ITEM 638 WATER MAINS AND SERVICE BRANCHES
638.05 Pipe Bedding
638.06 Pipe Laying
638.07 Pipe Joints
638.09 Hydrostatic Tests
638.10 Disinfection of Completed Water Work
638.11 Steel Pipe Encasement
638.12 Polyethylene Encasement
638.13 Valves and Equipment
638.14 Fire Hydrant
638.15 Fire Hydrant Adjusted
638.16 Service Branches
638.17 Meter and Chamber Removed and Reset
638.18 Valve Box and Service Box Adjusted to Grade
638.19 Method of Measurement
638.20 Basis of Payment
638.01 Description. This work consists of constructing water mains and service branches, including fire hydrants, water meters, corporation stops, service boxes, service stops, valves, fittings, and valve boxes, and includes:
A. Excavation for items and preparation of the foundations, necessary for placing water mains and service branches, including fire hydrants, water meters, corporation stops, service boxes, service stops, valves, fittings, and valve boxes.
B. Furnishing and placing bedding and backfill.
C. Constructing and subsequently removing all necessary cofferdams, bracing, cribs and sheeting.
D. Pumping and dewatering.
E. Providing all joints as shown on the plans.
F. Furnishing and installing all necessary bends and branches.
G. Furnishing and installing all necessary tracer tape.
H. Joining to existing and proposed appurtenances as required in the project plans.
I. Performing all necessary test (leakage test, disinfections, hydrostatic).
J. Restoration of disturbed underground facilities.
K. Constructing all required blocking and wedging and/or thrust blocking.
L. Furnishing and installing all necessary restraining of joints and fittings.
M. Cutting and plugging as required existing water mains to be abandoned.
Pipe, joints, and fittings.
Ductile iron pipe, joints, and fittings........................ 748.01
Polyvinyl chloride (PVC) pipe,
.... joints, and fittings................................................ 748.02
Polyethylene (PE) service
.... branches and fittings........................................... 748.03
Copper service branches and fittings....................... 748.05
Steel pipe encasement.............................................. 748.06
Polyethylene encasement......................................... 748.07
Valves and equipment.
Gate valve and valve box......................................... 748.08
Inserting valve and valve box.................................. 748.09
Cutting-in sleeve, valve and valve box..................... 748.10
Tapping sleeve, valve and valve box........................ 748.11
Tapping saddle and corporation stop....................... 748.12
Service stop and service box.................................... 748.13
Meter, setting, stop and chamber............................. 748.14
Fire hydrant............................................................. 748.15
Granular Material..................................................... 605.02
Pipe bedding ....................................................... 611.02 H
Soil and granular embankment................................. 203.02
Structural backfill, Types 1, 2, and 3....................... 703.11
The Engineer will allow Type 3 structural backfill, conforming to 703.11, to be used as bedding below the pipe only when pumping operations do not control severe ground water problems. Place at least 12 inches (300 mm) of Type 1 structural backfill on top of the Type 3 structural backfill to prevent piping.
The metric equivalent pipe size may vary with material type for the same English size pipe.
A. The dates scheduled for testing and for disinfections of mains and branches.
B. Any clearances less than 1 foot (0.3 m) between new mains and existing pipes, sewers, and structures.
638.04 Excavation. Excavate according to Item 611 with the following additions:
A. Excavate the trench a suitable distance in advance of pipe laying to ensure proper clearance between the waterline and any utility crossing or underground structure. Suitably brace and support utilities and structures.
B. Excavate the trench walls vertically up to the top of the pipe. Ensure that the clearance on either side of a pipe is a minimum of 6 inches (150 mm) and a maximum of 12 inches (300 mm). In paved areas, neatly line cut the pavement at the surface a distance of at least 12 inches (300 mm) beyond the trench side and remove paving material.
C. Furnish cover over pipes of 5 feet (1.5 m) unless otherwise shown on the plans.
D. Pile excavated material in a manner that will not endanger the work or obstruct sidewalks and driveways. Keep gutters clear or make other satisfactory provisions for drainage. Do not obstruct natural water-courses.
E. Furnish holes for pipe bells at each joint, but make them no longer than necessary for joint assembly and assurance that the pipe barrel will be flat on the trench bottom.
F. Furnish, place, and maintain such sheeting and bracing as may be required. Immediately backfill and compact voids appearing outside of sheeting. Notify the maintaining agency of sheeting and bracing left in place. Do not remove sheeting and bracing until sufficient backfill has been placed to provide ample support to the sides of the excavation. When sheeting is left in place, cut it off at least 2 feet (0.6 m) below the proposed finished surface or subgrade in paved areas. The Department will pay for sheeting and bracing it orders to be left in place as a separate item of the work.
638.05 Pipe Bedding. Where specified, provide structural backfill for bedding according to Item 611 except the bedding is 4 inches (100 mm) thick.
B. Trench Dewatering. Where water is encountered in the trench, remove it during pipe-laying operations and maintain the trench water free until the ends of the pipe are sealed and provisions are made to prevent floating of the pipe. Do not allow trench water or other deleterious materials to enter the pipe at any time.
D. Existing Systems. Do not operate any valve or other control on the existing system. The maintaining agency will operate all valves, hydrants, air valves, and service stops.
E. Pipe Handling. Handle pipe in a manner that will prevent damage to the pipe, pipe lining, or coating. Load, unload, and place pipe and fittings using hoists and slings in a manner that will avoid shock or damage. Do not drop, skid, or roll pipe or fittings against other pipe.
F. Pipe Cutting. Whenever it becomes necessary to cut a length of pipe, make the pipe ends square with the longitudinal axis of the pipe and otherwise smooth so that good connections can be made. Cut pipe using cutters recommended by the manufacturer. Do not cut ductile iron pipe with an oxyacetylene torch. File or grind field-cut pipe lengths to obtain a chamfer on the outside of the pipe, according to the manufacturer’s recommendations. Remove rough or sharp edges from the cut end.
G. Pipe Laying. Ensure that pipe and fittings are clean when laid. Take precautions to prevent floating. Place the pipe on the trench bottom or bedding. After the pipe has been aligned and jointed, and thrust blocking has been placed, secure the pipe in place with approved backfill material. At times when pipe laying is not in progress, close the open ends of the pipe with a watertight plug.
H. Pipe Laying on Curves. If the pipe is shown curved on the plans, construct the curves by special fittings or by deflecting the joints according to the manufacturer’s recommendations. Do not make joint deflections at valves.
When rubber-gasketed pipe is laid on a curve, joint the pipe in a straight alignment and then deflect it to the curved alignment. Make trenches wider on curves for this purpose.
I. Pipe Laying Where Earth Grading is Necessary. Where a pipe is to be placed within an embankment or the top of the pipe is above the existing ground, construct the embankment to at least 6 inches (150 mm) above the top of the pipe before trenching for the pipe. Excavate the trench to the minimum width necessary for the proper placing and backfilling of the pipe.
J. Tracer Tape. Install tracer tape over copper and non-metallic water lines, including service lines. Place the tracer tape approximately 1 foot (0.3 m) above the top of the line and extend the tape for the line’s full length. Use tracer tape that is a detectable type and is marked “WATER.”
K. Blocking and Wedging. Lay fire hydrants, valves, and fittings on hardwood blocks and hold them in position by hardwood wedges. Bed blocks firmly in the bottom of the trench with uniform bearing and with the long dimension of the block perpendicular to the pipe barrel. Ensure that the blocks are level across the trench and that the proper number of blocks are placed one upon the other to bring the fittings to the required grade for jointing.
L. Thrust Blocking. Furnish plugs, caps, tees, hydrants, and elbows or bends having a deflection of 11 1/4 degrees or greater with concrete thrust blocking, unless suitably restrained joints are provided. Construct the thrust blocking by placing concrete Class QC-Misc between firm original undisturbed earth and the fitting to be anchored. Place and shape the thrust blocking in a manner satisfactory to the Engineer with the thrust force contained by the blocking. Place the hardwood blocks between the plugs, caps, and hydrants, and the thrust blocking. Place the thrust blocking so that it allows for pipe and joint accessibility or repair.
M. Restrained Joints and Fittings. Where conditions at an elbow, tee, or bulkhead are not conducive to the use of thrust blocking, restrain push-on or mechanical joints and fittings by bent or straight tie-rods, straps, clamps, or other devices, with required hardware. Protect the devices against corrosion by the application of an asphalt coating. Restrain mechanical joints by a wedge action type joint restraint with twist-off nuts. If polyethylene encasement is specified, ensure that the encasement covers the entire assembly. The Contractor may use restraining devices instead of thrust blocking when approved by the Engineer.
638.07 Pipe Joints. Furnish ductile iron pipe and cast iron or ductile iron fittings with push-on joints, mechanical joints, boltless-restrained joints, or ball-and-socket joints. Furnish joints with all accessories and install them according to the manufacturer’s recommendations. During any construction where the outside temperature is below 40 °F (4 °C), keep rubber gaskets and lubricants in a heated area to at least 40 °F (4 °C) until used. Maintain gaskets in a flexible condition until placed in the bell or on the spigot of the pipe.
638.08 Backfilling. Complete backfill from the pipe grade to the finished grade, or to the subgrade surface in paved areas. Furnish and compact backfill material for water mains and appurtenances under pavements in the same manner as for 611 non-plastic Type B conduits. Furnish and compact backfill material for water mains and appurtenances not under pavements in the same manner as for 611 non-plastic Type C conduits.
If hydrostatic testing is performed before the backfilling operation is completed, complete the portion of the backfill from pipe grade to the centerline of the pipe, fittings, or appurtenances and place sufficient backfill material over the pipe barrel between joints to prevent movement.
Place sand cushions at least 12 inches (0.3 m) thick between the pipe and existing pipelines or other conduits when encountered during construction and as directed by the Engineer.
Immediately after completion of the backfilling, restore the site according to Item 611.
638.09 Hydrostatic Tests. Apply a hydrostatic test to the whole system or to all individual valved-off sections of the mains where work has been performed. Perform the hydrostatic tests according to of AWWA, except make the test pressure greater than 150 pounds per square inch (1000 kPa). Ensure that the quantity of water lost from the main does not exceed the number of gallons (liters) per hour as determined by in AWWA or by the following formula:
L = allowable leakage, in gallons (L) per hour
N = number of joints in the length of pipe tested.
D = nominal diameter of the pipe, in inches (mm)
P = average test pressure during the leakage test, in pounds per square inch (kPa)
638.10 Disinfection of Completed Water Work. After passing the hydrostatic testing, disinfect the completed water work according to AWWA.
Make all necessary taps and furnish all equipment and labor required for the disinfections. Obtain the Engineer’s approval of the time and the section of line to be disinfected.
Make any necessary excavation to install the steel casing. Obtain the Engineer’s approval for the method of any boring or jacking operation. If placing the steel casing in an open cut trench, place it according to 638.05 and 638.08.
Join the casing pipe together with a full-circumference weld conforming to 513.21.
Ensure that the inside diameter of the casing allows the water main to be removed without disturbing the casing or roadbed. Ensure that the inside diameter of the casing is at least 2 inches (50 mm) greater than the largest outside diameter of the water main joints or couplings for carrier pipe that is less than 6 inches (150 mm). Ensure that the inside diameter is at least 4 inches (100 mm) greater than the largest outside diameter for carrier pipe 6 inches (150 mm) in diameter and over.
Install the main in the casing on hardwood blocking or stainless steel chocks designed to remain fixed in position. The Contractor may install polyvinyl chloride water main using casing insulators. Close both ends of the casing with mortared 4-inch (100 mm) bricks or a concrete bulkhead.
638.13 Valves and Equipment. Upon delivery at the work site, open valves to prevent the collection of water in the valve. Clean the interiors of valves of all foreign matter, and inspect them in both the open and closed position before installation.
Install valve boxes on all buried valves. Center the valve box and set it in a vertical position directly over the valve nut in such a manner that the box does not transmit shock or stress to the valve. Set the base of the valve box first, and support it with a minimum backfill, hardwood blocks, or a Styrofoam collar at least 2 inches (50 mm) in thickness. Do not allow the base to rest directly on the valve or main. Use valve boxes that are two or three piece boxes with covers. When necessary, furnish extension sections. Carefully tamp backfill around the valve box to a distance of 3 feet (1 m) on all sides or to the undisturbed face of the trench if closer. Set the valve box cover flush with the ground line or finished paved surface.
A. Gate Valve and Valve Box. Install gate valves directly in new mains or by means of a cutting-in sleeve in existing mains where maintenance of a continuous supply of water is not mandatory. Where it is mandatory not to interrupt the water supply, the Contractor may provide a branch to an existing main with a gate valve installed by means of a tapping sleeve.
Assemble the sleeve around the existing main through which water is flowing under pressure. Bolt the equipment to the sleeve, drill a hole through the existing main walls, and insert the valve, according to the manufacturer’s recommendations.
C. Cutting-In Sleeve, Valve, and Valve Box. Use cutting-in sleeves to install a gate valve in an existing main, without breaking pipe joints, where it is permissible to interrupt the flow for a short period of time. Install the valve by cutting an exact length of pipe from the existing main according to the manufacturer’s recommendation.
E. Tapping Saddle and Corporation Stop. Use corporation stops to provide individual service connections to mains. Ensure that the stops permit a shut-off of the service flow. Either assemble the stops directly to mains by means of a tap tool providing a tapped hole, or use a tapping saddle. Fasten the saddle around the main and drill a hole into the main by an attached drilling machine, then remove the machine and screw the stop into the saddle. Do not use corporation stops larger than 2 inches (51 mm) in size and locate them approximately 60 degrees from the top of the main.
F. Service Stop and Service Box. Install service stops in service lines to allow the shutting-off of individual services. Locate the stop beyond the pavement and provide it with a service box centered vertically over the stop operating nut such that the box provides maximum protection for the stop.
G. Meter, Setting, Stop, and Chamber. This pay item is for meters that are to be installed in frost-proof chambers. Set the chamber on hardwood blocks. The maintaining agency shall furnish meters unless otherwise indicated by the plans. Do not transmit shock or stress to the meter body.
638.14 Fire Hydrant. The item includes excavation and furnishing and installing a new fire hydrant complete with proper jointing, blocking, and backfilling as outlined below and all other incidental work necessary to complete this item of work. The Department will pay for all hydrant branches, gate valves, and valve boxes required to perform the work separately.
B. Setting Fire Hydrants. Provide a 3-foot (1 m) minimum radius unobstructed area around all hydrants. Set the sidewalk flange 2 inches (50 mm) above finished grade. Set hydrants on hardwood blocks according to 638.06.K. Provide thrust blocking according to 638.06.L.
C. Fire Hydrant Connections. Construct hydrant branches using a section of ductile iron pipe from the main to the hydrant, and include a gate valve and valve box set vertically and placed in the line as indicated. Locate the valve a minimum of 3 feet (1 m) from the hydrant streamer connection.
638.15 Fire Hydrant Adjusted. This item includes installing fire hydrants as described below complete with proper jointing, blocking, backfilling as outlined and all other incidental work necessary to complete this item of work. The Department will pay for all hydrant branches, gate valves, and valve boxes required to perform the work separately.
A. Fire Hydrant Extended or Adjusted to Grade. Where existing hydrants are to be adjusted to conform to new street alignment and grade, relocate the hydrant without disturbing the location of the hydrant lateral tee at the main.
Before excavating, close valves on hydrant branches to be cut. Where the distance of the center of the existing hydrant to the center of the gate valve on the hydrant branch is less than 4 feet (1.2 m), extend the trench to the hydrant branch valve to permit removal of the pipe. Adequately support the hydrant before being disconnected. Extend the hydrant branch with new pipe of the same size as the existing pipe. Thoroughly clean the removed hydrant of dirt, reset it, and connect it to the extended branch. Provide drainage pits and thrust blocking according to 638.14.A, and 638.06.L.
B. Fire Hydrant Removed and Reset. Where existing hydrants are indicated for removal, provide adequate support for the hydrant before disconnecting it and resetting it in the new location. Cap the existing branch line, and install adequate thrust blocking to brace the cap according to 638.06.L, unless the line is to be abandoned. Construct a new main tee, a new pipe branch, a new gate valve with valve box, with thrust blocking, and a drainage pit for the reset hydrant items. Adjust the valve box to the finished surface at the new location by raising or lowering the top portion and furnishing an extension section if needed.
C. Fire Hydrant and Gate Valve Removed and Reset. Conform to 638.15.B, except remove and reinstall the gate valve and valve box. Furnish a new tee and new pipe branch using the existing valve and box.
D. Fire Hydrant Removed and Disposed Of. Remove and dispose of fire hydrants designated for removal. Cap the existing line and place thrust blocking according to 638.06.L, unless the line is to be abandoned.
638.16 Service Branches. Furnish and install service branches, either pipe or tubing and fittings, as necessary, or as shown on the plans including the removal of the existing service branches or service boxes, as required according to the following situations. Tapping saddles, corporation stops, service stops, and service boxes, if required, are separate from this item:
A. Where a service branch is disturbed for lowering, raising, or relocation between the water main at the corporation stop and the service stop, replace it with new materials within these limits unless the connections can be made outside the limits of the proposed pavement, paved shoulder, or curb.
B. Where a service branch is disturbed for lowering, raising, extending, or shortening on the property side of the service stop, replace it with new materials from the existing service stop to the proposed service stop. However, if the existing service branch encountered is found to be lead or galvanized pipe, replace it from the corporation stop to the service stop with new material.
638.17 Meter and Chamber Removed and Reset. Remove and reset existing water meters and chambers as specified in 638.13.G. Remove existing chambers. Disconnect existing meters, and replace them with suitable connections if necessary. Reconnect the meters at new locations.
Excavate around the valve box or service box to permit the raising or lowering of the valve box or service box. The Contractor may adjust any screw-type boxes without the use of extensions provided that ample thread remains on the box to provide adequate rigidity to the box. Provide extension sections for boxes that are not of the screw-type and boxes not having ample thread for rigidity to adjust the top to grade. The Engineer will allow inserts or adapters. Adequately secure new sections of box stem to the existing stems. Backfill the hole after the box has been adjusted to grade.
The Department will measure Steel Pipe Encasement by the number of feet (meters) constructed, including the open cut or boring or jacking operation, encasement pipe, bedding and backfill, blocking to support the internal main, and end bulkheads.
The Department will measure Gate Valve and Valve Box; Inserting Valve and Valve Box; Cutting-In Sleeve, Valve and Valve Box; Tapping Sleeve, Valve and Valve Box; and Meter, Setting, Stop and Chamber separately as a complete item by the number of each.
The Department will measure Fire Hydrant, Fire Hydrant Extended and Adjusted to Grade, Fire Hydrant Adjusted to Grade, Fire Hydrant Removed and Reset, Fire Hydrant and Gate Valve Removed and Reset, and Fire Hydrant Removed and Disposed Of separately by the number of each.