ITEM 202 WATER DISTRIBUTION SYSTEM PRETENSIONED CONCRETE CYLINDER PIPE

Transcription

1 CITY OF ODESSA STANDARD SPECIFICATIONS ITEM 202 WATER DISTRIBUTION SYSTEM PRETENSIONED CONCRETE CYLINDER PIPE GENERAL These specifications shall govern the furnishing and placing of water distribution lines, fittings, valves, fire hydrants, and other appurtenances. The pipe and accessories shall be installed in accordance with the requirements of these specifications at the locations and depths indicated on the plans, and shall be of the classes, sizes and dimensions shown thereon. The installation of pipe shall include all joints, connections to new or existing pipes, and the installation of all fittings, valves, fire hydrants and appurtenances. Pretensioned concrete cylinder pipe shall consist of welded sheet steel cylinder lined with a dense concrete lining around which there is placed reinforcing rods wound helically under measured tension, with a dense concrete coating covering the cylinder and the rods. The steel joint rings shall be of the bell and spigot type with rubber gaskets. The design and fabrication of pipe and pipe fittings shall comply with American Water Works Association (AWWA) Standard Specification C303. Where American Society for Testing and Materials (ASTM) and AWWA are noted, the latest revision takes precedence. Pipe manufacturers shall have had a successful experience record in the design and manufacture of concrete cylinder pipe and shall have had a substantial footage of pipe of similar size, and with the same joint as offered for this project, in successful operation for at least five years. An affidavit from the manufacturer stating that the pipe and fittings furnished comply with AWWA C303 shall be submitted to the Engineer. Successful bidder shall submit four (4) sets of full and complete shop drawings prior to construction. All pipe, fittings, outlets, etc., shall meet the requirements of the Underwriter's Laboratories, Inc., and shall be acceptable by the National Board of Fire Underwriters. Where or approved equal is noted, written approval by the City Engineer is required prior to receiving bids or issuing construction permits MATERIAL A. Pipe and Fittings All materials for the manufacture of pipe and fittings shall comply with AWWA C303. Revised 1/

2 B. Joint Mortar Mortar cylinders shall attain a compressive strength of not less than 3000 psi in 7 days and 4500 psi in 28 days. Mortar shall not be placed when the ambient temperature is less than 50 F. or less than 40 F. with the temperature rising. The temperature of the mortar when deposited shall be between 50 F. and 80 F. C. Rubber Gasket Rubber gaskets shall conform to AWWA C303. D. Gate Valves All gate valves shall be iron body non-rising stem, with mechanical joint ends (unless otherwise specified in the plans). They shall be equipped with a 2" operating nut with the direction of opening to be left (counter-clockwise). All valves shall have double O ring stem seals and the thrust collar shall be isolated from the water pressure with continuous lubrication or shall have non-corrosive bronze thrust bearings above and below the thrust collar. The valve stem shall be so designed that under excessive torque conditions, external stem failure shall occur before failure of the internal pressure retaining parts in order that the valve may be operated after failure. All internal ferrous metal surfaces in the waterway (machined or cast) shall be factory coated with a non-toxic two component holiday-free thermosetting epoxy to a nominal thickness of 4 mils. Gate valves 3" through 12" shall be designed for a working pressure of 200 pounds per square inch and designed for vertical installation. These valves shall be resilient seatwedge type conforming to the requirements of AWWA C509 specification. Gate valves 14" through 48", inclusive, shall be bronze mounted, double disc, parallel seat type conforming to the requirements of AWWA C500 specification and shall be designed for a working pressure of 150 pounds per square inch and designed to operate with the stem horizontal or vertical as shown on the plans. Horizontal valves shall be provided with enclosed lubricated bevel gears, bronze gate rollers and tracks, bypass valve and 2" operating nuts on main and bypass valves. Gate valves shall be Mueller, Clow or approved equal, and unless otherwise specified shall be furnished complete with valve box. E. Butterfly Valves All butterfly valves shall be of the tight closing, rubber-seated type with rubber seats that are securely fastened to the valve body. No metal-to-metal seating surfaces shall be permitted. Valves shall be bubble-tight at rated pressures with flow in either direction and shall be satisfactory for applications involving valve operation after long periods of inactivity. All butterfly valves shall strictly conform to the design strength, testing and 202-2

3 performance requirements of AWWA C504. Minimum and maximum valve sizes are 14" and 48", respectively. Any alternate valve sizes must be approved by the City Engineer. Valve bodies shall be constructed of cast iron ASTM A-126 Class B. Valve bodies shall be of the mechanical joint style unless otherwise noted on plans. Valves shall have a retained seat and shall provide tight shut-off up to the full valve rating. Valve disc shall be cast ductile iron ASTM A-536 Grade and shall be of the offset design providing 360 uninterrupted seating. Valve shafts shall be turned, ground and polished and shall be constructed of materials and diameters as required in Table 3 of AWWA C504 (Optional - or of corrosion resistant material [stainless steel] and diameters which give equivalent strength.) All valve shafts may consist of a one-piece unit extending completely through the valve disc, or may be of the "stub shaft" type, which comprises two separate shafts inserted into the valve disc hubs. All valves shall have new natural or synthetic rubber resilient seats to provide tight shut off at the pressure specified. The resilient seats must be capable of replacement in the field without grinding or burning. Valves shall be fitted with sleeve-type bearings. Bearings shall be of corrosion resistant and self-lubricated materials that will not deteriorate natural or synthetic rubber. Where shafts project through the valve bodies for operator connection, a shaft seal shall be provided. All internal ferrous metal surfaces in the waterway (machined or cast) shall be factory coated with a non-toxic two component holiday-free thermosetting epoxy to a nominal thickness of 4 mils. All manually operated valves shall be of the traveling nut self-locking type and shall be designed to hold the valve in any intermediate position between fully open and fully closed without creeping or fluttering. All operators shall have externally adjustable mechanical stop limiting devices. Valves for buried service shall have a 2" square nut operator and shall be installed with extension stems where required to extend the operating nut to within 12" of the finished grade. Butterfly valves shall be manufactured by Mueller, Clow or approved equal and unless otherwise specified shall be furnished with valve box. F. Tapping Valves All tapping valves shall meet the requirements and standards of the gate valve specifications, part D, with the exception that one side shall be flanged to fit the tapping sleeve with provisions for attaching a standard tapping machine to the other side

4 G. Tapping Sleeves All tapping sleeves shall be Gifford Hill American or approved equal. H. Check Valves Check valves shall have a cast iron body, fully bronze mounted with mounted clapper disc accurately seated by a bronze clapper arm against a bronze seat ring conforming to the requirements of AWWA C508. The design shall minimize chatter and vibration. Check valves 2" through 12" in size shall be designed for 175 pounds per square inch working pressure and 350 pounds per square inch test pressure. Check valves 14" through 24" in size shall be designed for 150 pounds per square inch working pressure and 300 pounds per square inch test pressure. The clapper of the gravity operated type valve swings from a large diameter stainless steel hinge pin held in place by bronze bushings or plugs. The clapper of the lever operated type valve is to be secured to a large diameter stainless steel shaft which turns in bronze bushings or plugs. The plugs or bushings will be securely held in place by cap screws. Plugs and bushings are to be sealed by "O" rings. Make of check valves shall be Mueller, Clow or approved equal. I. Fire Hydrants Fire hydrants shall be of the dry barrel, traffic mode, compression type main valve that closes with line pressure, suitable for a working pressure of 150 pounds per square inch and shall comply with AWWA C502 specification. Each hydrant shall be factory tested to a hydrostatic pressure of 300 pounds per square inch with the valve in both the open and closed positions. The direction of opening shall be left (counter-clockwise) and shall be clearly cast on the head of the hydrant. The 1½" pentagon operating nut will be all bronze with an antifriction washer provided above the thrust collar. The hydrant bonnet shall have an oil lubricant reservoir surrounding the working parts of the hydrant and which shall be O ring sealed from water pressure and weather conditions. An oil fill plug shall be provided. The bonnets shall also be provided with a weather shield for freeze protection. Fire hydrants shall have two 2½" hose nozzles and one 4½" pumper (steamer) nozzle with National standard hose threads. The hose and steamer nozzles shall be minimum grade D, low zinc bronze and shall be threaded into the body of the nozzle section. Nozzle caps shall have durable gasket seals. The hydrant traffic feature shall consist of a breakable flange or bolts, and a breakable ferrous metal sleeve stem coupling with stainless steel or high strength bronze stem coupling pins. The bronze seat ring shall be a minimum 5¼" inside diameter and shall thread into a bronze drain ring or bushing forming an all bronze drainway with positive sealing resilient drain valve facing. All bronze shall be less than 16% zinc alloy and have a minimum yield 202-4

5 of 20,000 pounds per square inch as noted in Section 2.1, Table 1, of the above referenced standard. The main valve shall be replaceable through the top of the hydrant without digging up the hydrant. Fire hydrants shall be 4' bury (unless otherwise noted on the plans) and shall have a completely assembled 6" mechanical joint shoe inlet (unless otherwise noted on the plans). The underground flanging of these parts shall have a minimum of five full 3/4" rustprohibitive bolts or shall be stainless steel bolts. Fire hydrants shall be painted above the ground line with one coat of red primer paint and two coats of fire hydrant red enamel. All other exposed surfaces shall be coated with either coal tar or asphalt. The hydrant shoe, lower valve plate and cap nut shall be internally coated with a non-toxic two component holiday-free thermosetting epoxy to a nominal thickness of 4 mils. Make of fire hydrants shall be Mueller Centurion, Clow model F2500, or approved equal with required options. J. Corporation Stops Corporation stops shall be of the size specified on the plans. All stops shall be AWWA standard C800. Outlet shall be copper flare. Make of corporation stops shall be Mueller, H or approved equal. K. Curb Stops (Ball Valves) Curb stops shall be of the size and configuration specified on the plans. Ball valve curb stops shall be cast of red brass. The ball shall be fluorocarbon brass coated held in place by and sealed against Buna-N seals. The shaft that turns the ball shall be T-headed and of one (l) piece construction and shall be sealed by a Buna-N O-ring seal. The shaft and ball shall rotate 360 in either direction. One (l) lockwing shall be cast into the body of the valve and one (l) lockwing shall be cast into the T-head. L. Air Valves Air valves shall be of the type indicated on the plans. The assembly shall not leak nor shall the valve stick under service conditions. M. Services Services shall be seamless, cold drawn copper tubing ASTM B88, Type K. N. Valve Boxes Valve boxes shall be of cast iron with cover marked "Water". Valve boxes shall be Clow F-2454 (screw type) or approved equal

6 O. Concrete (Thrust Blocking) Concrete shall conform to the requirements of Item 400, "Concrete Construction" CONSTRUCTION METHODS A. General Concrete cylinder pipe, fittings, specials and valves are to be installed at locations shown on the plans and specified in these contract documents. Unless otherwise indicated, pipe in trenches shall be laid to the grade shown or an even grade from point to point for which elevations are furnished. All of the requirements of the specifications under Item 100, "Excavation and Backfill", govern for the excavation of trenches for laying concrete cylinder pipe, fittings, specials, and other accessories. B. Laying and Jointing Pipe, fittings, valves and other accessories shall be hauled to and distributed at the site of the project by the Contractor. They shall at all times be handled with care to avoid damage. In loading and unloading, they shall be lifted by hoists or cranes as specified below, or rolled on skidways in such manner as to avoid shock. Under no circumstances shall they be dropped. Pipe shall be placed on the site of the work parallel with the trench alignment and with bell ends facing the direction on which the work will proceed unless otherwise directed. Proper implements, tools, equipment and facilities shall be provided and used by the Contractor for the safe and convenient prosecution of the work. All pipe, fittings, specials, valves, etc., shall be lowered into the trench by means of a "side boom", crane or other suitable machines and shall not be rolled or "dumped" into the trench. The "side boom", crane, etc., shall lift and lower the pipe at a slow rate of speed, and shall be capable of stopping the lifting operation at any point without producing a shock or otherwise jerking or vibrating the pipe. The hoisting cable shall be connected to the pipe in such a manner to prevent damage to the coating. Before lowering into the trench, each joint of pipe shall be inspected and any unsound or damaged pipe shall be rejected. The pipe shall be kept clean during the laying operation and at the close of each operating day the open end of the pipe shall be effectively sealed against the intrusion of foreign objects. No pipe shall be laid in water or where the trench conditions are unsuitable for such work. All pipe shall be laid accurately to established lines and grades, with valves and fittings at the required location, and with joints centered and spigots home. Line and grade stakes will be provided by the Engineer. Where it becomes necessary to make major deflections in the line of pipe, sections of pipe with beveled ends or fabricated fittings shall be used. Minor deflection of the line may be 202-6

7 obtained in the pipe joints; however, the maximum joint opening caused by such deflection shall not exceed that specified in AWWA C303. Field cuts of pipe will not be permitted. Before laying each joint of pipe, the bell and spigot rings shall be thoroughly cleaned by wire brushing and wiping until clean and dry. Where pipe is being laid the gasket shall be placed on the spigot ring and the spigot end of the pipe shall then be entered into the bell of the adjoining pipe and forced into position. The gasket and the inside surface of the bell shall be lubricated with a suitable solution, e.g., flax soap, which will facilitate the telescoping of the joint. The inside joint recess between end of pipe sections up to 21 inches in diameter shall have a maximum width of 1" and a minimum width of 1/4". The inside joint recess between ends of pipe sections 24" to 54" in diameter shall have a maximum width of 1-1/4" and a minimum width of 1/4". No blocking up of pipe or joints will be permitted. The exterior joint shall be made by placing a cloth joint wrapper around the pipe which will be held in place with two strands of wire. The cloth wrapper shall be 7" wide and hemmed on each side so that the wire "ties" may be inserted to hold the wrapper in place. The cloth shall be of such length that it will encircle the pipe, leaving enough opening between the ends to allow the mortar to be poured inside the wrapper. The wire ties shall be 16 gauge black annealed wire, or approved equal, and shall be of such length to encircle the pipe and overlap at the ends about 8" for tying the ends. The wrapper shall be securely fastened before the joint is poured. The wire wrapper shall be similar and equal to the wrappers (diapers) as made by MAR-MAC Manufacturing Co. The grout used for pouring the joint shall consist of one part Portland cement to two parts of clean, fine, sharp (plaster) sand, and mixed to a consistency of thick cream. The joint shall be filled with grout from one side in a continuous operation until the grout has flowed entirely around the pipe. During the filling of the joint, it shall be rodded with flexible wire to settle the grout. Upon completion of the backfilling of the pipe trench, the inside joint recess shall be filled with Portland cement mortar consisting of one part cement to two parts of sand. After the joint has been filled, the surface of the joint shall be leveled with the interior surface of the pipe and the face of the joint brushed with a wet brush. Where concrete cylinder pipe or fittings are to enter into ductile iron bells, the joints shall be sealed with approved jointing compound, as specified for laying ductile iron pipe. Careful inspection shall be made of every joint to insure smooth, continuous interior surface. The interior of the pipe shall be thoroughly cleaned and any obstruction removed that may reduce its carrying capacity. Attention is directed to the provision of these specifications relative to the manufacturer of the pipe, wherein it is required that a factory-trained, qualified, job trained representative be available on an as needed basis. Wherever necessary to patch any inside surface cuts or to patch any chipped areas at the ends of pipe, such patches shall be made with a mortar as per manufacturer's recommendations. Pipe thus patched shall not be installed until the patch has been properly and adequately cured and approved for laying by the Engineer

8 Gasket material shall be kept in clean containers and shall not be allowed to come in contact with the ground. Gasket material which has become contaminated or dirty shall be destroyed. Mechanical joints shall be installed in accordance with the manufacturer's recommendation. Unless otherwise shown, valves shall be located on an extension of the street property line. The valve box shall not transmit shock or stress to the valve and shall be centered and plumb over the operating nut, with the cover flush with the pavement surface or such other level as directed. Hydrants shall be located as shown on the plans and in a manner that will provide complete accessibility and will prevent damage from vehicles. All hydrants shall stand plumb and shall have their pumper connections at right angles to the curb line. All hydrants, valves and fittings shall be anchored with thrust blocking as indicated on the plans. C. Water Main Wet Connections and Water Main Taps Wet connections are defined as connections made to a line in the existing system by interrupting water service. They shall be made at such points as are shown on the plans or as designated by the Engineer. The method and the equipment to be used shall be submitted to the Engineer for approval before any work is done. Water main taps are defined as connections made to a line in the existing system by not interrupting water service. These taps will be made under the supervision and direction of a representative of the Engineer for the City of Odessa. The Water Department of the City of Odessa will be required to operate all existing City owned water valves necessary to make the required wet connections or water main taps. Any time that the interruption of water service in the existing system is necessary because of operations under this contract, the Contractor shall notify the City Water Superintendent 48 hours in advance. D. Depth of Lines Minimum cover on water lines shall be 36" below finished grade. E. Disinfection of Pipe Lines Unless otherwise specified, disinfection of new water lines shall be done in accordance with AWWA C651 specification. The Contractor shall furnish all labor, equipment, and materials necessary for the disinfection of the new pipe lines, which shall be disinfected before being tested and placed in service. The lines shall be disinfected by the application of a chlorinating agent

9 The chlorinating agent may be liquid chlorine (AWWA B301) or a hypochlorite solution (AWWA B300), which shall be fed into the lines through a suitable solution feed device or other methods approved by the Engineer. Water from the existing distribution system or other approved source of supply shall be made to flow at a constant, measured rate into the newly laid water main. In the absence of a meter, the rate may be approximated by methods such as placing a Pitot gauge in the discharge, measuring the time to fill a container of known volume or measuring the trajectory of the discharge and using the formula shown in Figure 1 of AWWA C651. At a point not more than 10 ft downstream from the beginning of the new main, water entering the new main shall receive a dose of chlorine fed at a constant rate such that the water will have not less than 25mg/L free chlorine. To assure that this concentration is provided, measure the chlorine concentration at regular intervals in accordance with the procedures described in the current edition of Standard Methods for the Examination of Water or Wastewater or AWWA Manual M12. Table 1 Chlorine Required to Produce 25-mg/L Concentration in 100 ft of Pipe -- by Diameter Pipe Diameter 100% Chlorine 1% Chlorine Solution Table 1 gives the amount of chlorine required for each 100 ft of pipe of various diameters. Solutions of 1-percent chlorine may be prepared with sodium hypochlorite or calcium hypochlorite. The latter solution requires 1 lb of calcium hypochlorite in 8 gal of water. During the application of chlorine, valves shall be positioned so that the strong chlorine solution in the main being treated will not flow into water mains in active service. Chlorine application shall not cease until the entire main is filled with heavily chlorinated water. The chlorinated water shall be retained in the main for at least 24 hours, during which time all valve and hydrants in the treated section shall be operated to ensure disinfection of the appurtenances. At the end of this 24-hour period, the treated water in all portions of the main shall have a residual of not less than 10 mg/l free chlorine. Direct-feed chlorinators, which operate solely from gas pressure in the chlorine cylinder, shall not be used for application of liquid chlorine. The preferred equipment for applying liquid chlorine is a solution-feed, vacuum-operated chlorinator and a booster pump. The vacuum-operated chlorinator mixes the chlorine gas in solution water; the booster pump injects the chlorine-gas solution into the main to be disinfected. Hypochlorite solutions 202-9

10 may be applied to the water main with a gasoline or electrically powered chemical-feed pump designed for feeding chlorine solutions. Feed lines shall be of such material and strength as to safely withstand the corrosion caused by the concentrated chlorine solutions and the maximum pressures that may be created by the pumps. All connections shall be checked for tightness before the solution is applied to the main. At the end of the retention period, all treated water shall be thoroughly flushed from the lines until the replacement water in the lines shall have a chlorine residual of not more than 1.0 part per million. Where no suitable outlet is available for flushing dead ends, the Contractor shall furnish and install outlet valves of sufficient size to adequately flush the new mains at the locations designated by the Engineer, for which payment shall be made at the unit price bid for the size valve installed. After the lines are disinfected and flushed and tested as specified above, samples of water shall be taken from the mains for bacteriological tests. If the samples fail to meet the Texas Health Department's standard requirements, the disinfection process as outlined above shall be repeated and continued until the tests show results that meet the requirements of the Texas Health Department. F. Hydrostatic Test The Contractor shall provide all necessary equipment and shall perform all work required in connection with the tests. All pipe shall be tested after installation by hydrostatic pressure of 150 psi, for a period of 4 hours. The system shall be tested in sections between valves. The length of test sections shall not exceed 2,000 feet unless authorized by the Engineer. Each section tested shall be slowly filled with water, care being taken to expel all air from the pipes. If necessary, the pipes shall be tapped at high points to vent the air. Water lost shall be measured by a meter furnished by the City of Odessa. The pipe installation shall be accepted if the leakage for 4 hours is less than determined by the following formula: allowable leakage (gal/1000 ft.) = (nominal diameter of pipe [in] ) X (0.367) Sections failing to meet this test will be rejected and will not be accepted until they have met the above requirements. Upon completion of all disinfection and testing, the Contractor shall provide personnel to open all valves and operate all hydrants, as directed, in the presence of a representative of the Engineer

11 G. Water Service Connections Contractor shall install water service connections at the locations noted on the plans according to typical water service connection detail CLEANUP Cleanup shall be in accordance with Item 100 of these specifications BASIS OF PAYMENT AND MEASUREMENT A. Concrete Cylinder Pipe Concrete cylinder pipe shall be measured and paid for by the linear foot, as indicated on the proposal. Such measurement shall be along the central axis through all valves and fittings from end of line to end of line. Measurement of the spur or connecting pipe shall be made from the point of intersection of the central axis. B. Concrete Cylinder Fittings No separate payment will be made for concrete cylinder fittings. Cost of furnishing and installing concrete cylinder fittings shall be included in the unit price bid for concrete cylinder pipe. C. Water Main Taps Payment for water main taps shall be made at the contract unit prices bid for each, according to size. Payment for water main taps shall be full compensation for all work and materials involved in tapping into existing water mains without interrupting water service. D. Wet Connections Payment for wet connections will be made at the contract unit prices bid for each according to size. Payment for wet connections will be full compensation for all work and materials involved in cutting or connecting to existing water mains by interrupting water service. E. Butterfly and Gate Valves Payment for valves will be made at the contract unit prices bid for each individual valve of each size, which payment shall be full compensation for furnishing and transporting the valves; excavation and backfilling; concrete bedding; placing and jointing; and for all other items of material, labor, equipment, tools, and incidentals necessary to complete the valve installation in accordance with the plans and specifications

12 F. Fire Hydrants Payment for fire hydrants will be made at the contract price bid for each individual fire hydrant of each size as shown in the proposal, such payment shall be full compensation for furnishing and transporting hydrants; excavation, porous backfill and backfilling; concrete bedding; placing and jointing; and for all items of material, labor, equipment, tools and incidentals necessary to complete the hydrants in accordance with the plans and specifications. G. Water Service Connections Payment for service taps shall be made at the contract price bid for each according to size. Payment shall be full compensation for furnishing meter boxes, curb stops, corporation stops and the necessary copper tubing to connect the curb stop with the corporation stop, excavation, tools, and incidentals necessary to complete the items in accordance with the plans and specifications