[HISTORY: Adopted by the the Town of Barre
Board of Sewer Commissioners March 4-11-1988. Amendments noted where applicable.]
A.
BOARD
CONTRACTOR
DEVELOPER
ENGINEER
Definitions: As used in these regulations, the following
terms shall have the meanings indicated:
The Board of Sewer Commissioners of the Town of Barre, Massachusetts.
A person, partnership or corporation which has demonstrated
experience in the construction of sanitary sewers and appurtenances
and which has sufficient equipment, labor and resources to construct
the proposed project. The contractor shall be employed by the developer
and shall be responsible to the developer for the construction of
the sanitary sewers and appurtenances.
The legal entity which owns the property to be developed
and which desires to design and construct sanitary sewers and appurtenances
in the Town of Barre, Massachusetts.
The Engineer of record.
B.
Plans and profiles: The developer shall submit three
copies of all plans, profiles and details of the proposed project
to the Board for review and approval. All plans, profiles and details,
hereinafter referred to as "plans," shall be prepared by a registered
professional engineer and shall be drawn using a scale of 40 feet
to the inch horizontal and four feet to the inch vertical.
C.
Conformity with plans: The developer shall construct
the sanitary sewers and appurtenances in accordance with the approved
plans, the Sewer Use Rules and Regulations of the Board[1] and these standard specifications for sewer construction.
No changes in the approved plans will be permitted without prior approval
of the Board. All work on the project shall be performed under the
observation of the Engineer. The Engineer may request a pre-construction
meeting with the developer and the contractor.
D.
Materials and workmanship: All materials and workmanship
utilized on the project shall be subject to the review and approval
of the Engineer, acting on behalf of the Board. The developer shall
submit three copies of all shop drawings, details and the like which
are requested by the Engineer.
E.
Defective workmanship or materials: Any portion of
the work which is found to be defective or not in complete conformance
with the approved plans or these specifications shall be corrected
by the developer, at his expense, before the project is accepted by
the Board.
F.
Permits: The developer, and his contractor, shall
conform to all federal, state and local laws, rules, and regulations
in the conduct of their work. The developer shall obtain all permits
and licenses required by all federal, state, or local authorities.
G.
Engineering services: All engineering services required
by the Board on the project shall be performed under the "agreement
for engineering services" between the developer, the Board and the
Engineer. The Engineer shall be given 48 hours notice of the initiation
of work on the project. If the work on the project is interrupted,
the Engineer shall be given additional notice of 48 hours for each
subsequent starting of the work. All fees for engineering services
required by the Board on the project will be established in the agreement
for engineering services, and all fees for field services will be
based on a four-hour minimum charge per day.
H.
Insurance:
(1)
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:
(2)
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.
I.
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.
J.
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.
K.
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.
L.
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.
M.
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.
N.
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.
O.
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.
P.
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.
A.
Excavation:
(1)
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.
(2)
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.
(3)
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.
(4)
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.
(5)
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:
(a)
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.
(b)
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.
B.
Backfilling:
(1)
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.
(2)
Materials and placement:
(a)
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.
(b)
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.
(c)
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.
(d)
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.
A.
PVC pipe and fittings:
(1)
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).
(2)
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.
B.
Ductile iron pipe and fittings:
(1)
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).
(2)
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.
C.
Pipe laying:
(1)
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.
(2)
Handling and storage:
(a)
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.
(b)
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.
(3)
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.
(4)
Bottom of trench and bedding:
(a)
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.
(b)
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.
(5)
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:
(a)
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.
(b)
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:
(a)
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.
(b)
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.
(c)
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.
(d)
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:
(a)
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.
(b)
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:
(a)
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.
(b)
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.
(c)
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:
(a)
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.
(b)
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.
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.
A.
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.
B.
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.
C.
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.
D.
Approval: All bank gravel, screened gravel and ordinary
borrow shall be approved by the Engineer before incorporation into
the work.
A.
General description:
(1)
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.
(2)
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.
(3)
Section joints: Joints between manhole sections shall
be sealed with butyl rubber sealant compound.
(4)
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.
(5)
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:
(a)
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.
(b)
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.
(c)
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.
(d)
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.
B.
Installation:
(1)
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.
(2)
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.
(3)
Grout: All lift holes and interior manhole joints
shall be filled with nonshrink grout and smoothed.
(4)
Brick and mortar:
(a)
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.
(b)
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.
(c)
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.
(d)
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.
(5)
Dimensional restrictions: Maximum allowable distance
between manholes shall be not greater than 300 feet.
C.
Drop inlets:
(1)
In general, the use of a drop inlet will not be approved
unless a direct inlet is shown to be impractical.
(2)
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.
D.
Approval and testing:
(1)
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.
(2)
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
|
(3)
Manholes which fail to meet the above allowable test
times shall be repaired using methods approved by the Engineer. Manholes
shall then be retested using the vacuum test. Following a second vacuum
test failure, the manhole shall be repaired and tested using a water
exfiltration method, as determined by the Engineer.
A.
Concrete masonry: Concrete masonry shall be used for
thrust blocking, foundation material, pipe cradles (half section or
full section), manhole drop inlets, chimney encasement or as otherwise
determined by the Engineer.
B.
Concrete: Concrete shall be mixed using Portland cement,
crushed stone and clean, hard sand with enough clean water to ensure
proper mixing. Concrete may be job mixed or ready mixed, a nominal
1:2.5:5 mix, and shall contain not less than 4.5 bags of cement per
cubic yard.
C.
Steel reinforcement: Steel reinforcement shall be
deformed bars of approved type and structural quality free from dirt
or rust and shall be bent as required and accurately placed with depth
of cover not less than two inches.
Type I-1 bituminous concrete shall be used to
resurface trenches in existing public ways in accordance with the
rules and regulations of the Town of Barre Highway Department or the
Massachusetts Department of Public Works, whichever governs. Specific
depths and details of composition of materials are to be as agreed
upon in the application for the permit to open the public way. The
developer shall recut the edges of the trench in approximately parallel
lines; the edges shall be brushed clean, and a coat of RS-1 shall
be applied to act as a bonding agent, prior to resurfacing.