Section VII – Submersible Pump Station
Part 1 – GENERAL
1.01 WORK INCLUDED
A. The Contractor shall furnish and install a submersible wastewater pumping station consisting of two submersible pumps, controls, hatch covers, fast-out assemblies, guide rails, liquid level controls, panel, electrical connections, meter base, main disconnect switch, emergency transfer switch, wet well, valve box, and all necessary appurtenances, as shown on the drawings and specified herein, complete and ready for operation.
B. RELATED WORK
1. Section II – Structure Excavation & Backfill For Pump Station 2. Section III – Concrete
1.02 QUALITY ASSURANCE
A. DESIGN REQUIREMENTS
1. Wet Well Dimensions and Pump Design Capacity shall be as detailed on the drawings.
1. Shop Drawings
The Contractor shall provide six sets of shop drawings prepared by the manufacturer and submitted to the Design Engineer for review prior to the manufacture of the equipment. The shop drawings shall include outline dimensions and external connection diagrams.
A list of components, curves showing complete pump performance from shutoff to at least 15 percent below rated head conditions, brake horsepower and NPSH required, control panel one-line wiring diagram and specifications, and a copy of the manufacturer’s warranty shall be included with each set of submitted data. One copy of the approved submittals shall be provided to the Owner prior to the delivery of equipment or materials.
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Operating, maintenance, and repair manuals (4 copies) for all major equipment and items shall be submitted to the Owner’s Engineer.
All equipment shall be guaranteed against defects in material and workmanship for a period of one year from the date of Owner’s final inspection and acceptance to the effect that any defective equipment shall be repaired or replaced without cost or obligation to the Owner.
Part 2 – PRODUCTS
A. SUBMERSIBLE PUMPS
1. Pump Design
Each pump shall be designed with a close-coupled electric motor which permits continuous operation with the pump totally submerged or with the motor completely removed from the pumped media. Pumps shall be as manufactured by Flygt Corporation, Sulzer-ABS or Wilo Corporation.
All major parts, such as the pump casing, seal housing, motor housing, motor and cap, sliding bracket, and impeller, shall be of gray iron and shall be painted with a PVC epoxy primer with chloric rubber paint finish. All nuts, bolts, and miscellaneous hardware in the wet well or in contact with pumped material shall be stainless steel (Type 304).
Each pump shall be provided with a mechanical rotating shaft seal in an oil reservoir. The seals shall require neither maintenance nor adjustment, but shall be easily inspected and replaceable. The impeller shall be capable of handling solids, fibrous material, heavy sludge and other matter found in normal sewage applications. The impeller shall be statically and dynamically balanced.
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The electric motor shall be NEMA Design B with Class F insulation, and designed for continuous duty. The cable entry seal design shall be such to insure a watertight and submersible installation. Pump motor cable installed shall be suitable for submersible pump applications and this shall be indicated by a code or legend permanently embossed on the cable. Cable sizing shall conform to NEC specifications for pump motors and shall be sized to allow motor voltage conversion without replacing the cable.
Each motor shall incorporate an ambient temperature compensated overheated sensing device and a moisture sensing device wired in series. The protective devices shall be wired into the pump controls in such a way that if either device operates, the pump will shut down.
The manufacturer shall provide cast iron fast-out fixtures to allow the pump to be installed or removed without requiring personnel to enter the wet well. The fixtures shall consist of a discharge elbow permanently mounted to the floor of the wet well, a sliding guide bracket which shall be an integral part of the pump unit, two stainless steel slide rails which will guide the pump into position, and stainless steel lifting cable, as shown on the plans.
B. PUMP CONTROL PANEL
1. Scope and Panel Operation: The control logic shall operate two electrical submersible pumps at the power characteristics as specified.
The control logic shall provide for the operation of the lead pump under normal conditions. If the incoming flow exceeds the pumping capacity of the lead pump, the lag pump will automatically start to handle the increased flow. As the liquid level decreases, the pumps will shut off at the elevations shown on the plans. In the event of a malfunction or a flow that exceeds the capacity of the pumps, a high level audible and light alarm will be excited to indicate alarm conditions. A silencer shall lock out the audible alarm; however, the alarm light shall release only with the correction of the high level condition or depression of the high-level reset button. Pumps shall alternate as lead and lag pumps on a continuous basis.
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2. Construction and Materials: The control panel shall be NEMA 3R, Type 304 stainless steel with dead front aluminum inner door, and mounted as shown on the Drawings.
3. Panel Exterior: Mounted on the exterior enclosure shall be an alarm light and a high water level audible alarm with silencer button.
All exterior mounted accessories shall be constructed of corrosion proof materials such as stainless steel or aluminum.
Control wiring from the wet well shall enter the panel in a manner to prevent the possible entry of gases from the wet well.
4. Panel Inner Door: The inner aluminum door mounted on a continuous hinge, will be furnished for protection against exposed wiring and will have cutouts for access to the circuit breakers and pump resets mounted on the inner door will be pump run lights, level indication lights, hand-off-automatic switches, elapsed time meters, main circuit breaker, a fifteen (15) ampere ground fault duplex receptacle, motor resets, control circuit breaker, duplex receptacle breaker, motor circuit breakers, and lightning arrestor, motor high temperature lights, seal failure warning lights, high level light and reset buttons.
A permanently affixed 11″ x 17″ (minimum laminated panel wiring schematic and pump data sheet) shall be installed on the interior of the enclosure door.
5. Control Circuits: In order to ensure maximum personnel safety, all wet well (level sensor) circuits shall be run at 24 volts DC. The control circuit breakers shall be run at 115 volts.
6. Panel Components: The following power, control and alarm components shall be provided:
a. Circuit Breakers: All circuit breakers shall be heavy duty ER molded case breakers as manufactured by Siemens or equal. The main circuit breaker shall be provided with provisions for locking in an “on” or “off” position.
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b. Duplex Service Receptacle: A duplex service receptacle supplying 15 amps at 115 volts shall be provided on the panel door. The duplex receptacle shall be provided with ground fault protection.
c. Lightning Arrestor and Surge Capacitor: A lightning arrestor and surge capacitor shall be installed and wired to protect motors and control equipment from lightning induced line surges and transient voltage surges.
d. Elapsed Time Meters: Elapsed time meters shall be 115 volt non-reset types and shall indicate pump running time in hours and tenths of hours to 99999.9 hours; total of three, one for each pump and one for simultaneous operation.
e. Motor Starters: The panel shall contain two NEMA (FVNR) starters. The motor starters shall be across the line magnetic starters with individual overload protection on each power leg with motor resets installed through the dead front door. Acceptable manufacturer is Allen-Bradley or equal, approved by GSU.
f. Phase Monitor (for 3-phase pump motors only): A phase monitor shall be installed and wired to disconnect control power from the motor starters in the event of loss of power, phase reversal, loss of any phase or phase balance, or low voltage. The phase monitor shall automatically reset upon removal of any and all of the preceding conditions and shall be RK electronics Model PV RO-200-AR.
g. Pump Run Lights: A 115 volt pump run lights shall be connected in parallel with each motor starter and indicate when a particular pump is running.
h. Control System: The control system shall consist of: 115 volt transformer; plug-in relays; automatic alternator Furnas 47AB10AF with test switch; plug-in three phase monitor (as required); and terminal strips for the installation of four level regulators. All control wiring shall be color coded (minimum of 18 colors) size 16, rated for 300 volts, 80 C stranded tinned copper, PVC insulated, and shall be installed in wiring duct with cover.
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i. Audible Alarm: The audible alarm shall consist of a weatherproof high intensity electronic horn mounted on the side of the enclosure. The audible alarm shall be equipped with a control panel mounted push-button silencer. The alarm circuit will not automatically reset when the high liquid level condition is corrected, and can be canceled via panel mounted resets.
j. Liquid Level Indication Lights: A 115 volt level indication light shall be connected in parallel with each liquid level control sensor and indicate when a particular liquid level sensor is activated.
k. Alarm Light: The alarm light shall consist of a weatherproof light with lexan globe. The alarm circuit will not automatically reset when the high liquid level condition is corrected.
l. Moisture and Temperature Sensors: One moisture and one temperature sensing relay with associated red indicator lights for each pump shall be mounted in the dead front panel. These sensors shall operate on 115V and detect moisture in the casing of the submersible pump and excessive heat within the pump motor. If over-temp condition is noted, then the indication light shall light and the pump shall disconnect. If leak condition is noted, then indication light shall light but the pump shall not disconnect.
C. WET WELL AND VALVE VAULT
Wet Well and Valve Vault shall be of precast concrete as shown on the drawings and shall conform to the applicable requirements of Section III.
D. ACCESS COVERS
1. Wet Well: The Contractor shall furnish and install a single or double leaf aluminum access door. Door leaf shall be 1/4-inch aluminum diamond pattern plate to withstand a live load of 150 pounds per square foot. Access covers shall be hinged and hasp-equipped, including stainless steel guide rail bracket and holders with safety loops for lifting cable and motor cable. Access cover shall be provided with stainless steel hardware and shall have bituminous coating on all aluminum in contact with concrete. Minimum opening dimensions shall be in accordance with pump manufacturer’s recommendations.
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2. Valve Box: The Contractor shall furnish and install one double leaf aluminum access door. Door leaf shall be 1/4-inch aluminum diamond pattern plate to withstand a live load of 150 pounds per square foot. Access covers shall be hinged and hasp-equipped with stainless steel hardware and shall have bituminous coating on all aluminum in contact with concrete. Interior of valve box shall have a minimum of 24-inches clearance between inside wall and any pipe, valve or device.
3. Manual Lift Station By-Pass: The contractor shall install a manual bypass connection on the outside of the check valve vault. Connection shall be installed with a MJ or flanged tee, MJ or flanged gate valve w/cast iron valve box and top, MJ or flanged 90 degree elbow turned vertical, ductile spool piece with minimum 24� above grade level and another 90 degree flanged elbow w/6� mail cam lock fitting. 1. Materials Pipe – Class 51 ductile Gate Valve � Resilient seat w/2� operating nut Fittings � Tee 150# Class 350 ductile 90 degree elbows 150# Class 350 ductile 6� 150# threaded RF flange X 6� male cam Lock aluminum 6� cam lock dust cap aluminum E. LIQUID LEVEL CONTROLS
Liquid level sensors with electrical cables (of the proper lengths) shall be provided to control the pumps based upon the control level elevations as shown on the Drawings.
The liquid level sensors shall be type 316 S.S., 5-1/2″ diameter, #20 gauge floats, permanently assembled to the switch and cable. The cable shall be type S.O. with a nitrile PVC jacket, and 3-#14 AWG fine-stranded conductors. The switch shall be a mercury tilt type, with a less than 1″ level differential. The AC resistive rating shall be 20 amps at 115, 10 amps at 230. The AC lamp load shall be 1000 watts. The mounting pipe, brackets, and U bolts shall be 316 S.S., and shall be capable of mounting to the slide rail system as detailed on the Drawings. The liquid level control shall be as manufactured by Consolidated Electric Company – Model 9G Direct Acting Float Switch.
F. MISCELLANEOUS METAL
All Miscellaneous Metal items located within the wet well shall be stainless steel (304)
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Part 3 – EXECUTION
A. All site preparation, excavation, and backfill shall be performed in accordance with Section II – STRUCTURE EXCAVATION AND BACKFILL FOR PUMP STATION.
A. WET WELL
Wet Well shall be installed in accordance with Drawings and applicable portions of Section III – CONCRETE.
B. PUMP SYSTEM
All pumping equipment and accessories shall be installed in accordance with Manufacturer’s recommendations.
3.03 FIELD QUALITY CONTROL
A. MANUFACTURER’S REPRESENTATIVE
The services of a factory trained, qualified representative shall be provided to inspect the completed installation, make all adjustments necessary to place the system in trouble-free operation, and instruct the operating personnel in the proper care and operation of the equipment, prior to the final acceptance of the station.
B. INSULATION TEST
Circuit insulation tests shall be performed to prove each circuit free of faults after all wiring is completed prior to equipment and fixture connections, and again after the installation is complete and ready for use.
Tests shall be made at the main electrical service connection between all conductors and between line conductors and ground. Tests shall be made with a minimum 500 Vdc instrument capable of accurately measuring the resistance involved. Readings shall be taken in the presence of the Design Engineer or his representative for each test and the written results of each test shall be submitted to the Engineer.
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C. FIELD TEST
When the pumping facility is complete and ready for operation, then the station shall be inspected and tested for compliance to the contract documents. Test of the equipment shall be made by the Contractor in the presence of the Design Engineer, the Electrical Subcontractor (if used), the equipment manufacturer’s representative, and the Owner’s representative. The equipment tests shall include, but not be limited to, the following:
1. Pumps and Motors: Pumps shall be run and a determination made of the pumping capacity. Performance of the pumps shall meet the specified criteria when field tested. A pressure test shall be performed on each pump in the field.
2. Electrical: Recorded readings shall be made of voltage and amperage on all electrical components at start and operating conditions. Such readings shall be recorded on a form provided by the manufacturer and the results shall meet the manufacturer’s prescribed limits. If a tested item fails to meet its requirements, then it shall be replaced. Results of the tests shall be given to the Design Engineer with the serial number of the accessory tested.
3. Controls: Controls shall be tested to determine satisfactory performance for starting and stopping at the proper liquid levels, pump sequence and alarm actuation.
4. Equipment: Equipment shall be operated to determine if the alignment is visually correct, that there is no overload or overheating or objectionable vibration and that all the operating features are in working order. Submersible pumps and level sensors shall be raised completely and reset to assure proper seating and operation.
5. Inspection: A thorough inspection of all mechanical and electrical equipment and controls, piping, valves, fittings, brackets, mountings, seals, conduit, painting, sleeves, components, and features shall be made while the station is being tested to determine performance and compliance with design requirements and specifications.
6. Structure: The station shall be inspected for performance, structural soundness, and water tightness.
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7. Repairs, Adjustment and Replacements: The Contractor shall make any and all necessary repairs, adjustments, and replacements until performance has been demonstrated to the satisfaction of the Owner’s Engineer. The Contractor shall bear the cost of any repair, adjustment, and replacement.
D. SPARE PARTS
Spare parts for routine maintenance and repair as recommended by the equipment manufacturer shall be provided by the Contractor.
E. AS-BUILT DOCUMENTATION
As-Built documentation of the finished installation shall be made as a part of final acceptance and shall include certified record drawings, corrected submittals, operation and maintenance publications, and other data necessary to accurately define the final field installation.
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