SPECIFICATIONS FOR THE CONSTRUCTION OF WATER AND SEWER MAINS CONNECTING
TO THE WATER AND SEWER SYSTEMS OF THE CITY OF ITHACA, NEW YORK
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General information to Engineers, Contractors and persons
or corporations contemplating the construction of water and/or sewer lines
connecting to the City systems.
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It is the intent of these specifications to outline the
minimum acceptable requirements governing the construction of, and materials
used in water and sewer mains which will connect with the Ithaca water and
sewer systems, whether constructed for the City, either by City forces under
the direction of the Superintendent of Public Works, or by a contractor under
an agreement with the City; or constructed for private individuals, corporations,
or Water Districts, who may have received a permit, to connect with the City
system and which water and sewer mains are to be built by themselves or by
contractors under an agreement with them.
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No connections to any mains in the water or sewer system
may be made unless such connections are authorized by the Board of Public
Works, and the plans for the water or sewer main extension are approved by
the Board of Public Works.
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All work done on water and/or sewer main extensions connecting
to the Ithaca systems must conform to these specifications, and must be done
under the supervision and inspection of the Superintendent of Public Works
of the Board of Public Works, or under such inspection as may be otherwise
ordered by the Board of Public Works. The term "Inspector" hereinafter used
will mean the duly designated representative of the Board of Public Works.
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The rules and regulations of the Board of Public Works adopted January
28, 1970 and effective February 1, 1970 governing the installation and use
of service lines and mains, and the Plumbing Code of the City of Ithaca, shall
be considered a part of these specifications and shall govern such conditions
as are not herein specifically described.
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I - General
I-A EXCAVATION AND PREPARATION OF TRENCH
I-A-1. Description.
The trench shall be excavated to full depth and grade for
a distance of at least 50 feet in advance of pipe laying, but not more than
one average days pipe laying in advance of the work. The trench shall be so
braced and drained that the workmen may work therein safely and efficiently.
It is essential that the discharge from the trench dewatering pumps be conducted
to natural drainage channels, drains or storm sewers.
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I-A-2. Width of Trench.
The width of trench shall be ample to permit the pipe to
be laid and jointed properly, and the backfill to be placed and compacted
as specified. Trenches shall be of such extra width, when required, as will
permit the convenient placing of timber supports, sheeting and bracing, and
handling of fittings.
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Minimum width shall be sufficient to give clearance of at
least eight inches either side of the barrel of the pipe.
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I-A-3. Bell Holes.
Bell holes shall be provided at each joint to permit the
jointing to be made properly.
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I-A-4. Pipe Clearance in Rock.
Ledge rock, boulders, and large stones shall be removed
to provide a clearance of at least six inches below and eight inches on each
side of all pipe and fittings.
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I-A-5. Excavation to Grade.
The trench shall be excavated to the depth required so as
to provide a uniform and continuous bearing and support for the pipe on solid
and undisturbed ground at every point between bell holes. Any part of the
bottom of the trench excavated below the specified grade shall be corrected
with approved material, and thoroughly compacted as directed by the Inspector.
The finished grade shall be prepared accurately by means of hand tools.
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The subgrade beneath the center line of the pipe shall be
finished to within 0.03 feet of a straight line between pipe joints or batter
boards. All tolerance shall be above specified grade.
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If, in the opinion of the Inspector, soil conditions are
encountered at subgrade which require all or part of the work to be done in
accordance with Section I-A-6, the Inspector shall have the authority to order
the work to be done.
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I-A-6. Excavation in Poor Soil or Rock.
Where the bottom of the trench at subgrade is found to be
unstable or to include ashes, cinders, all types of refuse, vegetable or other
organic material, large pieces or fragments of inorganic material, or rock,
which in the judgment of the Inspector should be removed, the Contractor shall
excavate and remove such unsuitable material to the width and depth ordered
by the Inspector. Before the pipe is laid, the subgrade shall be made by backfilling
with an approved material in three-inch uncompacted layers. The layers shall
be thoroughly tamped as directed by the Inspector so as to provide a continuous
bearing and support for the pipe at every point between the bell holes, The
finished subgrade shall be prepared accurately by means of hand tools.
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The subgrade beneath the center line of the pipe shall be
finished to within 0.03 feet of a straight line between bell holes or batter
boards, and all tolerances shall be above the specified grade.
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I-A-7. Special Foundation in Poor Soil.
Where the bottom of the trench at subgrade is found to consist
of material which is unstable to such a degree that, in the opinion of the
Inspector, it cannot be removed and replaced with an approved material thoroughly
compacted in place to support the pipe properly, the contractor shall construct
a foundation for the pipe, consisting of piling, timber or other materials,
in accordance with plans approved by the Board of Public Works.
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I-A-8. Blasting.
Blasting for excavation will be permitted only after securing
the approval of the Inspector and only when proper precautions are taken for
the protection of persons or property. The hours of blasting will be fixed
by the Inspector. Any damage caused by blasting shall be repaired by the contractor
at his expense. The contractor's methods of procedure shall conform with State
laws and municipal ordinances.
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I-A-9. Braced and Sheeted Trenches.
Open-cut trenches shall be sheeted and braced as required
by any governing state laws, and as may be necessary to protect life, property
or the work. When close sheeting is required, it shall be so driven as to
prevent adjacent soil from entering the trench either below or through such
sheeting. Where sheeting and bracing are used the trench width shall be increased
accordingly.
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The Inspector reserves the right to order the sheeting driven
to the full depth of the trench or to such additional depths as may be required
for the protection of the work. Where the soil in the lower limits of a trench
has the necessary stability, the Inspector, at his discretion, may permit
the contractor to stop the driving of sheeting at some designated elevation
above the trench bottom. The granting of permission by the Inspector, however,
shall not relieve the contractor in any degree from his full responsibility
under the contract.
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Sheeting and bracing which have been ordered left in place
must be removed for a distance of three feet below the established street
grade or the existing surface of the street, whichever is lower. Trench bracing,
except that which must be left in place, may be removed when the backfilling
has reached the respective levels of such bracing. Sheeting, except that which
has been left in place, may be removed after the backfilling has been completed
or has been brought up to such an elevation as to permit its safe removal.
Sheeting and bracing may be removed before flushing the trench, but only in
such manner as will insure the adequate protection of the completed water
and/or sewer structures, and prevent the disturbance of adjacent ground.
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I-A-10. Care of Surface Material for Reuse.
All surface materials which, in the opinion of the Inspector,
are suitable for reuse in restoring the surface shall be kept separate from
the general excavation material, as directed by the Inspector.
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I-A-11. Piling Excavated Material.
All excavated material shall be piled in a manner that will
not endanger the work and that will avoid obstructing sidewalks, and driveways.
Hydrants under pressure, valve pit covers, valve boxes, curb stop boxes, fire
and police call boxes, or other utility controls shall be left unobstructed
and accessible until the work is completed. Gutters shall be kept clear or
other satisfactory provisions made for street drainage, and natural water
courses shall not be obstructed.
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I-A-12. Trenching by Hand Methods.
Hand methods for excavations shall be employed in locations
were obstructions are shown on drawings or where, in the opinion of the Inspector,
property can best be protected by digging by hand. In other locations the
contractor may use trench digging machinery.
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I-A-13. Barricades, Guards and Safety Provisions.
To protect persons from injury and to avoid property damage,
adequate barricades, construction signs, torches, lanterns and guards as required
shall be placed and maintained during the progress of the construction work
and until it is safe for traffic to use the highway. All material piles, equipment
and pipe which may serve as obstructions to traffic shall be enclosed by fences
or barricades and shall be protected by proper lights when the visibility
is poor. The rules and regulations of the local authorities respecting safety
provisions shall be observed.
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I-A-14. Maintenance of Traffic and Closing of Streets.
The contractor shall carry on the work in a manner which
will cause the least interruption to traffic, and may close to travel not
more than two consecutive blocks, upon the specific permission of the City,
including the cross street intersected. Where traffic must cross open trenches,
the contractor shall provide suitable bridges at street intersections and
driveways.
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The contractor shall post, where directed by the Inspector,
suitable signs indicating that a street is closed and necessary detour signs
for the proper maintenance of traffic.
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I-A-15. Structure Protection.
Temporary support, adequate protection and maintenance of
all underground and surface structures, drains, sewers and other obstructions
encountered in the progress of the work shall be furnished by the contractor
at his expense and under the direction of the Inspector. The structures which
may have been disturbed shall be restored upon completion of the work.
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I-A-16. Protection of Property and Surface Structures.
Trees, shrubbery, fences, poles and all other property and
surface structures shall be protected unless their removal is shown on the
drawings or authorized by the Inspector. When it is necessary to cut roots
and tree branches, such cutting shall be done under the supervision of the
Inspector.
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I-B BACKFILLING
I-B-1. Backfill Material.
All backfill material shall be free from cinders, ashes,
refuse, vegetable or organic material, boulders, rocks or stones, or other
material which in the opinion of the Inspector is unsuitable. However, from
one foot above the top of the pipe to the subgrade of the pavement, material
containing stones up to eight inches in their greatest dimension may be used,
unless specified otherwise herein.
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I-B-2. Use of Excavated Material as Backfill.
When the type of backfill material is not indicated on drawings
or specifications, the contractor may backfill with the excavated material,
provided that such material consists of loam, clay, sand, gravel, or other
material which, in the opinion of the Inspector, are suitable for backfilling.
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I-B-3. Sand or Gravel Backfill.
Where sand or gravel backfill is not indicated on the drawings
or specified herein, and in the opinion of the Inspector should be used in
any part of the work, the contractor shall furnish and backfill with sand
or gravel as directed.
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I-B-4. Backfilling Under Pipe.
All trenches shall be backfilled by hand, from the bottom
of the trench to the center line of the pipe, with sand, gravel, or other
approved material placed in layers of three inch and compacted by tamping.
Backfilling material shall be deposited in the trench for its full width on
each side of the pipe, fittings and appurtenances simultaneously.
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I-B-5. Backfilling Over Pipe.
From the center line of the pipe, fittings and appurtenances
to a depth of one foot above the top of the pipe, the trench shall be backfilled
by hand or by approved mechanical methods. The contractor shall use special
care in placing this portion of the backfill so as to avoid injuring or moving
the pipe.
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The backfill material from the center line of the pipe to
one foot above the pipe shall consist of approved excavated material which
shall be placed in three-inch layers and compacted by tamping.
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I-B-6. Backfilling in Freezing Weather.
Backfilling shall not be done in freezing weather except
by permission of the Inspector, and it shall not be made with frozen material.
No fill shall be made where the material already in the trench is frozen.
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I-B-7. Backfill Sand.
All sand used for backfill shall be a natural bank sand,
graded from fine to coarse, not lumpy, or frozen, and free from slag, cinders,
ashes, rubbish or other material which, in the opinion of the Inspector, is
objectionable or deleterious. It shall not contain a total of more than 10%
by weight of loam and clay, and all material must be capable of being passed
through a three-fourths-inch sieve. Not more than 5% shall remain on a No.
4 sieve.
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I-B-8. Backfill Gravel.
Gravel used for backfill shall consist of natural bank gravel
having durable particles graded from fine to coarse in a reasonably uniform
combination, with no boulders or stories larger than two inches in size. It
shall be free from slag, cinders, ashes, refuse or other deleterious or objectionable
materials. It shall not contain excessive amounts of loam and clay and shall
not be lumpy or frozen. No more than 15% shall be finer than No. 200 sieve.
Backfill gravel shall be used in the top 18 inches of backfill of all ditches
in City streets.
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II - WATER MAINS
II-A MATERIALS TO BE USED
II-A-1. Pipe and Fittings.
All pipe lines four inches in diameter and larger shall
be bell and spigot, tar-coated, cement lined, centrifugally cast pipe to meet
AWWA specifications; class of pipe used to be determined by the operating
pressure and conditions of the line. All fittings to be Class D, tar-coated,
long pattern, to meet AWWA specifications.
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The use of mechanical joints and rubber joint cast iron
pipe will be allowed by approval of the Board of Public Works.
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II-A-2. Valves.
Main line valves shall be "Darling" hub-end valves of the
type used by the City of Ithaca. Valves open left. (counterclockwise).
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II-A-3. Hydrants.
Hydrants shall be "Darling" B-50-B, five-inch hydrants,
of the type used by the City of Ithaca. Hoze nozzle threads to be City of
Ithaca standard. Hydrants shall be a 2-2 1/2" hoze nozzle and 1-4 1/2"
steamer nozzle.
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2 1/2" hoze nozzles to be City of Ithaca standard,
measuring 3" OD to top of thread with 7 1/2 threads to the inch. The
4 1/2" steamer nozzle shall be National standard measuring 5 3/4"
OD at the top of the thread and threaded four threads per inch.
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II-A-4. Valve Boxes.
Valve boxes shall be the Buffalo Screw Type roadway box,
with cover marked "Water."
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II-A-5. Manholes.
Manholes may be built of concrete masonry of 1-2-4 concrete,
using tight smooth forms, or standard cement manhole blocks loaned especially
for four-foot manholes.
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Manholes may be built of masonry using hard pressed brick.
Every fifth course of brick shall be laid as stretchers, the remainders to
be headers. Every brick shall have full mortar joints on the bottom and sides
which shall be formed at one operation by placing sufficient mortar on the
bed and forcing the brick into it. Horizontal joints shall not exceed 3/8"
and vertical joints on the inside of manholes shall not exceed 1/4". Joints
on the inside face are to be carefully rubbed full and struck as a manhole
is built up. In wet trenches water shall be kept drained away from manholes
until the concrete is set.
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No backfilling shall be done for 24 hours after completion
of the manhole.
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In freezing weather customary precautions of heating materials
and after protection shall be followed.
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Steps. Steps of cast iron, or of galvanized wrought iron,
3/4" in diameter, shall be securely placed in the inside of the manhole during
construction, not more than 18" apart.
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Diameter. Manholes five feet deep or less shall have a minimum
inside diameter of four feet at the bottom. Manholes 10 feet deep shall be
at least five feet in inside diameter and at intermediate depths the diameter
shall be in proportion.
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Frames and Covers. Manhole covers shall be set to the grade
given by the Inspector. Covers of manholes in streets shall correspond to
the type used and approved by the City of Ithaca in 1932, frame and cover
to weigh not less than 480 lbs. Depth of frame eight inches; diameter of cover
24 inches. Manholes in parkings where no traffic can be expected may use covers
of light weight type used in the City of Ithaca prior to 1932. Weight of frame
and cover not less than 245 lbs., depth of frame, four inches.
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II-B INSPECTION OF MATERIAL
II-B-1. Field Inspection.
All pipe and accessories shall be laid, jointed and tested
under pressure for defects and leakage in the manner specified and in the
presence of and as approved by the Inspector.
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II-B-2. Disposition of Defective Material.
All material found during the progress of the work to have
cracks, flaws, or other defects will be rejected by the Inspector. All defective
materials shall be promptly removed from the site.
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II-C HANDLING OF MATERIALS
II-C-1. Hauling.
Cast iron pipe, fittings, valves, hydrants and accessories
shall be loaded and unloaded by lifting with hoists or skidding so as to avoid
shock or damage. Under no circumstances shall such materials be dropped. Pipe
handled on skidways shall not be skidded or rolled against pipe already on
the ground.
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II-C-2. At Site of Work.
In distributing the material at the site of work, each piece
shall be unloaded opposite or near the place where it is to be laid in the
trench.
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II-C-3. Care of Pipe Coating and Lining.
Pipe shall be so handled that the coating and lining will
not be damaged. If, however, any part of the coating or lining is damaged,
the repair shall be made in a manner satisfactory to the Inspector.
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II-D ALIGNMENT AND GRADE
II-D-1. General.
The water main shall be laid and maintained to the required
lines and grades with fittings, valves and hydrants at the required locations;
spigots centered in bells; and all valves and hydrant stems plumb.
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Any changes in either line or grade shall be made by using
the proper fittings, and not by crowding the joints, except in laying pipe
along a curved line the Inspector may approve a small deviation in alignment
at each joint. See Section II-E-7.
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II-D-2. Depth of Pipe.
The top of the pipe shall be laid to a minimum depth of four feet below
the established grade. Any variations therefrom shall be made only with the
approval of the Inspector.
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II-E LAYING
II-E-1. Handling of Water Main Material into Trench
Proper implements, tools and facilities satisfactory to
the Inspector shall be provided and used for the safe and convenient prosecution
of the work. All pipes, fittings, valves and hydrants shall be carefully lowered
into the trench piece by piece by means of a derrick, ropes or other suitable
tools or equipment, in such a manner as to prevent damage to water main materials
and protective coatings and linings. Under no circumstances shall water main
materials be dropped or dumped into the trench.
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II-E-2. Hammer Test.
The pipe and fittings shall be inspected for defects and,
while suspended above grade, be rung with a light hammer to detect cracks.
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II-E-3. Cleaning Pipe and Fittings.
All lumps, blisters and excess tar-coating shall be removed
from the bell-and-spigot end of each pipe, and the outside of the spigot and
the inside of the bell shall be wire-brushed and wiped clean and dry and free
from oil and grease before the pipe is laid.
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II-E-4. Laying Pipe.
Every precaution shall be taken to prevent foreign material
from entering the pipe while it is being placed in the line. If the pipe-laying
crew cannot put the pipe into the trench and in place without getting earth
into it, the Inspector may require that before lowering the pipe into the
trench, a heavy, tight woven canvas bag of suitable size shall be placed over
each end and left there until the connection is to be made to the adjacent
pipe. During laying operations, no debris, tools, clothing or other materials
shall be placed in the pipe.
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After placing a length of pipe in the trench, the spigot
end shall be centered in the bell and the pipe forced home and brought to
correct line and grade. The pipe shall be secured in place with approved backfill
material tamped under it except at the bells. Pipe and fittings which do not
allow a sufficient and uniform space for joints shall be removed and replaced
with pipe and fittings of proper dimensions to insure such uniform space.
Precautions shall be taken to prevent dirt from entering the joint space.
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At times when pipe laying is not in progress, the open ends
of pipe shall be closed by a watertight plug or other means approved by the
Inspector. Joints of pipe in the trench which cannot be poured shall be caulked
with packing to make them as water tight as possible. This provision shall
apply during the noon hour as well as overnight. If water is in the trench,
the seal shall remain in place until the trench is pumped completely dry.
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II-E-5. Cutting Pipe.
The cutting of pipe for inserting valves, fittings, or closure
pieces shall be done in a neat and workmanlike manner without damage to the
pipe or cement lining and so as to leave a smooth end at right angles to the
axis of the pipe.
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When machine cutting is not available for cutting pipe 20
inches in diameter or larger, the electric-arc cutting method will be permitted
using a carbon or steel rod. Only qualified and experienced workman shall
be used at this work.
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The flame cutting of pipe by means of an oxyacetylene torch
shall not be allowed.
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II-E-6. Bell Ends to Face Direction of Laying.
Pipe shall be laid with bell ends facing in the direction
of laying unless directed otherwise by the Inspector.
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II-E-7. Permissible Deflection at Joints.
Whenever it is necessary to deflect pipe from a straight
line, either in the vertical or horizontal plane, to avoid obstruction or
plumb stems, or where long-radius curves are permitted, the amount of deflection
allowed shall not exceed that required for satisfactory caulking of the joint,
and shall be approved by the Inspector.
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Max. Deflection With Pipe Length of:
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Approx. Radius of Curve Produced by Succession of Joints With
Pipe Lead of:
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Pipe Diam.
(inch)
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Joint Opening
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16 ft.
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18 ft.
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20 ft.
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16 ft.
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18 ft.
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20 ft.
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4
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0.41
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14.8
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16.7
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18.5
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208
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234
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260
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6
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0.58
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14.8
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16.7
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18.5
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208
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234
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260
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8
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0.65
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12.9
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14.6
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16.2
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238
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268
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297
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10
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0.75
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12.4
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14.0
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15.5
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248
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279
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310
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12
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0.75
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10.5
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11.9
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13.2
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292
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327
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363
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16
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0.75
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7.9
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8.8
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9.7
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390
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440
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488
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II-E-8. Unsuitable Conditions for Laying Pipe.
No pipe shall be laid in water or when, in the opinion of
the Inspector, the trench conditions are unsuitable.
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II-F JOINTlNG
II-F-1. Yarning or Packing Material.
Yarning or packing material shall be molded or tubular rubber
rings. The above material shall be handled with care in order to prevent contamination
and shall be dry when put into place in the joint. The material shall be free
of oil, tar, or greasy substances.
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II-F-2. Placing of Yarning Material.
The yarning material shall be placed around the spigot end
of the pipe and shall be of proper dimensions to center the spigot in the
bell. When the spigot is shoved home, the yarning material shall be driven
tightly against the inside base or hub of the bell with suitable yarning tool.
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II-F-3. Depth of Jointing Material.
For lead joints a space not less than 2 1/4" in depth
shall be left in the bell in pipe having a nominal diameter of 20" or less;
2 1/2" in 24, 30 and 36" pipe; and 3" in pipe larger than 36".
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II-F-4. Lead.
Lead for caulking purposes shall contain not less than 99.73%
pure lead. Impurities shall not exceed the following limits:
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Arsenic, antimony and tin together
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0.015%
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Copper
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0.08%
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Zinc
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0.002%
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Iron
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0.002%
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Bismuth
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0.25%
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Silver
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0.02%
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The producer's name or the mark of Lead Industries shall be clearly
cast or stamped upon each piece of lead.
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II-F-5. Heating and Pouring of Lead.
Lead shall be heated in a melting pot kept in easy reach
of the joint to be poured--so that the molten metal will not be chilled in
being carried from the melting pot to the joint--and shall be brought to a
proper temperature so that when stirred it will show a rapid change of color.
Before pouring, all scum shall be removed. Each joint shall be made in one
continuous pouring filling the entire joint space with solid lead. Spongy
or imperfectly filled joints shall be burned out and repoured.
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II-F-6. Position of Joint Runner.
The joint runner shall fit snugly against the face of the
bell and the outside of the pipe shall be dammed with clay to form a pouring
lip to provide for filling the joint flush with the face and to the top of
the bell.
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II-F-7. Caulking Lead Joints.
After the lead has cooled to the temperature of the pipe,
lead joints shall be caulked with pneumatic or hand tools operated by competent
workmen, until such joints are thoroughly compacted and watertight. The finished
joint shall show a hard and even hammered surface overall. Care should be
taken not to overstrain the bells during caulking.
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II-G SETTING VALVES AND FITTINGS
II-G-1. General.
Valves, fittings, plugs and caps shall be set and jointed
to pipe in the manner heretofore specified for cleaning, laying and jointing
pipe.
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II-G-2. Valve Boxes and Manholes.
(See Sections II-A-4 and II-A-5.)
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A valve box or manhole shall be provided for every valve.
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The valve box shall not transmit shock or stress to the
valve and shall be centered plumb over the operating nut of the valve, with
the box cover flush with the surface of the ground, or such other level as
may be directed.
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Where valves are in manholes the operating nut shall be
readily accessible for operation through the opening in the manhole, which
shall be set flush with the surface of the finished pavement. Manholes shall
be so constructed as to permit minor repairs and afford protection to the
valve and pipe from impact where they pass through the manhole wall.
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II-G-3. Drainage of Mains.
Mains shall be drained through drainage branches or blowoffs
to dry wells from which the water can be pumped. Drainage branches, blowoffs,
air vents and appurtenances shall be provided with gate valves and shall be
located and installed as shown on the plans.
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Drainage branches or blowoffs shall not be connected to
any sewer, submerged in any stream or be installed in any other manner that
will permit back siphonage into the distribution system.
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II-G-4. Dead Ends.
All dead ends on new mains shall be closed with cast iron
plugs or caps, with or without a blowoff cock, as shown on the drawings.
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II-H SETTING HYDRANTS
II-H-1. Location.
Hydrants shall be located as shown or as directed and in
a manner to provide complete accessibility, and also in such a manner that
the possibility of damage from vehicles or injury to pedestrians will be minimized.
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When placed behind the curb, the hydrant barrel shall be
set so that no portion of the pumper or hoze nozzle cap will be less than
six inches nor more than 12 inches from the gutter face of the curb.
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When set in the lawn space between the curb and the sidewalk,
or between the sidewalk and the property line, no portion of the hydrant or
nozzle cap shall be within six inches of the sidewalk.
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II-H-2. Position.
All hydrants shall stand plumb and shall have their nozzles
parallel with or at right angles to the curb, with the pumper nozzle facing
the curb, except that hydrants having two hoze nozzles 90º apart shall
be set with each nozzle facing the curb at an angle of 45º. Hydrants
shall be set to the established grade, with nozzles at least 12 inches above
the ground, as shown or as directed by the Inspector.
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II-H-3. Connection to Main.
Each hydrant shall be connected to the main with a six-inch
cast-iron branch controlled by an independent six-inch gate valve, except
as otherwise directed.
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II-H-4. Hydrant Drainage in Pervious Soil.*
Whenever a hydrant is set in soil that is pervious, drainage
shall be provided at the base of the hydrant by placing course gravel or crushed
stone mixed with course sand, from the bottom of the trench to at least six
inches above the waste opening in the hydrant and to a distance of one foot
around the elbow. No drainage system shall be connected to the sewer.
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II-H-5. Hydrant Drainage in Impervious Soil.*
Whenever a hydrant is set in clay or other impervious soil,
a drainage pit two feet in diameter and three feet deep shall be excavated
below each hydrant and filled compactly with course gravel or crushed stone
mixed with course sand, under and around the elbow of the hydrant and to a
level of six inches above the waste opening.
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*Note: The Inspector shall determine whether II-H-4 or II-H-5 is applicable.
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II-I ANCHORAGE
II-I-1. Anchorage for Hydrants.
The bowl of each hydrant shall be well braced against unexcavated
earth at the end of the trench with stone or slabs or concrete backing.
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II-I-2. Anchorage for Plugs, Caps, Tees and Bends.
All plugs, caps, tees and bends deflecting 22 1/2º
or more on mains eight inches in diameter or larger shall be provided with
a reaction backing.
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II-I-3. Reaction Backing.
Reaction backing shall be concrete of a mix not leaner than
1 cement: 2 1/2 sand: 5. stone, and having a compressive strength of
not less than 2,000 psi, at 28 days. Backing shall be placed between solid
ground and the filling to be anchored; the area of bearing on the pipe and
on the ground in each instance shall be that shown or directed by the Inspector.
The backing shall, unless otherwise shown or directed, be so placed that the
pipe and fitting joints will be accessible for repair.
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II-J HYDROSTATIC TESTS
II-J-1. Pressure Test.
After the pipe has been laid and partially backfilled as
directed by the Inspector, all newly laid pipe, or any valved section thereof,
shall be subject to a hydrostatic pressure equal to a pressure 50% greater
than the computed working pressure of the section under test based on the
lowest point in the section under test and corrected to the elevation of the
test gage.
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II-J-2. Duration of Pressure Test.
The duration of each pressure test shall be at least one
hour.
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II-J-3. Procedure.
Each valve section of pipe shall be slowly filled with water
and the specified test pressure, based on the elevation of the lowest point
of the line or section under test and corrected to the elevation of the test
gage, shall be applied by means of a pump connected to the pipe in a manner
satisfactory to the Inspector.
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II-J-4. Expelling Air before Test.
Before applying the specified test pressure, all air shall
be expelled from the pipe. If hydrants or blowoffs are not available at high
places, taps at points of highest elevation shall be made before the test
is made, and plugs inserted after the test has been completed.
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II-J-5. Examination under Pressure.
All exposed pipes, fittings, valves, hydrants and joints
shall be carefully examined during the open-trench test. Joints showing visible
leaks shall be recaulked until tight. Any cracked or defective pipe, fittings,
valves or hydrants discovered in consequence of this pressure test shall be
removed and replaced with sound material, and the test shall be repeated until
satisfactory to the Inspector.
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II-J-6. Leakage Test.
A leakage test shall be conducted after the pressure test
has been satisfactorily completed. The duration of each leakage test shall
be two hours, and during the test the main shall be subject to a pressure
equal to the computed working pressure of the lowest point in the section
and corrected to gage elevation except that the test pressure shall be a minimum
of 100 lbs., square inch in the lowest point in the section.
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Leakage is defined as the quantity of water to be supplied
into the new laid pipe, or any valved section thereof, necessary to maintain
the specified leakage test pressure after the pipe has been filled with water
and the air expelled.
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No pipe installation will be accepted until the leakage
is less than the number of gallons per hour as determined by the formula:
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L = ND P/1,850
in which L equals the allowable leakage in gallons per hour; N is the
number of joints in the length of pipe tested; D is the normal diameter of
the pipe, in inches; and P is the average test pressure during the leakage
test, in pounds per square inch gage.
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II-J-7. Variation from Permissible Leakage.
Should any test of pipe laid disclose leakage greater than
that specified in Section II-J-6, the defective joints shall be located and
repaired until the leakage is within the specified allowance.
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II-J-8. Time for Making Test of Pipe
Lead-jointed pipe may be subjected to hydrostatic pressure
and inspected and tested for leakage at any convenient time after the trench
has been partially backfilled except at the joints.
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Where any section of a main is provided with concrete reaction
backing, the hydrostatic pressure test shall not be made until at least five
days have elapsed after the concrete reaction backing is installed. If high-early-strength
cement is used in the concrete reaction backing, the hydrostatic pressure
test shall not be made until at least two days have elapsed.
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II-J-9. Interruption of Service.
No valve or other control on the existing system shall be
operated for any purpose by the contractor. The City will operate all valves,
hydrants, blowoffs and curb stops.
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II-K DISINFECTION
II-K-1. Form of Chlorine and Means of Application.
Before being placed in service, all new water distribution
systems and repaired portions of, or extensions to, existing systems shall
be chlorinated. If the available water is more alkaline than pH 8, the holding
time in the main shall be increased at the discretion of the engineer.
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II-K-2. Form of Applied Chlorine
Any of the following methods of procedure (arranged in order
of preference) shall be followed, subject to the approval of the engineer:
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Liquid chlorine gas-water mixture
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Direct chlorine feed
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Calcium or sodium hypochlorite and water mixture
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Chlorinated lime and water mixture
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II-K-3. Liquid Chlorine.
A chlorine gas-water mixture shall be applied by means of
a solution-feed chlorinating device, or, if approved by the engineer, the
dry gas may be fed directly through proper devices for regulating the rate
of flow and providing effective diffusion of the gas into the water within
the pipe being treated. Chlorinating devices for feeding solutions of the
chlorine gas or the gas itself must provide means for preventing the backflow
of water into the chlorine cylinder.
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II-K-4. Chlorine bearing Compounds in Water.
On approval of the engineer, a mixture of water and a chlorine-bearing
compound of known chlorine content may be substituted as an alternative for
liquid chlorine.
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II-K-4.1. Chlorine bearing Compounds.
The chlorine-bearing compounds which may be used are: (1)
calcium hypochlorite, (comparable to commercial products known as "HTH," "Perchloron"
and "Pittchlor"), (2) chlorinated lime (frequently called chloride of lime
and known to industry as bleaching powder) and (3) sodium hypochlorite.
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II-K-4.2. Proportions of Mixtures.
A five-percent solution of the powder shall be prepared,
consisting of 5% of powder to 95% of water by weight, due attention being
given to the chlorine content of the product used. The calcium hypochlorite
or chlorinated lime and water mixture, first made into a paste and then thinned
to a slurry with clean water, shall be injected or pumped into the newly laid
pipe after preliminary flushing. If sodium hypochlorite is used mix the solution
as purchased, with water to obtain the desired concentration of chlorine and
feed into the pipe under treatment in the same manner as is used for feeding
other hypochlorites.
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II-K-5. Point of Application.
The preferred point of application of the chlorinating agent
shall be at the beginning of the pipeline extension or any valved section
of it and through a corporation stop inserted by the owner (except in new
distribution system) in the top of the newly laid pipe. The water injector
for delivering the chlorine-bearing water into the pipe should be supplied
from a tap on the pressure side of the gate valve controlling the flow into
the pipeline extension. In a new system, application of chlorine may be made
advantageously at the pumping station, the elevated tank, the standpipe or
the reservoir. When properly cleaned first, these units are thus chlorinated
adequately.
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II-K-6. Rate of Application.
Water from the existing distribution system or other source
of supply shall be controlled so as to flow slowly into the newly laid pipeline
during the application of chlorine. The rate of chlorine mixture flow shall
be in such proportion to the rate of water entering the pipe that the chlorine
dose applied to the water entering the newly laid pipe shall be at least 40
to 50 ppm. This may require as much as 100 ppm. of chlorine in the water left
in the line after chlorination. A convenient method of determining the rate
of flow of water into the line to be treated is to start with the line full
of water and measure the rate of discharge at a hydrant with a pilot gage.
Great flexibility is made possible by providing a series of orifices to give
good gage readings at high and low flows.
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II-K-7. Preventing Reverse Flow.
Valves shall be manipulated so that the strong chlorine
solution in the line being treated will not flow back into the line supplying
the water.
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II-K-8. Retention Period.
Treated water shall be retained in the pipe long enough
to destroy all nonspore-forming bacteria. This period should be at least 24
hours and preferably longer, as may be directed. After the chlorine-treated
water has been retained for the required time, the chlorine residual at the
pipe extremities and at other representative points should be at least 25
ppm.
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II-K-9. Chlorinating Valves and Hydrants.
In the process of chlorinating newly laid pipe, all valves
or other appurtenances shall be operated while the pipeline is filled with
the chlorinating agent.
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II-K-10. Final Flushing and Test.
Following chlorination, all treated water shall be thoroughly
flushed from the newly laid pipeline at its extremities until the replacement
water throughout its length shall, upon test, be proved comparable to the
quality of water served the public from the existing water supply system.
This quality of water delivered by the new main should continue for a period
of at least two full days as demonstrated by laboratory examination of samples
taken from a tap located and installed in such a way as to prevent outside
contamination.
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II-K-11. Repetition of Procedure.
Should the initial treatment fail to result in the conditions
specified in Section K-10, the chlorination procedure shall be repeated until
such results are obtained.
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III - SEWER MAINS
III-A MATERIALS TO BE USED
III-A-1. Pipe and Fittings.
All sewer mains shall be cement-asbestos with a minimum
inside diameter of eight inches.
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No other specifications for concrete, or cement asbestos
sewers are herein contained. The use of other materials is not prohibited
and may be done under standard specifications submitted to and approved by
the Board of Public Works.
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II-A-2. Manholes.
Manholes shall be constructed at every change of line or
grade of the sewer main, at every main intersection or branch, (except branches
for house connections) and in straight runs of main so that the distance between
manholes shall not exceed 300 feet, except where the grade of the sewer is
more than five feet in 100 feet the distance between the manholes shall not
exceed 250 feet.
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Manholes may be precast of concrete masonry of 1-2-4 concrete,
using tight smooth forms, or standard cement manhole blocks formed especially
for four-foot manholes.
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Manholes may be built of brick masonry using hard pressed
brick. Every fifth course of brick shall be laid as stretchers, the remainder
to be headers. Every brick shall have full mortar joints on the bottom and
sides which shall be formed at one operation by placing sufficient mortar
on the bed and forcing the brick into it. Horizontal joints shall not exceed
3/8" and vertical joints on the inside of the manholes shall not exceed 14".
Joints on the inside face are to be carefully rubbed full and struck as a
manhole is built. The outside of the manhole shall be smoothly and evenly
plastered with cement mortar one-half-inch thick. Such plaster coat shall
be applied in one operation after all brick has been placed and must not be
applied by the mason working within the manhole as the brick courses are laid
up. Plaster shall be proportioned one part Portland cement to 2 1/2 parts
mortar sand.
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Manhole Bottoms. Inverts of manholes shall be formed by
running the sewer pipe through the manhole cutting out the top half of the
pipe after the manhole has been completed. Concrete bottoms of manholes shall
be placed in two layers. The top of the bottom layer shall be level with the
horizontal diameter of the pipe, and upon this layer the brick masonry shall
be started. The depth of this concrete shall be everywhere at least six inches
thick. Particular care must be exercised to insure this depth under the invert.
After the top of the pipe has been cut off and the invert left in the concrete
base, a second concrete floor must be applied on top of the original bottom
to the height of the top of the sewer pipe leaving the manhole. This floor
shall be neatly shaped to meet the cut half of the sewer pipe, and shall serve
to confine the sewage from overflowing on the manhole bottom if the sewer
should flow more than half full.
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Where invert of manhole is below ground water level, manholes
shall be waterproof on the outside of the plaster coat with suitable bituminous
waterproofing to a line one foot higher than the apparent ground water level.
In wet trenches water shall be kept drained away from manholes until the concrete
work is set.
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No backfilling shall be done until the plaster coat on the
outside of the manhole shall have set for 24 hours.
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In freezing weather customary precautions of heating materials
and after pretection shall be followed.
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Steps. Steps of cast iron or of galvanized wrought iron,
3/4" in diameter, shall be securely placed in the inside of the manhole during
construction, not more than 18 inches apart.
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Diameter. Manholes five feet deep or less shall have an
inside diameter of four feet at the bottom. Manholes 10 feet deep shall be
five feet in inside diameter and at intermediate depths the diameter shall
be in proportion.
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Frames and Covers. Manhole covers shall be set to the grade
given by the Inspector. Covers of manholes in streets shall correspond to
the type used and approved by the City of Ithaca in 1932, frame and cover
to weigh not less than 480 lbs. Depth of frame eight inches, diameter of cover
24 inches. Manholes in parkings where no traffic can be expected may use covers
of the light weight type used in the City of Ithaca prior to 1932. Weight
of frame and cover not less than 245 lbs., depth of frame four inches.
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III-B DISPOSITION OF DEFECTIVE MATERIAL
All material found during the progress of the work to have
cracks, flaws, blisters or other defects shall be rejected by the Inspector.
All defective material shall be promptly removed from the site.
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III-C ALIGNMENT AND GRADE
Sewers shall be laid straight to line and grade between
manholes.
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The alignment and grade of the sewer line shall be checked
from a string line stretched along the center of the pipe between batter boards,
at every 25 feet. The batter board grades are taken from the engineer's grade
stakes. The elevation of the batter boards above the invert of the pipe shall
be constant for adjacent batter boards. Batter boards shall be set at every
change in line and grade.
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III-D LAYING
III-D-1. Handling Main Material into Trench.
Proper implements, tools, and facilities satisfactory to
the Inspector shall be provided and used for the safe and convenient prosecution
of the work. All pipe and fittings shall be carefully lowered into the trench
piece by piece by means of a derrick, ropes or other suitable tools or equipment,
in such a manner as to prevent damage to sewer main materials. Under no circumstances
shall sewer main material be dropped or dumped into the trench.
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III-D-2. Pipe Laying.
All pipe shall be laid with ends abutting and true to line
and grade, so fitted and matched that a smooth uniform invert will be formed.
The bottom of the trench shall be shaped so as to conform as nearly as possible
to the outside of the pipe, particular care being taken to recess the bottom
of the trench in such a manner as to relieve the bell of all load.
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III-D-3. Depth.
In streets or highways sewers shall be laid to a minimum
depth of three feet, grade permitting.
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III-D-4. Unsuitable Conditions for Laying Pipe.
No pipe shall be laid in water or when, in the opinion of
the Inspector, trench conditions are unsuitable.
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III-E JOINTING
III-E-1. Joints.
Pipe joints shall conform to both the materials and methods
of installation of the manufacturer of the particular cement-asbestos pipe
furnished for the job.
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III-E-2. Joints in Cold Weather.
No joints shall be poured when pipe is at a temperature
below freezing. When the air temperature is below 40º F. the part of
the pipe to be joined shall be heated and a paint coat of G-K primer, or equal,
applied both to spigot end and inside of bell before pipes are joined preparatory
to pouring.
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III-F TESTING
III-F-1. Cleaning and Flushing.
The interior of the sewer shall, as the work progresses,
be cleared of all dirt, surplus joint material and superfluous material of
every description.
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No sewer main shall be finally joined to the City System
until it has been satisfactorily cleaned and flushed.
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III-F-2. Testing.
On a completion of any sewer or such portion of the same
as may be directed, and before any connection has been made therewith, the
sewer may be tested for leakage or infiltration of ground water on the order
of the Inspector. Contractors shall supply all facilities for making such
tests. It is the intent of these specifications to have the sewer so constructed
that the quantity of infiltration will be kept at a minimum. The allowable
leakage shall not exceed a rate of flow of 175 gallons per 24 hours per inch
of diameter per 1,000 linear feet of sewer tested. Should any leaky or defective
joints or defective construction be found they shall be promptly made good,
and should any defective pipes or specials be discovered they shall be replaced
with sound pipes or specials in a satisfactory manner and without cost to
the City.
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