8-243 Section 825. Sanitary Sewer Systems
825.01 Description
This work consists of constructing sanitary sewer systems as requir ed by the contract and approved by the Engineer . This work includes trench excavation, dewatering, sheeting and/or bracing, backfilling, testing of the pipe, disposal of waste materials, connections to existing systems, maintaining sanitary service, and providing as- built plans and any related work necessary to complete the sewer installation.
825.02 Materials
Provide materials for the sanitary sewer work that meet the requirements of this section, AWWA Specifications, and the requirements of the sanitary sewer owner. Conc rete pipe must conform to sections 402 and 909 and as indicated on the plans. Ductile iron (DI) pipe must conform to the requirements of AWWA C151 (ANSI A21.51) of the sizes shown on the plans . The pipe must be thickness class 54. DI pipe must be lined with calcium aluminate mortar, PE, ceramic epoxy , or other approved material capable of withstanding the corrosive effects of wastewater . The outside of the pipe must be coated with the standard bituminous seal . The metal thickness class, net weight of the pipe without lining, nominal size, and the manufacturer ’s identifying symbol must be clearly marked on each length of pipe. PVC pipe for sewer main and service laterals must conform to the requirements of ASTM D3034 and must have a standard dimensi on ratio (SDR) of 26 . Provide homing marks on pipe sections and joint material to show the correct alignment during field installation. Provide joints with an elastomeric gasket push-on type conforming to ASTM D3212, unless specified differently on the plans . PVC fittings must be full fittings conforming to ASTM D3034 for pipe wall thickness of SDR 26. All pipe and fittings must be marked to provide manufacturer’s name, lot or production number, ASTM designation, nominal diameter, and SDR number, where applicable . Fittings, however, need not contain lot or production number. The gaskets used with DI pipe must meet all applicable requirements of AWWA C110 (ANSI A21.10) and AWWA C111 (ANSI A21.11) specifications. MDOT Standard Specifications for Construction Section 825 8-244 Flexible transition couplings must be used w hen connecting a proposed sanitary sewer to an existing sanitary sewer main or lateral where a manhole is not utilized at or near the point of connection. These connections must be watertight by use of a manufactured flexible transition coupling designed f or such purpose. Flexible transition couplings must be in accordance with ASTM D5926 and ASTM C1173. Acceptable manufacturers are Fernco, Inc., Cascade Flex -Seal, or approved equal. Couplings, fittings, solvents , and lubricants must be as recommended by the pipe or fitting manufacturer and as specified herein. Provide precast concrete sanitary manholes in accordance with section 403.
825.03 Construction
Perform all work in accordance with sections 203, 206, 402, and 403 and ASTM D2321, as well as federal, state, and local requirements .
A.General . The plans show the locations of existing utilities in accordance with available data. The Contractor will expose utilities shown on the plans to determine the actual locations . Provide the Engineer with a copy of the result s for review . Notify the Engineer in advance of work so the Engineer may give the municipality 3 working days’ notice. Maintain sanitary sewer service at all times during construction of the sanitary sewer and/or structures by temporary pumping, constructi on staging, or other means as approved by the Engineer . Provide bypass pumping equipment, labor , and materials to perform the work of bypass pumping for the interrupted flow of sewage in the sanitary sewer mains during construction of the proposed sanitary system and coordinate the progress with the Engineer . Equipment used for dewatering and bypass pumping must be of a size and type adequate to perform the job and must be operated in such a manner as to minimize disruption to the public . On operations that require continuous pumping over prolonged periods of time, provide pumps, generators , and other equipment that meet local and state noise ordinances . The work may need to be performed on weekends, holidays , or off -peak hours to minimize impact . Coordinate scheduling of connections with the municipality and obtain the Engineer’s approval of the schedule. Connections to the existing sanitary sewer service leads must be made at the right-of-way line and include a cleanout unless otherwise approved by the Engineer . Make pipe connections as recommended by the pipe manufacturer. The cleanout must be the same size and material type as the sewer lead and include a wye-branch, 45-degree sweep, section of riser pipe , and threaded plug installed at grade level . MDOT Standard Specifications for Construction Section 825 8-245 B. Trench Excavation . Excavate in accordance with subsection 823.03.
C.Disposal . Dispose of waste material as specified in section 205.
D.Laying of Pipe . Use laser equipment for the installation of all pipe. Lay pipe to the grade shown on the plans . Field verify invert elevations at each manhole and notify the Engineer immediately if deviations from plan elevations are encountered.
E.Abandoning Existing Sanita ry Sewers. Abandon existing sanitary sewers as specified in subsection 823.03.
F.Testing . Subject all sanitary sewer to air, infiltration, or exfiltration tests or a combination of same prior to approval of the sanitary sewer and structure.
1.Infiltration or Exfiltration Test. All sanitary sewer, where the groundwater level above the top of the s anitary sewer is more than 7 feet, must be subjected to the infiltration test . All sanitary sewer, where the groundwater level above the top of the sanitary sewer is 7 feet or less, must be subjected to the air test or exfiltration test . If an exfiltration test is performed, the maximum exfiltration rate is the same as that permitted for the infiltration test . For the purpose of exfiltration testing, the internal water level must be equal to the external water level plus 7 feet, as measured from the top of the pipe. Where groundwater conditions require dewatering operations in order to construct the sanitary sewer and structures, the Contractor may, at its option, perform a preliminary air test after backfilling and while the dewatering equipment is still operating. After dewatering operations have ceased and groundwater has stabilized at its normal level (7 feet or less above the sanitary sewer) and if the preliminary air test was satisfactory, the preliminary air test may be accepted as final to the satisfa ction of the Engineer. The maximum allowable infiltration must not exceed 100 gallons per inch of diameter per mile of pipe per 24 hours for any individual run between manholes.
2.Air Test . Test the sanitary sewer by applying an air pressure test described h erein. Methods of testing and measurement other than specified herein must be approved by the Engineer . Perform all testing in the presence of the Engineer and a representative of the municipality. Furnish all equipment and labor for air testing, including, but not limited to, a portable air compressor, standard air hose, one single and one triple connection pneumatic sanitary sewer plug, one hand air MDOT Standard Specifications for Construction Section 825 8-246 pump, stopwatch and one air gauge, range 0 to 30 pounds per square inch gauge (psig) graduated in tenths fr om 0 to 10 psig. Test the pneumatic plugs in the presence of the Engineer prior to actual line testing in the following manner: Remove all debris from the pipe prior to air testing. Lay one length of sanitary sewer pipe on the ground and seal at both ends with pneumatic plugs to be checked; introduce air into the pipe until the pipe pressure reaches 15 psig. The pneumatic plugs being checked must hold against this pressure without the need for bracing and without movement of the plugs out of the pipe. All pneumatic plugs must pass the test before being used to test the actual installation.
a.Air Test Procedures . Immediately following the pipe cleaning, introduce low pressure air into the sealed line until the internal air pressure reaches 3.5 psig greater than the average hydrostatic pressure of any groundwater that may be over the pipe. Allow at least 2 minutes f or the air pressure to stabilize. The portion of the line being tested will be accepted if the portion under the test meets or exceeds the requirements of ASTM F1417. The time, in minutes, required for the pressure to decrease from 3.5 to 2.5 psig greater than the average back pressure of any groundwater that may be over the pipe must not be less than the time shown for the given diameters listed in Table 1 of ASTM F1417. If the pipe diameter to be tested falls between the pipe sizes listed in ASTM F1417, use the next larger pipe size. If the system does not meet specified requirements, locate and repair the leaks at no extra cost to the Department and repeat the tests until the permissible leakage is obtained.
3.Video Inspection . Perform video inspect ion in accordance with subsection 402.03.K for all diameters of sanitary sewer main.
G.As-Built Plans . Provide as -built plans of the sanitary sewer and structures acceptable to the Engineer to be forwarded to the municipality . The minimal information required for acceptable as -built plans include pipe size, slope, pipe and manhole locations (station and offsets), manhole size, invert elevations, tees, tie-ins and individual service connections . Sanitary sewer work is not considered complete and payment may be withheld until acceptable as -built plans have been provided to the Engineer. MDOT Standard Specifications for Construction Section 825 8-247 825.04. Measurement and Payment The completed work, as described, will be measured and paid for at the contract unit price using the following pay item s: Pay Item Pay Unit Sanitary Sewer , DI, __ inch, Tr Det __ ....................................................... Foot Sanitary Sewer, PVC, __ inch, Tr Det __ ................................................... Foot Sanitary Sewer, Conc , __ inch, Tr Det __ .................................................. Foot Sanitary Structure, __ inch dia .................................................................. Each Sanitary Structure, Add Depth of __ inch dia, 8 foot to 15 foot .................. Foot Sanitary Structure, Add Depth of __ inch dia, more than 15 foot ............... Foot Sanitary Structure Cover , Type __ ............................................................ Each Sanitary Structure, Rem .......................................................................... Each Sanitary Structure, Tap, __ inch ............................................................... Each Sanitary Sewer, Serv Lead, PVC , __ inch ................................................. Foot Sanitary Sewer Cleanout, __ inch ............................................................ Each Sanitary Sewer Lead, Rem and Abandon ................................................. Each Sanitary Structure Cover, Adj, Case__ ..................................................... Each Sanitary Structure, Adj, Add Depth ............................................................ Foot
A.Sanitary Sewer . Sanitary Sewer, __, __ inch, Tr Det __ of the material, sizes, and trench details specified will be measured in place along the centerline of the pipe. The unit price includes all labor, equipment , and materials required to perform the work specified herein and shown on the plans, including excavation and backfill , locating and connecting to existing sanitary sewer mains, pumping/bypass pumping to maintain sanitary service, locating and connecting to existing service leads, dewatering (trench and/or pipe), testing, furnishing and installing all premium joints, bracing or sheeting, blocking and all other miscellaneous items necessary for the inst allation of the pipe. Sanitary Sewer, __, __ inch, Tr Det __ includes additional costs due to working weekends, holidays , and off -peak hours . Video inspection and integrity testing are included in the contract unit price for Sanitary Sewer, __, __ inch, Tr Det __ . Cost of all labor, equipment , and materials necessary to conduct specified testing and to remedy any unsatisfactory test, including removing and replacing any backfill or piping, is included in the contract unit price for associated sanitary sewer pay items and will not be paid for separately.
B.Sanitary Structure . Sanitary Structure, __ inch dia, Sanitary Structure, Add Depth, of __ inch, 8 foot to 15 foot , and Sanitary Structure, Add Depth of __ inch , more than 15 f eet to be measured and paid for i n accordance with section 403.04, Dr Structure, Add Depth, 8 foot to 15 foot, and Dr Structure, Add Depth, more than 15 foot. MDOT Standard Specifications for Construction Section 825 8-248 Payment includes furnishing all material, labor, and equipment required to perform the work specified herein and shown on the plans including resilient connections with straps, installing sanitary manhole cover , and any adjustments to final grade.
C.Sanitary Structure Cover . Sanitary Structure Cover , Type __ includes payment in full for furnishing all material, labor, and equipment required to install the sanitary manhole covers as shown on the plans.
D.Sanitary Structure Removal . Sanitary Structure, Rem will be measured and paid for in accordance with section 203.04, Dr Structure, Rem .
E.Structure Tap . The unit price for Sanitary Structure, Tap, __ inch will be measured per each. Connections and/or taps include the furnishing and installation of the approved equal flexible watertight boot connection system.
F.Sanitary Sewer Lead . Sanitary Sewer , Serv Lead, PVC, __ inch will be measured in place per foot along the centerline of the pipe. The price will include payment in full for furnishing all excavation and backfill, all material, labor, and equipment required to perform the work specified herein and shown on the plans, including temporary hook up to maintain sanitary service, locating and connecting to the existing service lead, connection to the existing or proposed sanitary main, dewatering (trench and/or pipe), all testing, furnishing and installing all premium joints, wyes, fittings, bracing or sheeting, blocking, and all other miscellaneous items necessary for the installation of the lead.
G.Sanitary Cleanout . The unit price for Sanitary Sewer Cleanout , __inch will be measured as each and includes dewatering (trench and/or pipe) ; furnishing and installing all premium joints, wyes, caps, fittings, bracing, or sheeting; blocking; and all other miscellaneous items necessary for the cleanout installation.
H.Sewer Lead Remove and Abandon. The unit price for Sani tary Sewer Lead, Rem and Abandon includes locating and verifying that the lead is abandoned, capping the existing service lead at the main, dewatering (trench and/or pipe), all testing, furnishing and installing all premium joints, wyes, caps, fittings, br acing or sheeting, blocking, and all other miscellaneous items necessary for the removal and abandonment of the lead.
I.Sanitary Structure Adjustment. Sanitary Structure Cover, Adj, Case__ and Sanitary Structure, Adj, Add Depth will be measured and paid for in accordance with section 403.04, Dr Structure Cover, Adj, Case __ and Dr Structure, Adj, Add Depth . MDOT Standard Specifications for Construction Section 825 8-249 Temporary lowering of sanitary structure covers, if required, will be measured and paid f or as Dr Structure, Temp Lowering in accordance with subsection 403.04.E . Video inspection, mandrel testing, and integrity testing are all considered as included in the contract unit price for sanitary sewer. Payment to remedy an unsatisfactory test, including removing and replacing any backfill, will be considered as included in the contract unit price for sanitary sewer and sanitary structures. As-built plans are included in the contract unit price for associated sanitary sewer pay items . Payment may be w ithheld until the as -built plans are acceptable to the Engineer.
Source: Michigan Standard Specifications for Construction, 2020 Edition. Pages 804–810 of 1,146.