[Ord. No. 1620 §1, 9-25-2006]
A. 
Sanitary sewer construction shall consist of furnishing all labor, materials and equipment for the complete installation of sewers and appurtenances in accordance with the approved design plans and specifications and all regulatory requirements of the City of Hermann.
B. 
When reference is made to a standard specification (ASTM, AWWA), the specification referred to shall be understood to mean the latest revision of said specification.
C. 
Development of all sanitary sewer infrastructure will be guided by strict compliance of the approved design plans and specifications. Until reviewed and approved by the City's consulting engineer, no changes or modifications shall be authorized and no deviations permitted from the originally approved design plans and project specifications. Change orders and design modifications will be submitted by the developer's project engineer only and no other person.
[Ord. No. 1620 §1, 9-25-2006]
A. 
Installation. All work shall be in accordance with ASTM D-2321 — Underground Installation of Flexible Thermoplastic Sewer Pipe.
1. 
The following tolerances shall be maintained from true alignment and grade:
a. 
Alignment. Three (3) inches.
b. 
Grade. One (1) inch.
2. 
Joint deflection shall not exceed the maximum allowable deflection per joint according to ASTM C-425, ASTM C-594 and AWWA C-600. Only one (1) correction for alignment and/or grade shall be made between adjacent manholes.
3. 
Except where pipe sections are being encased in concrete, no pipe is to be supported by blocks.
4. 
All transition in sewer main line and grade must be within a manhole.
5. 
Install pipe of size, material, strength class and joint type with embedment as shown on the approved plans.
6. 
Pipes installed on grades in excess of twenty percent (20%) shall be anchored securely with concrete anchors spaced as follows:
Grade
Maximum Anchor Spacing
20% — 35%
36 feet
35% — 50%
24 feet
Greater than 50%
16 feet
7. 
Insofar as possible, commence laying at downstream end of line and install pipe with spigot or tongue end downstream.
8. 
Clean interior of all pipe, fittings and joints prior to installation. Exclude entrance of foreign matter during discontinuance of installation. Close open ends of pipe with snug-fitting closures. Do not let water fill trench. Include provisions to prevent flotation should water control measures prove inadequate. Remove water, sand, mud and other undesirable materials from trench before removal of end cap. Install pipe only when weather and trench conditions are suitable. Do not lay in water. Brace or anchor pipe as required to prevent displacement after establishing final position.
9. 
The sewer trench shall be carried to a point not less than four (4) inches below bottom of pipe bell. Crushed stone bedding, compacted to full width of trench, shall then be placed and compacted to bottom of pipe with proper allowance for bell joints. After each length of pipe being laid has been shoved "home" and placed in proper alignment, it shall be securely anchored and held in position by crushed stone deposited simultaneously on each side of the pipe. This crushed stone backfill shall extend to a point not less than six (6) inches above the top of the pipe bell. If unstable conditions are encountered and it is determined by the engineer that the bedding specified will not provide suitable support for the pipe, additional excavation to the limits determined by the engineer will be required. This additional excavation shall be backfilled with crushed stone material approved by the engineer.
B. 
Jointing. Locate joints to provide for differential movements at changes in type of pipe embedment, concrete collars and structures. Support pipe from wall of manhole to first (1st) joint in normal sewer trench with concrete cradle structurally continuous with base slab or footing.
1. 
Clean and lubricate all joint and gasket surfaces with lubricant recommended by pipe manufacturer.
2. 
Utilize methods and equipment capable of fully homing or making up joints without damage.
3. 
Check joint opening and deflection for specification limits.
4. 
Examine each piece of pipe prior to installation for soundness and specification compliance.
C. 
Cutting. Cut in neat workmanlike manner without damage to pipe. Observe specifications regarding joint locations. Smooth cut by power grinding to remove burrs and sharp edges. Repair lining as required and approved.
D. 
Plugs. Provide and install plugs as manufactured by pipe supplier or as fabricated by contractor if approved.
1. 
Plugs shall be watertight against heads up to twenty (20) feet of water. Secure plugs in place in a manner to facilitate removal when required to connect pipe.
2. 
Plugs shall be installed as specified or where shown on plans. Also, the open end of the sewer shall be plugged at the end of the workday with a suitable mechanical plug to prevent entry of foreign material until work is resumed.
E. 
Connections To Existing Pipelines And Structures.
1. 
Connect pipe to existing structures and pipelines where indicated. Observe pertinent articles of specifications pertaining to joint locations.
2. 
Prepare structure by making an opening with at least two (2) inches clearance all around fitting to be inserted. Connector gasket shall be placed on pipe. Pipe shall be positioned in manhole wall prior to grouting. Opening between pipe and manhole shall be filled with an expansive grout in such a manner that a watertight condition will result.
3. 
Manholes to be built on an existing sewer shall be constructed in such a manner as will not disturb services of existing sewer. The manhole base, walls and invert shall be completed before the top half of the sewer pipe is cut or broken away. Rough edges of the pipe thus exposed shall be covered with expansive grout in such a manner as to produce a smooth and acceptable finish. Any portion of the existing sewer damaged by the contractor shall be repaired at no expense to the City.
4. 
Connections between different pipe materials shall be made using proprietary transition coupling unless otherwise specified on the plans.
F. 
Service Lines And Connections.
1. 
Wyes and saddles for service lines shall be installed at a forty-five degree (45°) angle measured from the horizontal centerline of the pipe for pipe sizes eight (8) inches through fifteen (15) inches in diameter. Service lines shall not be installed in pipe sizes eighteen (18) inches in diameter or larger unless approved by the City's consulting engineer. Wyes shall be eight (8) inches by four (4) inches with DVW branch and shall be installed on new sewer mains as the mains are installed.
2. 
Service lines under streets shall be installed by the developer extending from the main to the limits of the street right-of-way and shall be installed prior to construction of the street at a slope not less than one (1) foot per one hundred (100) feet (one percent (1.0%)). Service lines for each building unit shall be connected to the mains by means of a wye or tee and shall extend at least to the street right-of-way, but never less than ten (10) feet from the sewer main. Individual service lines shall not connect directly into manholes unless approved by the City's consulting engineer. Service lines shall be adequately plugged to prevent foreign matter from entering the pipe during construction. All service lines shall be constructed bell to spigot or shall have a solid glued sleeve.
3. 
Saddles are only to be used to connect to existing sanitary sewers. The saddle shall be installed over a hole sized to fit the saddle opening (four (4) inch minimum). Cut shall be made with non-impact rotary equipment.
4. 
The service line shall terminate at a capped cleanout. The cleanout top shall be maintained two (2) feet above ground or flush at finish grade.
5. 
The developer shall maintain an accurate record for the production of the as-built drawings of the location, size and direction of each tee and wye and location, size and length of each building service line. Locations will be referenced to the pipe line stationing as shown on the plans or the distance from the first (1st) downstream manhole.
[Ord. No. 1620 §1, 9-25-2006]
A. 
Scope. This Section governs the furnishing of all labor, equipment, tools and materials and the performance of all work incidental to the construction of manholes, drop manholes and special sewer structures complete with covers, steps, fittings and appurtenances as required in accordance with the approved plans.
B. 
General. As used herein, "special structures" refers to manholes on large sewers, special junction structures, metering stations, siphons and similar structures constructed on the pipeline. Manholes and special structures may be constructed of pre-cast concrete sections, cast-in-place concrete on existing mains or where space does not permit a pre-cast manhole.
C. 
Construction.
1. 
Manholes and special structures shall be constructed at locations indicated and in accordance with details as shown on the plans.
2. 
Pre-cast wall and reducing cone sections. Handle with care to avoid damage to joint ends of each section. Damaged sections may be subject to rejection at the discretion of the engineer. When using O-ring joints, care shall be exercised in placing the O-ring on the spigot end and lowering the bell section onto the spigot end so that a watertight seal is obtained.
3. 
When using bitumastic joints both spigot and bell ends shall be primed with solvent material compatible to the adhesive in the mastic. Approved bitumastic material shall completely fill the joints so that a minimum of one-fourth (¼) inch bead of material is visible after jointing, to be smoothed off after completion of the jointing operation.
4. 
When a flexible preformed butyl rubber or bituminous polymer compounded with modifiers is used to seal jointed sections of manholes, the extrusion of sealant from the joint is not required. The vertical spacing between manhole sections shall not exceed one-fourth (¼) inch. Preformed joint sealers remain flexible at temperatures as low as zero degrees Fahrenheit (0°F).
5. 
All bitumastic materials or preformed flexible joint sealants shall not be applied to wet or damp surfaces.
6. 
Cast-in-place. Consolidate concrete with mechanical vibrators to eliminate entrapped air voids and rock pockets. Forms shall be supported in such a manner as to prevent any movement of the forms while concrete is being cured. Any movement of the forms may be cause for rejection.
7. 
Invert channels. Alignment of the invert channels shall be as shown on the approved plans. When no specific details and dimensions are given, changes in flow direction shall be smooth, uniform and made with the longest radius possible. The cross section shape of invert channels shall match the lower halves of the entering and exiting pipes. The surfaces of the channels shall be steel-troweled to produce a dense, smooth surface. When filling openings around pipes through manhole walls, mortar and/or masonry units shall be placed so that the resulting joints are watertight. Mortar used in the joint closure shall not interfere with the invert channel.
D. 
Curing. Cast-in-place concrete shall be adequately protected from freezing and loss of moisture for the first twenty-four (24) hours. The curing methods and materials to be used shall be approved by the engineer.
E. 
Manhole Rings. All rings for manhole covers shall be set to match the existing surfaces, except in floodplains where the plans indicate that the ring is to be set at an elevation higher than existing ground. Each ring shall be set on a full mortar bed of bitumastic material if approved by the engineer. If masonry units are used to adjust rings to grade, the masonry work shall conform to Subsection (C)(7) of these specifications.
F. 
Waterproofing. Two (2) coats of an asphalt or coal-tar pitch waterproof coating shall be applied to the exterior of all structures from base to manhole ring. The coating shall be applied in sufficient quantity so that no bare or thin spots show. The coating shall be applied in sufficient time to permit proper curing prior to backfilling the excavation. Proper methods and materials shall be used during backfilling to prevent damage to the coating. Any damage to the coating that does occur shall be immediately repaired.
[Ord. No. 1620 §1, 9-25-2006]
A. 
Unless otherwise specified, all sewer trenches and excavation around structures shall be backfilled to the original surface of the ground with earth, earth and rock or other acceptable material. When earth and rock is used, it shall be placed and thoroughly consolidated with sufficient earth to completely fill all voids between the rocks. The developer shall so sort and stockpile the excavated material so that the proper material is available for backfill.
1. 
The backfill material shall be compacted to a minimum of eighty percent (80%) of optimum density as determined by the standard proctor test or shall be compacted to a density equivalent to the density of the immediate adjoining soil. The top six (6) inches of backfill in street right-of-way shall be compacted to a minimum density of ninety-five percent (95%) of optimum density as determined by the standard proctor test. Backfill material shall be placed and compacted only when its moisture content is within two percent (2%) of optimum moisture content as determined by standard proctor test.
2. 
The combination of the thickness of the layer, the method of compaction and the type of compaction equipment shall be at the discretion of the contractor subject to obtaining the densities as specified above.
3. 
The quality of the compactions shall be subject to compaction tests when deemed necessary by the City's consulting engineer. It shall be the developer's responsibility to make necessary excavation in order to accommodate compaction tests at locations specified by the City's consulting engineer. The compaction tests will be performed at no cost to the City. If the quality of the compaction does not meet the above requirements, the material will be removed and replaced to meet the above requirement at the expense of the developer.
4. 
Commercial sand backfill shall not be used.
5. 
Backfill material shall be carefully placed to avoid damage or displacement of sewer or structures.
6. 
Backfill shall not be placed when material contains frost, is frozen or a blanket of snow prevents proper compaction. Backfill shall not contain waste material, trees, organic material, rubbish, etc.
B. 
Backfill Of Pipe Trenches.
1. 
The area below a plane six (6) inches above the top of pipe bell shall be backfilled in accordance with the specifications for "pipe bedding".
2. 
Backfill above a plane six (6) inches above the top of pipe bell shall be made with suitable earth, earth and rock or other acceptable material except that the area below a plane one (1) foot above the pipe bell shall not contain any excavated rock. When earth and rock is used, the maximum dimension of the rock shall not exceed twelve (12) inches.
C. 
Backfill Around Structure.
1. 
No backfill shall be placed over or around any structure until the concrete or mortar therein has attained a minimum strength two thousand (2,000) psi and can sufficiently support the loads imposed by the backfill without damage.
2. 
The developer shall use utmost care to avoid any wedging action between the side of the excavation and the structure that would cause any movement of the structure. Any damage caused by premature backfill or by the use of equipment on or near a structure will be the responsibility of the developer.
3. 
Backfill shall be placed and compacted on all sides of the structure simultaneously and operations shall be so conducted that the backfill is always at approximately the same elevation on all sides of the structure.
4. 
No excavated rock larger than four (4) inches maximum dimension shall be placed within one (1) foot of the exterior surface of any structure.
[Ord. No. 1620 §1, 9-25-2006]
A. 
Visual Inspection.
1. 
Contractor shall clean pipe of excess mortar, joint sealant and other dirt and debris prior to inspection.
2. 
Sewer will be inspected by flashing a light between manholes and/or by physical passage where space permits. Determine from illumination and/or physical inspection the presence of any misaligned, displaced or broken pipe and the presence of visible infiltration or other defects.
3. 
Correct defects as required prior to conducting leakage tests.
B. 
Deflection Test. Gravity pipeline of flexible materials shall also be tested by pulling a mandrel. The test shall be conducted not less than one (1) month after backfill has been properly installed. The maximum allowable deflection shall not exceed five percent (5%) of the pipe's internal diameter.
C. 
Air Leakage Test. To be performed on the full length of all lines prior to acceptance.
1. 
The pipe plug for introducing air to the sewer line shall be equipped with two (2) taps. One (1) tap will be used to introduce air into the line being tested, through suitable valves and fittings so that the input air may be regulated. The second (2nd) tap will be fitted with valves and fittings to accept a pressure test gauge indicating internal pressure in the sewer pipe. An additional valve and fitting will be incorporated on the tap used to check internal pressure so that a second (2nd) test gauge may be attached to the internal pressure tap. The pressure test gauge will also be used to indicate loss of air pressure due to leaks in the sewer line.
2. 
The pressure test gauge shall meet the following minimum specifications:
Size (diameter)
4½ inches
Pressure range
0 — 15 p.s.i.
Figure intervals
1 p.s.i. increments
Pressure tube
Bourdon tube or diaphragm + 0.25% of maximum scale reading00.
Dial
White coated aluminum with black lettering, 270 degree arc and mirror edge.
Pipe connection
Low male ½ inch N.P.T. calibration data will be supplied with all pressure test gauges. Certification of pressure test gauge will be required from the gauge manufacturer. This certification and calibration data will be available to the engineer whenever air tests are performed.
3. 
Test each reach of sewer pipe between manholes after completion of the installation of pipe and appurtenances and the backfill of sewer trench.
4. 
Plug ends of line and cap or plug all connections to withstand internal pressure. One (1) of the plugs provided must have two (2) taps for connecting equipment. After connecting air control equipment to the air hose, monitor air pressure so that internal pressure does not exceed five (5.0) psig. After reaching four (4.0) psig, throttle the air supply to maintain between four (4.0) and three and one-half (3.5) psig for at least two (2) minutes in order to allow equilibrium between air temperature and pipe walls. During this time, check all plugs to detect any leakage. If plugs are found to leak, bleed off air, tighten plugs and again begin supplying air. After temperature has stabilized, the pressure is allowed to decrease to three and one-half (3.5) psig. At three and one-half (3.5) psig, begin timing to determine the time required for pressure to drop to two and one-half (2.5) psig. If the time in seconds for the air pressure to decrease from three and one-half (3.5) psig to two and one-half (2.5) psig is greater than that shown on the table below, the pipe shall be presumed free of defects.
Pipe Size
Required Time Per 100 LF
Maximum Time
8 inches
70 seconds
227 seconds
10 inches
110 seconds
283 seconds
12 inches
158 seconds
340 seconds
15 inches
248 seconds
425 seconds
18 inches
356 seconds
510 seconds
21 inches
485 seconds
595 seconds
24 inches
634 seconds
680 seconds
27 inches
765 seconds
765 seconds
30 inches
851 seconds
851 seconds
33 inches
935 seconds
935 seconds
5. 
If air test fails to meet above requirements, repeat test as necessary after all leaks and defects have been repaired. Prior to acceptance all constructed sewer lines shall satisfactorily pass the low pressure air test.
6. 
In areas where ground water is known to exist, install a one-half (½) inch diameter capped pipe nipple, approximately ten (10) inches long, through 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 line acceptance test, ground water level shall be determined by removing pipe cap, blowing air through pipe nipple into the ground so as to clear it and then connecting a clear plastic tube to pipe nipple. The hose shall be held vertically and a measurement of height in feet of water shall be taken after the water stops 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.
[Ord. No. 1620 §1, 9-25-2006]
A. 
A hydrostatic pressure and leakage test shall be performed in conformance with AWWA C-600 procedures as modified herein. Test shall apply to all pressure sewers and shall be performed after backfilling.
B. 
Test separately in segments between sectionalizing valves, between a sectionalizing valve and a test plug or between test plugs. Select test segments such that adjustable seated valves are isolated for individual checking. Developer shall furnish and install test plugs including all anchors, braces and other devices to withstand hydrostatic pressure on plugs. The developer shall be responsible for any damage to public or private property caused by failure of plugs. Limit full rate of line to available venting capacity.
C. 
Pressure Test. Conduct at one and one-half (1.5) times maximum operating pressure determined by following formula:
P pt
=
0.650 (OP-GE) in which
P pt
=
Test pressure in psi at gauge elevation.
OP
=
Operating pressure in feet as indicated for highest elevation of the hydraulic gradient on each section of the line.
GE
=
Elevation in feet at centerline of gauge. Perform satisfactorily prior to determining leakage.
D. 
Leakage Test. Conduct at maximum operating pressure determined by following formula:
P lt
=
0.433 (OP-GE) in which
P lt
=
Test pressure in psi at gauge elevation.
OP and GE
=
As in previous Subsection.
E. 
All joints shall be watertight and free from leaks.
[Ord. No. 1620 §1, 9-25-2006]
A. 
All manholes shall be vacuum tested by the contractor at his expense. Appropriate equipment and manpower will be furnished by the developer for this purpose. When vacuum testing manholes, the following criteria are to be used:
1. 
This method is applicable to pre-cast manholes only.
2. 
All lift holes shall be plugged with an approved non-shrink grout.
3. 
Manholes are to be tested after assembly and before backfilling. No standing water shall be allowed in the manhole excavation that may affect the accuracy of the test.
4. 
All pipes and other openings into the manhole shall be plugged and securely braced to prevent displacement of the plugs while the vacuum is drawn.
5. 
Installation and operation of vacuum equipment shall be in accordance with equipment specifications and instructions provided by the manufacturer.
6. 
The test head may be placed in the cone section of the manhole. The frame-cone joint will be visually inspected by the engineer.
7. 
A vacuum of ten (10) inches of mercury shall be drawn and the vacuum pump shut off. The time for the vacuum to drop to nine (9) inches of mercury shall be recorded.
8. 
Acceptance for four (4) foot diameter manholes shall be defined as when the time to drop to nine (9) inches of mercury meets or exceeds the following:
Manhole Depth
Diameter
Time To Drop 1 Inch of HG
10 feet or less
4 feet
60 seconds
10 feet to 15 feet
4 feet
75 seconds
15 feet to 20 feet
4 feet
90 seconds
9. 
For manholes five (5) foot in diameter, add an additional fifteen (15) seconds and for manholes six (6) foot in diameter, add an additional thirty (30) seconds to the time requirements for four (4) foot diameter manholes. If the manhole fails to test, necessary repairs shall be made with a non-shrink grout while the vacuum is still being drawn. Retesting shall proceed until a satisfactory test is obtained.