Chapter 402 Sewer Construction Standard Specifications

The developer shall purchase and maintain such comprehensive general liability and other insurance as is appropriate for the work being performed. The specific coverages and limits of liability shall be as required by law. The minimum amount of comprehensive general liability insurance coverage shall be as follows:

Bodily injury:

[1]

$1,000,000 each person.

[2]

$2,000,000 each occurrence.

Property damage:

[1]

$1,000,000 each occurrence.

[2]

$2,000,000 annual aggregate.

Certificates of insurance, which are acceptable to the Board, shall be submitted to the Board prior to the commencement of the work. These certificates shall contain a provision to the effect that coverages afforded under the policies will not be canceled unless at least 30 days prior written notice has been given to the Board.

Record drawings: The developer shall furnish all data, which the Engineer determines is necessary, to prepare record drawings of the completed project for the Board.

Notification: The developer shall be fully responsible for the proper notification of all underground utility locating services and any utilities which may be affected by the work.

Grades and layout: All roads and easements, through which any sewer or appurtenances are to be constructed, shall be at the proposed subgrade elevation before the sewer construction begins. The developer shall be responsible for and shall furnish all engineering design, field layout, grades and supervision, which is necessary for the project.

Testing: The developer shall conduct all tests which are required by these specifications and which may be required by the Engineer. All tests shall be conducted in the presence of the Engineer and at such time as is acceptable to the Engineer. The developer shall also provide all manpower which is necessary to assist the Engineer in any visual inspections or tests which the Engineer may perform.

Supervision by developer: The developer will supervise and direct all the work on the project, including the work of any contractor employed by the developer. The developer expressly accepts all responsibility for the construction means, methods, techniques, sequences and procedures and for safety precautions and programs. The developer shall employ and maintain a qualified supervisor or superintendent on the project who shall have been designated in writing by the developer as the developer's representative at the site. The supervisor shall have full authority to act on behalf of the developer, and all communications given to the supervisor shall be as binding as if given to the developer. The supervisor shall be present on the site at all times as required to perform adequate supervision and coordination of the work.

Rules and regulations: The developer shall be responsible for complete adherence to the Sewer Use Rules and Regulations of the Board,[2] particularly with regard to the requirements for obtaining all permits and licenses. The developer shall also be responsible for obtaining all other federal, state and local permits, which are required, before the work begins. The developer shall present evidence which is satisfactory to the Board that all permits have been obtained, before the work begins.

[2]

Editor's Note: See Ch. 403, Sewer Use Rules and Regulations.

Tripartite bond agreement: The developer shall be required to execute a tripartate bond agreement with the Board and an escrow agent, which is approved by the Board. The tripartate bond agreement shall secure the performance of the developer's obligation to complete the installation and testing of the sanitary sewers and appurtenances and the restoration of all areas affected by the developer's operations. A copy of a sample of a tripartate bond agreement is attached to these specifications.

Agreement for engineering services: The developer shall be required to execute an agreement for engineering services with the Board and the Engineer. The agreement shall outline the engineering services which will be provided by the Engineer for the Board. These engineering services will generally consist of the review of the developer's project plans for the Board; the observation on behalf of the Board of the construction by the developer of sanitary sewers and appurtenances; and the preparation of record drawings of the completed sanitary sewer and appurtenances for the Board. The developer shall be responsible for payment of the Engineer's fee for performance of these services.

§ 402-2 Excavation and backfill.

Excavation:

General: The developer shall make all excavations in earth and rock necessary or incidental to construct the proposed work as shown on the approved plans. All excavations shall be by open cut, except as otherwise permitted by the Engineer, and shall be of sufficient width to allow for thorough compaction of the refill material and for the inspection of the work.

Sheeting and bracing: The developer shall furnish and place such sheeting and bracing as may be required to properly perform the work. Sheeting and bracing shall be permanently left in place, if requested by the Engineer.

Depth of trench - earth: Bottom of earth trenches shall be excavated four inches below the barrel of the pipe to provide for granular bedding of the pipe, as specified under § 402-3.

Depth and width of trench - rock: The bottom of rock trenches shall be excavated a minimum of six inches below the barrel of the pipe and a minimum of nine inches clear on each side of the pipe.

Blasting: The removal of rock by blasting shall be accomplished by licensed individuals, and the developer shall obtain all necessary permits before the blasting occurs. All handling, storage and use of explosives shall be in accordance with the requirements of MGL c. 148, §§ 10 to 27 inclusive, latest revisions or additions thereto. Where ledge rock is encountered, the developer shall take accurate measurements from the top surface of the ledge to the proposed invert of the pipe. This information shall be recorded and made available to the Engineer.

(6)

Excavation in public ways:

All trench excavation in existing public ways shall be subject to the requirements of the rules and regulations of the Town of Barre Highway Department and the Massachusetts Department of Public Works. The developer shall be responsible for obtaining all street opening permits and licenses which are required.

Excavation in streets having an improved pavement shall be preceded by cutting the existing pavement so that pavement beyond the trench limits will not be disturbed. Before resurfacing, the edges of the pavement shall be inspected and recut if found to be broken or ragged. The developer shall furnish all materials and do all the work necessary to restore the street to its original condition and pavement depth. All work shall be subject to inspection and approval of the Barre Highway Department and the Massachusetts Department of Public Works.

(7)

Unsuitable foundation material: The developer shall remove all material that is determined to be unsuitable foundation material and refill the excavation with bank gravel, screened gravel or concrete, as determined by the Engineer.

(8)

Dewatering: The developer shall dewater the area in which work will be performed to allow the construction to proceed in conformance with these specifications. All water from dewatering operations shall be disposed of by the developer in a manner which is acceptable to the Engineer.

Backfilling:

General: The trenches and other excavations shall be backfilled as soon as possible after completion of the work. No backfilling shall be done until the Engineer has completed his observations.

Materials and placement:

The area below the pipe, and extending to a point six inches above crown of PVC pipe and to the side limits of the trench as excavated, shall be backfilled with screened gravel and compacted. The area below the pipe, and extending to a point half way up the barrel of ductile iron pipe and to the side limits of the trench as excavated, shall be backfilled with screened gravel and compacted.

The remaining volume of the trench above the screened gravel to a point 12 inches below the ground surface shall be backfilled with ordinary borrow, which has been approved by the Engineer. No rock fragment weighing more than 50 pounds will be permitted in the ordinary borrow. The ordinary borrow shall be placed in twelve-inch layers and thoroughly compacted, using mechanical compacting equipment.

The final 12 inches of the trench which is directly beneath the finished grade on paved surfaces shall be backfilled with bank gravel and compacted in six-inch layers, using mechanical compacting equipment.

The developer shall be fully responsible for the proper backfilling and compaction of all trench bedding and refill material. Alternate methods of compaction shall be submitted to the Engineer for approval before the work begins.

(e)

The final 12 inches of the trench which is directly beneath the finished grade on unpaved surfaces shall be backfilled with eight inches of bank gravel and four inches of loam. The bank gravel shall be thoroughly compacted with mechanical compacting equipment. All loam shall be approved by the Engineer. Final restoration of disturbed areas by seeding, sodding, mulching or other method shall be approved by the Engineer.

§ 402-3 Pipe and fittings.

PVC pipe and fittings:

PVC main sewers: Pipe and fittings for main sewer shall be polyvinyl chloride (PVC), which meets the requirements of ASTM-D-3033 or D-3034-77 (latest revision) and which has a pipe diameter to wall thickness ratio (SDR) of 35. Maximum pipe length shall be 13.0 feet, and the elastometric ring, bell and spigot style joint shall meet the requirements of ASTM D3212-76 (latest revision).

PVC lateral sewers: Pipe and fittings for lateral sewers shall be polyvinyl chloride (PVC) meeting the same requirements as the main pipe. Fittings shall be molded, one-piece construction, and a PVC cap, designed for use on a bell end of a pipe, shall be installed on each lateral sewer.

Ductile iron pipe and fittings:

Ductile iron pipe force mains: Force mains shall be constructed using ductile iron pipe and fittings. Ductile iron pipe shall meet the requirements of ANSI A21.51-76 (latest revision), fittings shall meet the requirements of ANSI A21.10-71 (latest revision), and mechanical joints shall meet the requirements of ANSI A21.11 (latest revision).

Ductile iron gravity sewers: In areas where ductile iron gravity sewer pipe is required by regulation or as directed by the Engineer (such as in shallow trenches; when passing through existing drainage structures or manholes; and in proximity to water supplies or recreational areas) the developer shall furnish and install Class 52 ductile iron pipe and fittings. Tees or wyes with mechanical joints shall be furnished and installed for lateral sewers. A mechanical joint plug or cap shall be furnished and installed on the lateral inside the property line to allow air testing of the system.

Pipe laying:

Lines and grades: The developer shall provide all engineering services which may be required to ensure that the pipelines are constructed in accordance with the approved plans and these specifications. Laser beam aligning equipment will be permitted if the developer demonstrates that the equipment and operators can produce the required line and grade of the sewer to be constructed.

Handling and storage:

All pipe shall be handled carefully to avoid injury to persons, other structures, or to the pipe itself. Only equipment or methods approved by the Engineer shall be employed in handling pipe. Pipe or fittings damaged, for whatever reason, shall be removed from the job site immediately.

Care shall be taken to stack and store all PVC pipe properly and in accordance with the pipe manufacturer's recommendations. All PVC pipe shall have a straight barrel. The deflection of the pipe prior to installation shall not exceed 1/16 inch per two-foot length.

Foundation: All pipe shall be laid on a stable foundation to prevent settlement. All material which is determined to be unsuitable by the Engineer shall be removed and replaced with suitable material as described in these specifications.

Bottom of trench and bedding:

In general, the bottom of the trench shall be excavated to a depth of four inches below the bottom of the pipe barrel and a compacted granular bedding placed for pipe laying. The granular bedding shall be washed screened gravel or crushed stone, ranging in size from 1/2 to one inch. After the pipe has been set to line and grade, additional granular material, of the same size and characteristics as that which has been placed below the pipe, shall be lightly tamped in place to a point six inches above the barrel of the pipe. This material, and the granular material beneath the pipe, shall be placed to the full width of the trench, as excavated, or to the inside surfaces of the sheeting.

Similar bedding shall be provided in rock trenches except that there shall be six inches clear under the pipe to the rock surface and nine inches clear on each side. Under no circumstance will the pipe be permitted to bear directly on the rock. All backfilling shall be performed in accordance with § 402-2 of these specifications.

Exclusion of mud or dirt: Care shall be taken by the developer to exclude mud and/or water containing dirt from entering the pipelines. Temporary plugs shall be installed and the developer shall weight the pipes or backfill to prevent flotation from water in the trench.

(6)

Concrete cradles and envelopes: The developer shall install a half section, or full envelope section, of concrete around the pipe when called for by design or if determined by the Engineer. All concrete cradles or envelopes shall be approved by the Engineer.

(7)

Jointing:

Polyvinyl chloride (PVC) pipe shall be bell-and-spigot-type joint, with elastometric ring supplied by pipe manufacturer. Immediately prior to jointing, the spigot, bell and gasket shall be thoroughly cleaned and a lubricant applied, as supplied by the pipe manufacturer. Extreme care shall be exercised during the jointing process, to ensure that the pipe is in the correct position within the bell. Pullers, or other types of mechanical equipment which may damage the pipe or joint, shall not be allowed.

Ductile iron pipe joints shall be mechanical. The bell and spigot shall be washed clean and, after installing the rubber ring and gland, the bolts shall be tightened, in alternating sequence, with a torque wrench set at 75 foot pounds.

(8)

House service connections:

House service connections (lateral sewers) shall be six-inch diameter polyvinyl chloride (PVC) SDR 35, with corresponding wye branch, sweep, and cap. Connections to the main sewer shall be made at a wye branch which has been installed during installation of the main sewer.

House service connections shall be installed to a point beyond the sideline of the roadway layout and capped to allow testing prior to connection to a building. Laterals shall be laid in granular bedding, as specified for main sewer pipe, and the same backfilling procedures shall be followed throughout the installation.

Lateral sewers may be connected to existing main sewers with cast-iron saddles. Saddles shall be cast iron with a rubber ring at the joint to the main. The joint to the lateral pipe shall be rubber ring or boot with stainless steel clamps. Mortar joints will not be acceptable. The saddle shall be attached to the main by the use of a wide-band stainless steel strap and stainless steel bolts. The opening in the main sewer for installation of the saddle shall be machine cut, using a six-inch diameter shell cutter. The use of a hammer and chisel or hand tools to make the opening will not be permitted.

A lateral shall not be connected to a building until a permit to connect has been issued by the Board. Permits to connect laterals to buildings shall not be issued until mains and laterals have been tested and accepted by the Board. All connections from house sewers to the main sewer shall be performed in accordance with these specifications and by licensed drainlayers.

(e)

In locations where ductile iron pipe main sewers and laterals are required, the developer shall furnish and install six-inch diameter branch wyes with mechanical joints and six-inch diameter Class 52 ductile iron pipe with mechanical joint fittings and end caps.

(f)

At such time as the building sewer has been connected to the town's sewer system, any existing septic tanks, cesspools and similar private wastewater disposal facilities shall be abandoned and filled with sand, gravel or other suitable material which is acceptable to the Board and the Engineer.

(9)

Chimneys: Chimneys shall be furnished and installed as required by the depth of the sewer main and as determined by the Engineer. Chimneys shall be precast concrete sections which are specifically manufactured for this purpose. Alternate methods of construction shall be approved by the Engineer.

(10)

Force mains:

Force mains shall be ductile iron mechanical joint pipe, furnished and installed by the developer, from the lift station to the point of discharge. Ductile iron pipe shall be Class 52, cement lined, tar coated and sealed, with compatible fittings. All fittings shall be installed with concrete thrust blocks.

In combination trenches, which contain both the gravity sewer and the force main, the force main shall be laid on a shelf excavated in the side of the trench. A minimum of four to six inches of cover material shall be maintained in all cases.

(11)

Testing:

Gravity sewers, including laterals, shall be air tested for leakage after backfilling and compaction has been completed, and the base course of bituminous concrete has been installed. The equipment and method used to conduct the air test will be subject to the approval of the Engineer. The developer shall furnish all labor and equipment for testing. No sewers will be accepted by the Board until all testing is completed to the satisfaction of the Engineer.

In general, a section between two manholes shall be isolated by inflatable plugs. Air shall be introduced into the pipeline to an internal pressure 4 psig greater than the average back pressure of the groundwater, or an increase of .434 psi for each foot of water above the top of the pipe. After stabilizing the pressure at 3.5 psig minimum, the air line shall be disconnected, and the pressure drop, if any, observed. The line shall be termed acceptable if the time required, in minutes, for the pressure to decrease to 2.5 psig is not less than one minute per inch of diameter.

The developer shall submit to the Engineer a record of the location and cause of each leak encountered, along with his method for replacement or repair, for approval, prior to completion of the work. A second test shall be made to determine the acceptability of the work. Any pipe which fails the air test shall be replaced or repaired to the satisfaction of the Engineer.

(12)

Cleaning and visual inspection:

After laying of the pipe is completed between manhole sections, the interior of the sewer pipeline shall be thoroughly cleaned of construction debris or other foreign matter. The section shall then be closed off by bulkheads at the outlet side of the manholes. All bulkheads shall be sufficient to prevent the wash of mud or dirt into the completed section of pipeline. Upon completion of the entire line, the bulkheads shall be removed, and any debris shall be cleared from the pipes and manholes.

§ 402-5 Bank gravel; screened gravel; ordinary borrow.

Prior to acceptance, the Engineer shall conduct a visual inspection of the pipeline, and the developer shall supply all materials and labor necessary for this inspection.

(13)

Deflection test - PVC pipe: All PVC pipe shall be checked for deflection after backfilling and compaction is complete. The pipeline to be checked shall be thoroughly cleaned prior to testing. A mandrel shall then be pulled through the pipe to check overall deflection. The mandrel shall have an OD 5% less than the pipe ID. A pipe through which a mandrel can not be pulled without extreme force shall be considered to have failed the test. Pipe which has failed the test shall be excavated and replaced. The pipe shall be retested after backfilling and compaction is complete.

(14)

Leakage test - force mains: Force main pipes shall be tested with water pressure. The pipe shall be slowly filled with water, and all the air shall be expelled at the discharge end of the force main. The discharge end shall then be plugged and blocked and the pressure inside the force main raised to 150 pounds per square inch. The amount of water added to the pipeline, to maintain this pressure, shall be metered, and if the amount added exceeds one gallon the pipe shall be considered to have failed the test. The developer shall locate the leak or leaks and shall make all necessary repairs. The pipes shall then be retested.

§ 402-4 Miscellaneous structures.

The developer shall submit to the Engineer four copies of materials and method of construction of all miscellaneous structures which shall include, but not be limited to, the following: pump stations, inverted siphons, culvert or stream crossings, railroad crossings, state highway encroachment, and drain sump manholes.

Bank gravel: Bank gravel shall be furnished and placed by the developer as trench refill for roadway subbase and for all other disturbed areas. Bank gravel shall consist of hard, durable stone and coarse sand free from loam, clay, mud or other unacceptable materials.

Screened gravel: Screened gravel shall be furnished and placed by the developer as granular bedding material for the pipelines and may be washed and graded bank-run gravel or crushed stone ranging in size from 1/2 inch to one inch.

Ordinary borrow: Ordinary borrow shall be furnished and placed by the developer as trench refill material. It shall not contain any rock fragment weighing more than 50 pounds, and it shall be free of loam, clay, vegetation or other unacceptable material.

Approval: All bank gravel, screened gravel and ordinary borrow shall be approved by the Engineer before incorporation into the work.

§ 402-6 Manholes.

General description:

Precast structures: Manholes shall be constructed of reinforced precast concrete in monolithic sections and shall meet the applicable requirements of ASTM Spec. C 478-70T (latest revision). Manholes shall generally consist of a base section, barrel sections and a dome or flat top section. All precast manhole sections shall be designed for H-20 loading.

Pipe connector: Pipe-to-manhole connections shall be made with a flexible rubber boot and stainless steel clamp. The flexible rubber boot shall be installed during manufacture of precast manhole sections and shall include a stainless steel screw clamp designed specifically for use on the size and type of pipe utilized on the project. A continuous bead of silicone shall be applied to the inside of the boot at the clamp location, prior to installation of the pipe.

Section joints: Joints between manhole sections shall be sealed with butyl rubber sealant compound.

Brick: Red clay brick for constructing the table and the invert, and for adjusting castings to grade, shall be hard burned, and shall conform to ASTM C32 (latest revision). Cement bricks or blocks will not be allowed.

Steps: Manhole steps shall be aluminum alloy 6061 T6, extruded, safety type, cast in place, 12 inches on center, in the barrel and dome sections. The portion of step imbedded in concrete, plus an additional two inches, shall be coated with aluminum oxide.

(6)

Frames and covers:

Cast-iron frames and covers shall meet the requirements of ASTM Specification of Grey Iron Castings, Cast Iron Class 20. All castings shall be clean and without blow holes or sand holes or defects of any kind. Plugging or other stopping of holes will be cause for rejection. Castings shall not vary more than 5% from the specified weight.

All manhole frames and covers shall be carefully cleaned of all rust, dirt, and scale, and then shall be given a full coat of coal-tar pitch varnish which is applied hot. The finish of the castings shall be satisfactory to the Engineer. Any rusted or uncoated surfaces shall be cause for rejection of the castings.

Manhole covers shall closely fit the frames. The underside of the cover and upper side of the lip of the frame must present parallel plane surfaces. These points of contact shall be machined to prevent the covers from rocking in the frames. Covers shall bear evenly on the frames for the entire circumference and shall be interchangeable with other frames.

Manhole frames and covers shall be the Massachusetts Department of Public Works Standard (Plate 201.6.0) and, in general, shall be eight inches in height with a twenty-four-inch clear opening. The total weight of the frame plus the cover shall be a minimum of 475 pounds. The manhole cover shall have three-inch high letters ("SEWER") cast into the top.

(e)

Watertight frames and covers shall be as manufactured by LeBaron Foundry Co., Model LBW 268-2, C.M. White Iron Works, or Mechanics Iron Foundry Co., or equal. In general, frame shall be eight inches high with a twenty-two-inch clear opening, complete with interior cover, locking bar and sealed seating surfaces. Watertight frames and covers shall be used where indicated on the approved drawings or as determined by the Engineer.

(7)

Grade adjustment: Red clay brick shall be used for grade adjustment, with all joints completely filled with mortar. The inside and outside faces of the brick shall also be covered with mortar and troweled smooth. The maximum height allowable for grade adjustment with brick masonry shall be 12 inches.

Installation:

Base: The developer shall excavate to a depth of six inches below the bottom of the manhole base, compact and fine grade, and install washed screened gravel subbase material. Base section shall be installed at the correct grade and leveled. Pipes shall be installed and shall extend approximately one inch inside the interior wall. The clamps on the rubber boot shall be tightened and mortar shall be troweled on the inside face of the manhole at the pipe connection.

Joints: Joint between the base section and the barrel section shall be brushed clean, and a strip of butyl rubber shall be placed completely around the joint prior to placement of the barrel section. Once the barrel section has been placed, a timber shall be placed across the top of the dome, and a controlled downward pressure shall be applied with the hydraulic excavating machine to complete the joint. The same method shall be used in making the joints between the remaining barrel sections and dome section. A precast concrete flat slab top section shall be used if height limitations prohibit the use of a dome section, or as determined by the Engineer.

Grout: All lift holes and interior manhole joints shall be filled with nonshrink grout and smoothed.

Brick and mortar:

Inverts and table shall be constructed of red clay brick with mortar joints. Care shall be taken in construction of brick inverts that the width of the invert shall be slightly larger than the ID of the larger of the pipes entering the manhole wall. Bricks shall be laid in a full bed of mortar with push joints, and all brick shall be thoroughly wet immediately before laying.

Mortar shall be made of one part of Portland cement and two parts of clean fine sand, well mixed and tempered. Water shall be clean and free from impurities affecting its value. Sand and cement shall be first thoroughly mixed dry and only enough water added to make the mortar uniform and workable. No greater quantity of mortar is to be prepared than is required for immediate use, and it shall be constantly worked until used. Any mortar that has once set shall not be retempered and used in the work.

The table shall be constructed at an elevation even with the top of the pipe, and shall slope up toward sidewalls. Inverts shall be constructed in a manner to provide smooth flow through manholes, with no sharp turns or projecting portions of brick. Brick for inverts shall be laid on edge. Brick for the table shall be laid flat.

Frames shall be set upon a full bed of mortar, and mortar shall be brought up alongside of the frame to provide a watertight joint.

Dimensional restrictions: Maximum allowable distance between manholes shall be not greater than 300 feet.

Drop inlets:

In general, the use of a drop inlet will not be approved unless a direct inlet is shown to be impractical.

If approved, drop inlets shall be constructed using tees and a section of pipe, which are the same size as the main, and all encased within Class B concrete. Concrete shall be placed upon the same subbase material as the manhole. A brick masonry dam shall be constructed in the outlet of the upper pipe at the interior face of the manhole, and extend from the invert to 3/4 pipe.

Approval and testing:

All manholes delivered to the site shall be subject to the approval of the Engineer. Any rejected manholes shall be immediately removed from the site by the developer.

All manholes shall be vacuum tested by the developer. All testing shall be performed under the observation of the Engineer. The developer shall be responsible for providing all labor and equipment required to complete the tests. Individual manholes shall be tested by plugging all inlet and outlet piping and placing an approved vacuum base at the top of the manhole cone section. An initial vacuum of 10 inches Hg shall be drawn. The test time shall be that time allowed for the pressure to drop from 10 inches Hg to nine inches Hg. Maximum allowable test times shall be as follows:

	Manhole Depth	Maximum Test Time
	0 to 10 feet	1 minute
	10.1 to 15 feet	1 minute 15 seconds
	15.1 to 25 feet	1 minute 30 seconds