A.
Ductile iron pipe and fittings.
(1)
Ductile iron pipe shall be centrifugally cast and shall conform
to the requirements of the American Water Works Association Specifications
C-151, as amended and revised to date.
(2)
Ductile iron pipe shall be thickness Class 52. All ductile iron
pipe and fittings shall be cement-lined in accordance with American
Water Works Association Specifications C-104, as amended.
(3)
Ductile iron pipe shall be provided with mechanical joints,
or shall be push-on Tyton® joint pipe as manufactured by the United
States Pipe and Foundry Company, or approved equal, conforming to
the American Water Works Association Specifications C-110 and C-111.
All iron fittings, including Y-branches, shall conform to American
Water Works Association Specifications C-110, latest revision, except
that fittings shall be provided with joints suitable for use with
the adjoining pipe. Ductile iron saddles shall be subject to the approval
of the engineer.
B.
Asbestos-cement pipe and fittings.
(1)
Asbestos-cement pipe and fittings shall conform to the requirements
of the American Society for Testing Materials Specifications C-428
for nonpressure sewer pipes, and C-296 for pressure pipes, as amended
and revised to date. Asbestos-cement pipe and fittings shall be a
minimum of Class 2400 for depths of cover under 10 feet, and a minimum
of Class 3300 for depths of cover 10 feet or more.
(2)
All asbestos-cement pipe and fittings shall be furnished complete
with sleeve and gasket-type couplings designed for use with the size
and class of pipe specified.
(3)
Ductile iron fittings for use with asbestos-cement pipe shall
conform to the requirements for ductile iron fittings hereinbefore
specified.
C.
Vitrified clay pipe and fittings.
(1)
Vitrified clay pipe and fittings shall conform to the requirements
of the American Society for Testing Materials Specifications C-700,
as amended and revised to date. Vitrified clay pipe and fittings shall
be extra strength.
(2)
All vitrified clay pipe and fittings shall have factory-fabricated,
gasket-type couplings with "O" ring joints which conform to the American
Society for Testing Materials Specification C-425, as amended and
revised to date.
D.
Concrete. Any concrete required for cradles, pads, drop connections
at manholes, and any other miscellaneous items shall be 4,000 psi
conforming to the requirements set forth elsewhere herein.
Excavation and backfill shall conform to the requirements for
subsurface structure excavation. The contractor shall provide adequate
equipment and so operate it as to maintain an essentially dry excavation,
stable trench bottoms, suitable working conditions, and protection
from water damage throughout and until the completion of the work.
A.
Pipe shall be laid in straight lines between manholes except when
otherwise specifically provided or directed by the engineer. When
deviation from straight line is permitted, the deflection of each
joint shall not exceed the manufacturer's recommended maximum for
the type of joint and size of pipe being installed. All pipe shall
be laid to uniform grades between manholes.
B.
Before making each joint, the ends of the pipes and all joint members
shall be thoroughly cleaned. All jointing shall be done in strict
accordance with the manufacturer's recommendation and the direction
of the engineer.
C.
No defective or leaking pipe, fittings, joints, connection, manholes
or other parts of the work will be acceptable. All visible leakage
of any description, and no matter where located shall be corrected
by the contractor in a manner satisfactory to the engineer, whether
or not the total leakage into the sewer is within the allowable maximum
as determined by exfiltration tests.
A.
Exfiltration tests shall be made under the supervision of the engineer,
and no connections to flowing lines permitted until the testing is
complete and satisfactory results have been obtained. The contractor
shall furnish all labor, material and equipment necessary for the
exfiltration tests.
B.
Prior to the start of the exfiltration test, all construction work
for the system under test shall be completed. This includes backfilling
and completion of all manholes.
A.
The test is conducted between two consecutive manholes, as directed
by the engineer.
B.
The test section of the sewer lines is plugged at each end. One of
the plugs used at the manhole must be tapped and equipped for the
air inlet connection for filling the line from the air compressor.
C.
All service laterals, stubs and fittings into the sewer test section
should be properly capped or plugged, and carefully braced against
the internal pressure to prevent air leakage by slippage and blowouts.
D.
Connect air hose to tapped plug selected for the air inlet.
E.
Connect another air hose between the air compressor (or other source
of compressed air) and the air control equipment. This completes the
test equipment set up. Test operations may commence.
F.
Supply air to the test section slowly, filling the pipeline until
a constant pressure of 3.5 psig is maintained. The air pressure must
be regulated to prevent the pressure inside the pipe from exceeding
5.0 psig.
G.
When constant pressure of 3.5 psig is reached, throttle the air supply
to maintain the internal pressure above 3.0 psig for at least five
minutes. This time permits the temperature of the entering air to
equalize with the temperature of the pipe wall. During this stabilization
period, it is advisable to check all capped and plugged fittings with
a soap solution to detect any leakage at these connections. If leakage
is detected at any cap or plug, release the pressure in the line and
tighten all leaky caps and plugs. Then start the test operation again
by supplying air. When it is necessary to bleed off the air to tighten
or repair a faulty plug, a new five-minute interval must be allowed
after the pipeline has been refilled.
H.
After the stabilization period, adjust the air pressure to 3.5 psig
and shut off or disconnect the air supply. Observe the gauge until
the air pressure reaches 3.0 psig. At 3.0 psig, commence timing with
a stop watch which is allowed to run until the line pressure drops
to 2.5 psig, at which time the stop watch is stopped. The time required,
as shown on the stop watch, for a pressure loss of 0.5 psig is used
to compute the air loss. Most authorities consider it unnecessary
to determine the air temperature inside the pipe line and the barometric
pressure at the time of the test.
I.
If the time, in minutes and seconds, for the air pressure to drop
from 3.0 to 2.5 psig is greater than that shown in Table 16.112.020
for the designated pipe size, the section undergoing test shall have
passed and shall be presumed to be free of defects. The test may be
discontinued at that time.
J.
If the time, in minutes and seconds, for the 0.5 psig drop is less
than shown in Table 16.112.020 for the designated pipe size, the section
of pipe shall not have passed the test; therefore, adequate repairs
must be made and the line retested.
|
Table 16.112.020
Time Requirement for Air Testing
| ||
|---|---|---|
|
Pipe Size
(inches)
|
Time
| |
|
Minutes
|
Second
| |
|
4
|
2
|
32
|
|
6
|
3
|
50
|
|
8
|
5
|
6
|
|
10
|
6
|
22
|
|
12
|
7
|
39
|
|
14
|
8
|
56
|
|
15
|
9
|
35
|
|
16
|
10
|
12
|
|
18
|
11
|
34
|
|
20
|
12
|
45
|
|
21
|
13
|
30
|
|
(For larger-diameter pipe, use the following: minimum time in
seconds = 462 x pipe diameter in feet)
|
|
Notes for Table 16.112.020
| |
|
a.
|
Pipe sizes with their respective recommended minimum times,
in minutes and seconds, for acceptance by the air test method are
shown.
|
|
b.
|
For eight-inch and smaller pipe only: if, during the five-minute
saturation period, pressure drops less than 0.5 psig after the initial
pressurization and air is not added, the pipe section undergoing test
shall have passed.
|
|
c.
|
Multi-pipe sizes: When the sewer line undergoing test is eight-inch-or-larger-diameter
pipe and includes four-inch or six-inch laterals, the figures in Table
16.112.020 for uniform sewer main sizes will not give reliable or
accurate criteria for the test. Where multi-pipe sizes are to undergo
the air test, the engineer can compute the average size in inches,
which is then multiplied by 38.2 seconds. The results will give the
minimum time in seconds acceptable for a pressure drop of 0.5 psig
for the averaged diameter pipe.
|
K.
Adjustment required for groundwater. An air pressure correction is
required when the prevailing groundwater is above the sewer line being
tested. Under this condition, the air test pressure must be increased
0.433 psi for each foot the groundwater level is above the invert
of the pipe.
Where groundwater is known to exist or is anticipated in the
area before the air testing would be conducted, the following procedure
shall be used at the time the sewer main and manholes are constructed:
A.
Install one-half-inch-diameter pipe nipple (threaded one or both
ends, approximately 10 inches long) through the manhole wall directly
on top of one of the sewer pipes entering the manhole with threaded
end of nipple extending inside the manhole;
B.
Seal pipe nipple with a threaded one-half-inch cap;
C.
Immediately before testing, determine the groundwater level by removing
the threaded cap from the nipple, blowing air through the pipe nipple
to remove any obstructions, and then connect a clear plastic tube
to the pipe nipple;
D.
Hold plastic tube vertically, permitting water to rise in it to the
groundwater level;
E.
After water level has stabilized in plastic tube, measure vertical
height of water, in feet, above invert of sewer pipe;
F.
Determine air-pressure correction, which must be added to the 3.0
psig normal starting pressure of test, by dividing the vertical height
in feet by 2.31. The result gives the air-pressure correction in pounds
per square inch to be added;
G.
Example:
(1)
If the vertical height of water from the sewer invert to the
top of the water column measures 11.55 feet, the additional air pressure
required would be:
|
(11.55)
2.31
|
= 5 psig
|
(2)
Therefore, the starting pressure of the test would be 3.0 plus
5 or 8.0 psig, and the one-half-pound drop becomes 7.5 psig. There
is no change in the allowable drop (0.5 psig) or in the time requirements
established for the basic air test.
Lamping of all gravity sanitary sewer lines shall be performed
by the engineer in accordance with the following requirements:
A.
Lamping consists of visually examining inside of pipe between two
consecutive manholes with the aid of a light and mirror;
B.
A light is shown from one manhole towards the other manhole;
C.
A mirror is held at the invert of pipe and adjusted so the light
and barrel of pipe can be seen;
D.
The barrel of the pipe shall have no vertical deflection and at least
75% of the barrel shall be visible in the horizontal direction;
E.
In the event that lamping shows the pipe not laid true and to grade,
it shall be repaired and be lamped as necessary until the lamping
complies with these requirements.
In addition to the visual and lamping inspections, the Township
may employ the use of television cameras to inspect sewers after or
during construction. If defective workmanship or materials are found,
these shall be corrected and the cost of TV inspection paid for by
the applicant. No TV inspection costs shall be assessed against the
applicant if the workmanship and materials are found to be satisfactory.
A.
Y-branches and service laterals which are not to be immediately connected
to flowing lines shall be securely plugged with an approved type of
plug which will provide a permanent watertight seal. Plugs shall be
braced as shown on the standard detail. The contractor shall accurately
record the station of each Y-branch placed and direction of the Y.
He shall also show the location of each Y-branch on his copy of the
plans and permanently mark each location with a crosscut on the curb
or a two-inch-by-four-inch stake driven at the plugged end of the
lateral.
B.
All lateral connections to existing sanitary sewer lines shall be
installed with bolt-on type saddles unless otherwise specified by
the engineer.
Drop connections at manholes are shown on the standard details.
Concrete cradles over existing pipe shall be constructed where and
as directed by the engineer. All concrete work shall conform to the
requirements as set forth elsewhere herein.
When so required by the engineer, the contractor shall flush
such newly completed sewers as may be designated by the engineer,
in order to remove any foreign matter which may have accumulated therein
during construction. The contractor shall furnish all labor, material,
equipment and water necessary for flushing and shall provide for the
disposal of water used for flushing.
