Chapter 18.28
WATER SYSTEM
Sections:
Article I. Water System Design
18.28.005 Water system design.
18.28.020 Pipeline installation.
18.28.030 Hydrostatic test of newly installed water line.
18.28.040 Sterilization of newly installed water line.
18.28.060 Cross-connection control and backflow assemblies.
Article II. Requirements for Water System Vault Installations – Vaults for Water Meters, PRVs, Fire Service and Domestic Backflow Devices
18.28.070 General requirements.
Article I. Water System Design
18.28.005 Water system design.
The following section is intended as a guide for the design, installation, and testing of water system improvements. An approved water system capable of supplying required fire flow for fire protection shall be provided to all premises upon which buildings are to be constructed. The required fire flow must be available with a minimum residual pressure of 20 pounds per square inch (psi). Questions on required fire flow may be referred to the fire marshal’s office. The engineer may request that modifications be made for a specific project. In general, the following guidelines should be followed:
(1) All material shall be of new manufacture. No rebuilt, reconditioned, or used material will be allowed.
(2) Minimum size mains shall be six inches.
(3) Minimum pipe cover is 30 inches, measured from finish grade to the upper surface of the pipe barrel.
(4) Dead-end mains normally shall not be allowed. When they are permitted, a blow off assembly will be required.
(5) Main extensions shall be installed through new developments to allow a logical extension of the city water line grid and to allow future development of adjacent undeveloped or underdeveloped properties.
(6) Valves shall be located, whenever possible, at intersections. In general, sufficient valves should be provided to permit shutting down any section of the line, not exceeding 500 feet, with valve operations in not more than three locations.
(7) Valves shall be installed in clusters at pipeline intersections.
(8) Valves 10 inches and smaller shall be gate valves. All gate valves shall be resilient wedge valves conforming to AWWA C-505. The city accepts Clow R.W., Mueller, and Kennedy valves, or city-approved equal. Two-inch or smaller valves shall be as specified by public works or the city engineer.
(9) Valves 12 inches and greater shall be butterfly valves. All butterfly valves shall be rubber-seated valves conforming to AWWA C-504. The city accepts Mueller and Kennedy AWWA valves, or city-approved equal.
(10) Fire hydrants shall not be connected to mains less than six inches in diameter. As per the UFC, fire hydrants shall be located to allow a 36-inch clear space surrounding the hydrant. For example, streetlights, signposts, protective posts, or retaining walls shall be no closer than 36 inches from the nearest portion of a hydrant. There shall also be no obstructions directly in line with any of the ports of the hydrant.
(11) For required fire hydrant location and spacing, contact the fire marshal’s office.
(12) All water system installation shall be designed to provide a pressure range of 50 psi to 90 psi at all times, including during peak demand.
(13) Pressure-reducing devices are to be approved on a per project basis to ensure compliance with the Uniform Plumbing Specialty Code.
(14) Water service size shall be one-inch type K copper.
(15) Water services are to be single runs from the main line to each meter.
(16) At high points in the water system, combination air and vacuum release valves (CARV) shall be installed as required by the city engineer. All Air-Vac, air evacuation, and vacuum prevention valves of sizes two inches and larger shall vent to the outside of the vault. If construction of the valve does not permit the venting of leakage to the outside of the vault, a screened drain to daylight of at least the supply line size must be provided at a level that will prevent cross-connection and/or backflow problems. This decision will be made by the city engineer prior to the plan approval. (Ord. 2875 Appx. § 610, 2003)
18.28.010 Materials.
(1) Water Pipes. Pipe shall be push-on joint ductile iron pipe. Fitting joints shall be mechanical joint ends. Push-on joint ductile iron pipe shall be cement-mortar lined and conform to ANSI/AWWA C104/A21.4 and ANSI A21.11, or city-approved equal. The type and thickness class shall be 50. The rubber ring gaskets shall conform to ANSI A21.11, be suitable for the specified pipe sizes and pressures, and shall be furnished with the pipe. A nontoxic vegetable soap lubricant shall be supplied with the pipe in sufficient quantities for installing the pipe furnished.
(2) Pipe Fittings.
(a) Mechanical Joint Fittings. Mechanical joint ductile iron fittings shall conform to ANSI/AWWA C104/A21.4 and shall be of class at least equal to that of the adjacent pipe. Mortar lining for fittings shall be the same thickness specified for pipe.
(b) Flanged Ductile Iron Fittings. Flanged fittings shall conform to ANSI B16.12 and shall be faced and drilled 125-pound ANSI. The fittings shall be cement-mortar lined to same thickness specified for pipe, and shall meet ANSI/AWWA C110/A21.11 for all other aspects.
(c) Gaskets. Gasket material for flanged joints in ductile iron pipe shall be cloth-inserted sheet rubber gaskets conforming to AWWA/ANSI C207/B16.21, one-eighth inch thick. The gasket shall be full-cut, with holes to pass bolts. Gasket material shall be free from corrosive alkali or acid ingredients.
(d) Mechanical Couplings. Mechanical couplings, not a part of the pipe itself, shall be ductile iron couplings with rubber rings and ductile iron bolts and nuts. Couplings shall be Mueller, Kennedy, or as approved by the city engineer. (Ord. 2875 Appx. § 610.1, 2003)
18.28.020 Pipeline installation.
The work necessary to excavate, bed, and backfill water pipelines shall conform to the requirements of Articles VII and VIII of Chapter 18.08 SHMC, and the standard drawings of this title.
(1) Distributing Pipe. Distribute material on the job from the cars, trucks, or storage yard no faster than can be used to good advantage. In general, distribute no more than one week’s supply of material in advance of the laying.
(2) Handling Material. Provide and use proper implements, tools, and facilities for the safe and proper prosecution of the work. Lower all pipe, fittings, and appurtenances into the trench, piece by piece, by means of a crane, slings, or other suitable tools or equipment, in such a manner as to prevent damage or contamination to the pipeline materials and protective coatings and linings. Do not drop or dump pipeline materials into the trench.
(3) Cleaning Pipe and Fittings. Remove all lumps, blisters, and excess coal-tar coating from the bell and spigot ends of each pipe. Wire brush the outside of the spigot and the inside of the bell and wipe clean, dry, and free from oil and grease before the pipe is laid. Wipe the ends of mechanical joint pipe and fittings and of rubber gasket joint pipe and fittings clean of all dirt, grease, and foreign matter. Check interior of pipe for obstructions or debris and, if found, remove from pipe.
(4) Placing of the Pipe in the Trench. Do not allow foreign material to enter the pipe while it is being placed in the trench. If because of trench configuration or shoring detail it is necessary to place pipe in such a manner that bedding material may enter pipe, then engineer shall require tight woven canvas boots be used and removed when placing pipe.
(5) Push-On Joint Pipe. After the first length of push-on joint pipe is installed in the trench, secure pipe in place with approved backfill material tamped under and along sides to prevent movement.
(6) Cutting Pipe. Cut pipe for inserting valves, fittings, or closure pieces in a neat and clean manner without damaging the pipe or lining and so as to leave a smooth end at right angles to the axis of the pipe.
Cut pipe with milling-type cutter or saw. Do not flame cut.
(7) Dressing Cut Ends. Dress cut ends of push-on joint pipe by beveling, as recommended by the manufacturer.
(8) Bell End to Face Direction of Laying. Unless otherwise directed, lay pipe with bell end facing in the direction of the laying. For lines on steep slopes, face bells upgrade only.
(9) Installation of mechanical joint pipe shall be as specified in AWWA C111, including bolt torque ranges. Mechanical joint gaskets shall be vulcanized rubber and no more than three years old.
(10) All material shall be of new manufacture. No rebuilt or reconditioned material will be allowed.
(11) Permissible Deflection of Joints. Wherever it is necessary to deflect pipe from a straight line either in a vertical or horizontal plane, or where long-radius curves are permitted, the amount of deflection allowed shall not exceed the values in the following table:
|
MAXIMUM DEFLECTION PERMITTED* 18-Foot Length Pipe |
||||
|---|---|---|---|---|
|
MECHANICAL JOINT** MAXIMUM DEFLECTION |
PUSH-ON JOINT MAXIMUM DEFLECTION |
|||
|
DIAMETER INCHES |
ANGLE DEGREES AND MINUTES |
DEFLECTION INCHES |
ANGLE DEGREES |
DEFLECTION INCHES |
|
4 |
8-18 |
31 |
5 |
18 |
|
6 |
7-07 |
27 |
5 |
18 |
|
8 |
5-21 |
20 |
5 |
18 |
|
10 |
5-21 |
20 |
5 |
18 |
|
12 |
5-21 |
20 |
5 |
18 |
* The maximum deflection shall be whichever is less, the table or that recommended by the pipe manufacturer.
** Safe deflection for 150 pounds pressure. For higher pressure, reduce tabulated deflection proportionally 10 percent for each 150 pounds added pressure.
(12) Alignment. Pipelines intended to be straight shall not deviate from the straight line at any joint in excess of one inch horizontally or vertically.
(13) Unsuitable Conditions for Laying Pipe. Do not lay pipe in water or when, in the opinion of the engineer, trench conditions are unsuitable.
(14) Joining Push-On Joint Pipe and Mechanical Joint Fittings. Lay and join pipe with push-on-type joints in strict accordance with the manufacturer’s recommendations. Provide all special tools and devices, such as special jacks, chokers, and similar items required for the installation. Lubricant for the pipe gaskets shall be furnished by the pipe manufacturer, and no substitutes will be permitted under any circumstances.
Mechanical joint fittings vary slightly with different manufacturers. Install the particular fittings furnished in accordance with the manufacturer’s recommendations. In general, the procedure shall be as hereinafter specified. Clean the ends of the fittings of all dirt, mud, and foreign matter by washing with water and scrubbing with a wire brush, after which, slip the gland and gasket on the plain end of the pipe. If necessary, lubricate the end of the pipe to facilitate sliding the gasket in place. Then guide the fitting onto the spigot of the pipe previously laid.
(15) Anchorage and Thrust Blocking. On all pipelines six inches in diameter or larger, securely anchor by suitable thrust blocking all tees, plugs, caps, and bends exceeding 11 and one-fourth degrees, and at other locations where unbalanced forces exist, as determined by the engineer.
Provide reaction or thrust blocking as directed. The concrete mix shall have a compressive strength of not less than 3,000 pounds per square inch. Place blocking between the undisturbed ground and the fitting to be anchored. The bearing surface shall be as shown on Standard Drawing 430. Place the blocking so that the pipe and fitting joints will be accessible to repairs.
(16) Additional Restraints. Meg-a-lugs are acceptable restraints under certain conditions as approved by the city engineer. Fire hydrants shall be installed with a fully restrained system using a combination of meg-a-lugs and field lock gaskets.
(17) Downtime Protection. When stopping work for the day, the contractor shall plug pipe ends to prevent rodents, other small animals, or debris from entering the pipe. Plugs used shall be tight-woven canvas, securely tied around outside of pipe end. (Ord. 2875 Appx. § 610.2, 2003)
18.28.030 Hydrostatic test of newly installed water line.
The contractor shall make pressure and leakage tests on all newly laid pipe. The contractor shall furnish all necessary equipment and material, make all taps in the pipe as required, and conduct the tests. The engineer will monitor the tests, record the results, and provide a copy of those results to the city. The engineer shall also indicate that the thrusting blocks have obtained the needed strength to resist the pressures obtained during the hydrostatic test.
The contractor shall furnish the following equipment and materials for the tests:
|
AMOUNT |
DESCRIPTION |
|---|---|
|
2 |
Approved graduated containers. |
|
2 |
Pressure gauges (maximum two psi increments). |
|
1 |
Hydraulic force pump approved by the engineer. Suitable hose and additional equipment as required. |
Conduct the tests after the trench has been backfilled or partially backfilled. Where any section of pipe is provided with concrete reaction blocking, do not make the pressure tests until at least five days have elapsed after the concrete thrust blocking is installed. If high-early cement is used for the concrete thrust blocking, the time may be cut by two days or as permitted by the engineer.
Conduct pressure tests in the following manner, unless otherwise approved by the engineer. After the trench has been backfilled or partially backfilled as specified herein, fill the pipe with water, expelling all air during the filling. The minimum test pressure shall be 150 pounds per square inch (psi).
(1) Duration. The duration of each pressure test shall be 60 minutes, unless otherwise directed by the engineer.
(2) Procedure. Fill the pipe with water and apply the specified test pressure by pumping, if necessary. Then valve off the pump and hold the pressure in the line for the test period. At the end of the test period, operate the pump until the test pressure is again attained. The pump suction shall be in a clean barrel or similar device approved prior to filling with clean water, or metered so that the amount of water required to restore the test pressure may be measured accurately.
(3) Leakage. “Leakage” shall be defined as the quantity of water necessary to restore the specified test pressure at the end of the test period. No pipe installation will be accepted if the leakage is greater than the number of gallons per hour as determined by the following formula:
|
L = |
SD(P)1/2 |
|
|
133,200 |
In the above formula:
L = Allowable leakage, in gallons per hour.
S = Length of pipe to be tested, in feet.
D = Nominal diameter of pipe, in inches.
P = Average test pressure during the leakage test, in pounds per square inch.
(4) Correction of Excessive Leakage. Should any test of pipe laid disclose leakage greater than that allowed, locate and repair the defective joints or pipe until the leakage of a subsequent test is within the specified allowance.
(5) Isolation of Existing Systems Prior to Testing. Existing water pipelines shall be protected from contamination during the testing process for new construction. Use of special “blind flanges” will be necessary if the line being tested cannot be adequately separated from existing systems. The engineer shall submit shop drawings and proposed procedures to the city prior to installing any special testing device. (Ord. 2875 Appx. § 610.3, 2003)
18.28.040 Sterilization of newly installed water line.
Pipeline intended to carry potable water shall be sterilized before placing in service. Sterilizing procedures shall conform to AWWA C-651. (Ord. 2875 Appx. § 610.4, 2003)
18.28.050 Tapping.
All tapping of four-inch and larger public water pipe shall be performed using an all stainless steel tapping sleeve.
If a live tap is required in order to extend a line over 10 inches in diameter a gate valve will be allowed. All valves shall be installed with valve boxes and lids per city standards.
Prior to tapping, all items that may come in contact with the public water shall be swabbed with a 300-mg/L chlorine solution. The following items shall be the minimum items swabbed: tapping machine bit and cutter, tapping valve, tapping sleeve, and the exterior section of pipe to be tapped after the pipe has been cleaned with a wire brush (to be extended a minimum of six inches outside the tapping area). (Ord. 2875 Appx. § 610.5, 2003)
18.28.060 Cross-connection control and backflow assemblies.
When required, backflow prevention assemblies for protection of the public water system shall meet the requirements set forth in the current OAR 333-61-070 and the Uniform Plumbing Code.
The assembly shall be installed at the location normally established for water meters, usually at the property line. A water service shall not be turned on until all required backflow prevention assemblies are installed, inspected, tested, approved, and registered with the city of St. Helens. Costs of all installations, including all costs of inspection and testing fees, shall be the responsibility of the customer. The backflow prevention assembly will remain the property of the customer. The customer will be responsible for all maintenance and testing of the assembly and vault.
There are three types of backflow prevention assemblies which the city will allow as protection of the public water system. The Oregon Health Division, Drinking Water Section, provides a list of approved assemblies.
The type of backflow prevention assembly required is determined by the aforementioned rules and codes, based on the type of premises to which water service is being provided. The approved types of assemblies are listed below with some of the types of premises that must be protected by each type of assembly. However, these lists are not complete, they are only intended to give you some basic guidelines.
(1) Reduced Pressure Backflow Assembly. An approved reduced pressure backflow assembly shall be installed on the service connection above ground to the following:
(a) Any tax lot that has an auxiliary water supply on or available to it. This will include any above or below ground water source. (The most commonly encountered type of auxiliary water supply is a private well.)
(b) Commercial buildings which are located within an industrial zone.
(c) Hospitals, medical centers, and clinics.
(d) Mortuaries and nursing homes.
(e) Gas stations.
(f) Sewage pumps and lift stations.
(g) Dry cleaners and commercial laundries.
(h) Any water system which has a pump to supplement pressure.
(2) Double Check Assembly or Double Detector Check Assembly. An approved double check assembly or an approved double detector check assembly shall be required (provided that all internal plumbing is installed and maintained in accordance with the Uniform Plumbing Code) on the service connection to premises where there is:
(a) Any fire system or water line to a private fire hydrant.
(b) Shopping centers or large retail stores.
(c) Restaurants or fast food establishments.
(d) Any water service which is larger than two inches in diameter.
(3) Installation and Testing. Backflow prevention assemblies shall be installed at the water service connection on the customer side of the meter. Backflow assemblies three-inch diameter and larger shall be installed in a vault in accordance with Article II of this chapter. Backflow prevention assemblies smaller than three inches shall be installed in a typical meter box, all-concrete construction, with a one-piece full traffic lid.
After installation, all backflow prevention assemblies that are installed must be tested by a state of Oregon certified tester. The results of the testing shall be received by the city prior to issuance of “final occupancy.” (Ord. 2875 Appx. § 610.6, 2003)
Article II. Requirements for Water System Vault Installations – Vaults for Water Meters, PRVs, Fire Service and Domestic Backflow Devices
18.28.070 General requirements.
To ensure proper operation and accessibility of all assemblies, the following requirements shall apply to installation of these assemblies, unless otherwise approved by the city of St. Helens:
(1) Provide approved ladder if the vault or chamber depth is five feet, zero inches or greater and entry is through the vault or chamber roof.
(2) Adequate drainage for the vault or chamber shall be provided. (Drainage to piped storm systems allowed with check valve.)
(3) Vault must be equipped with a moisture-proof light fixture if adequate lighting is not available.
(4) Vault is to have no other use, except for use described by these standards.
(5) Vault shall be installed on undisturbed base or compacted three-fourths to zero gravel base.
(6) No piping shall be installed in excess of three feet above the vault floor.
(7) Assembly is to be adequately supported from the floor, and suitably restrained from movement. Supports shall consist of steel supports or approved equal; no wood supports shall be used.
(8) All electrical wiring shall be inspected by the Columbia County electrical inspector (permit is required).
(9) The assembly shall be readily accessible with adequate room for maintenance.
(10) All new services are to be pressure-tested and disinfected by the contractor and proven to be bacteriologically safe from the existing main to the vault.
(11) The assembly shall be protected from freezing and other severe weather conditions. (Ord. 2875 Appx. § 620.1, 2003)
18.28.080 Water meter vaults.
The vault is to be provided and installed by the contractor, per Standard Drawing 405. (Ord. 2875 Appx. § 620.2, 2003)