SECTION: 22 13 29 PUMPS; SEWAGE AND SLUDGE[b1]
- Quality Assurance: EP 415-1-261, Volume 1
- UFGS SECTION 22 13 29 PUMPS; SEWAGE AND SLUDGE
Changes or Criteria Notes to Unified Facilities Guide Specifications (UFGS)
Paragraph # and Title (if any)
Note to Designer
a. All sewage lift stations on Fort Lewis shall be of a wetwell configuration. Submersible pump shall be capable of remote removal (on rails), shall have float controls and above-ground
enclosed electrical control panel.
b. System shall be redundant (at least two pumps), 100% capacity. Provide lockable hatch access to wetwell, audible and visual high level alarms.
c. Provide 2 inch water service to site with minimum 1 � inch washdown hose and nozzle.
d.Site shall be fenced, with lockable 12 foot gate (see Fence Section 32 31 13) and driveway access.
e.Provide area lighting which illuminates lift station, valve box and control panel for night work.
e;. All pumps serving flow greater than or equal to 50 gpm shall be Chopper. less than 50 gpm shall be grinder.
2. Wet-Pit Sump Pump. Construct and furnish pumps in accordance with the applicable requirements of HI M100 standards and those specified herein.
a. Include with the duplex pump unit two individual, vertical, submerged, volute, centrifugal pumps mounted below a coverplate; vertical, flexible connected, solid-shaft motors; motor and bearing-support housing attached to the coverplate; pump-support and shaft-housing pipes; discharge pipes.
Design the installation of the unit to permit removal of one pump assembly without disturbing the operation of the other.
b. Ensure requirements for each material designation are in accordance with the applicable definition listed in the centrifugal pump section of HI M100 standards. Materials for components and accessories not covered by these definitions are as specified herein.
c. Avoid contact between dissimilar metals. Where such contact cannot be avoided, protect joints between dissimilar metals against galvanic corrosion by plating, organic-insulation coatings, gaskets, or other suitable means.
3. Pump Selection
a. Where parallel pump operation is indicated, select pumps with characteristics specifically suited for the service without unstable operation.
b. Provide a pump unit that delivers, at rated speed, not less than the specified gallons per minute against the specified or indicated discharge head while the liquid level is not more than 1 foot above the datum elevation of the pump. Use the level of the entrance eye of the impeller as the datum elevation. Include in the calculations of the discharge head, both the friction head of the system piping external to the pump unit and the static head measured from a point of reference on the sump to the highest point in the system. Base ratings on pumping clear, fresh water at a temperature of 68 degrees F.
a. Furnish and install 2 submersible non-clog chopper/grinder wastewater pump(s). Each pump shall be equipped with an a non-overloading meter over the entire pump opening range, submersible electric motor connected for operation on 460 volts, 3 phase, 60 hertz, 3 wire service, with 50 feet of submersible cable (SUBCAB) suitable for submersible pump applications. The power cable shall be sized according to NEC and ICEA standards and have P-MSHA Approval.
4. Pump Design Configuration (Wet Pit Installation)
The pump shall be automatically and firmly connected to the discharge connection, guided by no less than two guide bars extending from the top of the station to the discharge connection. There shall be no need for personnel to enter the wet-well. Sealing of the pumping unit to the discharge connection shall be accomplished by a machined metal to metal watertight contact. Sealing of the discharge interface with a diaphragm, O-ring or profile gasket will not be acceptable. No portion of the pump shall bear directly on the sump floor. Each pump shall be fitted with stainless steel lifting chain or stainless steel cable. The working load of the lifting system shall be 50% greater than the pump unit weight.
5. Pump Construction
a. Major pump components shall be of gray cast iron, ASTM A-48, Class 35B, with smooth surfaces devoid of blow holes or other irregularities. The lifting handle shall be of stainless steel. All exposed nuts or bolts shall be AISI type 316 stainless steel construction. All metal surfaces coming into contact with the pumpage, other than stainless steel or brass, shall be protected by a factory applied spray coating of acrylic dispersion zinc phosphate primer with a polyester resin paint finish on the exterior of the pump.
b. Sealing design shall incorporate metal-to-metal contact between machined surfaces. Critical mating surfaces where watertight sealing is required shall be machined and fitted with Nitrile or optional Viton
rubber O rings. Fittings will be the result of controlled compression of rubber O rings in two planes and O-ring contact of four sides without the requirement of a specific torque limit.
c. Rectangular cross sectioned gaskets requiring specific torque limits to achieve compression shall not be considered as adequate or equal. No secondary sealing compounds, elliptical O-rings, grease or other devices shall be used.
6. Chopper Pumps
a. The portable submersible chopper pump shall be specifically designed to pump waste solids at heavy consistencies without plugging or dewatering of the solids. Materials shall be chopped/macerated and conditioned by the pump as an integral part of the pumping action. The pump must have demonstrated the ability to chop through and pump high concentrations of solids such as plastics, heavy rags, grease and hair balls, wood, paper products and stringy materials without plugging, both in tests and field applications.
b. Casing and Back Pull-Out Plate: The pump casing shall be of volute design, spiraling outward to the flanged centerline discharge. Back pull-out design shall incorporate jacking bolts for accurate adjustment of impeller-to-cutter bar clearance. Casing & backplate shall be ductile cast iron with all water passages to be smooth, and free of blowholes and imperfections for good flow characteristics. A pressure tap shall be included on or near the discharge flange. Backplate shall include a replaceable Rockwell C 60 steel cutter adjustable for 0.005-0.015" clearance to cut against the rotating impeller pumpout vanes for removing fiber and debris.
c. Impeller: Shall be semi-open type with pump out vanes to reduce seal area pressure. Chopping/maceration of materials shall be accomplished by the action of the cupped and sharpened leading edges of the impeller blades moving across the cutter bar at the intake openings, with a maximum set clearance between the impeller and cutter bar of 0.015-0.025" cold. Impeller shall be cast alloy steel heat treated to minimum Rockwell C 60 and dynamically balanced. The impeller shall be eyed to the shaft and shall have no axial adjustments and no set screws.
d. Cutter Bar Plate: Shall be recessed into the pump bowl and shall contain at least 2 shear bars extending diametrically across the intake opening to within 0.010-0.020" of the rotating cutter nut tooth, for the purpose of preventing intake opening blockage and wrapping of debris at the shaft area. Chopper pumps utilizing individually mounted shear bars shall not be acceptable. Cutter bar shall be alloy steel heat-treated to minimum Rockwell C 60.
e. Cutter Nut: The impeller shall be secured to the shaft using a cutter nut, designed to cut stringy materials and prevent binding using a raised, rotating cutter tooth. The cutter nut shall be cast steel heat treated to minimum Rockwell C 60.
f. Upper Cutter: Shall be threaded into the back pull-out adapter plate behind the impeller, designed to cut against the pump-out vanes and the impeller hub, reducing and removing stringy materials from the mechanical seal area. Upper cutter shall be cast steel heat treated to minimum Rockwell C 60. The upper cutter teeth are positioned as closely as possible to the center of shaft rotation to minimize cutting torque and nuisance motor tripping. The ratio of upper cutter cutting diameter to shaft diameter in the upper cutter area of the pump shall be 3.0 or less.
g. Shafting: Pump shafting shall be heat-treated alloy steel. The pump shaft shall directly couple to the motor shaft, with a bolt and keyway.
h. Pump and motor assemblies shall be UL listed for Class 1, Group D
j. A heat sensor thermostat shall be attached to top end of motor winding and shall be connected in series with the magnetic contactor coil in control box to stop motor if motor winding temperature reaches 221�F. Thermostat to reset automatically when motor cools.
j. Motor shall be protected by two mechanical seals mounted in tandem with a seal chamber between the seals. Seal chamber shall be oil filled to lubricate seal face and to transmit heat from shaft to outer shell. A double electrode shall be mounted in the seal chamber to detect any water entering the chamber through the lower seal. Water in the chamber shall cause a red light to turn on at the control box. This signal shall not stop motor but shall act as a warning only, indicating service is required.
k. Pumps shall be rated to operate continuously in air because of the low pump shut off float elevation.
a. Check Valve: Installed in each pump discharge line (4") shall include be a ductile iron 4" ball check with BUNA ball and clean-out port.
b. Replace any existing 1" Air / Vacuum release valve in common 4" discharge
8. Guide Rail Assembly: The grinder pump shall be mounted on a base elbow with a guide rail assembly for removal for repair and maintenance without entering the lift station. The guide rail assembly shall have the following salient features:
a. Rail mounted installation systems shall consist of guide rails, a sliding bracket, and a discharge connection elbow. Guide rails shall be of the size and type standard with the manufacturer and shall not support any portion of the weight of the pump. The sliding guide bracket shall be an integral part of the pump unit. The discharge connection elbow shall be permanently installed in the wet well along with the discharge piping. The pump shall be automatically connected to the discharge connection elbow when lowered into place and shall be easily removed for inspection and service without entering the pump well.
b. All Stainless Steel guide rails.
c. Fasteners, hoisting chains and anchor bolts shall be grade 300 Stainless Steel minimum.
d. Pump slide quick-disconnect shall be brass to prevent sparking.
e. Pump hoisting chain shall be stainless steel, permanently attached to the pump and securely fastened at the top of the guide rail assembly to prevent loss of the lifting chain, possible entanglement with level floats / pump cables and ingestion into the eye of the pump.
9. KTR shall restrain existing Force Main discharge flange to the wall of the wet well with 304 Stainless steel fasteners and threaded rod to prevent movement. The restraint shall be a minimum of two �" rods, through the existing flange bolt holes. The threaded rod shall be connected to �" Rod Coupling Nuts back to all thread rod anchored into the wall of the wet well with a structural epoxy anchor system. The epoxy anchor system shall be installed in accordance with the manufacturer's guidelines.
10. Duplicate pump data plates shall be permanently attached to the inside of the control panel cover.
11. The KTR shall install an 8" x 10" permanent plastic sign, white background with red letters "Lift station in event of alarm call PW Customer Service 967-3131". Sign shall be attached to the control panel or control panel support.
12. Electrical and Controls:
a. All electrical work shall be in accordance with the latest edition of the NEC, NFPA 70.
b. The KTR shall provide and install a "Dead front" UL listed Duplex Weatherproof Sewage Pump Control Panel. The control panel shall be a pre-engineered off the shelf unit and be coordinated with the chopper pumps by KTR. The new control panel shall mounted on galvanized strut or angle iron.. The Control Panel shall have the following salient features:
(1) 208V, 3 ph, 60 hz.
(2) Hand-Off Automatic (H-O-A) pump selection switches
(3) Numbered terminal strip-screw type.
(4) NEMA 4X, flashing red light
(5) NEMA 4X, fiberglass enclosure with gasketed hinged door and stainless steel hardware.
(6) Solid State printed circuit control board with float indicator lights.
(7) NEMA 4X alarm horn (95db)
(8) Surface mount alarm horn silence button.
(9) Condensation heater
(10) Elapsed time meter, non resettable, for each pump.
(11) Cycle counter, for each pump.
(12) High temp indicator with shutdown.
(13) Seal Failure alarm with trouble light.
(14) Control Transformer sized as required.
(15) Pump Alternator
(16) UL listed Intrinsically Safe Barriers for float switches
(17) Four float system
a. Lead Pump Start
b. Lag Pump Start
c. Pump Stop
d. Hi-level Alarm
(3) Control Floats
(a) Supply and install 4 internally weighted non-mercury UL listed control duty float switches. Float switch variations shall be coordinated by the KTR with the control panel logic. (normally open or normally closed)
(b) Control floats shall be supplied with all required appurtenances for a complete and useable system. floats shall be suspended from a commercially available pre-engineered stainless steel control float bracket. All floats cables shall use appropriate strain relief. All excess cable shall be bundled, looped, or eliminated to prevent ingestion into the pump accidentally.
(c) Raceways and Junction Boxes
(1) Control Float and Pump power cables shall be kept separate in separate raceways and junction boxes.
(2) No terminations shall be made within the wet well of any kind.
(3) The KTR shall provide and install separate Rigid Galvanized raceways for power and instrumentation from the wet well to the new panel. The conduits from wet well to the control panel shall be sealed off prior to the entry into the control panel.
(4) The KTR shall power the new control panel from same circuit and conductors powering the existing control panel. The KTR shall provide and install all required components to provide a complete and useable system.
13. SCADA. All Supervisory Controls and Data Acquisition (SCADA) for water systems on Joint Base Lewis McChord shall follow the JBLM SCADA Master Plan, latest edition for design and specification, programming and implementation of new, repaired, or upgraded systems
Notes to Designers on Drawing Content
Applicable Points of Contact