prior to installation of equipment or wiring.
C. Fire Protection During Construction
The fire protection water supply system, including fire hydrants, shall be installed and be in at least the functional status prior to placing combustible materials on the project site. If phased construction is planned, coordinated installation of the fire protection water system is permitted. Coordination of the water system will be done through the Department of Development Services. Functional status would include meeting all standards set forth in Section 6.06 "Testing and Inspection".
1. General
Valves shall be installed on all branches from feeder mains and hydrants according to the following schedule: 3 valves at crosses; 2 valves at tees; and one valve on each hydrant branch. When a loop section of water line is connected back into the feeder main within a distance of 200 feet or less, only one valve will be required in the feeder main.
Where no water line intersections are existing, a main line valve shall be installed at every 100 feet per 1 inch diameter main up to a distance of 2000 feet between valves.
Valves shall be properly located, operable and at the correct elevation. All valves and reducers shall be rodded to the tee or cross if one is located within 10 feet as shown in the Details. If reducers can not be rodded, concrete blocking or other restraining methods will be required. The valve box shall be centered over the wrench nut and seated on compacted backfill without touching the valve assembly. All valve boxes shall be encased in a trowel finished 2' X 2' x 6" pad of 3000 psi concrete beneath the asphalt with the cover flush with the top of the pavement or flush with finished grade. Precast concrete valve box encasements may be used for valve box encasement outside of paved areas. The maximum depth of the valve nut shall be 5 feet. When valve extension kits are used, they must be manufactured by the same company which manufactured the valve.
2. Combination air valves
Combination air valves shall be installed at all high points of water lines 8 inches in diameter or larger and at other locations as directed by the Town. The water main shall be installed at a grade which will allow the air to migrate to a high point where the air can be released through an air valve. A minimum pipe slope of 1 foot in 500 feet should be maintained. The valve shall be manufactured for a 150 PSIG working pressure, sized by the Engineer, and approved by the Town.
Combination air valves shall be of the single housing style that combines the operation of both an air/vacuum and air release valve. The valve must meet the requirements of AWWA C512 and be installed in accordance with the Details.
3. Gate Valves
Gate valves 2 inches and greater shall meet all requirements of AWWA C500 for a working pressure of 150 psi. All shall be mechanical joint with iron body, bronze mounting double disc parallel seat type with a non-rising stem and open left with a double O-ring seal.
Gate valves, up to and including 12 inches, shall be installed in a vertical position.
Gate Valves 16 inches and larger must be approved by the Engineering Director. They may be installed horizontally and equipped with bevel gears, grease case, rollers, tracks scrapers, and a bypass located on the side of the body (fully revolving disc valves shall not require rollers), or vertically and be equipped with spur gears enclosed in a grease case and with a bypass located on the side of the body. In either case, the roller and scraper operators shall be installed in a manhole.
4. Resilient seat wedge gate valves
Resilient seat wedge gate valves shall be manufactured in accordance with AWWA C509.
5. Butterfly Valves
Butterfly Valves shall be installed in water lines 16 inches or greater. All shall meet the requirements of AWWA C504 with mechanical joints, 2 inch open left operating nut. All valves 24 inches and greater shall be installed in a manhole as shown in the Details.
6. Valve boxes
Valve Boxes shall be cast iron, screw or telescopic type, with a 5 inch opening and "water" stamped on the cover. Valve box ring adjustments will not be allowed.
1. Pipe fittings
Pipe Fittings shall be cast or ductile iron designed and manufactured as per AWWA C110. Sizes of fittings up to and including 12 inches shall be designed for an internal pressure of 250 psi, and larger size fittings shall be designed for an internal pressure of 150 psi. Compact ductile iron mechanical joint fittings designed and manufactured as per AWWA C111 are also acceptable. Joints for fittings shall be mechanical and lined with cement mortar with a seal coat of bituminous material, all in accordance with AWWA C104.
2. Blowoffs
Blowoffs shall be a minimum of 2 inches and installed at the end of all dead-end water lines. Where there is not sufficient pressure or fire hydrants to thoroughly flush the system, a larger blowoff will be required.
Blowoff Assemblies shall be constructed as shown in the Details. The valves shall be gate type with a non-rising stem and a 2 inch operating nut. A full size valve is required on mains that are planned to be extended.
3. Thrust Restraint
Reaction Blocking for all fittings or components subject to hydrostatic thrust shall be securely anchored by the use of concrete thrust blocks poured in place. The reaction areas are shown in the Details. No concrete shall interfere with the removal of fittings. Material for reaction blocking shall be 3000 psi concrete. A minimum 4 mil plastic shall cover the fitting to ensure that no concrete will interfere with removal of the fitting. Alternative restraining methods and mechanical joint restraints may be used upon approval by the Director of Engineering.
1. Individual water services, and multiple branch services, shall be provided from the main to each water meter for single family residences in accordance with the Details. All connections shall be made by wet taps.
Service connections shall be made perpendicular to the main and shall run straight to the meter.
All water meter boxes and vaults shall be located at the edge of the serviced lot’s right of way or easement. Water meter boxes shall not be placed in streets, sidewalks, parking areas or obstructed by fencing or buildings. Exceptions to these conditions will be at the direction of the Director of Development Services.
Provisions for backflow prevention shall be in accordance with the NC Plumbing Code for plumbing.
2. The water meter shall be sized based on water demand. Multiple branch services size shall be determined by the designer
3. Service taps to existing water lines shall be made by the Town. Service taps to new water lines shall be made by the Contractor in accordance with the Specifications.
Service taps greater than 2 inches shall be made by a Contractor of the Developer. A strainer shall be provided upstream of the meter on lines greater than 2 inches.
1. Taps
The maximum size of direct taps without a fitting, tapping sleeve or saddle for ductile iron water mains shall be as follows:
4" main - 3/4" tap
6" main - 1" tap
8" main - 1 1/4" tap
10" main - 1 1/2" tap
12" main - 2" tap2. Tapping Sleeves
Tapping Sleeves shall be 2 piece split cast iron. The sleeve shall be mechanical joint to the main line and flanged to the tapping valve. Stainless steel tapping sleeves are allowed only on asbestos pipe per the approved manufacturer’s material list.
3. Tapping Saddles
Tapping Saddles shall be used on mains 16 inches and larger. Saddles shall be made of ductile iron providing a factor of safety of 2.5 with a working pressure of 250 psi. Saddles shall be equipped with a AWWA C110 flange connection on the branch. Sealing gaskets shall be O-ring type, high quality molded rubber having an approximate 70 durometer hardness, placed into a groove on the curved surface of the saddles. Straps shall be alloy steel.
The maximum size saddle outlet for each size of pipe to be tapped shall be as follows:
Size pipe |
Maximum
size |
16" |
8" |
|
|
|
|
24" and larger |
|
4. Corporation Stops
Corporation Stops shall be ball type, made of brass and complete with a compression or flared coupling and AWWA Standard threads as per AWWA C800. Taps shall be located at 10:00 or 2:00 o'clock on the circumference of the pipe. Service taps shall be staggered alternating from one side of the water main to the other and at least 12 inches apart. The taps must be a minimum of 24 inches apart if they are on the same side of the pipe.
No burned taps will be allowed and each corporation stop will be wrapped with Teflon tape for ductile iron pipe water mains. No taps are allowed on a fire hydrant line. No tapping shall be made where rodding is placed.
5. Service saddles
Service Saddles shall be bronze body (85-5-5 waterworks brass) and double strap for taps over 1 inch with silicon bronze nuts conforming to ASTM A98 and factory installed grade 60 rubber gaskets.
6. Copper Service Tubing
Copper service tubing shall be type K soft copper tubing per ASTM B88. The longest available length of service line shall
be used with no unions (e.g. for 3/4 inch, only 1 union will be allowed for each 100 foot section). Unions shall be made with flare type or compression couplings.7. Meter Boxes for 3/4 inch services
3/4" meter boxes shall be cast iron and a complete unit (less meter) for setting a 5/8 inch by 3/4 inch water meter. Meter stops shall be O-ring sealed and have an inlet angle of 60 degrees with non-locking lid. Residential service meters shall be installed by the Town. Meter box grade adjuster rings are not acceptable.
8. Meter boxes for 1 inch services
1" meter boxes shall be cast iron box and cover with a meter yoke and or copper resetter.
9. Meter boxes for 1 1/2 and 2 inch services
1 1/2" and 2" meter boxes shall be light weight polymer concrete as indicated in the Standard Details. Piping for 1 1/2 and 2 inch water meters shall be constructed from brass and copper tubing and shall be equipped with angled check valve outlets and by-pass flanged valve or by-pass flanged ball valve inlets. To ensure positive discharge, the box should be tied into the existing storm drain system, or shall have an open bottom to all drainage through stone.
10. Meter Vaults
Meter vaults and access doors within street right of way shall meet HS-20 loading requirements and shall be located outside of travel areas. The access double doors shall be aluminum with a flush drop lift handle, stainless steel hinges and bolts, a stainless steel slam lock, an automatic hold open arm, and compression springs to allow for easy opening. To ensure positive drainage, the vault shall be tied into the existing storm drainage system. If positive drainage is unobtainable, a sump pump shall be located and operated in the vault.
All irrigation systems shall be provided with privately maintained reduced pressure principle backflow prevention installed in accordance with the NC Plumbing Code and the Foundation for Cross Connection Control and Hydraulic Research. Reduced pressure zone backflow preventers must have an appropriately sized drainage system or be installed above ground in an insulated box.
All irrigation systems within public street right of way require an encroachment agreement from the Town or NCDOT prior to installation. Plans designating the location, size, material, and depth shall be submitted with the agreement application to the Department of Development Services - Inspection & Permits Division.
Pipe material for the mainline proposed to be used within the public right of way shall be Schedule 40 PVC or greater. A distance of at least 2 feet shall be provided from the back of curb. A minimum depth of 2 feet of cover shall be provided.
The irrigation mainline pipe system shall be hydrostatically tested per Section 6.06 with a minimum pressure of 200 psi or 50 psi above working pressure.
All street crossings of irrigation systems shall be encased in ductile iron or steel conduit. Irrigation systems installed in the medians of Town maintained roadways must also have french drains installed behind the curb and gutter which are piped to a storm system.
All materials must be approved by the inspector prior to installation. Materials rejected by the Inspector shall be immediately removed from the job site.
The Contractor shall furnish all materials, labor, and equipment to perform all testing and inspections to the satisfaction of the Inspector. The Town shall provide water for testing purposes on water mains in accordance with Town Standard Procedure 10-3, Control and Monitoring of Water System Flow Activity.
1. Hydrostatic Testing
No valve in the Town water system shall be operated without authorization in accordance with the Town Standard Procedure 10-3 Control and Monitoring of Water System Flow Activity. A section of line which is to be hydrostatically tested shall be slowly filled with water at a rate which will allow complete evacuation of air from the line. Hand pumps shall not be used for the pressure testing of water mains. Taps used for testing purposes shall be removed after testing and repaired using a stainless steel full circle repair clamp.
The line shall be tested to a pressure of 200 psi as measured at the lowest elevation of the line for a duration of 2 hours. The pressure gauge used in the hydrostatic test shall be calibrated in increments of 10 psi or less. At the end of the test period, the leakage shall be measured with an accurate water meter.
Pipe Size |
Allowable Leakage |
4 |
0.85 |
6 |
1.28 |
8 |
1.70 |
12 |
2.56 |
16 |
3.40 |
20 |
4.24 |
24 |
5.10 |
All visible leaks shall be repaired regardless of the amount of leakage.
2. Chlorination
All additions or replacements to the water system shall be chlorinated before being placed in service under the supervision of the Town’s Inspector in the following manner:
a) Taps shall be made at the control valve at the upstream end of the line and at all extremities of the line including valves.
b) A solution of water containing 70% HTH available chlorine shall be introduced into the line by regulated pumping at the control-valve tap. The solution shall be of such a concentration that the line shall have a uniform concentration of 100 ppm total chlorine immediately after chlorination. The chart below shows the required quantity of 70% HTH compound to be contained in solution in each 1000 feet section of line to produce the desired concentration of 100 ppm.
Pipe Size |
Pounds High Test Hypochlorite (70%) per 1000 feet of line |
| 6 | 1.76 |
| 8 | 3.12 |
| 10 | 4.84 |
| 12 | 7.00 |
| 14 | 9.52 |
| 16 | 12.44 |
| 20 | 19.52 |
| 24 | 28.00 |
The HTH Solution shall be circulated in the main by opening the control valve and systematically manipulating hydrants and taps at the line extremities. The HTH solution must be pumped in at a constant rate for each discharge rate so a uniform concentration will be produced in mains.
HTH solution shall remain in lines for no less than 24 hours or as directed by the Town’s Inspector.
Extreme care shall be exercised at all times to prevent the HTH solution from entering existing mains.
3. Bacteriological Sampling
Free residual chlorine after 24 hours shall be at least 10 ppm or the Inspector will require that the lines be rechlorinated.
Flushing of lines may proceed after 24 hours, provided the free residual chlorine analysis is satisfactory. Flushing shall be contained until an orthotolidine check shows that the lines contain only the normal chlorine residual. Samples for bacteriological analysis shall be collected by the Town’s Inspector 24 hours after flushing is completed. The Contractor shall furnish the sample bottles, the testing agency and such help as may be required to secure these samples. The contractor shall also submit the test results to the Town’s inspector.
If test results are unsatisfactory, the Contractor shall immediately rechlorinate lines and proceed with such measures as are necessary to properly sterilize the lines.
The new water system shall be valved off from the existing system until a satisfactory bacteriological sample has been obtained and the Inspector has authorized the use of the new water system.
Joint leaks of Cast Iron Pipe, Ductile Iron Pipe, and PVC pipe shall be repaired by use a bell joint leak repair clamp as manufactured by Rockwell, or other approved equal.
Line Breaks or Punctures shall be repaired by a full circle repair clamp as manufactured by Rockwell, Mueller, or other approved material.
Line Splits or Blow Outs shall be repaired by replacing the damaged section with ductile iron pipe with a cast iron coupling at each end. The following cast pipe couplings shall be used for each pipe material indicated:
| A.C. Pipe | - | Rockwell 441 cast coupling or other approved equal |
| Ductile Iron Pipe | - | Rockwell 431 cast coupling or other approved equal |
| PVC Pipe | - | Rockwell 411 cast coupling or other approved equal |
For A.C. Pipe to PVC or Ductile Iron Pipe use a cast pipe coupling with different end diameters sized specifically for the pipe materials and pipe outside diameter at each end.
Water Service Line Repairs
A water service line severed between the water main and the water meter shall be repaired using new type K copper tubing and bronze or brass 3 piece compression unions.
A corporation stop pulled out of a PVC pipe water main shall have a new service saddle and a new corporation stop installed on the water main.
A corporation stop pulled out of a ductile iron pipe shall have a full circle repair clamp placed over the old tap hole. A new tap shall be made and a new corporation stop installed on the water main.