Division 13-09-006
Sewer and Water Line Materials
Sections:
13-09-006-0001 Sewer and Water Line Materials and Construction
13-09-006-0002 General Requirements
13-09-006-0003 Pipe Bedding
13-09-006-0004 PVC Pipe for Sanitary Sewers
13-09-006-0005 PVC Pipe for Water Lines
13-09-006-0005.1 General
13-09-006-0005.2 Specifications
13-09-006-0005.3 Affidavit of Compliance
13-09-006-0005.4 Approved Manufacturer and Model
13-09-006-0006 Fire Hydrants
13-09-006-0006.1 Fire Hydrant Testing
13-09-006-0006.2 Fire Hydrant Specifications
13-09-006-0006.3 Fire Hydrant Installation Notes
13-09-006-0006.4 Fire Lines
13-09-006-0007 Backflow Prevention Devices
13-09-006-0001 Sewer and Water Line Materials and Construction
A. New public sewer lines may be constructed using the following materials:
1. Polyvinyl chloride (PVC), SDR 35, plastic sewer pipe conforming to the appropriate MAG section for diameters fifteen (15) inches and less. For pipe diameters greater than fifteen (15) inches, ductile iron pipe (DIP) shall be used as specified in subsection (A)(2) of this section.
2. Class 150 ductile iron pipe (DIP) conforming to the appropriate MAG section. DIP may be used for sewer lines, eight (8) inches through fifty-four (54) inches in diameter. All ductile iron pipelines shall be polyethylene encased in accordance with MAG Specifications. When DIP is used, it shall be lined with Protecto 401 ceramic epoxy. Special design considerations may require a higher class rating of DIP.
3. High density polyethylene (HDPE) sewer pipe conforming to MAG Sections 603 and 738. The maximum pipe allowed shall be ten (10) inch for HDPE.
4. When utilizing "pipe-bursting" technology to replace an existing sewer service, HDPE SDR17 pipe, conforming to AWWA C901/C906 and ASTM D2239, D2237, D3035, and F714, may be used.
B. New public water lines may be constructed using the following materials:
1. Polyvinyl chloride (PVC) plastic water pipe conforming to AWWA C-900.
2. Class 350 ductile iron pipe (DIP) four (4) inch to ten (10) inch diameter, and Class 250 DIP for twelve (12) inch and larger, conforming to MAG Sections 750.2 and 750.3, with polyethylene corrosion protection conforming to MAG Section 610.6.2. Deflected ductile iron pipe shall be designed to deflect no more than one-half (1/2) the maximum as recommended by the manufacturer, horizontally and vertically. Ductile iron pipe mains shall be protected from exterior corrosion. This protection may consist of encasement in a polyethylene protective wrapping or other approved methods.
3. Ductile iron pipe fittings shall be new and conform to MAG Section 750.4 with UL and FM approvals. Domestic fittings are allowed; imported fittings are allowed if they meet these standards and are approved by the Utilities Director and City Engineer.
4. Valves. Gate valves with AWWA C515 two hundred fifty (250) psi rating shall be used on water mains that are twelve (12) inches and smaller in diameter. Gate valves with nonrising stems shall be used for all locations and be resilient seat and epoxy coated inside and out. For water mains fourteen (14) inches and larger in diameter, the gate valve shall be buried so that the top of the bonnet is at least thirty-six (36) inches below subgrade. When circumstances do not allow for this minimum depth, the gate valve shall be buried horizontally and use a bevel gear actuator.
5. Pipe Casing. Casings are required on all pipes installed using boring methods or other special conditions. The casing material used shall be a minimum of one-quarter (1/4) inch thick steel (design calculations must be submitted by the developer’s engineer) and conform to ASTM A283, Grade B, C, or D. All joints shall be welded. Interior joints shall be grounded to a smooth finish. All welding shall be performed in accordance with AWWA C201, AWWA Standard for Fabricated Electrically Welded Steel Water Pipe. Coatings for steel casings are not required. The pipe casing shall be laid true to line and grade with no bends or changes in grade for the full casing length. The pipe shall be symmetrically supported about its centerline inside the casing at each joint end, with a City of Flagstaff Utilities Department approved stainless steel casing spacer (sized and designed in accordance with manufacturer recommendations). The casing ends shall be sealed with end seals by Advanced Products and Systems, or approved equal. (See Detail 9-06-010.)
For water and sewer lines greater than eight (8) inches in diameter, the City Engineer may authorize the use of alternate pipeline materials when shown and detailed on the construction plans.
C. The design engineer may submit a carefully documented and considered written proposal for alternate pipeline materials and construction methods. The City Engineer and the Utilities Director will review this proposal for use of alternate pipeline materials and methods. Proposals found to be in conformity with good engineering design that can be easily maintained by the City may be given written approval for incorporation into the construction plans if found to be in the public interest. (Ord. 2017-22, Rep&ReEn, 07/05/2017; Ord. 2024-13, Amended, 4/16/2024 (Res. 2024-15))
13-09-006-0002 General Requirements
A. No water settling will be allowed in trenches.
B. The pipe shall be handled and installed in accordance with the manufacturer’s recommendation when not in conflict with other City specifications.
C. Affidavits of compliance by the manufacturer stating that the materials comply with all applicable provisions of City specifications may be required and shall accompany each truck or carload of pipe at the time of delivery. Affidavits shall be forwarded to the City by the contractor. (Ord. 2017-22, Rep&ReEn, 07/05/2017; Ord. 2024-13, Amended, 4/16/2024 (Res. 2024-15))
13-09-006-0003 Pipe Bedding
A. The City of Flagstaff will accept backfilling of trenches with a non-shrink backfill as an alternative to standard trench backfill material. The non-shrink backfill shall be proportioned as follows: two thousand six hundred (2,600) pounds of three-eighths (3/8) inch minus aggregate, eight hundred (800) pounds sand, ninety-four (94) pounds cement and eleven (11) gallons of water. All material shall be mixed by means of a ready mix truck. Non-shrink backfill may be used in either paved or unpaved sections of City right-of-way.
1. Mechanical compaction will not be required when this non-shrink backfill is used.
2. No compaction testing will be required.
B. The utility governing use of the trench shall determine the appropriate installation criteria for its facility. Refer to the applicable standard (Detail 9-06-030). (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0004 PVC Pipe for Sanitary Sewers
A. The pipe material used shall be SDR35.
B. The pipe shall be installed in accordance with MAG Specifications.
C. All pipes shall be checked for deflection with a properly sized deflection mandrel after backfill and before acceptance. Any deflection shall not exceed the manufacturer’s recommendation. Any pipe with excessive deflection shall be removed and replaced with a full length of the pipe. No cutting and splicing will be allowed. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0005 PVC Pipe for Water Lines
13-09-006-0005.1 General
A. PVC water line, in conformance with AWWA C-900 standards and the City of Flagstaff requirements, will be allowed for water distribution mains, eight (8) inch to twelve (12) inch. C-900 PVC shall conform to AWWA C-900 standards, Table 2, Cast-Iron-Pipe Equivalent outside diameters with elastomeric gasket couplings. Ductile iron pipe shall be used for mains greater than twelve (12) inches unless written approval is obtained from the City Engineer for each individual situation.
B. All other standards applying to water line construction shall continue to apply.
C. The contractor shall furnish the City of Flagstaff any information from the manufacturer upon request so that the products furnished under this specification may be properly evaluated for acceptance or rejection. Only products of approved manufacturers will be accepted. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0005.2 Specifications
A. All polyvinyl chloride (PVC) pipe shall be new and shall conform to AWWA specification C-900, latest revision, except as modified herein.
B. All PVC pipe shall be Class 305, unless otherwise designated.
C. All PVC pipe furnished shall be integral bell with elastomeric gaskets or plain ends with elastromeric gaskets and couplings. Deflected pipe shall be designed to deflect no more than one-half (1/2) the maximum as recommended by the manufacturer, horizontally and vertically.
D. The type of pipe furnished shall be marked in accordance with AWWA C-900 specifications, Section 2.5, include date of manufacture and manufacturer’s code.
E. PVC connections to cement asbestos and ductile iron pipe shall be accomplished by transition couplings ductile iron solid sleeve.
F. PVC pipe shall be provided in nominal twenty (20) foot (plus or minus one (1) inch) laying lengths for all sizes. Short lengths may be field cut for making required horizontal or vertical deflections. At least eighty-five percent (85%) of the total footage of pipe in any class and size shall be furnished in standard lengths, the remaining fifteen percent (15%) in random lengths. Random lengths shall not be less than ten (10) feet long. All standard, random, and short pieces and couplings shall have proof of meeting applicable hydrostatic testing provisions of AWWA C-900 standards at the point of manufacture.
G. Shipping, handling, unloading, cutting, joining, installation and storage of PVC pipe shall be accomplished in accordance with the manufacturer’s guidelines to insure the integrity and quality of the PVC pipe.
1. Storage shall be accomplished in such a manner as to protect the PVC pipe from prolonged exposure to sunlight and/or extreme heat.
H. Lubricant for joining of PVC pipe joints shall be completely compatible for use with a potable water system, and meet pipe manufacturer’s guidelines.
I. Disinfection of PVC pipe shall be in accordance with ADEQ Bulletin No. 8. Tablet method of chlorination shall not be accepted.
J. All PVC pipe furnished shall be such as to be tapped with standard tapping (over two (2) inches) and drilling tools (three-quarters (3/4) inch to two (2) inches). All tapping with sleeves and/or service connections shall be accomplished in accordance with the manufacturer’s guidelines and applicable City of Flagstaff standard specifications and practices. Direct tapping without the use of saddles will not be permitted.
K. Pipe fittings for PVC pipe shall be mechanical joint. Pipe is not to be longitudinally deflected at fittings.
L. Fittings and valves furnished for use with PVC pipe shall be ductile iron and polyethylene encased in accordance with applicable City specifications and AWWA C-110 (minimum pressure rating is two hundred fifty (250) psi).
M. Hydrostatic pressure testing and leakage testing shall be in accordance with the applicable portions of City and AWWA specifications as directed by the Engineer, and in accordance with the following specifications:
1. Test pressures for all sizes Class 305 PVC pipe shall be two hundred (200) psi at the lowest end of the section under test. Test duration shall be a minimum of two (2) hours.
2. Allowable leakage for the PVC pipe shall be in accordance with the following table and formula:
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U.S. GALLONS PER HOUR |
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AVERAGE TEST PRESSURE IN LINE - 200 P.S.I. |
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Nominal Pipe Size Inches |
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Allowable Leakage (gph) (per 1,000 Feet or 50 Joints) |
|
6 |
|
|
0.57 |
|
8 |
|
|
0.76 |
|
10 |
|
|
0.96 |
|
12 |
|
|
1.15 |
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Formula |
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English Units |
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L = |
(ND x P1/2) |
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|
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7,400 |
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Design Basis |
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|
|
|
WHERE: |
L |
= Allowable Leakage (gph) |
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|
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N |
= Number of Joints in the Tested Line (pipe and fittings) |
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|
|
D |
= Nominal Diameter of Pipe (inch) |
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|
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P |
= Average Test Pressure (psi) |
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WARNING: WATER PRESSURE TESTING ONLY. AIR TESTING IS NOT ALLOWABLE. |
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(Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0005.3 Affidavit of Compliance
Affidavits of compliance by the pipe manufacturer shall be required of all tests applicable under AWWA Specification C-900, latest revision, except that all inspection and testing shall be performed in the United States of America at the pipe manufacturer’s plant, or at an approved testing laboratory in the United States. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0005.4 Approved Manufacturer and Model
A. Manufacturer submittal required for the establishment of an approved list. The manufacturer shall submit five (5) sets of its written guidelines for shipping, handling, unloading, cutting, joining, installation, storage, and/or any other facets of working with its PVC pipe to the City of Flagstaff along with his submittal and affidavit of compliance.
1. Approved Manufacturer List.
a. Vinyltech.
b. Johns-Manville.
c. Certainteed.
d. PW Pipe by Pacific Western Extruded Plastics Co.
e. Uponor ETI.
f. North American Pipe Corporation.
g. Diamond Plastics. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0006 Fire Hydrants
13-09-006-0006.1 Fire Hydrant Testing
A. Fire hydrants shall be installed in accordance with standard fire hydrant installation drawings.
B. Fire hydrant main valve and auxiliary main valve shall be in the full open position during the filling of the system for the first time in order to allow all of the air in the lines to escape. Filling shall be done at a very slow rate to avoid compressing the entrapped air in the lines.
C. Fire hydrant main valve may be closed as soon as water is clear, no longer milky, and running free. The line test is then continued against the closed main valve until completed. The use of a fire hydrant for testing with the main valve open shall not be considered as a true test of the line’s ability to hold pressure.
D. Fire hydrant auxiliary valve may be closed after the line test is completed and the fire hydrant main valve fully opened. With a hose cap removed, the hydrant may be flushed by throttling with the auxiliary valve. Should an obstruction be encountered in the main valve, the main valve shall not be forced into a closed position, rather opened several times to flush out the obstruction. If the obstruction remains, the main valve shall be removed. With all internal parts removed, the auxiliary valve may be opened slowly until the obstruction is flushed out. Should the obstruction remain, it shall then be removed manually from the bottom of the hydrant.
E. Fire hydrant main valve may be opened with the hydrant caps securely tightened and tested for leaks at the normal main pressures. When this test is completed, the main valve shall be shut and a cap removed. When placing the palm of the hand over the end of the nozzle, suction should be felt if the hydrant drain is operating correctly. Allow hydrant to drain fully before installing caps.
F. Fire hydrant main valve shall be closed tightly but not forced, the auxiliary valve shall be in an open position, and the nozzle caps shall be snug tight. Thus, the hydrant will be in a ready condition for Fire Department use.
G. Fire hydrants shall never be forced in the open or closed position as stops are provided inside the hydrant to stop the travel of the main valve. Forcing will result in damage to the hydrant. The fire hydrant operating nut shall be packed off slightly into the free play position after closing the hydrant. Damage resulting from improper installation or care of the fire hydrant during installation shall be the sole responsibility of the contractor involved.
H. Fire hydrants shall not be used to take samples for bacteriologic testing. AWWA C601-68:
1. "Samples for bacteriologic analysis shall be collected in sterile bottles treated with sodium thiosulfate. No hose or fire hydrant shall be used in collection of samples."
2. Installation of a saddle and corporation stop for testing is required. After testing is completed, the corporation stop shall be removed and the saddle plugged.
I. A dry-barrel hydrant with unplugged drains shall not be tested at the same time as the water main; the main shall be tested with the hydrants closed (see AWWA C600). The water main cannot be tested satisfactorily if the hydrant is connected to it because of allowable leakage through the hydrant drains (see subsection (J) of this section). If desired, the gate valve in the hydrant lateral may be closed and the hydrant pressure tested by introducing water under pressure through an outlet nozzle.
J. Dry-barrel hydrants with unplugged drains may exhibit slight leakage (up to five (5) fl. oz. per min) through the drains in accordance with the current AWWA Standards for Testing. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0006.2 Fire Hydrant Specifications
A. Hydrants shall be designed, manufactured, and tested in compliance with the latest edition of AWWA C502 "Standard for Dry-Barrel Fire Hydrants" as published by the AWWA.
B. Hydrants shall be "TRAFFIC" type with a replaceable "breakable" flange unit immediately above the ground line for minimizing repairs due to traffic damage. Nozzle section must rotate 360°. Traffic flange shall be a minimum of two (2) inches above ground level, six (6) inches maximum above finish grade of curb, sidewalk, or landscaping.
C. Hydrant shall be of a dry barrel configuration to prevent water loss due to traffic damage and freezing.
D. Hydrants shall be constructed such that the main valve closes with water pressure (opens against) to assure no loss of water in the event of damage to the upper portion of the fire hydrant or if the operating stem should shear and to allow maintenance of upper portion of fire hydrant without having to close the lead valve.
E. Main valve opening shall have a diameter of at least five and one-quarter (5-1/4) inches to assure optimum flow.
F. Standpipe (hydrant barrel) inside diameter shall not be less than seven and one-quarter (7-1/4) inches.
G. Hydrant shall have a sealed oil reservoir type bonnet with O-ring seals to allow lubrication of stem threads.
H. Hydrant operating nut must turn left (counter-clockwise) to open.
I. Operating and cap nuts will be pentagon in shape; dimension shall be one and one-half (1-1/2) inches point to flat (National Standard).
J. Hydrants shall have a six (6) inch inlet of MJ design.
K. Hydrants shall have an automatic drain operated by the main valve rod and shall have a minimum of two (2) drain ports in the shoe of the hydrants. These drain ports shall be brass lined to prevent rusting.
L. Hydrants shall have two (2) two and one-half (2-1/2) inch nozzles and one (1) four and one-half (4-1/2) inch pumper nozzle having national standard threads.
M. Hydrants shall have a main valve seat ring of bronze threaded into a bronze drain ring; all working parts should be removable through the upper barrel.
N. Hydrant shall have nozzles mechanically locked into the nozzle section; no leaded nozzles will be accepted.
O. All barrels above ground shall have one (1) primer coat and two (2) coats of epoxy enamel yellow paint.
P. The center of the lowest nozzle shall have a ground clearance of not less than fifteen (15) inches.
Q. All fire hydrants, when installed, shall have a clear, level working area extending not less than three (3) feet around the hydrant. No obstructions such as fences, phone pedestals, trees, street signs, landscaping logs, or other impediments will be allowed within this three (3) foot area. Banks shall be excavated to obtain such clearance and an approved retaining wall with footing shall be constructed where the excavated bank exceeds eighteen (18) inches in height, as shown in the Engineering Standard Detail 13-03-011.
R. A class "A" concrete pad four (4) to six (6) inches thick and three (3) feet by three (3) feet square shall be placed around a fire hydrant barrel a minimum of two (2) inches and a maximum of eight (8) inches below the bottom of a traffic flange.
S. Fire hydrant types shall be limited to Waterous Pacer Model WB-67-250 with eighteen (18) inch upper standpipe, Mueller Super Centurion Model 250, and A423 and Clow Medallion Model F-2545. (Ord. 2017-22, Rep&ReEn, 07/05/2017; Ord. 2024-13, Amended, 4/16/2024 (Res. 2024-15))
13-09-006-0006.3 Fire Hydrant Installation Notes
A. All fire hydrant installations shall conform to the City Fire Code and the following requirements of the Utilities Division (see Detail 13-03-011):
1. A thrust block shall be placed at the back of the hydrant shoe from the ditch bottom to a point three-quarters (3/4) of the way up the back of the shoe and "V" shaped to solid ground. Thrust blocks shall be a minimum of two (2) feet wide at this point and shall not obstruct bolts or drain holes on the shoe. All bolts below grade shall be checked for tightness before backfilling.
2. Pipes, valves, and fittings shall be ductile iron with mechanical joint (MJ) connections except when the valve is located at the main it shall be flanged to the tee at the main.
3. Hydrant barrels must be installed plumb and the lead line must be level.
4. In the event of a long fire hydrant run, or if a run is eight (8) inches and reduced to six (6) inches, there shall be two (2) valves; one (1) flanged x MJ at the main and one (1) MJ x MJ by the fire hydrant a minimum of two (2) feet from the fire hydrant with the valve meg-lugged to the hydrant lead run.
5. Fire hydrants shall also be strategically located to avoid conflicts with vehicular traffic as follows:
a. When a hydrant is located near the intersection of two (2) streets, it should be located no less than ten (10) feet from the curb returns of the intersection.
b. When a hydrant is located adjacent to a driveway of a private property, it shall be located behind the sidewalk and no less than ten (10) feet from the edge of the driveway.
c. When ten (10) foot spacing from the edge of the driveway is not practical, the design shall maximize available space behind the sidewalk.
6. Fire hydrants installed within curbed islands shall be located a minimum of six (6) feet from the edge of the fire hydrant to the back of curb. If this cannot be achieved, bollards will be required around the fire hydrant. (See Detail 13-03-012).
7. Fire hydrants shall be installed within three hundred (300) feet of all parts of a commercial building. Hydrants shall also be placed within one hundred (100) feet of Fire Department connection to sprinkler and standpipe systems.
8. Off-site spacing shall be three hundred (300) feet between hydrants for commercial areas and five hundred (500) foot spacing for one (1) and two (2) family subdivisions.
9. Fire hydrants will have a maximum six (6) foot bury.
10. Where a fire hydrant is located in a concrete section (sidewalk, slab, or other concrete structure) a four (4) foot by four (4) foot block out shall be required around the hydrant.
11. In cul-de-sacs, where a fire hydrant is required at or near the end of a dead end main, it shall be installed at the end of the main instead of a blow-off.
12. Detector check devices with bypass meter assemblies may be required when one (1) or more of the following conditions exists or will exist:
a. The on-site water system includes outlets for future connections.
b. The on-site water system allows fire demand flow rates to occur without activating an alarm.
c. There is or will be an obvious means by which water from the on-site fire system might be used for purposes other than fire fighting.
13. If a developer is required to move an existing fire hydrant, the existing top portion of the hydrant must be salvaged and provided to the City, and the developer shall install a new hydrant at the developer’s cost. (Ord. 2017-22, Rep&ReEn, 07/05/2017; Ord. 2024-13, Amended, 4/16/2024 (Res. 2024-15))
13-09-006-0006.4 Fire Lines
A fire line is a private pipe system connected directly to the City water system. A fire line, by the nature of its function and use, is susceptible to backflow. Consequently, it is subject to the requirements for backflow prevention contained in these regulations.
All commercial fire sprinkler lines shall have a minimum four (4) inch (FLANGE x MJ) valve at the main. The four (4) inch valve shall be public, but the remainder of the line (including all fittings and gaskets on the outlet side of the valve) from the valve to the building shall be private. All commercial fire sprinkler lines shall be separate from domestic lines unless approved by the Utilities Division. Fire lines may not exceed one hundred (100) feet in length from the water main to the backflow assembly inside the fire riser room.
A. The fire line backflow assembly shall be installed immediately inside the building being served, but in all cases, before the first branch line leading off the service line. Such backflow prevention device assembly(ies) shall be installed and approved before water service shall be provided. All backflow prevention device assemblies, once installed, shall be inspected by the City of Flagstaff Industrial Waste Section, and before use, shall be tested by a State of Arizona certified backflow tester paid for by owner/developer with the results forwarded and received by the City of Flagstaff Industrial Waste Section, prior to acceptance of service.
B. Above-ground installation of backflow prevention devices shall conform to the City ordinance on backflow prevention and cross-connection control, and City of Flagstaff Standard Engineering Details for Backflow Assemblies, Details 9-06-071 through 9-06-075.
C. All fire risers, commercial and residential, shall be designed with a testable backflow prevention assembly that has been approved by the City of Flagstaff’s Industrial Waste Section. (Ord. 2017-22, Rep&ReEn, 07/05/2017)
13-09-006-0007 Backflow Prevention Devices
Backflow preventers shall be installed as required by Section 7-03-001-0015, Cross Connection Control, and shall be installed in accordance with City of Flagstaff Details 9-06-071 through 9-06-075. (Ord. 2017-22, Rep&ReEn, 07/05/2017)