All work done shall be inspected and approved by the engineer-inspector authorized by the Select Board, herein called the "Engineer," acting within the authority and with the approval of the Select Board and the DPW Director of the Town of Merrimac. The Engineer shall determine the quality and acceptability of the work and materials. Study and consultant fees are the responsibility of the developer.
[HISTORY: Adopted by the Town Meeting of the Town of Merrimac as Appendix B of the 2016 General Bylaws. Amendments noted where applicable.]
The work shall conform to plans approved by the Water Department for the work involved, and to the requirements of these specifications.
The contractor shall take all responsibility of the work and shall take all precautions for preventing injuries to persons and property in or about the work. They shall keep themselves fully informed of all laws, ordinances and regulations in any manner affecting those engaged or employed in the work, or the materials used in the work or in any way affecting the conduct of the work and shall comply with all such existing and future laws, ordinances, regulations, orders and decrees. The contractor shall take full responsibility for the safety and quality of the work and for the sufficiency of the methods employed in its prosecution. They shall provide and install such equipment and plant and shall use such methods and appliances for the performance of all the operations connected with the work to be done as will secure a satisfactory quality of work.
All materials, fixtures, fittings and supplies shall be of standard, first-grade quality and of the best workmanship and design. Where the characteristics of any materials are not particularly specified, such approved materials shall be used as is customary in first-class work of the nature for which the material is employed. No inferior or low-grade articles will be either approved or accepted, and all work of assembly and construction must be done in a neat, first-class and workmanlike manner.
Inspection of the work shall not relieve the contractor from any of their obligations to perform the work as specified, and not withstanding that such work or materials may have been previously overlooked by the Engineer. If the work or any part thereof shall be found defective at any time before the final acceptance of the whole work, the contractor shall make good such defect in a manner satisfactory to the Engineer, and if any material brought upon the ground for use in the work or selected therefor shall be condemned by the Engineer as unsuitable or not in conformity with the specifications, the contractor shall immediately move such material from the vicinity of the work. The contractor shall employ only competent and skillful persons to do the work.
All lines and grades shall be subject to check by the Engineer, and the contractor shall provide such material and give such assistance as may be required, and the marks so given shall be carefully preserved.
Sanitary conveniences, properly screened from public observation, for the use of all persons employed on the work shall be provided and maintained by the contractor.
A.
Trenches shall be excavated to sufficient depth to provide four-and-one-half-foot cover and to such widths as will give ample room for laying and inspection of the work. At pipe joints, additional width and depth shall be excavated to properly make the joints.
B.
All the excavation shall be done by open cut from the surface, except as may be otherwise expressly permitted or ordered by the Engineer, or as otherwise stipulated in this contract. Bottom of trenches in earth shall be excavated reasonably flat and the trench shall be excavated at the pipe bells to allow the pipe barrel to rest on the prepared trench bottom. Pipe shall not be placed on blocking to allow clearance for pipe bells without specific approval of the Water Department of the methods to be used in compaction of the backfill under and around the water main. Excavation in excess of this amount shall be refilled by suitable material properly place to the satisfaction of the Engineer.
C.
All pipes and structures are to be laid on good foundation of sufficient stability to prevent settlement. If the material forming the bottom at the grade of pipe is not suitable for foundation, a further depth or width shall be excavated and the space filled with other material, as hereinafter specified.
D.
Where rock is encountered, it shall be removed to a depth of six inches below the bottom of the pipe or fitting and to such widths as will give clearance of at least nine inches on each side of the pipe or fitting.
F.
The contractor shall provide pumps and equipment of adequate capacity and type to exclude or remove from the excavation the water which may be encountered and in such manner as not to interfere with the progress of the work or to cause damage to adjacent property.
G.
All existing gas pipes, conduits, water pipes, sewers, drains or other structures which are uncovered by the excavation and which do not, in the opinion of the Engineer, require to be changed in location shall be carefully supported and protected from injury by the contractor; and if injured or removed, they shall be restored by them.
A.
The trenches and other excavations shall be backfilled unless otherwise directed by the Engineer as soon as the laying of the pipe or the completion of other structures will permit. In all backfilling, selected materials shall be placed adjacent to the pipe or other structure, and if necessary, excavated material shall be moved from one trench to another in order to provide suitable material for backfilling. The space between the pipe and the bottom and sides of trench shall be filled with selected earth thoroughly tamped by light tampers as placed and brought up evenly on both sides of the trench to a point not less than 18 inches above the top of the pipe, in layers not exceeding six inches in thickness, thoroughly consolidated in such a manner as will bring no unbalanced pressure on the work. No mud or similar material, and no rock, shall be placed within 18 inches of the top of the pipe. The remainder of the trench above an elevation of 18 inches higher than the top of the pipes shall be backfilled with approved material, thoroughly tamped with mechanical rammers, in layers not exceeding one foot in depth. No rock will be permitted in backfilling until there is at least two feet of suitable earth fill over the main, and no rock fragment weighing more than 100 pounds will be used for refilling trenches.
B.
When, in the opinion of the Engineer, the backfilling of elevations higher than one foot above top of pipe can be compacted in a suitable manner by flooding, jetting or puddling with water, the contractor will be permitted to do so.
C.
In existing public ways, the top 18 inches of backfill shall be bank gravel suitable for road base placed and compacted during the backfilling operation and treated with calcium chloride to maintain the surface until resurfacing is placed.
A.
All pipe for water mains shall be ductile iron. Ductile iron pipe shall meet the requirements of ANSI/AWWA C151/A21.51-81 or latest revisions thereto. Pipe joint shall be push-on type, meeting ANSI/AWWA C111/A21.11-80 or latest revision thereto.
B.
Thickness class for ductile iron pipe shall be Class 52 (0.33 inches) for eight-inch pipe and (0.31 inches) for six-inch pipe.
C.
Thickness class for other pipe sizes shall be as determined by the Select Board.
D.
Compact fittings shall be mechanical joint, all bell, ductile iron, minimum pressure rating of 350 psi, meeting the requirements, of ANSI/AWWA C153/A21.53-84 or latest revision thereto, including gland, rubber ring, bolts and nuts.
E.
All pipe and fittings are tar-coated and cement-lined, 1/8 minimum thickness and meeting the requirements of ANSI/AWWA C104/A21.4-85 or latest revision thereto.
F.
The contractor shall be responsible for the handling and storage of all pipe and accessories. Material shall be handled so as to avoid damage. The interior of pipe and fittings shall be kept free from dirt and other foreign matter and protected from possible damage by freezing of trapped water.
G.
Retainer glands for hydrant branches shall be cast of high-strength ductile iron filled with cup-point, square-head, double-heat-treated, steel-set screws, six of each for six-inch gland and tightened to 75 foot-pounds torque.
H.
Tapping sleeves and valves shall be designed for installation under pressure without interrupting service, manufactured in two sections for easy installation and with closely spaced bolts located close to the side gaskets to ensure a watertight joint and provide reinforcement of the main. Sleeve joints shall be mechanical and branch flange shall be female-faced to accommodate the raised male face of the tapping gate.
I.
Gate valves for tapping sleeve shall be flange-mechanical joint, resilient seal, iron body, bronze-mounted, double disk, open left, designed for 200 pounds' working pressure and shall meet AWWA specifications.
J.
Valves shall be Mueller® Co., A2360-20 series, resilient wedge gate valves, with sealed and enclosed AWWA operators with two-inch square nut, open left. Valves shall be mechanical-joint type. Valve shaft shall be solid steel extending in one piece through the entire valve body and operator, hexagonal in cross section. Valve disc shall be machined to fit the hexagonal shaft without the use of locking pins or keys to maintain alignment. Valve body shall be provided with a machined stainless steel seat; valve disc shall have vulcanized rubber seat. Valves shall be bubble-tight under all pressure conditions up to 150 psi.
K.
Valve boxes shall be cast iron, five-and-one-fourth-inch diameter, two-piece sliding type, with lid marked "Water."
L.
Hydrants shall be mechanical-joint type, with two-and-one-half-inch nozzle and one pumper connection, with a five-and-one-fourth-inch valve opening. Hydrant shall conform to ANSI/AWWA C502-85, or latest revision, designed for 150 psi, working pressure, dry-bonnet type, with breakable flange and compression type main valve. Hydrant shall be Mueller Co., Centurion 250, A423.
A.
All pipe and fittings shall be laid in accordance with best waterworks practice and the applicable requirements of ANSI/AWWA C600-82, or latest revision thereto. Pipe shall be laid true to line and grade as given by the Engineer, and properly supported and braced and backfill thoroughly tamped around and under the pipe and fittings to provide proper support.
B.
All pipe fitting, valves, hydrants and accessories shall be carefully lowered into the trench by means of derrick, ropes, or other suitable equipment in such manner as to prevent damage to pipe and fittings. Under no circumstances shall pipe or accessories be dropped or dumped into the trench. The pipe and accessories shall be inspected for defects prior to lowering into trench. Any defective, damaged or unsound pipe shall be replaced. All foreign matter or dirt shall be removed from the interior or pipe before lowering into position in the trench. Pipe shall be kept clean by means approved by the Engineer during and after laying.
C.
Fittings shall be carefully aligned and supported and shall be braced as required by the Engineer. Mechanical joints shall be assembled in accordance with manufacturer's recommendations and shall be thoroughly wire-brushed before assembly to remove loose rust or foreign matter and end of pipe, bell socket, and gasket brushed with soapy water just prior to assembly. Glands shall be brought up evenly and bolts tightened with torque measuring or indicating wrenches for 75 foot-pounds torque or otherwise recommended by the manufacturer. Pipe shall not be deflected either vertically or horizontally in excess of that recommended by the manufacturer, and only with the approval of the Engineer. When pipe laying is not in progress, the open end of pipes shall be closed by approved means to prevent the entry of dirt or trench water into the line. No pipe shall be laid in water or on frozen trench bottom or when, in the opinion of the Engineer, the trench conditions or the weather are unsuitable for such work.
D.
Where pipe cutting is required, it shall be carefully and accurately accomplished, leaving a smooth, clean cut. Particular care must be exercised to prevent damage to the cement lining.
E.
Hydrants shall be placed at the beginning of every project and spaced at intervals of 500 feet.
F.
Hydrant branches shall be securely anchored to the water main using anchor-type mechanical joint glands, retainer glands, or tie rods.
G.
Hydrants and valves shall be set plumb and secure with gate stems vertical and boxes centered to provide for ready application of gate wrench. Hydrants and valves shall be provided with concrete blocking, stone bed, supports and retainer glands as shown on contract drawings or as directed by Engineer. Care shall be taken when placing concrete thrust block behind hydrant to keep drip clear and free to drain.
H.
Bends, tees, valves and hydrants and other fittings shall be provided with reaction or thrust blocking by concrete placed between solid ground and the fittings to be anchored and a retainer gland. Concrete shall be 1:2 to 1/2:5 mix.
I.
After the pipe has been laid, all pipe shall be subjected to hydrostatic pressure 50% above normal operating pressure but not exceeding 50 pounds more than the rated working pressure of the pipe. The normal operating pressure shall be defined by the Engineer. Test shall be made only after completion of partial or complete backfill as specified, and not until at least 36 hours after the first concrete thrust or reaction backing has been cast with high-early strength, or at least seven days after the last concrete thrust or reaction backing has been cast with standard cement.
J.
The duration of each pressure test shall be 30 minutes unless otherwise directed by the Engineer.
K.
Each section of pipeline shall be slowly filled with water, and the specified test pressure, measured at the point of lowest elevation, shall be applied by means of a pump connected to the pipe in a manner satisfactory to the Engineer.
L.
The pump, pipe connection, and all necessary apparatus except gauges shall be furnished by the contractor.
M.
During the filling of the pipe and before applying the specified test pressure, all air shall be expelled from the pipeline. To accomplish this, taps shall be made, if necessary, at point of highest elevation, and after completion of the test, the taps shall be tightly plugged unless otherwise specified.
N.
During the test, all exposed fittings, valves, and hydrants will be carefully examined. If found to be cracked or defective, they shall be removed and replaced by the contractor with sound material in the manner prescribed. The test shall then be repeated until satisfactory to the Engineer.
O.
No pipe installation will be accepted until the leakage for the section of line tested is less than 12 gallons per 24 hours per mile per inch diameter of pipe, at a pressure of 150 psi.
P.
See ANSI/AWWA C600-82 Section 4, Hydrostatic Testing, for allowable leakage at different test pressures.
Q.
Should any test of a section of pipe line disclose joint leakage greater than permitted, the contractor shall at their own expense locate and repair the defective joints until the leakage is within the permitted allowance.
R.
After completion of tests, the pipelines shall be disinfected by application of chlorine either as calcium hypochlorite or liquid sodium hypochlorite in an amount to produce a solution of 50 ppm for a contact period of 24 hours and afterward flushed until the chlorine residual is reduced to less that 1.5 ppm. Chlorine dosage shall be applied by pumping into the line to be treated a sufficient amount of chlorine in solution, which, when mixed with the water in the pipeline, will meet the required concentration.
S.
The mixture shall be pumped through the section being treated and shall be discharged and monitored at a point farthest from the point of introduction of the chlorine. When the solution reaches the required concentration of 50 ppm, the pump and discharge valve shall be closed and the liquid left in the section being chlorinated for 24 hours.
T.
The contractor shall furnish all materials and equipment for the sterilization of the mains, but the Water Department will furnish necessary assistance in flushing, operation of gate valves and the water for flushing and testing.
In public ways, contractor shall resurface all trenches and other excavation as herein specified. In general, the work shall be done in cooperation with and according to directions of the Highway Department acting through the Engineer. In general, the following specifications shall apply; however, the Select Board may modify these requirements to meet special conditions of State Highway Permits or to suit particular locations:
A.
After consolidation and settlement of the trench, temporary resurfacing shall be placed in one course to a compacted thickness of 1 1/2 inches using Type I bituminous concrete rolled to a smooth surface even with the existing road grade with a slight crown across the trench. This surface shall be maintained by the contractor until the placing of permanent resurfacing.
B.
After final settlement and a winter season have passed, the trenches shall be permanently resurfaced, as specified. Any temporary resurfacing shall be removed and the gravel base trimmed to provide for the permanent resurfacing and the edges cut to straight lines and sharp edges and traffic kept off until resurfacing is placed. Cut edge of existing pavement shall be coated with an oil emulsion primer.
C.
Type I bituminous concrete shall be placed to a total compacted thickness of 2 1/2 inches, consisting of a base course of 1 1/2 inches and a surface course of one inch. The base course shall be binder material with coarse aggregate and placed to a depth of 1 1/2 inches after compaction and carefully rolled to grade. The surface course shall have peastone aggregate carefully placed and raked and rolled to conform to existing road surface with a slight crown across the trench to avoid pockets or depressions and with a thickness after compaction of one inch. Roller weight for finish course shall approximate 1.5 tons per foot width of roller. After placing and rolling bituminous concrete, the joint between the new and old pavement shall be sealed with a primer coat of bitumen and fine sand applied three inches each side of joint.
D.
Existing grass lawn areas cut by trenches or in other location as directed by the Engineer shall be replaced by a six-inch layer of suitable loam rake and rolled to grade, fertilized with Scotts® Turf Builder® or equal, applied at the rate of 1/10 pound per square yard and seeded with Scotts® lawn seed, special purpose blend, or approved equal, applied at the rate of 1/10 pound per square yard; sods may be cut and replaced.