A.
Pipe and fittings.
(1)
All pipelines four inches in diameter and larger shall
be bell-and-spigot, tar-coated, cement-lined, centrifugally cast pipe
to meet American Water Works Association specifications, the class
of pipe used to be determined by the operating pressure and conditions
of the line. All fittings shall be Class D, tar-coated and long pattern,
to meet American Water Works Association specifications.
(2)
The use of mechanical joints and rubber joint cast-iron
pipe will be allowed by approval of the Board of Public Works.
B.
Valves. Main line valves shall be Darling hub-end
valves of the type used by the City of Ithaca. Valves open to the
left (counterclockwise).
C.
Hydrants.
(1)
Hydrants shall be Darling B-50-B five-inch hydrants
of the type used by the City of Ithaca. Hose nozzle threads shall
be City of Ithaca standard. Hydrants shall have two two-and-one-half-inch
hose nozzles and one four-and-one-half-inch steamer nozzle.
(2)
Two-and-one-half-inch hose nozzles shall be City of
Ithaca standard, measuring three inches OD to the top of thread with
7 1/2 threads to the inch. The four-and-one-half-inch steamer
nozzle shall be National standard, measuring 5 3/4 inches OD
at the top of the thread and threaded four threads per inch.
D.
Valve boxes. Valve boxes shall be the Buffalo screw
type roadway box, with the cover marked "water."
E.
Manholes.
(1)
Manholes may be built of concrete masonry of 1-2-4
concrete, using tight smooth forms, or standard cement manhole blocks
formed especially for four-foot manholes.
(2)
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 inch, and vertical joints on
the inside of manholes shall not exceed 1/4 inch. Joints on the inside
face are to be carefully rubbed full and struck as the manhole is
built up. In wet trenches water shall be kept drained away from manholes
until the concrete is set.
(3)
No backfilling shall be done for 24 hours after completion
of the manhole.
(4)
In freezing weather, customary precautions of heating
materials and after-protection shall be followed.
(5)
Specifications.
(a)
Steps. Steps of cast-iron or of galvanized wrought
iron 3/4 inch in diameter shall be securely placed in the inside of
the manhole during construction, not more than 18 inches apart.
(b)
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.
(c)
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. The frame and cover shall weigh not less than 480 pounds,
the depth of the frame shall be eight inches, and the diameter of
the cover shall be 24 inches. Manholes in parking areas where no traffic
can be expected may use covers of lightweight type used in the City
of Ithaca prior to 1932. The weight of the frame and cover shall be
not less than 245 pounds, and the depth of the frame shall be four
inches.
A.
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.
B.
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.
A.
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.
B.
At the site of the work. In distributing the material
at the site of the work, each piece shall be unloaded opposite or
near the place where it is to be laid in the trench.
C.
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.
A.
General.
(1)
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.
(2)
Any changes in either line or grade shall be made
by using the proper fittings and not by crowding the joints; except
that, in laying pipe along a curved line, the inspector may approve
a small deviation in alignment at each joint. See Subsection G below.
B.
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.
A.
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.
B.
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.
C.
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.
D.
Laying pipe.
(1)
Every precaution shall be taken to prevent foreign
material from entering the pipe while it is being placed in the line.
If the pipelaying 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.
(2)
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 ensure such uniform space. Precautions shall
be taken to prevent dirt from entering the joint space.
(3)
At times when pipelaying 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 watertight 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.
E.
Cutting pipe.
(1)
The cutting of pipe for inserting valves, fittings
or closure pieces shall be done in a neat and professional 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.
(2)
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 workers shall be used on this work.
(3)
The flame-cutting of pipe by means of an oxyacetylene
torch shall not be allowed.
F.
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.
G.
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.
|
Maximum Deflection with Pipe Length of:
|
Approximate Radius of Curve Produced by
Succession of Joints with Pipe Lead of:
| |||||||
|
Pipe Diameter
(inches)
|
Joint Opening
|
16 Feet
|
18 Feet
|
20 Feet
|
16 Feet
|
18 Feet
|
20 Feet
| |
|
4
|
0.41
|
14.8
|
16.7
|
18.5
|
208
|
234
|
260
| |
|
6
|
0.58
|
14.8
|
16.7
|
18.5
|
208
|
234
|
260
| |
|
8
|
0.65
|
12.9
|
14.6
|
16.2
|
238
|
268
|
297
| |
|
10
|
0.75
|
12.4
|
14.0
|
15.5
|
248
|
279
|
310
| |
|
12
|
0.75
|
10.5
|
11.9
|
13.2
|
292
|
327
|
363
| |
|
16
|
0.75
|
7.9
|
8.8
|
9.7
|
390
|
440
|
488
| |
H.
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.
A.
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.
B.
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 a suitable yarning tool.
C.
Depth of jointing material. For lead joints, a space
not less than 2 1/4 inches in depth shall be left in the bell
in pipe having a nominal diameter of 20 inches or less, 2 1/2
inches in twenty-four-, thirty- and thirty-six-inch pipe and three
inches in pipe larger than 36 inches.
D.
E.
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.
F.
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.
G.
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 workers 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.
A.
General. Valves, fittings, plugs and caps shall be
set and jointed to pipe in the manner heretofore specified for cleaning,
laying and jointing pipe.
B.
(1)
A valve box or manhole shall be provided for every
valve.
(2)
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.
(3)
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.
C.
Drainage of mains.
(1)
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.
(2)
Drainage branches or blowoffs shall not be connected
to any sewer, submerged in any stream or installed in any other manner
that will permit backsiphonage into the distribution system.
D.
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.
A.
Location.
(1)
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.
(2)
When placed behind the curb, the hydrant barrel shall
be set so that no portion of the pumper or hose nozzle cap will be
less than six inches nor more than 12 inches from the gutter face
of the curb.
(3)
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.
B.
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
hose nozzles 90° apart shall be set with each nozzle facing the
curb at an angle of 45°. 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.
C.
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.
D.
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 coarse gravel or crushed stone mixed with coarse 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. (NOTE: The Inspector shall determine whether this subsection or Subsection E is applicable.)
E.
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 coarse gravel or crushed stone mixed with coarse sand under and around the elbow of the hydrant and to a level of six inches above the waste opening. (NOTE: The Inspector shall determine whether this subsection or Subsection D is applicable.)
A.
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.
B.
Anchorage for plugs, caps, tees and bends. All plugs,
caps, tees and bends deflecting 22 1/2° or more on mains
eight inches in diameter or larger shall be provided with a reaction
backing.
C.
Reaction backing. Reaction backing shall be concrete
of a mix not leaner than one cement to 2 1/2 sand to five stone
and having a compressive strength of not less than 2,000 pounds per
square inch at 28 days. Backing shall be placed between solid ground
and the fitting to be anchored, and 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.
A.
Pressure test.
(1)
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 gauge.
(2)
The duration of each pressure test shall be at least
one hour.
B.
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 gauge, shall be applied by means of a
pump connected to the pipe in a manner satisfactory to the inspector.
C.
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.
D.
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.
E.
Leakage test.
(1)
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 gauge elevation, except that
the test pressure shall be a minimum of 100 pounds per square inch
in the lowest point in the section.
(2)
"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.
(3)
No pipe installation will be accepted until the leakage
is less than the number of gallons per hour as determined by the formula:
|
L
|
=
|
ND ** P/1,850
| ||
|
Where:
| ||||
|
L
|
=
|
The allowable leakage in gallons per hour.
| ||
|
N
|
=
|
The number of joints in the length of pipe tested.
| ||
|
D
|
=
|
The normal diameter of the pipe, in inches.
| ||
|
P
|
=
|
The average test pressure during the leakage
test, in pounds per square inch gauge.
| ||
F.
Variation from permissible leakage. Should any test of pipe laid disclose leakage greater than that specified in Subsection E, the defective joints shall be located and repaired until the leakage is within the specified allowance.
G.
Time for making test of pipe.
(1)
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.
(2)
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 was 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.
H.
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.
A.
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 8.0, the holding time
in the main shall be increased at the discretion of the Engineer.
B.
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:
C.
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.
D.
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.
(1)
Chlorine-bearing compounds. The chlorine-bearing compounds
which may be used are:
(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.
E.
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 a 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.
F.
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
parts per million. This may require as much as 100 parts per million
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 gauge. Great flexibility is
made possible by providing a series of orifices to give good gauge
readings at high and low flows.
G.
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.
H.
Retention period. Treated water shall be retained
in the pipe long enough to destroy all non-spore-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 parts per
million.
I.
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.
J.
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.
