A.
Permits.
(1)
Highway permit. The licensed pipelayer shall be required
to obtain a highway opening permit prior to any excavations within
a public way.
(2)
State highway permit. When making a sewer connection
in a state highway, the necessary permits from the Massachusetts Department
of Public Works must be obtained prior to the issuance of a permit
to construct sewer lines. All work shall then be done in accordance
with the requirements set forth in the permit issued by the Massachusetts
Department of Public Works. Any cost in connection therewith shall
be borne by the licensed pipelayer.
B.
Protection of excavation. All excavation and backfilling
shall be done in accordance with these detailed standards herein and
in compliance with the highway opening permit. All excavations and
obstructions shall be adequately barricaded and protected at all times
to provide public safety to the satisfaction of the DPW, an authorized
representative of the Highway Division and the Police and Fire Chiefs.
[Amended 10-18-2000 ATM, Art. 14]
C.
Protection of property. Power shovels, bulldozers,
loaders, trucks and other equipment shall not be operated on or across
sidewalks, berms, curbs, etc., until protection, such as planking
or other approved means, has been provided. All damage resulting from
the licensed pipelayer's operations shall be repaired by the licensed
pipelayer.
D.
Resurfacing.
(1)
Resurfacing material. Asphaltic concrete and associated
materials shall be in compliance with the Massachusetts Department
of Public Works Standard Specifications for Highways and Bridges,
Section 460, M3.11.00, Class I, Type I-1.
(2)
Temporary resurfacing. Asphaltic concrete temporary
resurfacing, two-inch depth, shall be required on all excavations
within roadway areas and shall be maintained by the licensed pipelayer
for a period of three (3) months or until ordered replaced by an authorized
representative of the Highway Division.
(3)
Permanent resurfacing. Bituminous concrete permanent
resurfacing shall be required on all excavations within roadway areas.
Depth and type of mix shall be determined by the DPW or an authorized
representative of the Highway Division. Prior to placement of permanent
resurfacing, edges of existing pavement shall be cut to neat parallel
lines and all loose pavement and temporary resurfacing shall be removed
to a depth to allow placement of permanent surfacing. Existing edges
of pavement shall be coated with RS-1, and sand shall be applied on
the surface of the joint.
[Amended 10-18-2000 ATM, Art. 14]
(4)
Failure of the licensed pipelayer to respond to the
request of an authorized representative of the Highway Division to
complete the work of maintaining temporary resurfacing or to apply
permanent resurfacing may result in the revoking of his license.
(5)
In the event that the public sewer main or sanitary
building sewer crosses existing concrete pavement, sidewalks or driveways,
the temporary bituminous patch shall be removed after three (3) months
and the paved surface shall be restored with cement concrete pavement,
three thousand (3,000) pounds per square inch design mix.
A.
Lines of excavation. The licensed pipelayer shall
make all excavations in earth and rock necessary or incidental to
construct and inspect the proposed work as shown on the approved construction
drawings.
B.
Type of excavation. All excavations shall be by open
cut, except as otherwise permitted by the Superintendent, and shall
be of sufficient width to allow for thorough compaction of the refill
material and for the inspection of the work.
C.
Field location. It shall be the licensed pipelayer's
responsibility to contact Dig-Safe for accurate field locations prior
to construction. The licensed pipelayer shall be familiar with and
comply with all Massachusetts General Laws relating to excavations,
such as M.G.L.A. C. 82, § 40.
D.
Underground facilities. It shall be the licensed pipelayer's
responsibility to contact all utility companies, the Highway Division,
the Water and Sewer Division and any other agency which may have underground
facilities within the construction area for accurate field locations
prior to construction, and the licensed pipelayer shall mark the location
of such utilities so that they may be avoided in the operation of
the excavating equipment. Excavation by hand tools shall be used where
required to prevent damage to existing utility lines or other structures.
E.
Discharge. The licensed pipelayer shall provide suitable
temporary channels for the flow of all watercourses and shall hold
the town harmless against all claims for damages growing out of obstruction
to the flow in sewers, drains or gutters or because of injury to gas,
water or other pipes or conduits or fixtures relating to the same,
and he shall give sufficient notice to the proprietors of such pipes
or fixtures in time to permit them to cooperate in protecting their
property.
F.
Ledge measurement. Where ledge rock is encountered,
the licensed pipelayer shall take accurate measurements relating the
top surface of the ledge to the proposed invert of the pipe or the
bottom of other structures. This information shall be recorded and
made available to his engineer for use in completing the record drawings.
G.
Explosives. The removal of ledge shall be accomplished
by licensed individuals, and the licensed pipelayer shall obtain the
necessary permits before the blasting occurs. The handling, storage
and use of explosives shall be in accordance with the requirements
of M.G.L.A. C. 148, §§ 10 to 27, inclusive, latest
revisions or additions thereto. The licensed pipelayer shall furnish
and place any blasting mats as may be required to perform the work
safely.
H.
Trench support. The licensed pipelayer shall furnish
and place such sheeting and bracing as may be required to perform
the work safely and shall leave in place, if ordered by the Superintendent,
that portion necessary to maintain the base fill material and the
walls of the excavation during and after the backfilling process has
been completed. The use of a steel support box may be used in place
of sheeting and bracing.
I.
Excavation below grade. The licensed pipelayer shall
remove unsuitable foundation material under the pipelines and refill
it with bank gravel, screened gravel or concrete, as ordered by the
Superintendent. Sheeting, if necessary, to contain the refill material
shall be furnished, installed and left in place at the order of the
Superintendent.
J.
Control of water. Dewatering of the area in which
work will be done, including pump station sites, will be the responsibility
of the licensed pipelayer, using pumps of sufficient capacity to lower
the water table in the immediate trench area to a level below excavation.
K.
Existing pavement. Trench excavation in existing public
ways shall be subject to the requirements of the Construction Standards
and Rules and Regulations of the town. Excavation in streets having
an improved pavement shall be preceded by cutting the existing pavement
to ensure 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 licensed pipelayer shall
furnish all materials and do all the work necessary to restore the
paved surface to its original condition, with depth and type of mix
to be determined by the authorized representative of the Highway Division.
The work shall be subject to inspection and approval of the authorized
representative of the Highway Division.
A.
General. The trenches and other excavations shall
be backfilled as soon as possible after laying the pipe or the completion
of other structures. No backfilling shall be done until the Superintendent
has inspected the work.
B.
Placement. The area below the pipe and extending to
six (6) inches above the crown of PVC pipe and D.I. pipe shall be
backfilled with compacted granular material, as specified under pipe
laying, and thoroughly tamped by light tampers as placed. The remainder
of the side fill to a minimum depth of twenty-four (24) inches above
the top of pipe shall be a select, fine ordinary borrow material,
approved for such use by the Superintendent, placed in twelve-inch
layers and compacted by hand tamping. No stones larger than three
(3) inches across the largest dimension will be allowed within this
stratum of backfill.
C.
Compaction.
(1)
The remainder of backfill to the surface of the ground
or to the bottom of the gravel subbase in roadway locations shall
be ordinary borrow, approved by the Superintendent, placed in twelve-inch
layers and thoroughly compacted by mechanical rammers or vibrators.
No rock larger than twelve (12) inches in diameter will be allowed
within this stratum of backfill, and all voids within rock backfill
must be completely filled. Alternate methods for compaction within
this stratum presented by the licensed pipelayer will be considered
by the Superintendent, and the licensed pipelayer shall be required
to demonstrate to the Superintendent's satisfaction that his proposed
method of compaction will produce the intended results for the various
conditions and materials encountered.
(2)
Alternate compaction. Approval of this alternative
method of compaction will not relieve the licensed pipelayer of his
responsibilities in regard to maintenance of settled trenches. The
responsibility for proper bedding of the pipe shall be the licensed
pipelayer's, and pipe failures due to improper bedding or compaction
shall be removed and replaced.
D.
Subbase. For trenches within roadways, the top eighteen
(18) inches of backfill shall be bank gravel, placed and compacted
during backfilling operation. The licensed pipelayer shall fine grade
the gravel surface, apply dust control treatment and maintain the
surface in a condition which will allow normal vehicular traffic until
temporary resurfacing is installed.
A.
PVC pipe. Pipe and fittings for main sewer pipe may
be polyvinyl chloride (PVC) made by a manufacturer of established
reputation, meeting the requirements of ASTM-D-3033 or D-3034-77 or
the latest revision thereto, with a pipe diameter to wall thickness
ratio (SDR) of thirty-five (35). Maximum pipe length shall be thirteen
(13) feet with elastomeric ring, bell and spigot style joint, meeting
the requirements of ASTM-D3212-76 or the latest revision thereto.
B.
Laterals. Pipe and fittings for laterals shall be
polyvinyl chloride (PVC), six (6) inches in size and meeting the same
requirements as for the main pipe. Fittings shall be molded one-piece
construction, and a PVC cap, designed for use on the bell end of the
pipe, shall be used where necessary.
C.
Force mains. Pipe for sewer force mains shall be ductile
iron (D.I.) push-on joint, meeting the requirements of ANSI A21.51-76
(AWWA C151-76) or the latest revision thereto, thickness Class 52,
within the immediate area of the pump station. Force mains beyond
the limits of the pump station shall be Class 50, cement-lined, tar-coated
and sealed.
D.
Fittings. Fittings for ductile iron pipe shall be
manufactured of ductile iron, mechanical joint, all bell, compact
design, rated for three hundred fifty (350) pounds per square inch.
Fittings shall meet or exceed the requirements of ANSI-A21.53-1984
and shall be cast with the following identifying designations: Class
C153, pressure rating three hundred fifty (350), opening diameter,
manufacturer's identification, country where cast, degree of bend
and D.I. or ductile. Ductile iron fittings that are not presently
manufactured to the compact design but are manufactured to meet or
exceed the requirements of ANSI A21.10-1971 (AWWA C110-7) standard
for cast-iron fittings, or the latest revision thereto may be utilized.
Mechanical joints for fittings shall meet or exceed the requirements
of ANSI A21.11 (AWWA C111), including bituminous-coated glands, rubber
ring and T-head bolts.
E.
Retainer glands. Retainer glands for all ductile iron
main bends shall be cast of high-strength ductile iron and fitted
with cap joint, square head and double-heat-treated-steel set screws.
The quantity of screws shall be as recommended by the manufacturer
of the gland.
F.
D.I. gravity sewer pipe. In areas where ductile iron
gravity sewer pipe is required, i.e., shallow trenches three and five-tenths
(3.5) feet or less or depths greater than thirteen and zero-tenths
(13.0) feet in the immediate area of water supplies or recreational
areas, the licensed pipelayer shall furnish and install Class 50 ductile
iron pipe and ductile iron tees or wyes for sanitary building sewer
connections, with mechanical joints. A mechanical joint plug or cap
shall be furnished and installed on the lateral at the roadway taking
line to allow air testing of the system. Alternative materials will
be considered for shallow or deep trench conditions, if appropriate
design data and installation methodology is submitted to substantiate
the choice of materials.
G.
Sanitary building sewer connections. Wyes shall be
required for all sanitary building sewer connections to the public
sewer main and shall be the same type of material and manufacture
as the pipe. Connections to an existing public sewer main shall be
accomplished by the use of a cast-iron saddle with stainless steel
strap and bolts.
A.
Alignment. The licensed pipelayer shall provide such
engineering services as may be required to ensure that the pipelines
are constructed in accordance with the approved drawings. Engineering
services provided by the developer or licensed pipelayer shall include
the establishment of lines and the setting of grades. Pipe installed
which does not conform to the approved drawings shall be removed and
reinstalled at the developer's or licensed pipelayer's expense. Laser
beam aligning equipment will be permitted on sewer main construction
if the licensed pipelayer demonstrates that the equipment and operators
can produce the required line and grade of the public sewer main.
B.
Handling. All pipe shall be handled carefully to avoid
injury to workmen, other structures or to the pipe itself. Only equipment
or methods approved by the Superintendent shall be employed in handling
pipe. Pipe or fittings damaged for whatever reason shall be removed
from the job site immediately.
C.
Protection of pipe. If PVC pipe is used, care shall
be taken to stack the pipe properly and, if stored for a period exceeding
sixty (60) days exposed to the ultraviolet rays of the sun, pipe shall
be covered with canvas or other opaque material, and provision for
the circulation of air beneath the covering shall be provided.
D.
Condition of pipe. PVC pipe must be straight barrel,
and deflection prior to installation is not to exceed one-sixteenth
(1/16) inch per two-foot length. Pipe not meeting this requirement
shall not be installed and shall be removed from the construction
site.
E.
Trench bottom. All pipe shall be laid on a stable
foundation to prevent settlement. If soft or unsatisfactory material
is found at grade, it shall be removed and replaced with other material
to provide an adequate foundation.
F.
Bedding. In general, the bottom of the trench shall
be excavated to a depth of four (4) inches below the bottom of the
pipe barrel for PVC pipe and D.I. pipe placed for all gravity mains,
force mains and laterals. The granular bedding shall be washed screened
gravel or crushed stone, ranging in size from one-half (1/2) to one
(1) inch. After the pipe has been set to line and grade, additional
granular material of the same size and characteristics shall be lightly
tamped in place to an elevation equal to a point six (6) inches above
the crown of PVC pipe. The granular material around the pipe shall
also be placed the full width of the trench, as excavated, or to the
inside surfaces of the sheeting which is required to contain the foundation
material in unstable trenches.
G.
Backfilling. Material for backfilling to a point twenty-four
(24) inches above the crown of the pipe shall be select borrow, containing
no large stones, loam, clay or other substances unsuitable for backfill
material. Select borrow shall be placed in layers suitably tamped
to the side limits of the trench as excavated. Material from a point
twenty-four (24) inches above the crown of the pipe to a point eighteen
(18) inches below subgrade, within roadway locations, shall be ordinary
borrow, placed in layers and thoroughly tamped. No rock fragment larger
than twelve (12) inches in diameter will be permitted within this
section of backfill. The top eighteen (18) inches of the trench shall
be backfilled with road grade bank gravel which, when compacted in
place, will form a suitable foundation for the base course of road
surfacing.
H.
Rock trenches. Similar bedding shall be provided in
rock trenches, except that there shall be six (6) inches clear under
the pipe to the rock surface and nine (9) inches clear on each side.
Under no circumstances will the pipe be permitted to bear directly
on the rock.
I.
Jointing. Polyvinyl chloride (PVC) pipe shall be bell-and-spigot-type
joint, with elastomeric ring supplied by the pipe manufacturer. Immediately
prior to jointing, the spigot, bell and gasket shall be thoroughly
cleaned and a lubricant supplied by the pipe manufacturer applied.
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 shall not be allowed, preventing
the possibility of splitting or deforming the joint.
J.
Ductile iron pipe shall be push-on-type joint with
rubber gasket. Prior to assembly, the bell and spigot shall be cleaned
of foreign matter and a lubricant applied. Cut sections of pipe shall
have the spigot end filed to a slight taper to prevent damage to the
gasket. The pipe shall be aligned both horizontally and vertically
and forced into position with deflection, if necessary, accomplished
after the joint is assembled and within the manufacturer's allowable
tolerances.
K.
Maintenance of pipe. Care shall be taken by the licensed
pipelayer to exclude mud and/or water containing dirt from entering
the pipelines. Temporary plugs shall be installed, and the licensed
pipelayer shall weight the pipes or backfill if inspection has been
made to prevent flotation from water in the trench.
L.
Ductile iron (D.I.) fittings shall be mechanical-joint
type. Prior to assembly all foreign matter shall be removed from the
bell and spigot and the gland and gasket placed and the spigot carefully
inserted into the bell. The joint shall be assembled and bolts tightened
in an altering sequence to a final torque of seventy-five (75) to
ninety (90) foot-pounds. Deflection shall be accomplished after the
joint is assembled.
A.
General. Sanitary building sewers will not be allowed
to have more than two (2) angle points or a total angular deviation
of one hundred eighty degrees (180°) unless granted variance by
the Superintendent. Cleanouts shall be constructed as shown on the
attached drawings[1] and shall consist of a wye, forty-five-degree, horizontal
bend PVC piping and a cast-iron cap and a rubber insert with stainless
steel clamps to provide an absolutely watertight installation. Under
certain circumstances, manholes may be used in place of cleanouts,
if approved by the Superintendent.
[Amended 10-18-2000 ATM, Art. 14]
[1]
Editor's Note: Said drawings are on file in
the Town Clerk's office, the Department of Public Works, the Planning
Office and the office of the Building Inspector and may be examined
there during regular business hours.
B.
Backwater valves are to be installed as shown on the
attached drawings for each sanitary building sewer installation.[2] The backwater valve shall be six (6) inches in size and
constructed of PVC with solvent-welded joints to six-inch SDR 35 PVC
sewer pipe.
[Amended 10-18-2000 ATM, Art. 14]
[2]
Editor's Note: Said drawings are on file in
the Town Clerk's office, the Department of Public Works, the Planning
Office and the office of the Building Inspector and may be examined
there during regular office hours.
C.
Special conditions. Sanitary building sewers in excess
of one hundred (100) feet in length are subject to review by the Superintendent
and other requirements as may be found necessary to assure a functional
connection.
D.
Excavation and backfill shall be typical as detailed
for main sewer installation, and no backfilling shall be permitted
until the Superintendent has inspected and approved the installation.
E.
Pipe elevation. All sanitary building sewer pipe shall
be laid to a minimum slope of one-fourth (1/4) inch per foot unless
otherwise approved by the Superintendent. The sanitary building sewer
should be brought to the building on a uniform slope and at an elevation
appropriate to the connection with the existing sanitary building
drain. In any building in which the building drain is too low to permit
gravity flow to the public sewer, sanitary sewage carried by such
building drain may be lifted by an approved means and discharged to
the sanitary building sewer.
F.
Existing septic system. Sanitary building sewers connected
to existing septic system piping shall be made on the building side
of the septic tank and the tank or cesspool pumped dry and removed
or refilled with approved material. Connection to existing pipe shall
be accomplished with rubber adaptor couplings and stainless steel
clamps, designed specifically for the type of application intended.
G.
Additional connections. No direct or indirect connection
will be allowed between the sanitary building sewer and roof drains,
foundation drains, cellar drains, sump pump or other sources of surface
runoff groundwater.
H.
Approval to connect. Actual connection of the sanitary
building drain (wastewater plumbing) to the sanitary building sewer
may not be accomplished prior to an approval to connect from the DPW.
An additional fee as set by the Department of Public Works for existing
structures or for new structures must be submitted with the permit
application for each tap to be made by the contractor. If a sanitary
building sewer must be connected directly to the public sewer main,
the licensed pipelayer shall carefully excavate, dewater and expose
the main, supply the cast-iron saddle with a stainless steel retainer
strap and conduct the actual tapping to the main under the Superintendent's
supervision.
[Amended 10-18-2000 ATM, Art. 14]
A.
General. Chimneys shall be constructed at locations
required by the depth of the sewer main and as approved by the Superintendent.
The chimney may consist of a PVC tee or ninety-degree saddle, forty-five-degree
PVC bend, PVC riser pipe with field cut end, a PVC adapter and a ninety-degree
PVC elbow. The entire assembly is to be encased in Class B concrete,
reinforced as shown on the standard drawing. At the top of the chimney,
a PVC tee may be substituted for the ninety-degree elbow if the chimney
is to serve dual use.
B.
Sonotube. The use of a twenty-four-inch diameter sonotube
for a vertical concrete form will be permitted. Form work for the
concrete section at the main sewer will be constructed to the lines
shown on the standard drawing. In constructing the concrete encasement,
forms shall be placed so that the weight of the chimney shall bear
directly on the foundation material and not on the sewer main. A flexible
joint, approved by the Superintendent, shall be installed a minimum
distance of twenty-four (24) inches from the vertical face of the
concrete.
C.
Precast chimneys. The contractor may option to use
a precast chimney, which shall be constructed similar to that as specified
for a cast-in-place unit. The precast unit shall consist of six-inch
PVC pipe encased in concrete, cast in vertical sections, with O-ring
neoprene gaskets and a noncorrosive mechanical clamping mechanism.
The unit shall straddle the sewer main, carrying the weight of the
unit directly to the trench. The unit shall consist of a base section
and a top section, with an intermediate section varying in height
from one (1) foot to four (4) feet. The top and bottom sections shall
contain a neoprene water stop around PVC fitting to prevent entry
of groundwater.
A.
Type of pipe. Force mains may be ductile iron push-on
joint pipe, furnished and installed by the licensed pipelayer, from
lift and pump stations to point of discharge. D.I. pipe shall be Class
52, cement-lined, tar-coated and sealed, with mechanical joint fittings
installed with concrete thrust blocks and retainer glands.
B.
Combination trenches. In combination trenches, gravity
sewer and force main, the force main shall be laid on a shelf excavated
in the side of the trench with the main (gravity) sewer, with a minimum
cover of four (4) feet six (6) inches. If, because of the depth of
cut of the gravity sewer or material encountered, the excavation of
a shelf proves to be impractical, the developer shall excavate separate
adjacent trenches for the two (2) pipes.
[Amended 10-18-2000 ATM, Art. 14]
All plans for sewage pumping or ejector stations
proposed for use shall be submitted to the DPW for approval prior
to ordering, purchase or installation. Three (3) sets of plans shall
be submitted to the DPW, two (2) sets to be transferred to the engineer
for review and the final set for the DPW file.
A.
Construction. Manholes shall be constructed of reinforced
precast concrete monolithic base sections, barrel sections and dome
sections and shall meet the applicable requirements of ASTM Specification
C478-7OT, latest revision, design based upon H-20 loadings. All manholes
delivered to the site must be approved by the Superintendent. In general,
reasons for rejection will include, but not be limited to, porous
or cracked walls, misformed joints and pipe connectors which vary
more than one (1) inch from those indicated on the plans. Rejected
manholes shall be removed from the site by the licensed pipelayer.
B.
Preliminary inspection. All precast manhole sections
shall be delivered to the construction site without exterior coatings.
Upon on-site approval by the Superintendent, the licensed pipelayer
shall apply, by roller or brush, a heavy application of emulsified
asphalt waterproofing compound.
C.
Pipe-to-manhole connection shall be made with a flexible
rubber boot and stainless steel clamp. The flexible rubber boot pipe-to-manhole
connector 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. If PVC pipe is used, a continuous bead of silicone shall
be applied to the inside of the boot at the clamp location prior to
installation of the pipe.
D.
Manhole installation. The licensed pipelayer shall
excavate to a depth of six (6) inches below the bottom of the manhole
base, compact and fine grade and install washed screened gravel subbase
material. The base section shall be placed to grade and the pipes
connected. Pipes shall extend approximately one (1) inch inside the
interior wall, with clamps on the connector tightened and mortar troweled
on the inside face of the manhole-to-pipe connection.
E.
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 inside diameter 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.
F.
Mortar shall be made of one (1) part of portland cement
and two (2) 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 tempered and used in the work.
G.
Red clay brick for table, invert and grade adjusting
courses shall be hard burned of uniform Grade B. Red clay brick shall
be laid with all joints completely filled with mortar and the inside
and outside faces covered with mortar and troweled smooth. The maximum
height allowable for grade adjustment of the manhole frame with the
brick masonry shall be twelve (12) inches.
H.
Manhole joints. The 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 section and a controlled
downward pressure shall be applied with the hydraulic excavating machine
to the complete joint. The same method shall be used in making the
joints between the remaining barrel section and dome section. Precast
concrete flat slab top sections shall be used if height limitations
prohibit the use of a dome section.
I.
Manhole steps shall be aluminum alloy 6061 T6, extruded,
safety-type, cast in place, twelve (12) inches on center, in the barrel
and dome sections, and the portion of the step imbedded in concrete,
plus two (2) inches, shall be coated with aluminum oxide. Steps may
also be constructed of continuous grade 60 steel bar, three-eighths
(3/8) inch outside diameter, molded within polypropylene plastic with
a safety tread surface. All interior steps shall be installed during
manhole manufacture.
J.
Manhole table. The table shall be constructed at an
elevation even with the top of the pipe and shall slope up toward
side walls. Inverts shall be constructed in a manner to provide smooth
flow through manholes, with no sharp turns or projecting portions
of brick. Bottom sections of straight line manhole inverts may be
constructed using one-half (1/2) section of pipe cut longitudinally
and carefully set to grade, upon approval of the Superintendent. The
half-pipe section must be securely braced during installation of concrete
fill around the invert to prevent flotation. Brick for inverts shall
be placed on edge and laid flat for table.
K.
Sealing of joints. Once the manhole has been assembled
and prior to backfill, hydraulic cement shall be applied to all lift
holes and manhole joints, including exterior boot-to-manhole joint.
L.
Backfilling. Once the vacuum test has been completed,
select ordinary borrow shall be backfilled around the manhole, with
no stone larger than three (3) inches within eighteen (18) inches
of the concrete wall. Material shall be placed leveled and compacted
in twelve-inch lifts.
M.
Castings. Cast-iron frames and covers shall meet the
requirements of ASTM Specification for Grey Iron Castings, Cast Iron
Class 20. All castings shall be clean and without blow holes, sand
holes or defects of any kind. Plugging of such holes will be cause
for rejection, and the castings shall not vary more than five percent
(5%) from the weight calculated for the cubic content indicated by
the shop drawings, with iron at four hundred fifty (450) pounds per
cubic foot. The acceptance of any casting varying more than five percent
(5%) will be at the option of the Superintendent.
N.
Casting preparation. The cast-iron manhole frames
and covers shall be carefully cleaned of all rust, dirt and scale,
and while free and clean from rust shall be given a full coat of coal
tar pitch varnish applied hot and satisfactory in quality to the Superintendent.
The finish of the castings as delivered shall be satisfactory to the
Superintendent, and any rusted or uncovered surfaces shall be the
cause of rejection of the castings until the same have been refinished.
O.
Casting fit. Manhole covers must fit the frames with
clearances as shown on the standard drawing. The underside of the
cover and upper side of the lip of the frame must present parallel
plane surfaces, and at these points of contact, the frames and covers
must be machined to prevent the covers from rocking in the frames
under traffic conditions. Covers shall bear evenly on the frames for
the entire circumference and be interchangeable with other frames.
Frames shall be set upon a full bed of mortar, and the mortar shall
be brought up alongside of the frame to provide a watertight joint.
P.
Casting manufacturer. Standard frames and covers shall
be as manufactured by LeBaron Foundry Company, Model LT-101, Mechanics
Iron Foundry Company, Model K 6004, or C.M. White Iron Works, Model
R-258, and, in general, be eight (8) inches in height with a twenty-two-inch
clear opening.
Q.
Watertight castings. Watertight frames and covers
shall be as manufactured by LeBaron Foundry Company, Model LBW 268-2,
Type BW, C.M. White Iron Works or Mechanics Iron Foundry Company,
or equal. In general, the frame shall be eight (8) 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 required by the design approved by the DPW. 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.
[Amended 10-18-2000 ATM, Art. 14]
R.
Drop inlet. Manhole drop inlets, if approved, shall
be constructed utilizing standard SDR 35 PVC sewer pipe and fittings,
as shown on the detail drawings located in the Appendix.[1] The piping shall be connected to the manhole utilizing
the rubber boots, fully assembled and then encased in concrete, carrying
concrete to stable base at trench bottom. A brick dam shall be placed
in upper pipe to prevent overflow, which can be easily removed to
service pipe. The size of the horizontal pipe shall match the incoming
pipe. The use of a drop inlet at the manhole will not be approved
without submittal of data justifying the necessity of a drop inlet
rather than a direct inlet.
[Amended 10-18-2000 ATM, Art. 14]
[1]
Editor's Note: The Appendix is on file in
the Town Clerk's office, the Department of Public Works, the Planning
Office and the office of the Building Inspector and may be examined
there during regular office hours.
A.
General. Gravity sewer mains, both polyvinyl chloride
(PVC) and ductile iron (D.I.), including sanitary building sewers
from the main to the side line of the roadway layout, shall be air-tested
for leakage after backfilling and compaction to road subgrade has
been completed. The equipment and method used to conduct the air test
will be subject to prior approval by the Superintendent.
B.
Test guidelines. All testing shall be done by an individual
or company experienced and equipped in this type of work. A certification
of the test results shall be required for each section between manholes,
with the stationing corresponding to the submitted plans. The Superintendent
shall be notified forty-eight (48) hours in advance of testing. At
no time shall construction proceed further than two thousand (2,000)
feet from the last section tested.
C.
Gravity main test. In general, a section between two
(2) manholes shall be isolated by inflatable plugs. Air shall be introduced
into the pipeline to an internal pressure four (4) pounds per square
inch gauge greater than the average back pressure of the groundwater
or an increase of four hundred thirty-four thousandths (.434) pounds
per square inch for each foot of water above the top of the pipe.
After stabilizing the pressure at three and five-tenths (3.5) pounds
per square inch gauge, plus the adjustment to compensate for the exterior
head of water, 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 reduce to the allowable
residual pressure is not less than one (1) minute per inch diameter.
The licensed pipelayer shall supply all equipment and labor necessary
to assist the Superintendent in this test.
|
Air-Testing Chart
| |||||
|---|---|---|---|---|---|
|
Groundwater Above Pipe (feet)
|
Pressure Adjustment (pounds per square
inch)
|
Initial Pressure (pounds per square inch)
|
Stabilized Pressure (pounds per square
inch)
|
Allowable Residual Pressure (pounds per
square inch)
| |
|
0.0
|
0.0
|
4.0
|
3.5
|
2.5
| |
|
1.0
|
0.43
|
4.43
|
3.93
|
2.93
| |
|
2.0
|
0.87
|
4.87
|
4.37
|
3.37
| |
|
3.0
|
1.30
|
5.30
|
4.80
|
3.80
| |
|
4.0
|
1.74
|
5.74
|
5.24
|
4.24
| |
|
5.0
|
2.17
|
6.17
|
5.67
|
4.67
| |
|
6.0
|
2.60
|
6.60
|
6.10
|
5.10
| |
|
NOTE: Elapsed time for pressure to reduce to
the allowable pressure should not be less than one and zero-tenths
(1.0) minute per inch diameter of the particular pipe being tested.
|
D.
Unacceptable pipe. The licensed pipelayer shall submit
to the Superintendent a record of the location and cause of each leak
encountered, along with his method for replacement or repair prior
to completion of the work after completion of repair. A second test
shall be made to determine the acceptability of the work after the
completion of repair. In general, pipe which fails the air test shall
be replaced, but under certain circumstances, upon approval of the
Superintendent, a stainless steel band-type clamp, designed for pressure
service, may be used. The minimum width of the clamp shall be fifteen
(15) inches, and band and bolts shall be stainless steel.
E.
Cleanup. A visual inspection by the Superintendent
shall also be required on all main sewer pipe installed, and the interior
of the sewer pipeline shall be thoroughly cleaned from construction
debris or foreign matter. Bulkheads shall be installed at the outlet
side of the manholes sufficient to prevent the wash of mud or dirt
into the completed section of pipeline and, upon completion of the
entire line, shall be left free and clear of such debris and the bulkheads
removed.
F.
Deflection test. All PVC main line pipe shall be checked
for deflection after backfilling and compaction is complete, but at
no time shall construction proceed further than two thousand (2,000)
linear feet from the last section tested. The pipeline to be checked
shall be thoroughly cleaned and plugged. A mandrel shall be pulled
through the pipe to check overall deflection, and the pipe through
which a mandrel cannot be pulled without extreme force shall be considered
failed. The mandrel shall have an outside diameter seven percent (7%)
less than the pipe inside diameter and shall be supplied by the pipe
manufacturer for this purpose. Pipe which has deflected more than
seven percent (7%) shall be excavated and replaced or backfill around
the pipe compacted to provide adequate support and the pipe retested.
Deflection shall be computed by multiplying the amount of deflection
(nominal diameter less minimum diameter when measured) by one hundred
(100) and dividing by the nominal diameter of the pipe.
G.
Television inspection. All main line pipe shall be
television-tested upon completion of backfilling and compaction. This
testing shall be done by a company specializing in this type of work,
with a minimum of three (3) years' experience. The camera shall be
drawn through the pipe, with a color image projected upon a color
video screen, which includes a distance meter. Photographs of all
defects, faults, imperfections, points of infiltration, etc., shall
be taken and submitted to the Superintendent in duplicate. A written
report shall also be submitted in duplicate, broken into sections
between manholes, including stations of all manholes, wyes, imperfections,
defects, faults, points of filtration, horizontal or vertical misalignment
of pipe, condition of manholes, etc.
H.
Force main and siphon test.
(1)
Ductile iron force main and siphon pipe shall be tested
hydraulically, by slowly filling the line with water and expelling
the air at the discharge end of the force main and all points of high
elevation along the force main. The discharge end shall then be plugged
and blocked and the hydrostatic pressure increased to one and five-tenths
(1.5) times the working pressure. Each section of pipeline shall be
slowly filled with water with the specified test pressure measured
at the point of lowest elevation. The amount of water added to the
line to maintain this pressure within five (5) pounds per square inch
shall be metered, and if the amount added exceeds the amount determined
by the formula below, the test shall be considered a failure.
|
L
|
=
|
(S x D x P0.5)/133,200
| ||
|
Where:
| ||||
|
L
|
=
|
Allowance leakage in gallons per hour.
| ||
|
S
|
=
|
The length of pipe tested in feet.
| ||
|
D
|
=
|
The nominal diameter of the pipe in inches.
| ||
|
P
|
=
|
The average test pressure during the leakage
test in pounds per square inch.
| ||
(2)
The licensed pipelayer shall locate the leak or leaks
and, after obtaining prior approval as to method and materials for
making the repair from the Superintendent, shall repair the leak(s)
until the line meets the testing approval criteria.
I.
Manhole vacuum test.
(1)
The licensed pipelayer shall conduct a vacuum test
on all manholes prior to backfilling. All openings shall be plugged
with hydraulic cement, and suitable plugs shall be inserted in pipes.
All equipment and manpower for the test shall be supplied by the licensed
pipelayer and equipment shall be manufactured for that purpose. An
initial vacuum of ten (10) inches Hg shall be drawn. The test time
shall be determined by that time required for the pressure to drop
from ten (10) inches mercury to nine (9) inches mercury. Allowable
test times are given below:
|
Depth of Manhole
(feet)
|
Minimum Test Time
| |
|---|---|---|
|
0 to 10
|
1 minute
| |
|
10.1 to 15
|
1 minute 15 seconds
| |
|
15.1 to 25
|
1 minute 30 seconds
|
(2)
Vacuum test failure. Manholes which fail to meet the
above minimum test times shall be repaired using methods approved
by the Superintendent. Manholes shall then be retested using the vacuum
test. Following a second vacuum test failure, it shall be uncovered,
disassembled, reconstructed or replaced as directed by the Superintendent.
The manhole shall be retested by the vacuum test.
A.
General. Approval drawings shall be submitted by the
developer or licensed pipelayer for all structures or appurtenances
which shall eventually be connected to the municipal sewer system,
such as pump or ejector station, auxiliary power units for station,
etc. Drawings for special sewer construction, such as inverted siphons,
culverts or stream crossings, drain crossings, railroad or state highway
crossings, etc., shall also be submitted for approval.
B.
Bank gravel furnished and placed by the licensed pipelayer
shall consist of inert material that is hard durable stone and coarse
sand, free from loam and clay, surface coatings and deleterious materials,
and shall meet or exceed the specifications for gravel borrow listed
under Section M1.03.0 of the 1973 Massachusetts Department of Public
Works Standard Specifications for Highways and Bridges or the latest
revision thereto.
C.
Washed screen gravel furnished and placed by the licensed
pipe layer shall be washed and graded bank-run gravel or crushed stone
ranging in size from one-half (1/2) inch to one (1) inch and shall
be hard, durable and reasonably free from flat or laminated particles
so as to furnish a free-draining gravel base for sewer construction
or other foundation as directed by the Superintendent.
D.
Ordinary borrow furnished and placed by the licensed
pipelayer shall be material suitable for trench refill, as approved
by the Superintendent, conducive to compaction by the method of consolidation
approved for use on the project, free of stones larger than twelve
(12) inches in diameter, free from loam and clay, surface coatings
and deleterious materials and meeting or exceeding state Department
of Public Works Classification M1.01.0.
E.
Concrete masonry shall be used for thrust blocking,
foundation material, pipe cradles, half-section or full-section, manhole
drop inlet or chimney encasement or as otherwise directed by the Superintendent.
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 one-to-two-and-five-tenths-to-five
mix, and shall contain not less than four and five-tenths (4.5) bags
of cement per cubic yard. Steel reinforcement indicated on standard
sewer construction drawing[1] 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 (2) inches.
[Amended 10-18-2000 ATM, Art. 14]
[1]
Editor's Note: Said drawings are on file in
the Town Clerk's office, the Department of Public Works, the Planning
Office and the office of the Building Inspector and may be examined
there during regular office hours.
