The following requirements shall govern sanitary sewer improvements:
(A) Where an adequate public sanitary sewer system is reasonably accessible, in the determination of the City Planning Commission, public sanitary sewers shall be installed to adequately serve all lots, including lateral connections to the public system. Public sewer system extensions shall meet the requirements of the Ohio Environmental Protection Agency and city standards. Sewers designed to carry sanitary sewerage and storm drainage simultaneously shall be prohibited.
(1) Materials. The materials used in this work shall all be new. A copy of the manufacturer's installation recommendations for each kind of pipe used must be provided to each foreman and inspector prior to construction and must be followed during construction unless otherwise instructed.
(a) PVC pipe.
1. PVC (Poly-Vinyl Chloride) pipe shall be used in all mains and service connections.
2. PVC pipe shall conform to the requirements of ASTM D-3034 rigid PVC (SDR-35) and/or ASTM F679T-1 SDR 35 or PVC equivalent. The pipe shall have bell and spigot joints with an approved gasketed joint. The spigot end shall be marked so that the installer and the inspector can determine when the pipe is properly installed.
3. Pipe entrances to manholes shall be sealed watertight with O-ring gaskets or other method as specified and approved by the city and must meet ASTM F-477 or PVC equivalent.
4. Services shall be of materials specified. Where the service material is not designed to fit the PVC pipe wye tightly, an approved commercial adaptor joint shall be used to connect the service pipe to the PVC pipe and must meet ASTM D-3212 or PVC equivalent.
(b) Service pipe. Service pipe materials shall be PVC sewer pipe (ASTM D-3034 or Schedule 40 or PVC equivalent).
(c) Manholes.
1. All manholes shall be constructed with precast sections unless otherwise approved.
2. Precast concrete manhole sections shall be manufactured to standards at least equal to or greater than the requirements of the Standard Specifications for Precast Reinforced Concrete Manhole Sections, ASTM Designation C478. The internal diameter for sanitary manholes shall be 48 inches unless shown otherwise. Manholes shall conform to all requirements as shown on the detail drawings. Manholes shall have steps unless otherwise specified. Precast manhole joints shall be made watertight with Ram-Nek material or approved O-ring gasket at each joint. The Ram-Nek and primer must be used in accordance with the manufacturer's instructions.
3. Rubber O-rings used for precast manhole joints should be R-4 joint or shall be designed in accordance with ASTM Designation C361.
4. The concrete base shall be cast-in-place concrete of the size and depth shown on the drawings. Concrete used for bases shall have a 28-day compressive strength of at least 3,000 pounds per square inch. Approved precast concrete bases will be allowed if placed in an approved manner.
5. Manhole frames and covers. Manhole frames and covers shall have a round base, 22-inch opening non-locking type, with frame and cover weighing approximately 327 pounds. Cover and frame seat shall be machine finished to prevent any rocking of cover in its associated frame. Cover shall have the word SEWER clearly cast on its surface.
6. Manhole steps. All manhole steps shall be cast-iron or polypropylene covered alloy. Steel or wrought iron steps of any kind will not be permitted. Steps shall be drop-front design with minimum tread width of nine inches. Rubber-covered “Wedglok” manhole steps may be used in lieu of the above.
(d) Granular materials. Granular materials furnished for foundation, bedding, encasement or other purposes shall consist of any material or synthetic mineral aggregate such as sand, gravel, crushed rock, crushed stone or slag, that shall be so graded as to meet the gradation requirements specified herein for each particular use.
(e) Select backfill. Job excavated select backfill material shall be free from debris, organic material, and stones larger than three inches in diameter.
(2) Alignment and grades.
(a) All roadways shall be constructed in accordance with lines and grades shown on the approved drawings.
(b) The developer shall provide an experienced instrument man, competent assistants and such instruments, tools, stakes, and other materials required to complete the survey, layout, and measurement work.
(c) Any work done without being properly located may be ordered removed and replaced at the developer's expense.
(3) Detour - traffic control - temporary crossings and barricades.
(a) Traffic will be permitted to use the street at all times, unless a detour is specifically permitted on the drawings or by the city. Safe access to all abutting residences and properties shall be maintained to the maximum extent possible.
(b) The developer shall construct and maintain temporary crossings, complete with flaggers, whenever necessary to expedite the work or to maintain traffic. Temporary crossings shall be of ample size to safely carry the load which comes upon them. The Developer shall furnish sufficient signs and barricades to facilitate the directing of traffic.
(4) Laying of pipe.
(a) All foreign matter or dirt shall be removed from the inside of the pipe before it is lowered into its position in the trench, and it shall be kept clean by approved means during and after laying. All openings along the line of the sewer shall be securely closed as directed and, in the suspension of work at any tie, suitable watertight stoppers shall be placed to prevent earth, water or other substances from entering the sewer.
(b) Piping shall be laid to the lines and grades indicated on the drawings.
(c) Fine grading to the bottom of the barrel shall proceed ahead of the pipe laying and, should any over-excavation exceeding two inches be encountered, the material added shall be moistened and compacted to the satisfaction of the Engineer or foundation material shall be added.
(d) Holes shall be dug for the pipe bells and the material placed along the preceding pipe laid. The pipe shall be supported for the bottom 90° and throughout its length (except for the minimum distance necessary at the bell holes) as shown on the drawings. Bell holes shall be adequate to make the joint, but no larger than necessary so that maximum support on undisturbed ground will be provided for the pipe. The remainder of the pipe shall be surrounded to at least the mid-point of the pipe by granular bedding, shovel placed and hand stamped, to fill completely all spaces under and adjacent to the pipe. Non-granular materials must be used for PVC pipe.
(e) Pipe laying should proceed upgrade with the spigot ends pointed in the direction of flow. No pipe shall be laid in water or when the trench conditions are unsuitable for such work. The Developer shall make all connections of pipe to the manholes which have previously been constructed.
(f) When connecting to existing sewers, the developer shall take every precaution necessary to prevent dirt or debris from entering the existing lines. The developer shall use an approved watertight plug to securely plug the new sewer at the connection to the existing sewer immediately after the connection has been made. The plug shall be braced as necessary and tied to the manhole by a rope or chain. This plug shall remain until the new sewer system has been accepted by the city.
(5) Construction of manholes.
(a) Excavation shall be to a depth and size to provide for construction of the manhole as shown in detail on the drawings.
(b) Concrete bases shall be poured on undisturbed ground. Precast concrete bases shall be carefully lowered onto six inches minimum layer of well compacted sand accurately laid to a smooth level surface using a straight edge and hand level or three inches of concrete poured on undisturbed soil.
(c) Walls shall be of precast concrete as shown on the drawings and shall be constructed to form a complete watertight structure.
(d) Provide a minimum of six inches and a maximum of 18 inches in two-inch layers of sewer brick or precast concrete adjusting rings between the cast iron frame and the manhole tope section. Each ring or brick shall be set on a full bed of mortar and shall be made watertight. Wood or other foreign material will not be allowed. Adjusting rings shall conform to the size and shape of the casting frame. Frames and covers shall be set to the designated elevation in a full mortar bed.
(e) On streets that are not at design grade, sewer manholes shall be built with such additional adjusting rings or short manhole sections as necessary to allow for adjustment of the street to the proposed grade as shown on the drawings. Manhole casting tops shall be ¼-inch below the street surfacing.
(f) When manholes are to be constructed in new streets, manhole rings shall be set to final grade before street wearing course is laid. In unpaved roadways, the manhole ring shall be brought to grade and surrounded by a three-inch thick asphalt apron at least five feet in diameter.
(g) The bottom of all manholes shall be smoothly shaped to conform to the pipe so as to allow a free, uninterrupted flow of sanitary sewage.
(h) Unless shown otherwise on the drawings, the sanitary sewer pipe should be laid continuously through the manholes and broken or cut out when the manhole base is finished. Manhole couplings or rubber ring stops must be used where the pipe joins the manholes.
(6) Backfilling and grading.
(a) All excavation in trenches shall be backfilled to the original ground surface or to such grades as specified or shown on the drawings. The backfill shall begin as soon as practical after the pipe has been placed and shall thereafter be carried on as rapidly as the protection of the balance of the work shall permit.
(b) Backfilling and compacting shall be done as thoroughly as possible so as to prevent after-settlement. Depositing of the backfill shall be done so the impact of falling material will not injure the pipe or structures.
(c) Granular bedding shall be deposited in the trench simultaneously on both sides of the pipe for the full width of the trench to a height at least to the mid-point of the pipe, shovel placed, and hand stamped to fill completely all spaces under and adjacent to the pipe. Encasement material will then be placed around and over the pipe to a height of at least 12 inches above the top of the pipe but need not be hand placed. Nongranular materials may be used for encasement except for PVC pipe.
(d) In the event that natural, suitable, granular material is not encountered during the normal excavation of the sewer trench, or when the material encountered is determined unsuitable by the city for encasement around the pipe as required, the developer shall provide and place such approved material. For PVC pipe, approved granular encasement material must be placed and hand stamped to at least six inches over the top of the pipe. The remaining six inches may be nongranular material if specifically approved by the city.
(e) Succeeding layers of backfill above the 12-inch level may contain coarse materials not exceeding three inches in the largest dimension, but shall be free from large pieces of rock, frozen material, concrete, roots, stumps, tin cans, rubbish, and other similar articles whose presence in the backfill would cause settlement of the trench or damage to the pipe.
(f) Whenever select material that exists in place in the upper four feet of the finished grade of the paved or traveled portions of the street or roadway, is removed by the trench excavation, the contractor shall replace the material (or material of equal quality) as backfill in the upper four feet of the finished grade. Where select material does not exist in place as described above, provide and place sufficient select backfill to stabilize the finished grade.
(g) Backfilling shall be done in lifts of uniform layers which will produce the required compaction. Each lift shall be completely compacted over the full-width of the excavated area. Compacting shall continue until the specified relative compaction has been attained or until no more settlement occurs. Water jetting of backfill shall not be permitted.
(h) Special compaction shall be performed around all manholes, valve boxes, curb boxes, other structures, and utilities by the use of pneumatic tampers, plate tampers, or plate vibrators.
(i) Sewer service trenches in the right-of-way must be compacted in the same manner as the main trenches. In streets open to traffic, service trenches must not be left open overnight. In areas where curb and gutter exist, sufficient curbing shall be removed to allow this compaction over the entire disturbed area.
(j) The relative compaction of the soils in place shall be determined by using either the sand-cone method ASTM Standard Test Designation D1556-64, or nuclear methods, ASTM Standard Test Designation D2922-71. Relative compaction of all backfill materials must meet the following requirements as determined by AASHO T-99 (ASTM D-698) method A or C. The compaction required in paved areas, areas to be paved, or graveled areas shall be as follows:
(k) Ninety-five percent compaction from 24 inches above top of pipe to the finished surface, except that in no case shall this 95% compaction zone be less than 48 inches deep. Ninety percent compaction from pipe zone to start of 95% compaction zone.
(l) The compaction required outside paved areas, outside areas to be paved or outside graveled areas shall be 90%.
(m) The developer is responsible for the complete maintenance of his work at all times.
(n) The contractor shall remedy at his own expense any defects that appear in the backfill following completion and during the one-year guarantee period.
(7) Service connections.
(a) It shall be the duty of the developer to keep an accurate record of service connections as to the location, elevation of the service at the property line, type of connection provided, and the like. Location shall be made in respect to the survey line stationing and house corners or lot corners. All services must be approved by the inspector prior to backfill.
(b) Generally, a four-inch or six-inch wye shall be used in the main line. An approved adaptor or other approved method of connection to the wye shall be installed.
(c) All house connections shall be capped with stoppers recommended by the pipe manufacturer, sealed firmly in place, or by other methods accepted by the Engineer, which shall effectively prevent water from entering the sewer until the connection is placed in service. The house connection end shall be clearly marked by a rebar extending from the pipe end to at least three feet above the ground.
(d) Risers are to be constructed at all points where the depth of cover over the invert of the sewer line is 15 feet or more at other locations as determined by the Engineer.
(8) Testing - sanitary sewer.
(a) Upon completion of all utility construction by this contract and before any house services are connected, tests will be required of all sanitary sewer lines.
(b) The contractor has the option of performing either an air test or an exfiltration test.
Test shall be performed after complete compaction and backfill and completion of manholes, but may be performed before paving.
1. Air tests.
A. The contractor shall perform these tests with suitable equipment specifically designed for air testing sewers.
B. The air test shall be made when the sewer is clean. Sections of sewer pipe to be tested, may be wetted before the air test. The line shall be plugged at each manhole with pneumatic balls. Low pressure air shall be introduced into the plugged line until the internal pressure reaches (4.0) psig greater than the average back pressure of any ground water pressure that may submerge the pipe. At least two minutes shall be allowed for the air temperature to stabilize before readings are taken and the time started.
C. The portion being tested shall pass if it does not lose air at a rate to cause the pressure to drop from 3.6 to 3.0 psig (greater than the average back pressure of any ground water that may submerge the pipe) in less time than listed below.
Pipe Diameter in Inches | Minimum Allowable Minutes 3.6 - 3.0 psig Pressure |
Pipe Diameter in Inches | Minimum Allowable Minutes 3.6 - 3.0 psig Pressure |
4 | 2.0 |
6 | 3.0 |
8 | 4.0 |
10 | 5.0 |
12 | 6.0 |
15 | 7.5 |
18 | 9.0 |
21 | 10.5 |
24 | 12.0
|
D. If the installation fails this test, the testing equipment may be used to determine the location of the pipe leak.
E. All service plugs shall be secured in place to prevent displacement during testing operations.
2. Exfiltration test.
A. In lieu of the standard sanitary sewer air test, the contractor may make exfiltration tests on sewers.
B. The test section shall be bulkheaded at both ends and the pipe subjected to a hydrostatic pressure produced by a head of water at a depth of three feet above the top of the sewer at the upper manhole under test. In areas where ground water exists, this head of water shall be three feet above the existing water table.
3. A. The head of water shall be obtained by means of an open ended standpipe projecting from test plug on upper manhole. Placing water in the upper manhole is not permissible as a means of obtaining the necessary pressure head of water.
B. This head of water shall be maintained for a period of one hour during which it is presumed that full absorption of the pipe body has taken place, and thereafter for a further period of one hour for the actual test of leakage. During this one hour test period, the measured maximum allowable rate of exfiltration for any section of sewer, including service stubs, shall be as listed below:
Main Sewer Diameter in Inches | Maximum Allowable Exfiltration Gallons Per Hour Per 100 Feet |
Main Sewer Diameter in Inches | Maximum Allowable Exfiltration Gallons Per Hour Per 100 Feet |
4 | 0.6 |
6 | 0.9 |
8 | 1.2 |
10 | 1.5 |
12 | 1.9 |
15 | 2.3 |
18 | 2.8 |
21 | 3.3 |
24 and larger | 3.8
|
C. In case measurements indicate an exfiltration greater than the maximum allowable leakage, additional measurements shall be taken and continued until all leads are located and the necessary repairs and corrective work have reduced the leakage in the section being tested below the maximum allowable by the specifications. For purposes of the test, the line between adjoining manholes will be considered a section and will be tested as such.
D. The introduction of any substance into the water used for testing with the intent of sealing such leaks as may be indicated will not be permitted.
E. If results of either of these tests are not satisfactory, repairs or pipe replacement will be required until the Engineer is satisfied that the leakage requirements are being met. All repair methods and materials used must be accepted by the Engineer.
(9) PVC deflection test.
(a) All PVC pipe shall be subject to a deflection test by use of cage type approved mandrel.
(b) In paved areas or areas to be paved, either:
1. Testing PVC sewer lines with a 4% deflection mandrel after complete backfill and compaction of trench but before paving; or
2. Testing PVC sewer lines with a 5% deflection mandrel after paving is complete.
(c) In non-paved areas contractor has the option of:
1. Testing PVC sewer lines with a 4% deflection mandrel after complete backfill and compaction of trench but before placing and spreading top soil; or
2. Testing PVC sewer lines with a 5% deflection mandrel after placing and spreading top soil (but before seeding).
(d) All mandrels shall be precisely made to the diameters specified below (which include allowances for pipe manufacturer's outside diameter tolerance, excess wall thickness tolerance, and out-of-roundness tolerance).
Nominal Pipe Diameter | Mandrel Minimum O.D. for 4% Deflection | Mandrel Minimum O.D. for 5% Deflection
|
4" | — | — |
6" | — | — |
(10) Video tape. Following the construction of all sanitary sewer mains in the city, in addition to holding a pressure test as required by this code, the city will be given a tape of the televising of the lines as they have been constructed in place. This tape shall be of the size, quality and specification that it can be played and monitored on the existing video equipment owned by the city.
(B) Where a public sanitary sewer system is not reasonably accessible, the subdivider may provide:
(1) A central treatment plant for the group, provided that such central treatment plant is installed in accordance with regulations requirements of the Ohio Environmental Protection Agency; or
(2) Lots may be served by individual disposal systems if the provisions of this section are met.
(C) (1) Where the installation of individual disposal systems is considered, the suitability of the soil for individual systems, the absorptive ability of the soil, surface drainage, ground water level, and topography shall be the criteria for determining whether or not the installation of individual systems is permissible. Criteria shall be in accordance with the requirements of the Ohio Environmental Protection Agency.
(2) Each lot so served shall be of a size and shape to accommodate the necessary length of field tile at a safe distance from and at a lower elevation than the proposed building(s). Such lot size and shape shall conform to the requirements of the zoning district in which they are located. If no zoning is in effect, the standards set forth in § 155.048 shall be met.
(3) At least one percolation test shall be made for each lot area being platted, and each test shall be located in close proximity to the proposed individual sewage disposal unit, be numbered and its location shown on the preliminary plat. All percolation tests shall be performed in accordance with the requirements of the City Planning Commission and the Ohio Environmental Protection Agency.
(4) Where the installation of individual disposal units is considered and where the average natural ground slope exceeds 10%, the installation of a step-up disposal system may be required subject to specification by the Ohio Environmental Protection Agency.
(Ord. 20-89, passed 6-28-89; Am. Ord. 4-94, passed 3-2-94; Am. Ord. 11-98, passed 6-10-98)