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SECTION 3 RAW SEWAGE PUMPING STATIONS
3.0 PUMP STATIONS
3.1 WET WELL/DRY WELL TYPE PUMPING STATIONS
3.2 WET WELL MOUNTED TYPE PUMPING STATIONS
3.3 STANDBY GENERATOR
3.4
3.5 SUBMERSIBLE SEWER PUMP STATION EQUIPMENT
SECTION 3.0 – PUMPING STATIONS
A. The following types of pumping stations are the permitted installations by the Authority based on the ultimate build-out of the watershed tributary to the proposed station location.
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POTENTIAL WATERSHED BUILD-OUT(1) |
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Type |
25 or less EDU's |
26 – 75 EDU's |
Greater than 75 EDU's |
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Low Pressure Sewer System |
X |
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Submersible Pump Station |
X(2) |
X(2) |
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Wet Well Mounted Pump Station |
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X(2) |
X(2) |
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Wet Well/Dry Well Pump Station |
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X |
(1) Watershed as determined by the Authority.
(2) Permitted use by Authority approval only.
B. The pump station building shall be of the walk-in type, of the size and dimensions as shown on the Standard Detail Drawings. The building shall be constructed of fiberglass, aluminum, or block/brick with a pitched roof dependent upon the pump station location and the decision of the Authority. Fencing shall be provided around fiberglass building, but shall not be required for block/brick building.
C. The pump station building shall house at a minimum, the following components:
1. Emergency stand-by power generator.
2. Electrical panels.
3. Door system with width to accommodate generator removal.
4. Lighting.
5. Exhaust fan, louvers, and dampers.
6. Unit heater.
7. Man down switches near floor for emergency.
8. Switches for lights, fan, and unit heater.
9. Receptacles.
10. Chemical system for odor control if required by the Authority.
D. Aluminum enclosures, as specified in Section 3.3.6 of these Minimum Standards may be used only as an alternate with Authority approval. The aluminum enclosure shall meet all applicable building codes and other regulations to the municipality in which it is to be located. Architectural and structural requirements, including but not limited to, foundation design, wall, roofing, insulation, etc., will be as imposed by the Authority.
3.1 WET WELL/DRY WELL TYPE PUMPING STATIONS
3.1.1 GENERAL
A. Factory-built, automatic pumping stations, shall have all items necessary for a complete facility, including but not limited to: wet well/dry well system, standby generator, concrete work, site piping, fences and other site work. Each pumping station shall be complete with all needed equipment factory-installed in a welded steel chamber with welded steel entrance tube and with a maintenance lift to provide access.
B. The principal items of equipment for each pumping station shall include a minimum of two vertical, closed-coupled, motor driven, non-clog pumps; valves; internal piping; flow metering equipment; central control panel with circuit breakers, motor starters and automatic pumping level controls; lighting; sump pump; ventilator; dehumidifier; maintenance lift; tele-metering; standby generator; and all internal wiring and service entrance. Also Authority approved alarm system, heater and wet well aerators are required.
C. The exterior of the station shall be designed so all welds exposed to ground water after installation are continuous or sealed throughout their length so that water cannot seep between uncoated steel surfaces. In addition, the structure shall be designed so that sharp corners and similar difficult-to-coat conditions are held to an absolute minimum. The thickness of the steel cylinder shall be determined by the structural requirements for the depth of bury involved and shall be a minimum of 1/4". It shall be the responsibility of the Manufacturer to determine the structural requirements of the shell based on the external loads specified on the plans.
D. Lifting eyes adequate to support the entire weight of the pump station shall be provided and welded to the station head. Tie-down holes shall be provided for anchoring the discharge line at the point it leaves the station. Lifting loops shall be located on the ceiling of the pump station over each pump at an adequate height to permit a hoist to be used for pump disassembly.
E. A sump with a wall of 1/4" structural-grade steel plate shall be provided. Where the ductile iron suction and discharge lines pass through the station walls, they shall be reinforced with 1/4" thick steel sleeves, welded inside and out to the station wall. The space between the ductile iron pipes and the steel sleeves shall be packed tight with grout to prevent leakage.
3.1.2 OPERATING CONDITIONS
A. Sewage Pumping Stations shall have a minimum of two pumps capable of delivering raw, unscreened sewage at a rate in accordance with the provisions set forth in the Pennsylvania Sewerage Manual. The maximum allowable speed for the pumps shall be 1760
3.1.3 PUMP CHAMBER
A. The station shall be built by the Manufacturer in two major sections, consisting of the pump chamber and the required section(s) of entrance tube, for ease in shipment and handling. These sections shall be joined at the job site by welding.
B. The field weld joints shall then be cleaned and heavily coated with Versapox - epoxy resin, provided by the Manufacturer. The pump chamber shall contain all pumps and other equipment and shall be a vertical cylinder of circular cross-section. The top and bottom of the station shall be 3/8" thick. Steel plate shall meet or exceed
C. Pumping stations shall be as manufactured by Smith and Loveless, Inc.,
3.1.4 ENTRANCE TUBE
A. The entrance tube shall be provided in one or more sections as required and the diameter shall be as shown on the drawings. The entrance tube shall be constructed of structural grade steel plate that meets or exceeds
B. A PVC ventilation duct with inlet vent shall extend from the top of the entrance tube into the station. The inlet vent shall be covered with a screen to exclude rodents and foreign objects.
C. The entrance tube cover shall be of fiberglass reinforced plastic and shall have a reflective color to reduce heat absorption. The cover shall have a suitable drip lip around the edge and shall be provided with a weatherproof lock of the pin tumbler type which can be opened from the inside without a key. The lock shall be self-locking upon closing the lid.
D. The fiberglass cover shall have a rung which forms an extension of the access ladder when the cover is latched in the open position. A latch mechanism shall be provided to keep the cover open under any normal load.
E. The access ladder shall be of heavy aluminum construction and have grooved non-slip rungs spaced on 12" centers.
3.1.5 MAINTENANCE LIFT
A. General - Sewage Pumping Stations shall be equipped with a power operated, chain driven maintenance lift unit, designed and manufactured by the pump station manufacturer to contribute to the personal safety of the operator and to facilitate access to the station. The lift shall have a minimum rated carrying capacity of 440 pounds and, when fully loaded, shall move at a rate not to exceed 25 feet per minute.
B. Construction - The maintenance lift unit shall consist of a frame welded steel construction, operating on guide rails securely welded to the sides of the ladder in the entrance tube and lift station. The aluminum grating floor of the lift shall have an area of not less than four square feet and shall be easily removable for emergency exit or entrance to the station by means of the ladder. The lift shall be enclosed by framework guards on the both sides securely bolted in place.
C. The guards shall be of welded steel construction and shall incorporate integral ladder rungs to facilitate entry to and egress from the lift when stopped at the top of the entrance tube. Solid steel toeboards shall be provided across the base of the guard work on both sides. The lift shall be so constructed as to operate with a clearance directly to the front, of at least four inches, measured from any point between the toe board and entrance tube.
D. The drive unit shall consist of a 3/4 HP, 1800
E. The motor and reduction gear unit shall incorporate two drive sprockets on each output shaft so that movement of the lift shall be accomplished by four supporting roller chains. Each chain shall be independently spring-loaded at both ends to prevent slack and to automatically equalize the lifting loads. Each chain shall be capable of supporting the entire weight of the lift plus the maximum rated load of 440 pounds, with a safety factor of not less than eight.
F. The lift shall be maintained in proper alignment by two needle bearing guide wheels traveling on each side of each of the guide rails. Two additional guide wheel assemblies shall be installed at each guide rail to absorb any side thrust imparted to the lift.
G. To facilitate electrical connections, an automatic rewind cord reel, complete with heavy- duty, four-conductor jacketed cable shall be located near the bottom of the guide rail ladder assembly in the pump station. The cord reel shall be of ample capacity to permit full travel of the lift, maintaining tension on the cord at all times without undue strain. The cord shall enter the lift through the strain relief bushing which is designed to prevent a strain on the conductors themselves.
H. To facilitate installation and maintenance, the front of the lift unit shall be removable to gain access to the operating components.
I. All fabricated steel components of the maintenance lift unit shall be protected from corrosion by a single heavy inert coating of Versapox epoxy resin, excepting chain, sprockets, control panel and gear motor. The dry coating shall contain a minimum of 85% epoxy resin with the balance being pigments and thixotropic agents.
J. Safety Features and Control - A maintenance lift control panel having a NEMA 12 enclosure shall be provided, securely mounted inside the pump station. Separate motor controllers shall be used for each direction of travel and each controller shall be equipped with thermal overload relays, sized to prevent operation with loads in excess of 150% of rated capacity. The entire maintenance lift unit control system shall operate on 115 volt, single phase, 60 cycle AC service.
K. The maintenance lift unit shall be equipped with up-down control switches on the lift and on the maintenance lift control panel in the pump station. Control switches shall be of a type that requires constant pressure for operation. A two-position selector switch on the lift shall determine which of the two control switches will control the movement of the lift.
L. A red-mushroom-head push button marked "Emergency Stop" shall be installed on the lift and a pressure-operated safety switch shall be installed under the lift platform. This safety switch shall cover the entire area of the bottom of the lift and operate if the lift is obstructed in its downward travel by a force exceeding four pounds. Both the emergency stop switch and the under-car safety switch shall be normally closed and momentary operation of either switch shall de-energize a normally "on" control system to stop movement of the lift in any direction.
M. Following momentary operation of either switch, the control system will remain de-energized until manually reset by operation of a shielded push button on the lift. Control systems which rely on the closing of contacts or the energizing of a relay to effect stopping will not be permitted.
N. Two independent sets of travel limit switches shall be installed in the lift mechanism. One pair of limit switches shall be installed in the hoist way and adjusted to stop movement of the lift at each end of its normal travel by interrupting the control circuits of the motor controllers. These switches shall stop the lift in its direction of travel while still allowing movement in the opposite direction.
O. The second set of limit switches shall be installed in the hoistway and adjusted to prevent further movement of the lift in either direction should the lift not be stopped by the normal travel limit switches. These terminal limit switches shall operate an independent controller to interrupt the power circuit to both motor controllers. All limit switches shall be of the normally closed, direct mechanical action type.
P. A centrifugal actuated overspeed governor shall be provided. The governor shall be actuated by the movement of the car in relation to the guide rails. At a prescribed overspeed the governor shall trip two self-locking safety stopping devices. The lift shall have a machine stop as a safety device to stop the car in case of failure of a single chain.
Q. The lift shall be installed and tested with the station at the factory. The entrance tube sections shall be temporarily assembled together to assure proper alignment of the guide rail ladder assembly when permanent installation in the field is completed.
R. In order to assure field installation of the entrance tube sections, identical to that arrangement tested at the factory, the sections will be marked during factory testing to designate the proper arrangement.
3.1.6 WELDING
All steel in the station structure shall be joined by electric arc welding with fillets of adequate section for the joint involved. Where required to exclude ground water, all welded joints on the exterior of the station shall be continuous throughout their length.
3.1.7 PROTECTION AGAINST CORROSION
A. After welding, all inside and outside surfaces of the structure, pumps and piping shall be steel shot-blasted to a 2-mil minimum profile commercial blast. Immediately after cleaning, a single 6-mil minimum thickness inert coating shall be factory applied to all inside and outside surfaces. The coating shall be Versapox epoxy resin, formulated for abrasion and corrosion resistance. The dry coating shall contain a minimum of 85% epoxy resin with the balance being pigments and thixotropic agents.
B. A touch-up kit shall be provided for repair of any mars or scratches occurring during installation. This kit shall contain detailed instructions for use and shall be the same material as the original coating. A heavy synthetic rubber mat shall be cemented to the station floor to protect the coating on the steel floor.
C. Two 17-pound magnesium anode packs shall be provided for cathodic protection. The anode packs shall be provided with 15' long insulated copper leads. Copper lugs shall be provided by the Manufacturer on opposite sides of the station for anode connections.
3.1.8 PUMPS
A. The pumps shall be vertical, non-clog type of heavy cast iron construction especially designed for the use of mechanical seals. In order to prevent seal wear caused by lineal movement of the shaft, the shaft bearing nearest the pump impeller shall be locked in place so that end play is limited to the clearance within the bearing. To minimize seal wear resulting from shaft deflection caused by the radial thrust of the pump, shaft diameters less than those specified shall not be acceptable. The shaft from the top of the impeller to the lower bearing supporting the impeller shall have a minimum diameter of 1-7/8" for motor frame sizes 213 through 286; 2-1/8" for motor frame sizes 324 and 326. The dimension from the lowest bearing to the top of the impeller shall not exceed 6".
B. The bearing nearest the impeller shall be designed for the combined thrust and radial load. The upper bearing shall be free to move axially with the thermal expansion of the shaft and shall carry only radial loads. Upper thrust bearings shall not be acceptable.
C. The shaft shall be a solid stainless steel shaft through the pump and bottom bearing to eliminate corrosion within the pump or the mechanical seal. Removable shaft sleeves shall not be acceptable.
D. The pump impellers shall be of the enclosed type made of close-grained cast iron and shall be balanced. The impeller shall be keyed and secured to the motor shaft by a suitable self-locking device. The impeller shall not be screwed or pinned to the motor pump shaft and shall be readily removable without the use of special tools. To prevent the buildup of stringy materials, grit and other foreign particles around the pump shaft, all impellers less than full diameter shall be trimmed inside the impeller shroud. The shroud shall remain full diameter so that close minimum clearance from the shroud to volute is maintained. (In lieu of full diameter shrouds, stainless steel wear rings may be furnished.) Both the end of the shaft and the bore of the impeller shall be tapered to permit easy removal of the impeller from the shaft.
E. The motor shall be attached to the pump volute by a one-piece cast iron adapter and backhead. The pump shall be arranged so that the rotating element can easily be removed from the volute without disconnecting the seal system or electrical wiring or disassembling the motor, impeller, backhead or seal, so that any foreign object may be removed from the pump or suction elbow. Volute or suction elbow clean-outs will not be an acceptable substitute.
F. The pump shaft shall be sealed against leakage by a double mechanical seal installed in bronze seal housing constructed in two sections with registered fit. The housing shall be recessed into the pump back-head and securely fastened thereto with stainless steel cap screws. The inside of the seal housing shall be tapered to facilitate the replacement of the seal parts. The seal shall be of double carbon and ceramic construction with the mating surfaces lapped to a flatness tolerance of one light band. The rotating ceramics shall be held in mating position with the stationary carbons by a stainless steel spring. The seal housing with assembled parts shall be so constructed as to be readily removable from the shaft as a unit and shall be provided with tapped jackscrew openings to assist in removing it from the back-head.
G. The seal shall be pressurized and lubricated by liquid taken directly from the pump backhead through a filter to the seal housing and introduced between the upper and lower sealing surfaces. The filter shall be of corrosion-resistant materials and shall screen out all solids larger than 50 microns. The seal system shall contain a brass valve connected near the top of the seal housing to permit the relief of any air trapped in the seal unit. A manually operated brass valve shall also be provided to vent the pump volute.
H. The pump volute shall be free from projections that might cause clogging or interfere with flow through the pump.
I. The pump shall be supported by a heavy cast iron base with four legs to provide maximum rigidity and balance. The height shall be sufficient to permit the use of an increasing suction elbow which shall be provided when the nominal pump size is smaller that the suction line.
J. The suction and discharge openings shall be flanged, faced and drilled 125-pound American Standard.
3.1.9 MOTORS
A. The pump motors shall be vertical, solid shaft, NEMA P-base squirrel-cage induction type, suitable for 3 phase, 60 cycle, 240/480 volt electric current. They shall have Class F insulation suitable for temperatures up to 115 degrees C. Motors shall be able to operate at 115% of rated load. The motors shall have normal starting torque and low starting current, as specified for NEMA Design B characteristics. The motors shall be open drip-proof design with forced air circulation by integral fan. Openings for ventilation shall be uniformly spaced around the motor frame. Leads shall be terminated in a cast connection box and shall be clearly identified.
B. The motors shall have 1.15 service factor. The service factor shall be reserved for the Owner's protection. The motors shall not be overloaded beyond their nameplate rating, at the design condition, nor at any head in the operating range as specified under Operating Conditions.
C. The motor-pump shaft shall be centered, in relation to the motor base, within .005". The shaft run-out shall be limited to .003".
D. The motor shaft shall equal or exceed the diameter specified under pumps, at all points from immediately below the top bearing to the top of the impeller. A bearing cap shall be provided to hold the bottom motor bearing in a fixed position. Bearing housing shall be provided with fittings for lubrication as well as purging old lubricant.
E. The motor shall be fitted with heavy lifting eyes, each capable of supporting the entire weight of the pump and motor.
3.1.10 CONTROL
A. All control equipment for all items listed in Paragraphs 2.23.10 through 2.23.11 shall be mounted within a NEMA Type 12, dead-front enclosure, fabricated of steel and reinforced as required. The circuit breaker, motor-starter section shall be provided with removable covers, complete with suitable latching devices. All circuit breakers, motor-starter reset buttons and pump control switches shall be mounted so that they are operable without opening the high voltage cabinet. The low voltage, automatic pump control section shall be isolated from the high voltage circuit breaker-motor starter section by a insulating barrier and shall be provided with a hinged access door and latch. The blower, timer, humidistat and thermostat shall be mounted on the face of automatic pump control section door. Pressure switches for control of the pump motors shall be mounted on the side of the cabinet. It shall not be necessary to remove the front of the cabinet to make minor adjustments to the blower timer, etc., or the pressure switches.
B. A grounding type convenience duplex outlet shall be provided on the side of the cabinet for operation of 115 volt AC devices, NEMA 5-20R configuration.
C. Thermal magnetic circuit breakers shall be provided for branch disconnect service and over-current protection of all motor, control and auxiliary circuits. Provide full voltage alternating current non-reversing starters, consisting of magnetic starters of types, sizes, ratings and NEMA sizes indicated. Equip starters with electrical interlocks where indicated, molded case circuit breaker or motor circuit protector and voltage/current/frequency monitoring relay(s) which trip all phases of the circuit breaker on specified occurrences of electrical service deviation. Equip starters with block type manual reset overload relays. Starters shall be Square D Class 8536 or approved equivalent.
D. All switches shall be labeled and a coded wiring diagram shall be provided.
E. To control the operation of the pumps with variations of liquid level in the wet well, an air bubbler system or pressure transducer system shall be provided. The pressure transducer (transducer system only) shall have a minimum opening of 1-1/2" and be designed specifically for raw water and waste water service in order to minimize maintenance. The Pump Level Control System shall be furnished complete, including two air compressors (bubbler system only), flow indicator, bubbler line (bubbler system only), and a sensitive pressure switch for each pump.
F. To protect the pressure switches (transducer system only), the pressure transducer, connecting piping and pressure switch diagrams shall be filled with an incompressible liquid. Isolation valves shall be provided in the connecting piping for the transducers to facilitate maintenance.
G. The two air compressors (bubbler system only) shall be of the close-coupled, oil-less type. Each compressor shall have a minimum capacity of 0.2 cubic feet of free air per minute at 10 PSI. It shall incorporate a single phase, 60 cycle, 115 volt, drip-proof, brushless type, electric motor. A motor driven timer shall be provided to automatically alternate the compressors every five minutes. Wiring and piping of the air compressors shall be so arranged that one compressor may be removed without removing the other compressor from service. If a stored air bubbler system is used, two (2) compressors with tanks shall be provided including an alternator to alternate the compressors. Additionally, a purge system to divert the full tank air pressure to the system shall be provided.
H. The pressure switches shall be of the mercury-tube type, with sensitive pressure elements and independent high and low adjustments for each pump settable for a maximum on/off time of ten minutes.
I. An elapsed running time meter for each pump shall be mounted on the face of the control cabinet. Each meter shall display elapsed run time in hours and tenths of hours.
J. An automatic alternator with manual "On-Off" switch shall be provided to change the sequence of operation of the pumps on the completion of each pumping cycle. Provisions shall also be made for the pumps to operate in parallel, should the level in the wet well continue to rise above the starting level for the low level pump.
K. Pilot devices shall be heavy duty, oiltight, of the same National Electrical Manufacturer's Association (NEMA) rating as the control panel in which they are housed. Pilot devices shall be comprised of a legend plate, the device operator and the necessary contact block(s) arrangement. Selector switches shall have the appropriate contact sequence(s) as shown. They shall have non-illuminated, standard know operators. Cams shall be field convertible and knobs shall be black and they shall operate at 120 VAC, unless specified otherwise. Pilot lights shall be self-contained transformer type, push-to-test. Lenses shall be plastic, the color indicated on the drawings. Push buttons shall have non-illuminated operators. They shall be of the momentary contact type, unless specified otherwise. Acceptable manufacturers for pilot devices are: Allen-Bradley, Square D.
L. Control relays shall be of the general purpose, heavy duty type, rated
1. Allen-Bradley
2. Square D
M. Timers shall be electromechanical repeat cycle type with time ranges up to 24 hours. Time settings shall be made by knob and pointer adjustment. Timer output shall be a contact closure, contacts rated at
1. Eagle Signal
2. Paragon
3. Agastat
N. The magnetic flow meter shall be of the electro-magnetic induction type and shall produce a DC voltage signal directly proportional to the liquid rate of flow. This type meter shall be used for metering process flows. The magnetic flow meter shall be furnished with a metering tube fabricated from 300 series stainless steel with a nonconductive liner of Teflon. The metering tube shall be field replaceable. Electrodes shall be bullet nose and made of Hastelloy "C" and shall be field replaceable without removing the magmeter form the line. Mechanical cleaning of electrodes shall not be permitted. End connections shall be 150 lb.
3.1.11 DEHUMIDIFIER
A. All ventilating requirements shall conform with the PaDEP - Domestic Waste-Water Facilities Manual.
B. A dehumidifier assembly with hermetically sealed freon refrigeration type compressor, expansion coil, fan and condenser coil shall be furnished to maintain the relative humidity of the air in the pump chamber low enough to keep the electrical equipment dry and to prevent condensation on the walls.
C. The moisture removing capability of the dehumidifier will vary with the temperature and relative humidity within the station. The minimum capacity rating at 80F and 68% relative humidity shall be 15.5 pints per day. The maximum capacity at 80F and 90% relative humidity shall be 25 pints per day. The dehumidifier shall be controlled automatically by an adjustable humidistat. The dehumidifier shall be located above the floor on a shelf and the condensate drained to the sump.
D. Fresh air shall be drawn into the station through the air inlet duct in the entrance tube. The squirrel-cage ventilating blower shall have a minimum capacity of 215 CFM and shall be controlled by a 15-minute cycle timer with a range of 0-100% so as to provide essentially continuous ventilation without exceeding the capabilities of the dehumidifier.
E. When the entrance cover is raised, the lights and ventilating blower shall be turned on automatically by a spring operated switch mounted just under the cover. A manual switch shall be mounted in the side of the duct just below the spring operated switch for operation of the lights with the cover closed. The vent lines shall have suitable covers to prevent the entrance of rain or snow and screened openings to prevent the entrance of rocks or other foreign matter.
3.1.12 LIGHTING
A. Minimum lighting shall consist of a twin 40-watt fluorescent lamp fixture provided for the convenience and safety of the operator. The lighting shall provide illumination for all areas in the station. The fixture shall be U.L. listed suitable for installation in wet locations. It shall be firmly secured to the structure and have a vapor tight, polycarbonate lense to insure that the lamps are secure in the fixture.
3.1.13 SUMP PUMP
A. A submersible sump pump with close-coupled, vertical motor shall be installed in the sump. It shall have a minimum capacity of 1000 GPH at design head. The design head this pump will operate against is the static head from the sump to 3' below grade, plus allowance for pipe friction both inside and outside the pump chamber. A mechanical seal on the shaft shall exclude liquid from the motor housing.
B. The sump pump shall be controlled automatically by a built-in float switch, capable of operation on a 5" differential. It shall discharge into the wet well through a 1-1/4" galvanized steel pipe, with two check valves and a gate valve within the pump chamber. The pipe shall enter the wet well at an elevation just below the frost line. An enclosure of 1/4" heavy galvanized steel mesh shall surround the sump and sump pump to keep out debris.
3.1.14 PIPING
A. Pump suction lines shall be Class 53, plain-end, ductile iron pipe terminating outside the pump chamber, with bronze fitted, disc gate valve inside the chamber. The discharge line from each pump shall be fitted with a bronze fitted check valve and a bronze fitted double-disc gate valve. The diameter of all pipe and valves shall be as required to meet conditions of flow.
B. The check valves shall be of the springloaded lever type so that the clapper can be lifted to back-flush the pump and suction line. Four-inch, straight-through check valves and increasing check valves up to 6" X 8" shall have stainless steel shafts with double "O" rings and grease fittings at both ends where the shaft passes through the body of the valve. Straight-through check valves 6" and larger and increasing check valves, 6" x 10", shall have stainless steel shaft with non-lubricated packing glands. The common discharge pipe and the discharge outlet shall be Class 53, plain-end, ductile iron pipe.
C. The air bubbler line in the station (bubbler system only) as furnished by the station Manufacturer shall be 1/2" nominal tubing, terminating in 1/2" NPT fitting in the entrance tube to accept the 3/4" piping extending to the wet well.
3.1.15 WIRING
A. The pump station shall be completely wired at the factory, except for the service entrance cable and entrance light switch. All wiring in the pump station shall meet the requirements of the latest revision of the National Electrical Code and shall be coded as indicated on the wiring diagram. All wiring outside the panel shall be in conduit, except for 115-volt accessory items, which are provided with connecting insulated service cord. The Manufacturer shall provide conduit from the control panel across the ceiling, and up the entrance tube to receive the service entrance cable. The conduit shall terminate in a threaded conduit connection through the wall of the entrance tube above ground level. The service entrance fused main disconnect (NEMA 4X enclosure), cable, conduit and all necessary appurtenances including proper grounding will be provided and installed by the Contractor.
B. Wire and cable shall be annealed, 98 percent conductivity, soft drawn copper. All wire and cable shall be the product of a single manufacturer. Wire and cable shall be 600 volt class insulation and shall bear the Underwriters' labels unless specified otherwise. All conductors, including 8 AWG and larger sizes, shall be stranded. All conductors, 8 AWG and smaller sizes, shall have a continuous colored outer cover. Insulated wires and cables for installation in interior raceways shall be Type THWN, as manufactured by Anaconda Wire & Cable Company, Rome-Cyprus Cable Company, or approved equivalent. Insulated wire and cable for installation in exterior raceways (above ground or underground) shall be XLP- Type USE, RHH, or RHW, cross-linked polyethylene insulation with temperature rating of 90oC.
C. Accessory items such as the sump pump, dehumidifier and air compressor shall be plugged into selectively polarized, grounded convenience outlets, located close to their installed position so that such items can be readily removed and serviced if necessary. A 240/120 volt, dry type transformer shall be installed in the pump station, sized to accommodate all single phase load with 10 percent expansion capacity, complete with both primary and secondary protection as needed.
3.1.16 PRESSURE GAGE
A. Each pump station shall have pressure gages installed on the discharge piping between the pump discharge gate valve and the station discharge junction tee. Gages shall read in psig and be graduated to a maximum scale appropriate for the maximum head of the pump station.
B. Pressure gages shall be located such that they can be easily read from floor level or operating platform.
C. Pressure gages shall be provided with shutoff cock or valve in sensing line. Compound gages shall be provided where normal operating pressure is at or near atmospheric. Locate pressure sensing tap so as to accurately sense fluid or gas pressure. Provide extension necks on pressure taps in insulated piping, vessels and equipment.
D. Scale divisions for all pressure gages shall be a maximum of 1 psi for ranges up to 60 psig and a maximum of 2 psi for ranges of 100 psig and 5 psig for ranges of 300 psig and over. All gages except those for testing shall be
E. All pressure gages shall be Bourdon tube type with minimum of 4-1/2 inch diameter dial, aluminum case, white face with black scale markings, brass or stainless steel movement, phosphor bronze tube and brass or stainless steel socket. Units shall have adjustment provisions for calibration without removing or bending pointer.
F. Approved manufacturers are Dresser Industrial Instrument Operations,
3.1.17 FACTORY TESTS
A. All components of the pump station shall be given an operational test at the pump station manufacturer's facility to check for excessive vibration, for leaks in the piping or seals and for correct operation of the automatic control system and all auxiliary equipment. The pump suction and discharge lines shall be coupled to a reservoir and the pumps shall recirculate water for a least one hour under simulated service conditions. The automatic controls shall be adjusted to start and stop the pumps at approximately the level required by the job conditions. The control panel shall undergo both a dry logic test and a full operational test with all systems operating. These tests cannot be performed in the field. Test records, certified by a registered professional engineer, shall be provided for the specific pumps furnished. Test-frame results for impeller only will not be acceptable. Each pump shall be tested as a complete unit after installation in the station.
B. Factory test instrumentation must include flow measuring with indicator; compound suction gauge; bourdon tube type discharge pressure gauge; electrical meters to measure amperes, volts, kilowatts and power factor; speed indicator and a vibro-meter capable of measuring both amplitude and frequency.
C. A description of test equipment must be included with submittal data.
3.1.18 SPARE PARTS
A complete replacement pump shaft seal assembly shall be furnished within the lift station. The spare seal container shall include complete installation instructions. A spare filter element for the seal filter shall also be provided, in the same container as the pump shaft seal. Spare volute gaskets for the main pumps shall also be furnished.
3.1.19 INSTALLATION
A. Installation of the pump chamber, entrance tube and related appurtenances shall be done in accordance with written instructions provided by the Manufacturer.
B. The Manufacturer shall further provide a complete and detailed Installation, Operation and Maintenance Manual. This manual shall cover, in addition to installation and general operating procedures, the operation, maintenance, and servicing procedures of the major individual components provided with the pump station. The Contractor shall furnish the Authority with three (3) bound copies of the Manufacturer's instructions covering installation, operation and maintenance for each pump station.
C. The Manufacturer shall provide the services of a factory-trained representative to perform initial start-up of the pump station and to instruct the Authority's operating personnel in the operation and maintenance of the equipment.
3.1.20 FIELD TESTS
A. After the pump station has been in operation for a period of not less than three (3) weeks, field acceptance tests shall be run, under the direction of the Authority and Engineer, to demonstrate that the capacities specified and efficiencies guaranteed for each unit can be met.
B. For the field test the quantity of sewage pumped will be measured by a weir, the power consumption will be measured by watt-hour meters installed on the incoming feeders to the pumping station, and the total head measured by mercury manometers and pressure gauges installed on the pump suction and discharge pipe.
C. In event it is demonstrated by the test that the capacities specified and efficiencies guaranteed by the pump manufacturer cannot be obtained, the pump manufacturer will be allowed three (3) weeks in which to make any revisions, adjustments or changes he feels necessary. During this period one pump at a time may be taken out of service. When the revisions, adjustments, etc., are completed, the pumps will be operated for a period of not less than two (2) weeks and a second test conducted. The cost of conducting all tests shall be borne by the Contractor.
D. Should the pumps fail to demonstrate during the second test that they comply with the capacities specified and efficiencies guaranteed, the Contractor shall, at no cost to the Owner, replace them with pumping units that do comply. Not less than one (1) unit shall be maintained in service during the replacement period.
E. The Contractor's attention is directed to the fact that there may not be sufficient sewage flow available to operate and test the pump station at the time he completed his work. The Contractor shall include the cost of supplying sufficient water to start up and test the pump station. After all adjustments have been made by the manufacturer's engineer and the station is ready to operate, the Contractor shall test the installations in the presence of the Engineer for final acceptance. The test shall be as hereinbefore specified.
F. Prior to the final acceptance of the pump station or such time as the station is placed in actual continuous operation, the Contractor shall be responsible for the maintenance and operation and all cost thereof shall be paid for by the Contractor.
3.1.21 MANUFACTURER'S EXPERIENCE
A. Pump stations shall be the product of a manufacturer who has installed at least twenty installations of equipment similar to that proposed, which have been in successful operation for a period of ten years or more.
3.1.22 DETAILED EQUIPMENT PLANS
A. Prior to the fabrication or purchase of the equipment to be furnished under this contract, the Contractor shall submit to the Engineer, in quadruplicate, for approval, manufacturer's detailed specifications and drawings covering the equipment proposed. The specifications and drawings shall show the materials and details of construction of the equipment and its layout in sufficient detail to indicate its relative location and/or incorporation with other facilities. Complete structural, mechanical and electrical drawings shall be submitted to the Engineers for approval. A complete written description of the equipment, as well as bill of materials of major items, and all control items shall be submitted. The mechanical drawings of the station shall show all piping details and equipment. The electrical drawings shall include control panel details, schematic diagrams and connection diagrams of the entire electrical system.
3.1.23 EQUIPMENT
A. The pump station shall be installed under the supervision of experienced personnel in strict accordance with the Manufacturer's instructions. Before the equipment is placed in operation, it shall be inspected by the Manufacturer's engineer who shall make all adjustments required for its successful operation.
B. All pump station equipment and accessories furnished shall be guaranteed by the Contractor and Manufacturer to be free from defects in design, materials or workmanship. The Contractor shall replace, without cost to the Authority, any parts or equipment which prove to be defective or which show undue wear within one year after the equipment has been placed in satisfactory operation and accepted by the Authority.
3.1.24 PATENTS
A. Attention is directed to the fact that the Contractor shall assume responsibility for all patent and royalty fees on all equipment proposed.
3.1.25 WET WELLS
A. The wet wells shall be constructed as approved by the Authority and Engineer. Ladder bars shall be installed as shown on the drawings and in conformance to Standard Drawing 2-40.
B. The bottom of the wet well shall be filleted with concrete.
C. Debris baskets with guides shall be furnished and installed in accordance with Standard Drawing 11-7.
D. Hatchways provided shall be Bilco or equal, size and type as indicated on the drawings. Hatchways shall be provided with a cylinder lock with key way protected by a threaded cover plug.
E. The manhole cover for the sewage pump station well shall be a 27 inch watertight, flush type manhole cover in accordance with Standard Drawing 2-52.
F. The foundation slabs shall be monolithic with the pump station foundation slabs. Complete details of the foundation slab and concrete ballast shall be submitted to the Engineer for approval.
G. The Contractor shall furnish all other material, appurtenances, etc., for the complete installation of the wet well in accordance with the drawings approved by the Engineer.
3.1.26 PUMP STATION SITE PIPING
A. All piping required for a complete installation shall be furnished and installed. The influent gravity sewer, pump suction lines, pump discharge lines and force main shall be ductile iron pipe. The sump pump discharge shall be 1-1/4 inch galvanized steel pipe installed as shown on the Manufacturer's drawings. The air bubbler tube (bubbler system only) shall be 3/4 inch Type L copper. The bubbler pipe (bubbler system only) and sump pump discharge shall be supported from a 3 inch by 3 inch by 3/8 inch steel channel angle bracket welded to the outside of the pump station and securely fastened to the wet well wall.
B. All steel pipe exterior to the station and in contact with the soil or with sewage shall be field coated with one coat of epoxy resin after installation.
C. The Contractor shall restrict his excavation, when required to preserve undisturbed foundations for all piping. The backfill under all pip