[Ord. No. 1250, 10-15-2002]
A.
All development shall be provided with an approved system for wastewater
disposal in accordance with this Article and subsequent Sections of
this Part.
B.
All sanitary sewer installations, extensions, pump stations, appurtenances,
and all collection and treatment systems shall be designed and constructed
in accordance with the most current regulations of the Missouri Department
of Natural Resources' rules, regulations, and Statutes of the State
of Missouri.
[Ord. No. 1250, 10-15-2002]
A.
Gravity Sewer Pipe. Gravity Sewer Pipe shall be PVC pipe conforming
to the following specifications:
1.
PVC pipe shall be solid wall meeting the requirements of ASTM
D3034, latest revision, with wall thickness SDR35 for sizes eight
(8) inches thorough fifteen (15) inches; and meeting ASTM F-679 for
eighteen (18) inches and larger. Pipe shall be extruded with one (1)
end to serve as a spigot end and the other as a bell end, with a gasket
groove molded inside for retention of a rubber gasket used in making
the joint. Standard laying lengths shall be twelve and one-half (12.5)
feet or twenty (20) feet.
a.
Drop Impact Test. Pipe shall withstand, without failure at seventy-three
degrees Fahrenheit (73° F.), an impact of a falling missile (twenty
(20) pounds Tup A) at the following levels, in accordance with ASTM
D2444 latest revision:
|
Nom. Size in Inches
|
Ft-Lbs.
|
|---|---|
|
8
|
210
|
|
10
|
220
|
|
12
|
220
|
|
15
|
220
|
b.
Pipe Stiffness. Minimum pipe stiffness (F/deltSD-y) at five
percent (5%) deflection shall be forty-six (46) PSI for all sizes
when tested in accordance with ASTM D2412, latest revision.
c.
Flattening. There shall be no evidence of splitting, cracking,
or breaking when a specimen of pipe, six-inches long, is flattened
between parallel plates in a suitable press until the distance between
the plates is forty percent (40%) of the outside diameter of the pipe.
The rate of loading shall be uniform and such that the compression
is completed within two to five minutes.
2.
Minimum Pipe Diameter. All gravity sewer mains shall have a
minimum diameter of eight (8) inches.
B.
Pressure Sewer Pipe. Pipe for pressure sewers shall be either PVC
or ductile iron.
1.
PVC pipe for pressure sewer lines shall be solid wall meeting
the requirements of ASTM D2241, latest revision, with wall thickness
SDR 21 (Class 200). Pipe shall have an integral bell with a locked-in,
solid cross section elastomeric gasket that meets the requirements
of ASTM F477, latest revision. Provisions must be made for contraction
and expansion at each rubber ring bell and spigot joint. Pipe shall
be made from clean, virgin, NSF approved PVC material conforming to
ASTM D1784, latest revision.
a.
SDR 21 pipe shall be suitable for use at maximum hydrostatic
pressures of two hundred (200) PSI at seventy-three degrees Fahrenheit
(73° F.)
b.
Physical And Chemical Tests. Pipe shall meet the following physical
and chemical test requirements. All physical and chemical tests shall
be conducted at seventy-three degrees Fahrenheit (73° F.) ±
three and six-tenths degrees Fahrenheit (3.6° F.)
|
Test
|
ASTM Ref.
|
Requirements
|
|---|---|---|
|
Quick Burst Test
|
D1599
|
630 PSI applied in 60 to 70 sec.
|
|
Sustained Pressure Test
|
D1598
|
1,000 hrs. @ 420 PSI
|
|
Acetone Immersion Test
|
D2152
|
No visible spalling or cracking after 20 minutes
|
|
Vise Test
|
—
|
No splitting or shattering when compressed 60% in 2 to 5 minutes
|
2.
Ductile iron pipe for pressure sewer lines shall be pressure
class 350 and shall conform to the latest revision of ANSI A21.51
- (AWWA C151) Standard for Ductile Iron Pipe Centrifugally Cast in
Metal Molds or Sand Lined Molds, for Water or Other Liquids. The pipe
shall be standard asphaltic varnish coated on the outside. Pipe shall
be cement mortar lined in conformance with ANSI A21.4-90 - (AWWA C104)
unless specified otherwise.
a.
Joints for ductile iron pipe that is to be buried shall be a
push-on type. The push-on type joints consisting of a single neoprene
gasket, which are acceptable, are "Tyton" as manufactured and licensed
by the U.S. Pipe and Foundry Company; "Fastite" as manufactured and
licensed by the American Cast Iron Pipe Company; and "Bell-Tite" as
manufactured and licensed by James B. Clow and Son, Inc. All required
joint material, including the neoprene gasket and the lubricant, shall
be furnished with the pipe.
C.
Pressure Sewer Fittings. Fittings for pressure sewer lines larger
than four (4) inches in diameter shall be mechanical joint of either
gray iron or ductile iron, and shall conform to the requirements of
ANSI/AWWA C110/A21.10-93 or C153/A21.53-94. All fittings shall be
coated and lined in the same manner as the pipe. All mechanical fittings
shall be pressure class 350 ductile iron. Fittings shall be standard
asphaltic varnish coated on the outside. Fittings shall be cement
mortar lined in conformance with ANSI A21.4-80 (AWWA C104). Mechanical
joint and push-on joint gaskets shall meet all applicable requirements
of ANSI 21.11-85 (AWWA C111).
1.
Fittings for pressure sewer lines four (4) inches in diameter
and smaller shall be of the same material as that of pipe.
D.
Precast Manholes And Manhole Drops.
1.
Materials.
a.
Portland Cement. Shall conform to ASTM C150, latest revision,
Type I, II, or V.
b.
Concrete Reinforcement. Shall be reinforcing bars conforming
to ASTM 615, Grade 60.
c.
Aggregate. Shall conform to ASTM C33, latest revision, for coarse
and fine aggregate.
d.
Mortar. Shall conform to ASTM C270, latest revision, Type M.
e.
Water. Mixing water shall be clean and potable.
f.
Dampproofing. Shall conform to Koppers Specifications for Coal
Tar Bitumastic Super Service Black or an approved alternate.
g.
Joint Sealant. Shall meet AASHTO Specification M-198, and shall
be suitable for application in vertical and horizontal joints. Sealant
shall be as manufactured by Hamilton-Kent, Ram-Nek, or approved equal.
h.
Manhole Pipe Connectors. Shall be a resilient connector designed
to make a watertight seal between the precast manhole and sewer pipe,
conforming to the requirements of ASTM C923, latest revision. Connectors
shall be SD-LOK, as manufactured by SD-LOK Products, Inc., or approved
equal.
i.
Grout. Grout shall be a pre-mixed, packaged, non-ferrous, aggregate
non-shrink grout. Grout shall be SEALTIGHT 588 Grout, as produced
by W.R. Meadows, or approved equal.
j.
Manhole Castings. All castings shall be made of clean, even
grain, tough gray cast iron. The casting shall be smooth, true to
pattern, and free from projections, sand holes, warp, and other defects
that would interfere with the use of, or impair the serviceability
of the casting. All castings shall be well cleaned before enamel coating
is applied. The iron used for these castings shall conform to ASTM
A48, latest revision, for Class 30 gray iron. The "B" test bar (one
and two-tenths (1.2) inches diameter by twenty-one inches (21) long)
shall be used to prove the quality of iron used. Manhole frames and
covers shall be designed for heavy duty service. Cover shall be solid
with two (2) pick holes and the total weight of the unit shall be
four hundred (400) pounds minimum.
k.
Manhole Steps. Manhole steps shall be copolymer polypropylene
plastic steps with one-half (1/2) inch grade 60 steel reinforcement
as manufactured by M.A. Industries, Inc., Model PSI-PF, or polyethylene
steps with three-fourth (3/4) inch O.D. 6351-T6 aluminum tubing as
manufactured by MSU Mississauga Ltd., Model 360, or approved equal.
l.
Manhole Drops. Shall be provided for a sewer entering a manhole
twenty-four (24) inches or more above the manhole invert. Type A drops,
constructed of SDR-35 PVC pipe, shall be provided for all drops of
two feet up to eight (8) feet. Type B drops, constructed of Class
50 ductile iron pipe, shall be provided for all drops greater than
eight (8) feet.
2.
Fabrication And Construction Requirements.
a.
Fabrication And Manufacturing. Precast reinforced concrete manholes
shall be manufactured to requirements of ASTM C478, latest revision
and shall be of the type, size, and configuration shown on the drawings.
Manhole tops shall be of the eccentric type. The minimum allowable
wall thickness shall be determined by the manhole depth as below:
|
Manhole Depth
|
Minimum Wall Thickness
|
|---|---|
|
0 to 16 feet
|
1/12 of internal diameter
|
|
16 feet or greater
|
1/12 of internal diameter + 1"
|
|
Minimum internal diameter of any manhole section shall be four
(4) feet. Dampproofing shall be factory applied on all interior and
exterior surfaces except to the interior surface of the bottom section.
Dampproofing shall be field applied to the interior surface of the
bottom section after base and fillet have been placed. Dampproofing
system shall be Koppers Coal Tar Bitumastic Super Service Black or
an approved alternate, applied to manufacturer's specifications. Two
(2) coats, each of minimum fourteen (14) mils dry thickness, shall
be applied. A seventy-five-volt maximum wet sponge detector shall
be employed to check for holidays in the dried finish film. Manhole
access opening shall be twenty-two (22) inches diameter, minimum.
|
b.
Construction.
(1)
Joints in the precast concrete manhole shall be
set in a pre-molded mastic material or a rubber gasket to produce
an absolutely watertight joint under full hydrostatic head conditions.
(2)
Bases shall be six (6) inches thick precast flat
bases, with inverts constructed in the field, or shall be a precast
bottom with precast integral bottom.
(3)
Precast riser sections shall be set plumb and oriented
with manhole steps and access opening to match the detailed drawings
designations.
(4)
Inlet and outlet pipes shall extend through the
walls of the structures a sufficient distance beyond the outside surface
to allow for connections, and shall extend six (6) inches beyond the
inside surface of the wall. The new manhole shall be cleaned of silt,
debris, or other foreign matter prior to acceptance.
(5)
Openings in manhole sections for inlet and outlet
pipes shall be formed at the factory, and shall utilize cast-in-place
manhole pipe connector gaskets.
(6)
Invert channels shall be smooth and semi-circular
in shape conforming to the inside of the adjacent pipe line sections
with change in flow direction made by a smooth curve of as large a
radius as the manhole size will permit, and changes in the size and
grade of the channels being made gradually and evenly. Manhole floor
shall rise a minimum of one (1) inch per foot from side of channel
to wall.
(7)
All lifting holes shall be thoroughly wetted and
completely filled with non-shrinking grout to form a watertight seal.
(8)
All castings, frames, and covers shall be set true
to line and to correct elevation upon a mastic gasket. Frames and
covers shall have true common bearing surfaces, such that the covers
will seat firmly without rocking or shifting.
(9)
Manholes shall not leak more than one and fourteen-hundredths
(1.14) gallons per day per vertical foot of manhole under a full hydrostatic
head.
(10)
The drop pipe in manhole drops shall be constructed
using standard pipe sections and fittings to enter at the bottom of
the manhole and also continue the incoming line in a straight line
to enter the manhole at a higher elevation, all as shown on the detailed
drawings.
3.
Inspection And Rejection. The quality of materials, the process
of manufacture, and the finished manhole sections shall be subject
to inspection and approval by the City. Manhole sections shall be
subject to rejection for failure to conform to any of the specified
requirements. In addition, individual sections may be rejected because
of any of the following:
a.
Fractures or cracks passing through the wall.
b.
Defects that indicate imperfect proportioning, mixing, and molding.
c.
Surface defects indicating honeycombed or open texture.
d.
Damaged or cracked ends where such damage would prevent making
a satisfactory joint.
e.
Any continuous crack having a surface width of one-hundredths
(0.01) inch or more and extending for a length of four (4) inches
or more.
E.
Pipe Bedding Material.
1.
Granular Stone. Granular stone pipe bedding material shall be
crushed limestone consisting of aggregate particles meeting the requirements
of ASTM C-33, latest revision, gradation 67, one (1) inch to No. 8
size as follows:
|
Sieve Size
|
Percent Passing
|
|---|---|
|
1"
|
100
|
|
3/4"
|
90-100
|
|
3/8"
|
20-55
|
|
No. 4
|
0-10
|
|
No. 8
|
0-5
|
F.
Steel Casing Pipe. Steel pipe for casing at highway and railroad
crossings shall conform to AWWA C200-91.
[Ord. No. 1250, 10-15-2002]
A.
Trenching, Bedding, Backfilling, And Compacting.
1.
Materials.
a.
Earth Backfill. Earth backfill shall be earth previously excavated
from the trench, free from perishable matter, frozen soil, stone over
four (4) inches in its largest dimension, and other matter liable
to become unstable when saturated with water and compacted.
b.
Select Backfill. Where previously excavated earth is determined
to be unsuitable for backfill, suitable material from an approved
source shall be obtained.
2.
Construction.
a.
Trench Excavation (Gravity Sewer Lines).
(1)
All trench excavation shall be made with a sufficient
working space to permit the placement, inspection, and completion
of all work contemplated in the contract. Excavated material that
is unsuitable for backfill, and all boulders exposed by trenching
shall be removed from the work area. Trenches shall be excavated in
accordance with the standard detail for trench width relative to trench
depth.
(2)
Trenches shall be excavated to six (6) inches below
established flow lines to provide clearance for the pipe bell and
not less than four (4) inches of granular stone bedding material.
Should the trench be excavated more than six (6) inches below the
flowline, only granular stone bedding material shall be used to establish
flow line grade.
(3)
In all cases, trench excavation shall be continuous
from the ground surface to the established trench depth. Materials
excavated shall be stockpiled at the sides of the trench and within
established area limits to minimize inconvenience to the public, and
damage to vegetation and structures in the area.
(4)
When unstable ground is encountered, the trenching
shall be carried out utilizing trench shoring, bracing, and shields
to prevent cave-ins.
(5)
Trench width from six (6) inches below the bottom
of the pipe to six (6) inches above the pipe joint shall be held to
twenty-four (24) inches minimum, or one and four-tenths (1.4) times
the pipe O.D., plus twelve (12) inches. Trench width above these levels
may be wider to accommodate shoring, bracing, and shields, but shall
be kept within practical limits.
b.
Trench Excavation (Pressure Sewer Lines).
(1)
Trench Depth. Trenches shall be cut as deep as
necessary on either side of natural depressions, ditches, waterways,
etc., to provide for not less than thirty-six (36) inches of cover
over the top of the pipe. Depth of cover shall be measured from the
outside top of the pipe vertically to the original ground surface
or pavement surface. Mounding over the trench to attain the specified
cover shall not be permitted. Trenches shall be cut to prevent high
spots that could lead to "air binding" of the line. Trenches shall
be excavated to four (4) inches below the bottom of the pipe to provide
clearance for not less than four (4) inches of pipe bedding material.
The maximum degree of deflection, either vertical or horizontal, shall
not cause a pipe joint's annular clearance in the bell to be less
than one-fourth (1/4) inch at its closest point. In case the trench
be excavated at any place more than four (4) inches below grade, it
shall be filled to the design grade with approved bedding material.
In all cases, trench excavation shall be continuous from the ground
surface to the established trench depth. Gutters and ditches shall
be kept clear, or other satisfactory provisions shall be made to facilitate
drainage. Ground adjacent to a trench shall be graded to prevent water
from flowing into the trench. Provisions shall be made for the continuous
flow of all waterways, ditches, drains, or sewers encountered during
construction. All ditches and waterways shall be restored to their
original conditions as soon as possible.
(2)
Trench Width. The width of the trench, as dug,
from the trench bottom to the top of the pipe, shall not exceed the
outside diameter of the pipe bell or socket plus twelve (12) inches,
or twenty-four (24) inches, whichever is greater. Trench width above
the top of the pipe shall be as required by field conditions to prevent
sliding and caving of the excavation.
3.
Sheeting, Shoring, Or Bracing. Sheeting, shoring, or bracing
shall be placed wherever necessary for the proper preserving of any
excavation, embankment, or structure. Where the ground is of such
a character or other conditions are such as to render it necessary,
the sheeting shall be closely driven and to such depth below the lowest
point of the final excavation as may be required. Shore up, protect,
and insure from injury all buildings, retaining walls, piers and footings,
storm sewers, sanitary sewers, gas lines, water lines, fences, curbs,
trees, or other property liable to be injured during the process of
the work. Sheeting, shoring, and bracing shall be provided, installed,
and maintained to protect the excavation and insure open trench operations.
4.
Placement Of Bedding Material.
a.
Granular Stone Pipe Bedding. Granular stone shall be placed
in the trench and shaped to provide uniform support for the bottom
quadrant of the pipe barrel. The bedding shall be not less than four
(4) inches in thickness. Following placement of the pipe, the trench
shall be filled with granular stone bedding material to a minimum
compacted depth of six (6) inches above the pipe barrel.
5.
Backfilling. Material used for backfilling of trenches shall
be free from perishable matter and from other material liable to become
unstable when saturated with water after having been compacted. No
frozen material shall be used in backfill. Care shall be taken to
prevent damage to the pipe and structures. Special precautions shall
be taken in backfilling over pipes. No backfill shall be placed over
any portion of pipes and/or joints not inspected by the City Engineer.
The bedding material shall be brought to a depth of at least six (6)
inches over the top of the pipe bell, with this material carefully
deposited in uniform layers not exceeding six (6) inches in depth,
and each layer carefully and solidly tamped with mechanical tampers
in such a manner as to avoid damage to pipe or disturbing completed
work. Unless noted otherwise on the drawings, backfilling for the
remainder of the trench shall be previously excavated gravel, sand,
or earth, and shall contain no stone over four (1) inches in its largest
dimensions. Stones smaller than that size may be used in proportion
not exceeding one (1) part of stone and three (3) parts of earth in
any place. This backfilling shall be deposited and spread in layers
and solidly tamped. Except as specified for roadway crossings, trench
backfill shall be compacted to eighty percent (80%) of the maximum
density at optimum moisture. As the trenches are backfilled, remove
all surplus material and regrade the surface, leaving it in good order.
The trenches shall be filled to the ground surface elevation which
previously existed.
6.
New Manhole Over An Existing Line. Construction of a new manhole
over an existing line shall be accomplished by blocking or plugging
flow from the first manhole upstream of the proposed manhole location,
removing two (2) joints from the existing sewer at the location of
the new manhole, installing the new manhole, and replacing the removed
joints of sewer pipe. This procedure will enable the new manhole to
be fabricated with flexible pipe connector gaskets. Temporary pumping
of flow from the plugged upstream manhole to the downstream manhole
shall be provided by the Contractor as necessary, to prevent raw sewage
discharges.
7.
Connections To Existing Manholes. Existing manholes used for
connecting new sewer lines to the existing sewerage system will have
the invert chipped out and grouted back with non-shrink grout as required
to facilitate the uninterrupted sewage flow from the new connection.
All new pipe to existing manhole connections shall be made with flexible
connector gaskets, such as INSERTSD-LOK connectors, as manufactured
by SD-LOK Products, Inc. Upon completion of the new connection, the
entire manhole shall be vacuum tested in accordance with Section 102-3
TESTING.
8.
Aerial Crossings. If permitted, aerial crossings shall comply
in all respects with 10 CSR 20-8.120 (10) of DNR's Design Guide for
Waste Treatment Design.
B.
Installation.
1.
Pipe Installation.
a.
General. Only workers competent at laying pipe shall be employed
on this phase of the work, and complete suitable equipment necessary
for the execution of same is required. Any incompetency observed must
be removed, and where improper equipment or lack of same appears to
be impairing the quality or speed of the work, such adjustment in
same shall be made.
b.
Handling Of Materials. The pipe, fittings and valves shall be
placed in the trench with care. Under no circumstances shall pipe
or other materials be dropped or dumped into the trench. If plastic
pipe is used, the pipe shall be snaked into the trench, either employing
the natural snaking tendency of some plastic pipe or the pipe shall
be laid from one (1) side to the other on alternate lengths.
c.
Pipe Cleaning During Laying Operations. The pipe, if furnished
from the factory with dust covers over the ends, shall be examined
carefully during laying operations to insure that such covers are
not lost inside the pipe. At the termination of pipe laying, the open
end of the pipeline shall be closed off by a suitable cover until
laying operations are resumed. No pipe shall be placed in the trench
unless it is intended to make the joint to the pipeline at that time.
d.
Inspection Of Materials During Construction. Any materials not
meeting the specifications, or obviously faulty material, shall be
rejected and removed from the job site.
e.
Joining Pipe. In joining sections of pipe, the installer shall
use good working practices. All pipe ends shall be cleaned thoroughly
inside and out before application of lubricant. The recommendations
of the manufacturer of the pipe shall be followed closely in joining
this type of pipe. Care shall be taken in lowering pipe into the trench
in order that a tensile stress is not created that would cause partial
or complete separation of the joints. Concrete thrust blocks shall
be installed on pressure sewer line construction at all bends, tees,
crosses, and reducers.
f.
Breaks In Pipe And Joints. Breaks in the pipe or joints shall
be repaired.
g.
Slope And Alignment. Gravity sewers shall be laid with uniform
slope between manholes. Gravity sewer lines twenty-four (24) inches
in diameter or less shall be laid with straight alignment between
manholes. Alignment shall be checked by laser beam or lamping.
h.
Bedding Of Plastic Pipe. The Contractor shall bed the pipe in
accordance with the requirements of Section 203-1, Trenching, Backfilling,
and Compacting.
i.
Avoidance Of Unnecessary Bends. Excessive bends in the alignment
of pressure sewer lines will not be permitted. Where obviously required,
sweep ells shall be used in making connections between two (2) sections
having differing alignment. Standard ninety degree (90°) elbows
are not to be used, except in confined locations.
2.
Anchorage Of Pressure Sewer Line Bends, Tees, And Plugs. All
tees, plugs, caps, and bends exceeding twenty-two and one-half (22-1/2)±
shall be squarely anchored by suitable thrust concrete backing. Such
concrete backing shall be so placed that the pipe or fitting joints
will be accessible for repair. The concrete shall be of 1:3:5 mix
and shall be placed between solid ground and the fitting to be anchored.
The area of the bearing on the pipe and the ground in each instance
shall be a minimum of four (4) square feet.
3.
Separation Of Sewer And Water Lines.
a.
Horizontal Separation. When sanitary sewers are to be laid parallel
to existing potable water lines, it will be necessary to maintain
at least ten (10) feet horizontal separation between the sewer and
water lines. The distance shall be measured between outside edge of
lines. In cases where it is not practical to maintain this specified
separation, the City may allow installation of a sewer line closer
to a water line, provided that the water main is located in a separate
trench or on an undisturbed earth shelf located on one (1) side of
the sewer at such an elevation that the bottom of the water main is
at least eighteen (18) inches above the top of the sewer.
b.
Vertical Separation (Crossings). Sewer lines crossing water
mains shall be laid to provide a minimum vertical distance of eighteen
(18) inches between the outside of the water main and the outside
of the sewer. This separation shall be provided whether the water
main is above or below the sewer. The crossing shall be constructed
such that the sewer joints will be equidistant and as far as possible
from the water main joints. Where a water main crosses under a sewer,
adequate structural support shall be provided for the sewer to prevent
damage to the water main.
4.
Stream Crossings. Stream crossings with sewer lines requiring
special construction shall be installed as shown on the standard details.
C.
Testing.
1.
Gravity Sewer Testing.
a.
General. All completed gravity sewers shall require pneumatic
or hydrostatic testing for the purpose of locating potential infiltration
and/or exfiltration within the system. Sewer service lateral lines
shall be excluded from testing requirements.
b.
Pneumatic Testing Procedure. Performance of low pressure air
testing on all sections of completed sewer eight (8) inch through
and including twenty-four (24) inch diameters, shall be conducted
in the presence of the City Engineer. It will be the responsibility
of the Contractor to furnish and operate equipment capable of making
the required tests. Pneumatic plugs shall be utilized to isolate sewer
sections for testing. Plugs shall have a sealing length equal to or
greater than the diameter of the pipe to be inspected. Pneumatic plugs
shall resist internal test pressure without requiring external bracing
or blocking. All air used shall pass through a single control panel
and three individual hoses shall be used for connections from the
control panel to: 1) pneumatic plugs for inflation; 2) sealed line
for introducing the low pressure air; and 3) to the sealed line for
continually monitoring the air pressure rise in the sealed line. Equipment
shall be Cherne Air-Loc equipment or approved equal. Testing methods
and air leakage rates shall conform to ASTM F1417, latest revision,
as a minimum. Otherwise, the following procedures shall be followed:
c.
Pipe Above Groundwater Table. All pneumatic plugs shall be seal-tested
before being used in the actual test installation. One (1) length
of pipe shall be laid on the ground and sealed at both ends with the
pneumatic plugs to be checked. Air shall be introduced into the plugs
to twenty-five (25) psig. The sealed pipe shall be pressurized to
five (5) psig. The plugs shall hold against this pressure without
bracing and without movement of the plugs of the pipe. After a manhole
to manhole reach of pipe has been backfilled and cleaned and the pneumatic
plugs are checked by the above procedure, the plugs shall be placed
in the line at each manhole and inflated to twenty-five (25) psig.
Low pressure air shall be introduced into this sealed line until the
internal air pressure reaches four (4) psig greater than the average
back pressure of any groundwater that may be over the pipe. At least
two minutes shall be allowed for the air pressure to stabilize. After
the stabilization period (three and five-tenths (3.5) psig minimum
pressure in the pipe), the air hose from the control panel to the
air supply shall be disconnected. The portion of line being tested
shall be termed "Acceptable" if the time required in minutes for the
pressure to decrease from three and five-tenths (3.5) to two and five-tenths(2.5)
psig shall not be less than the time shown for the given diameters
in the following table:
|
Pipe Diameter in Inches
|
Minimum Time
(min., sec.)
|
Max. Length
(ft.) for Min. Time
|
Time (sec.) for Longer Length
(L)
|
|---|---|---|---|
|
4
|
3:46
|
597
|
0.380 L
|
|
6
|
5:40
|
398
|
0.854 L
|
|
8
|
7:34
|
298
|
1.520 L
|
|
10
|
9:26
|
239
|
2.374 L
|
|
12
|
11:20
|
199
|
3.418 L
|
|
15
|
14:10
|
159
|
5.342 L
|
|
18
|
17:00
|
133
|
7.692L
|
|
21
|
19:50
|
114
|
10.470 L
|
|
24
|
22:40
|
99
|
13.674 L
|
|
27
|
25:30
|
88
|
17.306 L
|
|
30
|
28:20
|
80
|
21.366 L
|
|
33
|
31:10
|
72
|
25.852 L
|
|
36
|
34:00
|
66
|
30.768 L
|
d.
Pipe Below Groundwater Table. In areas where groundwater is
known to exist, install a one-half (1/2) inch diameter capped pipe
nipple, approximately ten (10) inches long, through the manhole wall
on top of one (1) of the sewer lines entering the manhole. This shall
be done at the time the sewer line is installed. Immediately prior
to the performance of the test, the groundwater shall be determined
by removing the pipe cap, blowing air through the pipe nipple into
the ground to clear it, and then connecting a clear plastic tube to
the nipple. The hose shall be held vertically and a measurement of
the height in feet of water over the invert of the pipe shall be taken
after the water has stopped rising in this plastic tube. The height
in feet shall be divided by two and three-tenths (2.3) to establish
the pounds of pressure that will be added to all readings. (For example,
if the height of water is eleven and one-half (11 1/2) feet,
then the added pressure will be five (5) psig. This increases the
three and five-tenths (3.5) psig to eight and five-tenths (8.5) psig,
and the two and five-tenths (2.5) psig to seven and five-tenths (7.5)
psig. The allowable drop of one (1) pound and the timing remain the
same.)
e.
Other Pipe Materials. Low pressure air testing of sewer lines
constructed with vitrified clay pipe or reinforced concrete pipe shall
be as specified above, except that the minimum specified times required
for a one (1.0) psig pressure drop shall be as called for in ASTM
C828, latest revision (vitrified clay pipe sewer lines), or ASTM C924,
latest revision (concrete pipe sewer lines).
2.
Testing Of Manholes. Make either hydrostatic or vacuum infiltration/exfiltration
tests of all manholes in the presence of the City, to demonstrate
that the manholes are free of leaks.
a.
Hydrostatic Testing. Where the top of the sewer is below water
level, a one-half (1/2) inch galvanized pipe nipple is to be cast
into each manhole wall and capped on the inside. The pipe nipple is
to be located at the top of the inside bore of sewer pipe. All tests
are to be conducted in the following manner:
(1)
Test plugs are to be placed in the end of each
sewer pipe on the downstream and upstream side of each manhole and
inflated to a maximum pressure of sixteen (16) psig. Plugs are to
be thoroughly blocked to prevent them from blowing out. The manhole
is to be filled with water to a level four and one-half (4 1/2)
feet above the groundwater level or seven (7) feet above the pipe
invert, whichever is higher. Ten (10) minutes shall then be allowed
for absorption, after which the water level shall be brought back
to the test elevation.
(2)
The specified head shall be maintained on the manhole
for a period of eight (8) hours. Sufficient water shall be added to
maintain this level. All water added shall be metered to within one-tenth
(0.1) of a gallon and recorded. The maximum allowable leakage shall
be as specified herein.
b.
Vacuum Testing. Vacuum testing, performed in accordance with
this specification, shall be allowed as a substitute for hydrostatic
testing of manholes.
(1)
The vacuum "test head" assembly shall be placed
inside the frame of the manhole cover, in order to include in the
test the seal between the frame and the manhole cone section, slab,
or adjusting rings.
(2)
Plugs shall be placed at least eight (8) inches
inside all pipes entering the manhole. Location of plugs shall be
such that when inflated, they are past the gasket seal or joint of
the manhole and sewer pipe. All plugs shall be braced sufficiently
to prevent the plug or pipe from becoming dislodged and drawn into
the manhole.
(3)
A vacuum of at least ten and one-half (10 1/2)
inches mercury shall be drawn on the manhole. The valve on the vacuum
line to the manhole shall be closed, and the vacuum line disconnected.
The vacuum within the manhole shall then be adjusted to ten (10) inches
to mercury by opening the vacuum line valve.
(4)
A liquid-filled pressure gauge having a face of
three and one-half (3 1/2) inches and reading from zero (0) to
thirty (30) inches of mercury shall be utilized.
(5)
The time for the vacuum reading to drop from ten
(10) inches of mercury to nine (9) inches of mercury must be equal
to or less than the following values in order for the manhole to be
considered as passing the vacuum test.
|
Manhole Depth
|
Time (minutes)
|
|---|---|
|
10 feet or less
|
2.0
|
|
10.1 feet to 15 feet
|
2.5
|
|
15.1 feet to 25 feet
|
3.0
|
(6)
If vacuum drops less than one (1) inch mercury
within the test time, the manhole is considered acceptable and passes
the test. If manhole fails and leaks, the contractor shall make the
needed repairs and test again until satisfactory results are obtained.
Test may be done before backfilling, but shall be repeated after backfill.
(7)
All safety procedures, placing of plugs, and bracing,
labor, and other work required for testing will be the responsibility
of the contractor.
3.
Infiltration/Exfiltration Allowance. Infiltration or exfiltration
for sewers eight (8) inch through twenty-four (24) inch diameter shall
not exceed two hundred (200) gallons per inch of pipe diameter per
mile per day for any section of sewer. Infiltration or exfiltration
for sewers greater than thirty (30) inch diameter shall not exceed
six thousand (6,000) gallons per day per mile of pipe. Infiltration
or exfiltration for manholes shall not exceed one and fourteen-hundredths
(1.14) gallons per day per vertical foot of manhole.
4.
Infiltration/Exfiltration Elimination. The Contractor shall
locate all sources of infiltration and exfiltration in the sewer lines,
manholes, and appurtenances, and shall correct deficiencies and eliminate
infiltration/exfiltration sources in a manner approved by the City
Engineer. All sections of sewer line, manholes, and appurtenances
shall be re-tested after corrections are finalized.
5.
Deflection Test. The rules of the Department of Natural Resources,
State of Missouri, ten (10) CSR 20-8.120 (G)5, state that a deflection
test shall be performed on all flexible pipe not less than thirty
(30) days after the placement of final backfill. The deflection test
shall consist of hand-pulling a rigid ball or mandrel through the
installed pipe in the presence of the City Engineer. The rigid ball
or mandrel shall have a diameter equal to ninety-five percent (95%)
of the inside diameter of the pipe. If the rigid ball or mandrel fails
to pull through the pipe, the section being tested fails the test
and will be replaced.
6.
Pressure Sewer Testing.
a.
All piping that is to convey liquid under pressure shall be
hydrostatically tested in conformance with Section 4 of ANSI/AWWA
C600-93. Testing shall include both a "pressure test" of at least
two (2) hours duration for the purpose of blowing defective joints,
and a "leakage test" to determine actual loss of water from the system.
The use of compressed air for testing pipe shall not be permitted.
During the pressure test, the piping shall be subjected to a hydrostatic
pressure of one hundred (100) psi.
b.
Adequately plug and brace, as necessary, the ends of the pressure
sewer, whether they be at the lift station or at the discharge manhole,
to allow for the hydrostatic testing.
7.
Certifications And Acceptance Of Tests. All acceptance tests
for sewer lines (gravity and pressure) and manholes shall be conducted
in the presence of the "certifying engineer" or his/her representative.
The "certifying engineer" is the engineer who will make written certification
to both the City and the Missouri Department of Natural Resources
that the sewer line has been built in accordance with approved plans
and specifications, and that the sewer line has passed all acceptance
tests.
D.
Roadway Surface Replacement.
1.
All roadway surfaces removed during sewer line construction
shall be replaced with the same type of surface as existed prior to
construction. The Contractor shall be responsible for determining
the nature and thickness of all pavement and surfacings to be cut
and replaced, including any base courses. Concrete pavement, asphaltic
pavement, macadam pavements, crushed stone, and any type of roadway
surface, whether public or private, which is cut or damaged during
construction of the project shall be replaced to conform to the lines
and grades of the original roadway surface, and shall be of a quality,
thickness, and appearance equal to or better than that of the roadway
as it existed prior to construction.
2.
Existing paving shall be cut vertically and horizontally to
straight lines. The trench shall be backfilled with granular stone
material compacted to ninety-five percent (95%) of maximum density,
to an elevation level with the existing riding surface of the roadway.
This level shall be maintained by the Contractor until all secondary
settling has occurred. Any crushed stone required to maintain the
trenches in a suitable condition for traffic during this period shall
be furnished at the Contractor's expense. When the trench has been
properly backfilled and has settled sufficiently to permit final repairs,
roadway surfacing shall be applied according to this specification.
At the time of final repairs, the Contractor shall remove sufficient
material to allow placement of roadway surfacing to the thicknesses
specified below.
a.
Granular stone shall meet the gradation requirements specified in Section 400.940(E).
3.
Asphaltic Concrete. Asphaltic concrete roadway surfaces of a
thickness greater than four (4) inches shall be replaced with a concrete
base of eight (8) inches thickness and two (2) inches of asphaltic
concrete. Edges of the existing pavement at the trench shall be trimmed
vertically to produce a neat even edge. The base surface and vertical
edge shall be sprayed with a prime coat of Grade RC-250 liquid asphalt
heated to no less than one hundred thirty degrees Fahrenheit (130°
F.), at a rate of fifteen-hundredths (0.15) gallons per square yard.
This primer shall be applied only when the base and existing pavement
are free of moisture. The asphaltic concrete shall be hot mixed in
an approved plant and delivered to the work Fahrenheit area in dump
trucks at a minimum temperature of two hundred seventy-five degrees
Fahrenheit (275° F.). The asphaltic concrete shall be placed and
then rolled while hot with an approved five (5) ton steel wheel roller
to the same thickness as the existing pavement. In no case shall the
total compacted thickness of a layer be less than two (2) inches or
greater than four (4) inches. No traffic shall be permitted on the
finished pavement until it has cooled to atmospheric temperature.
Concrete used for base beneath asphalt shall have a minimum twenty-eight-day
compressive strength three thousand (3,000) psi.
4.
Crushed Stone. Trenching along or across unpaved roadways, including
county roads, and city streets, as well as dirt, or gravel shoulders
of paved streets, roads, or highways, shall be backfilled with granular
stone material in compliance with these specifications. The trench
shall be backfilled to a level with the existing riding surface of
the roadway. When the trench has been properly backfilled and has
settled sufficiently to permit final repairs, the backfill shall be
removed as necessary for crushed stone surfacing. The crushed stone
shall be rolled and thoroughly compacted in layers to a minimum finished
thickness of six (6) inches.
5.
Concrete. Concrete surfaces, including private drives, shall
be replaced with concrete surfacing equal to the thickness of existing
pavement, plus a minimum of two (2) inches. Concrete shall have a
minimum twenty-eight-day compressive strength of three thousand (3,000)
psi.
6.
Chip And Seal Asphalt Paving. The area to be repaired shall
be bladed to eliminate minor depressions and humps. Following the
blading operation, the surface shall be thoroughly cleaned and swept
to remove all mud, matted earth, dust, and other foreign material.
A prime coat of liquid asphalt shall be applied at the rate of thirty-hundredths
(0.30) gallons per square yard at a minimum temperature of one hundred
twenty degrees Fahrenheit (120° F.) for asphalt grade CRS-2. On
the primed base, a course of aggregate shall be spread at the rate
of twenty-five (25) pounds per square yard. This stone shall be roller
compacted from sides to center with a steel wheeled roller weighing
a minimum of five (5) tons. Immediately following the compaction of
the first course of asphalt and aggregate, a second course, identical
to the first shall be applied. The finish surface shall be swept to
remove any loose stones. No traffic shall be allowed on the finished
surface until it has cooled to atmospheric temperature.
E.
Clean-Up.
1.
After completion of any portion of work, the construction area
shall be cleaned of all surplus material, earth, rubbish, etc., and
left in as near the original state as possible. All ditches and drainage
shall be restored to their original condition.
2.
All grassed areas shall be seeded, fertilized, and mulched as
required to restore the area to a condition equal to that which existed
prior to construction.
F.
Highway And Railroad Crossings. Where designated on the approved
design drawings, underground highway and railroad crossings shall
be installed. Such installations shall be accomplished by tunneling,
boring, or jacking methods. Each method shall provide for removal
of earth and rock encountered during installation of the carrier and
casing pipes. Where jacking or tunneling are utilized, the annular
space between the casing and earth shall be pressure grouted with
neat cement grout.
1.
Highway crossings shall be made in strict compliance with Missouri
Department of Transportation requirements. No highway crossings shall
be installed without the Contractor first obtaining all necessary
permits from the Missouri Department of Transportation.
2.
Railroad crossings shall be made in strict compliance with railroad
company requirements. No railroad crossings shall be made without
the Contractor first obtaining all necessary permits from the railroad
company.
3.
The Contractor shall insure that traffic interruptions are minimized
during the underground excavation operations. After the operation
is completed, the Contractor shall slide the sewer pipe in place.
After the pipe is in place, the annular space between the casing and
carrier pipe shall be backfilled with sand, pea gravel, or by spacers
approved for use in bracing the carrier pipe against uplift. Once
the carrier pipe has been fixed, the annular space at each end of
the casing pipe shall be sealed with sand bags or approved casing
seals.
4.
The Contractor shall take precautions to insure that the sewer
pipe is on line and grade following the installation operation.
