SECTION 19100
SEWAGE PUMP STATION
PART 1-GENERAL
1.1 Scope- The Contractor shall furnish, install and place into satisfactory operation, a duplex sewage pump station complete with two(2) submersible sewage pumps and a pump control panel, piping, valves and associated appurtenances as shown on the drawings and specified herein.
These specifications were prepared for the purpose of establishing a minimum standard of quality acceptable to the Owner. The Contractor may offer to provide equipment manufactured or marketed by other vendors: however, final evaluation and acceptance of the equipment remains the responsibility of the Engineer. The Engineer’s judgment of equipment will be based on the following criteria: pump hydraulic performance, pump and motor efficiency, mechanical construction, mechanical design features which result in reduced maintenance time and cost to the Owner, solids handling capabilities of the pumps and valves as set forth in the Ten State Standards, and compliance with the electrical specifications contained herein relating to the pump control center and liquid level control system.
Any pump station manufacturer, other than specified, proposing to offer the following equipment must submit sufficient information to the Engineer to determine that the equipment complies with the requirements of the Contract Documents. This information must be received by the Engineer not less than 14 days prior to the Bid Date. The Engineer will issue an addendum prior to the bid date which lists any preapproved equipment. Contractors and manufacturers are advised that a manufacturer named as an approved supplier is not excused from meeting all of the technical and performance requirements of this specification.
Each manufacturer shall include, as a minimum, the following information in their prebid qualification package:
1. Complete dimensional layouts of all pumps, piping, controls and wiring.
2. Complete pump performance data.
3. Detailed calculations showing total friction losses in pump station discharge piping.
4. Detailed calculations showing the pump system head curve at pump ON and pump OFF elevations including station piping.
5. Complete bill of materials listing pumps, valves, fittings and electrical components.
6. Detailed drawings and description of the level control system.
7. Standard catalog data sheets, performance curves and a reference list with names and telephone numbers demonstrating at least 5 years experience in the production and operation of pump stations.
1.2 Related Work Specified Elsewhere- The provisions and intent of the Contract Documents, including the General and Special Conditions, apply to the work specified in this Section.
1.3 Submittals- Shop drawings shall submitted for all items of equipment specified in this Section and as outlined in Division 1.
1.4 Quality Assurance- The equipment provided in this Section shall be of identical manufacture as the Owner’s existing equipment for ease of renewal purposes. No substitutions allowed.
PART 2-SUBMERSIBLE PUMPS
2.1 General- The Contractor shall provide and install the duplex nonclog submersible wastewater pumps as manufactured by US Filter/Davis EMU or preapproved equal and as indicated on the drawings. Pumps shall be slide rail mounted to allow pump maintenance without entry into the wetwell. All openings and passages shall be large enough to permit the passage of a 3” spherical solid and any trash or stringy material which can pass through a 4 inch house lateral. Each pump shall be capable of the following performance:
Design Point
Flow: 175 GPM
Head: 133 feet TDH
Shutoff Head: 155 feet
Minimum Motor Horsepower: 20.0 HP
Maximum Motor Speed: 1740 rpm
Minimum Hydraulic Efficiency: 44%
Alternate Design Point
Flow: 325 GPM
Head: 120 feet TDH
2.2 Casing- The pumps shall be designed and constructed to pump sewage, storm water, heavy sludge and fibrous materials without injurious damage during operation. Lifting cover, stator housing, volute casing and impeller shall be constructed of ASTM 48, Class 30 gray cast iron. The volute shall be of the center discharge design and shall be fitted with ANSI 125# flanges and tested to Hydraulic Institute Standards at 150% of shut-off head. The interfaces between the major castings shall be machined and fitted with Buna-N O-rings. All nuts, bolts, washers and other fastening devices shall be constructed of 316 stainless steel.
2.3 Impeller- The A536 cast iron impeller shall be of nonclog design, double shrouded with a smooth, long thoroughfare having no acute angles. The wear ring system shall be constructed of Series 400 stainless steel with a Brinell hardness of 200-300. The system shall provide efficient sealing between the volute and impeller.
2.4 Seal- The pump shall be provided with a balanced tandem mechanical seal cartridge. The seal case shall be constructed of 316 stainless steel with all seal faces and springs immersed in oil. The upper set of faces shall be tungsten carbide while the lower set of faces shall be silicon carbide. Seal faces shall be self-aligning, positively driven and each shall be held by separate spring systems. The construction shall be such that no spring is exposed to the pumped media.
2.5 Shaft- The pump and motor shaft shall be of Series 400 stainless steel with a Brinell hardness of 200. The shaft shall be designed such that the diameter of the shaft where it passes through the lower seal shall be 1.97 inches with a maximum shaft deflection due to axial and radial thrust loads of 0.16 mm. The shaft shall not extend more than 2.5 times its diameter below the nearest support bearing and shall be supported by double row lower and single row upper bearings with a B-10 life of 50,000 hours minimum at any point on the flow versus head curve.
2.6 Quick Removal System- Each pump shall be supplied with a universal coupling, ANSI 125# cast iron, which bolts to the pump discharge flange and accepts the discharge elbow provided by the pump manufacturer. Seal of the pump at the discharge flange shall be accomplished by a simple downward linear motion of the pump with the entire weight of the pump guided to and pressing against the discharge connection. There shall be no need for personnel to enter the wet well. No part of the pump shall bear directly on the sump floor and no rotary motion of the pump shall be required for sealing. Sealing at the discharge shall be effected by a replaceable rubber seal fitted to the machine discharge coupling to insure and guarantee a positive leakproof system and for ease of removal of the pump.
Furnish a T-bar guide rail system and stainless steel lifting chain for each pump to permit raising and lowering the pump. Guide rails shall be 2” X 2” X 1/4” angles of adequate length to extend from the lower guide holder on the pump discharge connection to the upper guide holder mounted on the access frame. Guide rails shall be constructed of stainless steel.
2.7 Motor- The pump motor shall be integral to the pump for submersible or dry pit operation. The squirrel cage induction type motor shall be designed with Class H slot liners with service factor of 1.25. The dual voltage copper wound stator, which will allow field changeability of voltage, shall be triple dipped in epoxy enamel to withstand a heat rise to 155 degrees C as defined in NEMA Standard MG-1. The NEMA starting code shall be G or less. The rotor shall be constructed of laminated steel plates with poured aluminum shorting bars. The rotor shall be both statically and dynamically balanced. All castings shall be machine fit utilizing metal-to-metal contact. All machine fits shall be additionally protected with Buna-N O-rings. The motor shall be oil-filled and positively cooled by movement of the oil through the windings to passages within the unit designed to transfer heat to the pumped fluid. Motors shall have thermal sensors for overload protection built into the motor casing. Air-filled motors or static oil-filled motors without an integral heat exchanger shall not be acceptable. A minimum of 85% of the heat generated by the motor must be conducted through the heat exchanger into the pumped liquid. This shall be supported with certified heat transfer calculations.
The motor power cable shall consist of SJO type insulated cable with a double jacketed protection system consisting of neoprene on the outside with synthetic rubber on the inside. Individual conductors shall be of the RUW type. The power cable will enter the pump through a vellums type cable entry constructed of cast alloy metal and galvanized for corrosion resistance. The heavy duty cable entry with strain relief shall be provided with an integral rubber grommet to protect against leakage once the cable is secured. The power cable leads shall be connected to terminals on an isolated terminal board. The terminal board shall be constructed of bakelite and will include individually O-ringed brass lugs on both the upper and lower side of the terminal board. The terminal board shall be totally isolated from the motor using Buna-N O-rings fitted to the terminal board and mating with the machined terminal board housing in the motor. This system will prevent moisture from entering the motor should leakage occur through the cable entry. Motor shall be equipped with a moisture sensor to stop pump operation if moisture is detected in the seal cavity.
The motor shall be sized to be nonoverloading throughout the entire range of the impeller curve.
PART 3-PUMP CONTROLS
3.1 Power Service- The incoming power service for the pump station shall be 240 volt, 3 phase and 4 wire. The control panel shall be furnished with a lightning arrestor connected to each line of the incoming side of the power input terminals. The arrestor shall protect the panel against damage due to lightning strikes on the incoming power line.
3.2 Transducer- The level of the wet well shall be measured by a submersible level transducer with a minimum bottom diaphragm of 2-5/8” providing a 4-20 mA instrumentation signal. The transducer shall be of the solid state head pressure sensing type mounted using 304 stainless steel clamps attached to a Contractor furnished 1” vertical Sch. 80 PVC pipe. The transducer housing shall be fabricated of type 316 stainless steel. A hydraulic fill liquid behind the diaphragm shall transmit the sensed pressure to a solid state variable capacitance transducer element to convert the sensed pressure to a corresponding electrical value. The sensed media shall exert its pressure against the diaphragm that flexes minutely so as to vary the proximity between an internal ceramic diaphragm and a ceramic substrate to vary the capacitance of an electrical created between the two surfaces. A stable, hybrid operational amplifier assembly shall be incorporated in the transducer to excite and demodulate the sensing mechanism. The internal pressure of the transducer assembly shall be relieved to atmospheric pressure through a urethane jacketed hose/cable assembly and a slack PVC bellows mounted in the upper assembly panel. The sealed breather system shall compensate for variations in barometric pressure and expansion and contraction of air due to temperature changes and altitude as well as prevent fouling from moisture and other corrosive elements.
The transducer shall be a U.S. Filter/Consolidated Electric Company Model A1000 or preapproved equal.
3.3 Pump Controller- The operation of the sewage pumps shall be controlled by a duplex pump controller. The controller shall receive a 4-20mA signal from the submersible transducer and display it on a 4” LED bargraph on the face of the controller. Directly aligned with the calibrated LED bar graph shall be 8 vertical receptacles with programming pins and adjacent range scales to match the calibrated bar graph giving full range, level differential ON/OFF operation of the pumps and alarms from the sensed level excursion. The controller shall provide automatic alternation of the pumps. The controller shall be a model D152 as manufactured by U.S. Filter/Consolidated Electric or preapproved equal.
3.4 Enclosure- The equipment shall be housed in a NEMA 3R, 14 gauge minimum galvanized steel enclosure painted with an exterior grade gray enamel coating. The outer door shall have a stainless steel hinge and pin and shall be padlockable. The enclosure shall be insulated and furnished with a condensation heater and thermoswitch and be suitable for wall or pedestal mounting where shown on the drawings.
3.5 Overtemperature Pump Protection- Overtemperature protection shall be provided in the control panel to operate in conjunction with the overtemperature switch in each pump motor. The control shall provide pump operation lockout upon the occurrence of high temperature. The circuitry shall also include a 1” diameter yellow “pump overtemperature” shutdown alarm indicating light and a manual reset pushbutton for two (2) pump motors.
3.6 Seal Failure Alarm- An inner door mounted 1” red seal failure alarm light and a panel mounted seal leakage relay shall be provided to indicate a pump seal failure alarm condition for two (2) sewage pumps.
3.7 Running Time Meters- An operator’s door mounted 120 VAC powered running time meter measuring hours and tenths of hours of operation up to 99999.9 hours shall be furnished for two (2) pump motors.
3.8 Local Alarm System- A top mounted weatherproof high water alarm light assembly shall be furnished. A weatherproof audible alarm horn producing 87 dB minimum at 10 feet shall be provided.
3.9 Power Handling-A thermal magnetic circuit breaker shall be supplied as branch circuit protection for each motor. The circuit breaker shall have a minimum ampere interrupting capacity of 14,000 symmetrical RMS amps. The circuit breakers shall be operable through the inner door of the enclosure and shall have a trip rating to allow full voltage starting and continuous operation of the motors.
A NEMA rated, full voltage, across the line magnetic motor starter with ambient compensated, quick trip class 10 overload sensing in each phase to provide overcurrent and running protection shall be provided for each motor less than 30 HP. The overload trip setting shall be determined by replaceable heater elements. Overload relays with an adjustable trip or requiring replacement of the entire overload relay to change the trip settings shall not be acceptable. Inner door mounted overload reset pushbuttons shall be provided.
A reduced voltage with ambient-compensated, quick-trip class 10 overload sensing in each phase to provide overcurrent and running protection shall be provided for any motor over 30 HP. Overcurrent protection shall be provided by accurately sized heater elements. Inner door mounted overload reset pushbuttons shall be provided. The pump motor starter shall be a solid-state reduced voltage type motor controller incorporating soft starting, motor overvoltage protection and energy saving characteristics. The controller shall include independent adjustments for the start time and initial torque on the soft start ramp as well as adjustments for overvoltage protection and energy savings. The starter shall include a line voltage limiter circuit to allow the output voltage of the control to be field adjusted to the motor nameplate value. The limiter shall prevent excessive voltage from reaching the motor in the event of a high line voltage condition.
120 VAC control power for each motor starter coil and H-O-A selector switch with 1” green run light shall be provided through a properly sized fuse.
3.10 Telephone Dialer Alarm conditions shall be forwarded via an automatic telephone dialer capable of dialing up to eight telephone numbers, each up to 24 digits in length. Telephone numbers shall be user programmable through the system keyboard or touch tone telephone. The dialer shall be a four channel device wired for the following alarms: Pump #1 Fail, Pump #2 Fail, High Water Alarm, Low Water Alarm and power failure.
The user shall be able to record and re-record messages for each input channel and for the station identification. Acknowledgment of an alarm call is to be accomplished by pressing a code on the touch pad of the receiving phone. The dialer shall continue to call the alarm status until it receives the acknowledgment code.
The dialer shall operate on normal 115 volt, single phase power. The unit shall include a 6 hour gel cell battery to allow for operation in the event of temporary power loss.
The dialer shall connect to a standard telephone line through a 4 pin modular jack (RJ-11). The dialer shall feature integral gas tube and solid state surge protection on all input lines including the telephone, power and input signal lines.
PART 4-EXECUTION
4.1 Warranty- All equipment shall be guaranteed against defect in material and workmanship for a period of one year from 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.
4.2 Field Service- The services of a factory trained field service technician shall be provided to inspect the completed installation, make all adjustment necessary to place the system in satisfactory operation and instruct the operating personnel in the proper care and operation of the equipment. This allowance shall be a minimum of three (3) eight hour days.