SECTION 07500
TABLE OF CONTENTS
07510 GENERAL
A. Design Requirements
B. Warranty
C. Submittals
07520 PUMP STATIONS
A. General
B. Site Work
C. Structures
D. Piping and Valves
E. Electrical - General
07530 PUMP STATION EQUIPMENT
A. Pumps
B. Pump Control Systems
C. Alarm Dialer/SCADA/Telemetry
D. Grinders
E. Generators
F. Automatic Transfer Switches
07540 FORCE MAINS
A. Design
B. Materials
C. Installation
D. Valves and Appurtenances
07550 ODOR/CHEMICAL FACILITIES
07560 INSPECTIONS, TESTING AND TRAINING
A. Inspections
B. Testing
C. Operator Training
07510 GENERAL
A. DESIGN REQUIREMENTS
1. These specifications apply to all pump stations, force mains, and associated facilities that are to be owned, operated, and maintained by the Town of Cary. Design of private pump stations and force mains and associated facilities is not covered by these specifications, and the applicant should look for guidance from other appropriate agencies (NCDENR, NC Plumbing Code, etc.).
2. All aspects of the design of pump stations, force mains, and associated facilities shall, at a minimum, meet the requirements of the latest version of the NCDENR "Minimum Design Criteria for the Fast-Track Permitting of Pump Stations and Force Mains". Requirements presented in the Town of Cary Standard Specifications hereunder that are more restrictive or go above and beyond the requirements of the Minimum Design Criteria are required by the Town of Cary.
3. All aspects of the design of pump stations, force mains, and associated facilities shall be submitted for review and approval to the Town of Cary Engineering Department. Materials necessary for the review and requiring approval include complete plans, specifications, design reports, and specific equipment submittals for the specific pump station, as described hereunder.
B. WARRANTY
1. All equipment, materials, and systems supplied under this specification shall be provided with a warranty from the manufacturer to the Town that the subject equipment, material's, and systems shall be free of defects in workmanship and material, and shall operate as intended under the known conditions, for a minimum period of one year. The warranty shall be in printed form and made applicable to the Town (as Warrantee) at the time of acceptance for maintenance by the Town.
C. SUBMITTALS
1. Design Report
a) A design report signed and sealed by a NCPE is required with the submittal of plans and specifications for any facilities covered under this section that are proposed for construction. This design report shall contain, at a minimum, the following design criteria:
i. Total dynamic head calculations for all applicable pumping situations.
ii. System curve and pump curve analysis used to determine pump selection and operating point.
iii. Pump station cycle and pump run times covering the high, low and average flows over the entire expected operating period of the pump station.
iv. Response time available in event of an emergency (time between the high water alarm and the first system overflow at average design flow and peak design flow).
v. Pump station flotation/buoyancy calculations.
vi. Minimum velocity within the force main, including an analysis of the capabilities of the pumps to completely flush any depressed sections of the force main in a single pumping cycle.
vii. Maximum detention times within the pump station and force main covering the low flows over the entire expected operating period of the pump station.
viii. An evaluation of the capability of the receiving sewer to handle the peak flow discharge from the proposed facility in addition to the existing or planned peak flows currently handled by the receiving sewer or sewage facility.
ix. Airflow calculations and chemical dosing calculations for the odor control facilities (if applicable).
x. Flow capacity and headloss calculations for the grinder unit.
xi. Calculations for the sizing of the backup power generator.
2. Project Review Submittals
a) Project Review Submittals shall be submitted to the Town of Cary Engineering Department for review and approval prior to application for a permit for the pump station or force main, and prior to entering into construction contracts or purchasing any equipment for the pump station or force main. Obtaining permits, entering into construction contracts, or purchasing any equipment in no way obligates the Town of Cary to accepting designs or equipment that do not meet the specified standards or other requirements the Town may have.
b) The Project Review Submittals shall include, at a minimum, complete plans and specifications, a design report as described above, and manufacturer's information on specific major equipment listed in this specification section. The information submitted on equipment shall include, at a minimum, the name of the manufacturer and the specific model being supplied, fabrication and assembly drawings, detailed specifications and data covering materials, parts, devices, and accessories forming a part of the equipment furnished. It shall also include any system hydraulic schematics, electrical wiring diagrams, and control panel schematics. Additional detailed information that may be required for submittal for specific equipment is listed in the appropriate equipment section.
3. Pre-Approved Equal Submittals
a) Equipment and systems of equal quality and efficiency may be available from manufacturers and suppliers other than those listed in the Approved Manufacturers List. No attempt is made to preclude the furnishing of similar quality items by other manufacturers. The use of alternate equipment and products will be considered if it can be demonstrated that these items have equal or superior construction performance, operating and maintenance costs, offer a present worth cost equal to or less than the specified items, and do not adversely affect other system components.
b) Equipment and systems other than those listed in the Approved Manufacturers List must receive approval from the Director of Engineering prior to application for a permit for the pump station or force main, and prior to entering into construction contracts or purchasing any equipment or systems for the pump station or force main. Purchasing equipment in no way obligates the Town of Cary to accepting equipment that does not meet the specified standards or other requirements the Town may have.
c) Pre-Approved Equal packages shall include the following information as a minimum:
i. Current catalog data sheets and complete technical data to support specification compliance.
ii. A point-by-point list clearly stating all differences between the named item and the proposed alternate and a separate list clearly stating all exceptions to the Specifications. If no exceptions are listed, then no exceptions to the Specifications will be allowed.
iii. Installation list with name, address and phone number of contact person for each of at least five (5) installations where the proposed equipment has been in similar service and satisfactory operation for at least two (2) years. The date of placing equipment in service at each listed installation shall be provided.
iv. Three (3) copies of Pre-Approved Equal information shall be submitted.
d) Equipment that meets the Pre-Approved Equal submittal requirements, the technical specification requirements, and all other requirements of the Town of Cary, will be approved by the Director of Engineering via letter within 14 calendar days of receipt of a complete package. Approval of Equal equipment or systems in no way eliminates the requirement for complete submittals at a later date.
4. Testing Results Submittals
a) The results of all testing shall be submitted to the Town of Cary Engineering Department for review prior to continuing progress on the particular equipment. If shop testing is required, results shall be submitted prior to delivery of the equipment. If installation verification is required, results shall be submitted prior to start-up and testing of the equipment. If final start-up tests are required, results shall be submitted prior to final acceptance of the equipment.
b) Three printed copies of all test results are required to be submitted for review.
c) A final, compiled summary of all testing done on all equipment shall be provided to the Town of Cary upon completion of the project prior to project closeout and final acceptance. This final, compiled summary shall consist of a single bound printed copy, and an electronic copy (CD).
5. Operation and Maintenance Manuals (O&M)
a) Operation and Maintenance (O&M) manuals are required for all equipment and systems furnished under this specification section. Three copies shall be supplied to the Town in printed format prior to startup of the subject equipment or systems. The O&M manuals shall contain all of the necessary information for proper operation and maintenance of the subject equipment and systems. At a minimum, the O&M manuals shall contain the following:
i. Final approved shop drawings.
ii. Design data including pump curves and system curves.
iii. Wiring diagrams and control schematics.
iv. Detailed inventory of installed equipment, including its functional description, and manufacturer name, address, and phone number (and the same for a local representative of the manufacturer).
v. Operating instructions.
vi. Troubleshooting techniques.
vii. Maintenance schedules.
viii. Assembly and disassembly instructions.
ix. Instructions for start-up and shutdown, as well as calibration and adjustment.
b) A final, compiled Operation and Maintenance (O&M) manual covering all equipment and systems supplied, shall be provided to the Town of Cary upon completion of the project prior to project closeout and final acceptance. This final, compiled summary shall consist of a single bound printed copy, and an electronic copy (CD).
07520 PUMP STATIONS
A. GENERAL
1. Pump stations shall be located on a parcel or an easement that is dedicated to the Town of Cary. The site shall be directly connected to a dedicated public right-of-way or have a dedicated access easement to a public right-of-way.
2. The Town requires sewage grinders, on-site backup power, and odor control facilities at all pump stations, unless the Director of Engineering grants approval otherwise. Sizing of these items will be based on expected flow volumes and characteristics.
3. All stations shall have a minimum of 2 pumps of equal capacity. The pumps shall be solids handling, submersible, centrifugal pumps each capable of pumping flows equal to or in excess of the expected peak flow. Where 3 or more pumps are required, they should be of such capacity that with the largest unit out of service, the remaining units shall have capacity to handle peak flows. Pumps and force mains shall be sized to provide a minimum velocity in the force main of 2.5 fps and a maximum velocity of 10 fps.
4. Pump stations shall remain fully functional, operational, and free from physical damage during a 100-year flood.
B. SITE WORK
1. The site shall be graded to drain away from the pump station, and to remove storm water runoff from the site in a non-erosive manner.
2. The site shall be stabilized by crushed stone, low maintenance vegetative ground cover or other suitable materials. No vegetative ground cover is allowed within the fenced area. Visual screening and landscaping shall be provided in accordance with the approved site plan.
3. The site shall be secured by a 6-foot high chain link fence topped with 3 strands of barbed wire placed at an outward 45 degree angle. Fence products shall be only new materials using hot dipped galvanized iron or steel components and aluminum coated fabric. Gates shall permit 180 degree opening, be located so as to provide vehicle accessibility for lifting the pumping units, and be a minimum width of 12 feet. All posts shall be set in concrete.
4. The pump station site shall permit the loading and removal of the all equipment (pumps, grinders, generators, etc.) from the pump station site with an appropriately sized truck and/or crane.
5. The site shall feature adequate turn around areas for a WB-40 service vehicle and provide a minimum 12 foot wide access road to the site with grades not to exceed 10%. If chemical feed systems are included, additional turning radius may be required.
6. A high pressure sodium vapor light of minimum 600 watt capacity is required. The light shall be mounted on a Class V utility pole at a height of 30 feet and be controlled by a photo cell.
7. Pump stations shall have a metered potable water supply from the Town of Cary public water distribution system. The supply shall have an approved backflow prevention system. A minimum of one (1) freeze proof yard hydrant is required within the fenced area. Emergency shower and eye washing basin shall be provided in pump stations with chemical odor control facilities.
C. STRUCTURES
1. General
a) The submersible pump station structures shall consist, at a minimum, of a grinder manhole, a wet well, and a valve vault. Large, integrated structures are permissible, however, there shall be walls separating the portions of the structure listed above. Grinders may be allowed if authorized by the Director of Engineering. Pump station structures other than the wet well shall be provided with a means to remove accumulated water and wastewater from the structure. Access hatches for equipment and personnel shall be provided for all structures, and sized appropriately.
b) Any portion of a pump station structure that is open and would allow floodwater entry into the wastewater system shall be built with a top elevation of 2 feet above the 100 year flood elevation. All structures not meeting the elevation requirement that could allow entry of floodwater into the wastewater system shall be sealed watertight with a vent elevated a minimum of 2 feet above the 100 year flood elevation.
2. Wet Well
a) The wet well shall have a minimum diameter of 6 feet, and shall be large enough to easily accommodate the removal of each pump and a basket strainer. The wet well shall be designed to have an operating volume sufficient to provide pump operating cycles to match the manufacturer's recommendations. The pump operating cycles must be between two and eight times per hour at design daily flow (without being excessively deep), unless otherwise authorized by the Director of Engineering.
b) The wet well shall be constructed of precast concrete manhole sections or cast-in-place concrete. Extended bases or another foundation shall be used to provide adequate bearing surface and flotation protection, if needed. All concrete shall have a minimum 28 day compressive strength of 3000 psi.
c) Precast concrete manhole wet wells shall conform to ASTM C‑78. Manhole section joints shall be of a durable mastic sealing material. The exterior of manhole wet wells shall have a factory applied bitumastic or asphaltic coating. The exterior of wetwell joints shall be overlapped by an approved material such as Conwrap, Conseal, etc. The interior side of the joints shall be plastered smooth with portland cement grout.
d) Cast-in-place wet wells shall be properly designed by a NCPE and include appropriate structural support, waterproofing, exterior coating, structure covers, access hatches, etc.
e) At a minimum, wet wells shall have a vent made from ductile iron with flanged joint pipe fittings. An insect screen shall be included at the exposed end of the vent pipe. The screen shall be bronze or aluminum insect screening. Forced air venting is also allowed and will be required on individual pump stations in conjunction with odor control measures, depending on circumstances.
f) Wet wells and wet well piping shall be coated with an approved epoxy coating at 80-mils. Care will be taken to ensure no epoxy coating is applied to the pump coupling face, the guide rails, or any other part that needs to allow movement or replacement on a regular basis.
3. Valve Vaults
a) The valve vault shall, at a minimum, consist of a precast concrete manhole base section at least 6 feet in diameter, or a cast in place concrete, custom built section, or a precast concrete rectangular structure at least 6 feet square. The valve vault shall be complete with a drain that goes to the wet well, access ladder attached to the vault wall, and access cover cast in the top slab. The drain pipe between the valve vault and the wet well shall have a back water valve at the wet well end. The access cover for the valve vault shall be a square hatch of 1/4 inch aluminum diamond pattern plate with steel hinges on an aluminum frame cast in place in the cover slab.
4. Manholes
a) Any manholes installed on the pump station site need to meet the standards described in Section 07000 of the Town of Cary Standard Specifications. All manholes installed on the pump station site shall receive an interior coating of an approved epoxy resin. All manholes located within the 100 year flood elevation shall receive an exterior coating as specified in Section 07000.
5. Buildings
a) Modular buildings to house chemical feed facilities shall be adequate to provide sufficient storage, clearance, and containment of chemicals. A removable roof or roof sections shall be required to allow sufficient access to all equipment and tanks within the building. All supplementary or miscellaneous items, appurtenances, and devices incidental to or necessary for a sound, secure, and complete installation shall be designed and sealed by a NCPE.
b) On a case by case basis, a building may be required to house all electrical and control equipment. This building shall be of precast, prefabricated, or built in place construction.
c) All buildings located on a pump station site shall have the first floor elevation a minimum of 2 feet above the 100 year flood elevation.
D. PIPING AND VALVES
1. Suction and discharge piping shall be Class 50 ductile iron flanged pipe in accordance with AWWA C 141. Discharge piping and valves shall produce a minimum head loss while maintaining a minimum velocity of 2.5 feet per second. All exposed piping shall have adequately sized and located thrust rods.
2. The discharge connection elbow shall be a straight through fitting with no flap valve and shall be permanently installed in the wet well along with the discharge piping. The pumps shall be automatically connected to the discharge connection elbow when lowered into place. The entire weight of the pump shall bear upon the guides and base support with no part of the pump bearing directly on the floor of the wetwell. A stainless steel chain shall be provided for lifting each pump from the wet well. All hardware used shall be 316 stainless steel.
3. An external weight check valve and a plug valve shall be provided for the discharge pipe of each pump. A 1/4 turn plug valve shall be provided on the discharge pipe from the valve vault (the beginning of the force main).
4. Check Valve: Check valves shall be iron bodied, fully bronze mounted with bronze clapper disc and bronze seat ring, and shall have a spring loaded lever arm capable of being mounted on either side of the valve.
5. Plug Valve: Plug valves shall be 1/4 turn, eccentric action and resilient plug facing with heavy duty stainless steel bearings and welded-in corrosion resistant nickel seat. Pump station plug valves shall be "full-port" cross-sectional area perpendicular to the flow of at least 100% of the adjoining pipe.
6. Plug valves and check valves on the discharge side of each pump shall be located in a valve vault separate from and adjacent to the wet well. A Victaulic type coupling shall be installed on each discharge main between the wet well and the valve vault.
7. A +/- 2% accuracy pressure gauge with a 3 inch or larger dial, stainless steel case, and graduated to 30 psi shall be provided on each discharge pipe. The gauge shall be installed between the check and plug valves. Isolation seals and cut-off ball valve shall be provided between the gauge and force main. The gauge shall be oriented so that it is easily legible from the valve vault.
8. Anchor Bolts.
a) Anchor bolts and nuts shall be furnished as required for each item of equipment. Anchor bolts, together with templates or setting drawings, shall be delivered sufficiently early to permit setting the anchor bolts when the structural concrete is placed. Anchor bolts shall be at least 3/4 inch in diameter.
b) Anchor bolts shall be accurately located and centered in pipe sleeves having an inside diameter approximately 2.5 times the bolt diameter and a length approximately 8 times the bolt diameter. A square anchor plate with thickness of approximately 0.5 the bolt diameter and side dimensions 4 times the bolt diameter shall be welded to the bottom of each sleeve, with the anchor bolt extended through the plate and welded thereto. Two nuts and a washer shall be furnished with each anchor bolt.
c) Anchor bolts shall be long enough to accommodate 1.5 inches of grout beneath the baseplate and to provide adequate anchorage into structural concrete. Bolts shall have a "J" bend anchoring them into the concrete.
d) Anti-seize compound will be applied to the threads of all stainless steel bolts before assembly.
E. ELECTRICAL - GENERAL
1. All electrical systems associated with any of the items covered under this section shall meet all applicable electrical standards and code requirements, including, but not limited to: ANSI, ASTM, NEMA, IEEE, DEMA, EEI, HEI, ISO, NFPA, SAE, NEC, UL508, as well as any other federal, state, or local codes.
2. Electrical service to all pump stations shall be three phase, 240 VAC or 480 VAC, with automatic transfer switches to automatically starting on-site emergency generators. The electrical power entrance shall be through a meter base, followed by a NEMA 3R heavy duty, single throw, fusible safety switch with a solid neutral. This shall be followed by a NEMA 3R heavy duty, double throw, three pole safety switch which feeds the control panel from one side and heavy duty, circuit breaking 4 wire, 4 pole receptacle assembly as manufactured by Crouse-Hinds or other approved equal from the other side.
3. Electrical equipment inside the wet well shall meet the requirements for Class I, Division I, Group C/D service.
4. All of these electrical components shall be suitably sized to be capable of service with all electrically powered equipment running.
5. All electrical components, including panels, shall be sealed off in accordance with the N.C. Electrical Code requirements for electrical service to gas pumps.
6. The use of rigid conduits is required. PVC shall be used below ground and galvanized steel shall be used above ground. Flexible conduits are only allowed with approval of the Director of Engineering.
7. Pump station electrical and control equipment shall be located in a building as described above, or under a weatherhood. An aluminum weatherhood with a clear height of 7 feet, an overhang of at least 4 feet and a thickness of 3/16 inch shall be provided for control equipment exposed to the weather. The back panel and side panel shall also be 3/16 inch thick aluminum. The support structure for the weatherhood shall be made from structural steel members assembled to provide individual, direct support to the control equipment panel, transfer switch, safety switches, meter base and the weatherhood. The steel frame shall be painted with a two component, high build epoxy polyamide paint system designed for severe service. All weatherhoods shall be provided with a light and GFI protected 120V outlet.
8. All electrical equipment, including non-submersible motors, electrical panels, control panels, alarm/telemetry systems, backup generators, etc., shall be located a minimum of 2 feet above the 100 year flood elevation.
07530 PUMP STATION EQUIPMENT
A. PUMPS
1. General
a) Pumps, motors, and major accessories shall be supplied by a single manufacturer as listed in the Town of Cary Approved Manufacturer's List.
b) Each pumping unit shall be complete with a close-coupled, submersible electric motor, and all other appurtenances specified, or otherwise required for proper operation.
c) The equipment provided under this section shall be suitable for the service conditions and shall be capable of meeting all operating requirements of the pumping system.
d) Each pumping unit including motor and all integral controls shall be rated and labeled for use in a Class 1, Division 1 or Division 2, Group D area as defined by the National Electric Code.
e) Each item of equipment and each part shipped separately shall be identified with indelible markings for the intended service. Tag numbers shall be clearly marked on all shipping labels and on the outside of all containers.
f) Abbreviations. Reference to standards and organizations herein shall be as indicated by the following designations.
i. AFBMA Antifriction Bearing Manufacturers Association
ii. AGMA American Gear Manufacturers Association
iii. AISI American Iron and Steel Institute
iv. ANSI American National Standards Institute
v. ASME American Society of Mechanical Engineers
vi. ASTM American Society of Testing and Materials
vii. NPT National Pipe Thread
viii. SAE Society of Automotive Engineers
2. Submittals
a) Complete fabrication and assembly drawings, together with detailed specifications and data covering materials, parts, devices, and accessories forming a part of the equipment furnished, shall be submitted in accordance with the submittals section. The data and specifications for each unit shall include, but not be limited to, the following:
i. Pumps
- Name of Manufacturer
- Type and model
- Rotative speed
- Size of suction elbow inlet
- Size of discharge elbow outlet or nozzle
- Net weight (mass) of pump and motor only
- Complete performance curves showing capacity versus head, bhp (brake kW), NPSH required, and efficiency
- Data on shop painting
ii. Motors
- Name of manufacturer
- Type and model
- Type of bearings and method of lubrication
- Rated size of motor, hp (kW), and service factor
- Insulation class and temperature rise
- Full load rotative speed
- Net weight
- Efficiency at full load and rated pump condition
- Full load current
- Locked rotor current
b) Operation and Maintenance Manuals shall include, at a minimum, the following information:
i. Equipment function, normal operating characteristics, and limiting conditions.
ii. Assembly, installation, alignment, adjustment, and checking instructions.
iii. Operating instructions for startup, routine and normal operation, regulation and control, shutdown, and emergency conditions.
iv. Lubrication and maintenance instructions.
v. Guide to troubleshooting.
vi. Parts lists and predicted life of parts subject to wear.
vii. Outline, cross-section, and assembly drawings; engineering data; and wiring diagrams.
viii. Test data and performance curves.
3. Quality Assurance
a) Performance and Balance Requirements
i. All specified conditions shall be at rated speed unless otherwise indicated.
ii. Overall (wire-to-water) efficiency for constant speed pumps shall include losses in the pump and motor. Overall (wire-to-water) efficiency for variable speed pumps shall include losses in the pump, motor, adjustable frequency drive, and any transformers supplied as part of the adjustable frequency drive equipment.
iii. The minimum hydrostatic test pressure shall be 1.5 times shutoff head plus max suction pressure.
iv. Pump performance shall be stable and free from cavitation and noise throughout the specified operating head range at minimum suction submergences. The design running clearance between the impeller inlet and the casing wearing ring (if provided) shall be not less than 0.01 inch or 1 mil per inch of casing wearing ring diameter, whichever is greater.
v. When required, pumping units shall be designed so that maximum reverse rotation due to reverse flow at the head as required will not cause damage to any component. Pump supplier shall coordinate this provision with the motor supplier.
vi. All rotating parts shall be accurately machined and shall be in as nearly perfect rotational balance as practicable. Excessive vibration shall be sufficient cause for rejection of the equipment. The mass of the unit and its distribution shall be such that resonance at normal operation speeds is avoided. In any case, the unfiltered vibration velocity, as measured at any point on the machine including top of motor, shall not exceed the maximum velocity as indicated for vertical, end suction, solids handling pumps. At any operating speed, the ratio of rotative speed to the critical speed of a unit or its components shall be less than 0.8 or more than 1.3.
4. Materials
a) Stator housing, oil chamber housing, impeller casing, and impeller shall be cast iron, ASTM A48.
b) Casing wearing ring shall be bronze, ASTM B62, or rubber, or martensitic stainless steel, Brinell 300+.
c) Bottom wearing plate shall be cast iron, ASTM A48 with spiral grooves.
d) Impeller wearing plate shall be martensitic stainless steel, Brinell 200-250.
e) Shaft shall be alloy steel, hard chrome plated, or martensitic stainless steel, AISI type 416 or 420.
f) Mechanical seals shall be 2 tandem single type, oil lubricated with silicon or tungsten carbide seal rings at all points, except the upper rotating seal, which shall be carbon.
g) Discharge base shall be cast iron or fabricated steel.
h) Guiderails shall be stainless steel pipe, ASTM A312, Schedule 40S.
i) Upper guiderail bracket, cable hooks, and chain hooks shall be AISI type 304 stainless steel.
j) Pedestal base shall be cast iron or fabricated steel.
5. Pumps
a) Pumps shall be submersible, non-clog centrifugal sewage pumps capable of passing a 3 inch sphere. Pumps shall be capable of handling raw, unscreened sewage. Major pump components shall be of gray cast iron devoid of burrs, pits or other irregularities.
b) The impeller casing shall have well-rounded water passages and smooth interior surfaces free from cracks, porosity, blowholes, or other irregularities. The discharge nozzle shall be flanged, with dimensions and drilling conforming to ANSI B16.1, Class 125. The discharge nozzle shall be flanged and sufficiently rigid to support the pumping unit under all operating conditions.
c) The impeller shall be a semi-open and enclosed recessed one-piece casting with not more than two nonclog passages with the impeller completely out of the flow path. The interior water passages shall have uniform sections and smooth surfaces and shall be free from cracks and porosity. The impeller shall be dynamically balanced and securely locked to the shaft by means of a key and self-locking bolt or nut.
d) For pumping units 20 hp and larger, renewable wearing rings shall be provided in the casing and on the impeller. The rings shall be positively locked in place. For pumping units less than 20 hp a renewable wearing ring or axially adjustable wearing plate shall be provided in the casing. Casing wearing ring shall be securely fastened to the impeller casing front cover to provide either an axial or radial running clearance. Axially adjustable wearing plate shall be arranged to permit adjustment of the axial running clearance between the impeller and plate. The wearing plate shall have an outward spiraling groove designed to force stringy solids outward and away from the impeller.
e) The oil chamber shall contain a drain plug and a vent plug. Food grade oil shall be used.
f) Each pump shall be provided with two mechanical rotating shaft seals arranged in tandem and running in an oil chamber. Each interface shall be held in contact by an independent spring system designed to withstand maximum suction submergence. The seals shall require neither maintenance nor adjustment and shall be readily accessible for inspection and replacement. Shaft seals lacking positively driven rotating members or conventional double mechanical seals which utilize a common single or double spring acting between the upper and lower units and requiring a pressure differential to offset external pressure and effect sealing, will not be acceptable. The seals shall not rely upon the pumped media for lubrication and shall not be damaged if the pumps are run unsubmerged for extended period while pumping under load.
g) All mating surfaces of major components shall be machined and fitted with O-rings where watertight sealing is needed. Sealing shall be accomplished by O-ring contact on four surfaces and O-ring compression in two planes, without reliance on a specific fastener torque or tension to obtain a watertight joint. The use of elliptical O-rings, gaskets, or seals requiring a specific fastener torque value to obtain and maintain compression and watertightness will not be acceptable. The use of secondary sealing compounds, gasket cement, grease, or other devices to obtain watertight joints will not be acceptable.
6. Pump Motors
a) The pump motors shall be sealed submersible type, and shall be three phase, 60 Hertz, 240v/480v motors with a maximum speed of 1800 RPM. The motors shall meet the U.S. requirements of Class I, Division I, Group D for hazardous locations, and shall be sized to non-overloading throughout the entire operating range of the pump.
b) A heated sensor thermostat shall be attached to and embedded in the winding and be connected in series with the motor starter contactor coil to stop motor if temperature of winding is more than 220 degrees F. Thermostat shall reset automatically when motor cools to safe operating temperature. The common pump motor shaft shall be of 416 stainless steel.
c) The motor shall be protected by mechanical seal system as described above. 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 panel. This signal shall not stop the motor but shall act as a warning only.
d) Power cables to pumps shall be AWG (min) hypalon jacketed type SPC cable a minimum of thirty (30) feet in length.
e) Motors shall be provided by the pump manufacturer and shall be air-filled, totally submersible. Motor nameplate rating shall exceed the maximum power required by the pump in the operating head range. Each motor shall have a voltage, frequency, and phase rating as required and shall have a service factor of 1.15. The stator housing shall be an air-filled, watertight casing. A cooling jacket shall encase the motor housing for each pump where needed to maintain adequate cooling. Cooling jacket shall require no external source of cooling water. Motor insulation shall be moisture resistant, Class F, 180 degrees Celcius. Each motor shall be NEMA Design B for continuous duty at 40 degrees Celcius ambient temperature, and designed for at least 10 starts per hour.
f) Each motor housing shall be provided with a moisture detection system complete with all sensors, control power transformer, intrinsically safe control modules, and relays. The moisture detection system shall be rated for a 120V AC or 240V AC supply. The moisture detection system shall provide two normally open dry output contacts rated 5 amps at 120 volts AC. The contacts shall close when moisture is detected in the motor housing and the pump shall be shut down. All moisture detection system components shall be furnished by the pump supplier and shall be shipped loose for installation into the motor controller enclosure, or if required to be mounted separately all components shall be mounted in a NEMA 4 stainless steel enclosure.
g) The motor bearings shall be antifriction, permanently lubricated type. The lower bearing shall be fixed to carry the pump thrust and the upper bearing free to move axially. The bearings shall have a calculated AFBMA L10 Live Rating of 40,000 hours when operating at maximum operating head. Maximum shaft runout at the mechanical seals shall not exceed 2 mils at any point in the operating head range.
h) Thrust bearings shall be protected by bearing temperature switches. The switches shall be normally closed automatic reset type rated 5 amps at 120V AC.
i) Each motor shall be capable of continuous operation in air (unsubmerged) for at least 24 hours under pump full load conditions, without exceeding the temperature rise limits for the motor insulation system.
j) Each pump shall be equipped with one or more multiconductor cable assemblies for power and control. Each multiconductor assembly containing power cables shall be provided with a separate grounding conductor. Each cable assembly shall bear a permanently embossed code or legend indicating the cable is suitable for submerged use. Cable sizing shall conform to NEC requirements.
k) All cables shall be of sufficient length to terminate in a junction box outside the wetwell as indicated on the drawings, with 10 feet of slack that shall be coiled on a cable hook at the top of the wetwell. Each cable shall be supported by AISI Series 300 corrosion-resistant stainless steel Kellems type woven grips to prevent damage to the cable insulation. Mounting of cable supports in the wetwell shall be coordinated to prevent damage to the cable.
l) The cable entry water seal shall include a strain relief and a grommet type seal designed so that a specific fastener torque is not required to ensure a watertight submersible seal. The cable entry junction box and motor shall be separated by a stator lead sealing gland or a terminal board. The junction box shall isolate the motor interior from moisture gaining access through the top of the stator housing.
m) Motors with an adjustable frequency type speed controller shall be derated to compensate for harmonic heating effects and reduced self-cooling capability at low speed operation so that the motor does not exceed Class B temperature rise when operating in the installed condition at load with power received from the adjustable frequency drive. All motors driven by adjustable frequency drives shall be supplied with full phase insulation on the end turns and shall meet the requirements of NEMA MG 1, Part 31. In addition to the requirements of NEMA MG 1, Part 31, motors shall be designed to be continually pulsed at the motor terminals with a voltage of 1600 volts ac.
n) Adjustable Speed Drives. Adjustable frequency drives shall be provided as specified by the Director of Engineering on a case by case basis.
7. Appurtinances
a) The lift out systems shall consist of a straight elbow that bolts to the bottom of the basin, a combination disconnect assembly with a seal flange that mounts to the pump, rail support guides that fasten to the wall of the basin and guide and support brackets that mount to the pump. The guide rails shall be type 316 stainless steel.
b) Guiderail Mounted Base. A discharge base and discharge elbow shall be furnished by the pump manufacturer. The base shall be sufficiently rigid to firmly support the guiderails, discharge piping, and pumping unit under all operating conditions. The base shall be provided with one or more integral support legs or pads suitable for bolting to the floor of the wetwell. The face of the discharge elbow inlet flange shall be perpendicular to the floor and shall make contact with the face of the pump discharge nozzle flange. The diameter and drilling of the elbow outlet flange shall conform to ANSI B16.1, Class 125. The pump and motor assembly shall be automatically connected to and supported by the discharge base and guiderails so that the unit can be removed from the wetwell and replaced without the need for operating personnel to enter the wetwell.
c) Sliding Bracket. Each guiderail mounted pumping unit shall be provided with an integral, self-aligning guiderail sliding bracket. The bracket shall be designed to obtain a wedging action between flange faces as final alignment of the pump occurs in the connected position. The bracket shall maintain proper contact and a suitably sealed connection between flange faces under all operating conditions. The sliding bracket shall be non-sparking.
d) Guiderails. Each guide rail mounted pumping unit shall be equipped with one or more guiderails. Guiderails shall be sized to fit the discharge base and the sliding bracket and shall extend upwards from the discharge base to just below the bottom of the access hatch. An upper guiderail bracket shall be provided at the pump access opening. Guiderails shall be made of stainless steel.
e) Lifting Chain. Each guide rail mounted pumping unit shall be provided with a chain suitable for removing and installing. The chain shall be stainless steel. A suitable chain hook shall be provided at the top of the wetwell.
f) Special Tools and Accessories. Equipment requiring periodic repair and adjustment shall be furnished complete with all special tools, instruments, and accessories required for proper maintenance. Equipment requiring special devices for lifting or handling shall be furnished complete with those devices.
8. Shop Painting
a) All iron and steel parts which will be in contact with pumped liquid or submerged after installation, including the inside of the casing, the impeller, and the discharge elbow, shall be shop cleaned in accordance with the coating manufacturer's recommendations and painted with the epoxy coating system specified. The coating shall have a dry film thickness of at least 10 mils and shall consist of a prime coat and one or more finish coats. At least 1 quart of the finish coat material shall be furnished with each pump for field touchup.
b) All other iron and steel surfaces, except stainless steel and machined surfaces, shall be protected with suitable protective coatings applied in the shop. Surfaces of the equipment that will be inaccessible after assembly shall be protected for the life of the equipment. Exposed surfaces shall be finished, thoroughly cleaned, and filled as necessary to provide a smooth, uniform base for painting. Electric motors, speed reducers, starters, and other self-contained or enclosed components shall be shop primed or finished with an oil resistant enamel or universal type primer suitable for top coating in the filed with a universal primer and aliphatic polyurethane system.
c) Surfaces to be coated after installation shall be prepared for painting as recommended by the paint manufacturer for the intended service, and then shop painted with one or more coats of the specified primer.
B. PUMP CONTROL SYSTEMS
1. All components of the Pump Control Systems shall be properly designed and installed to meet all NEC and other industry standards, as well as all federal, state, and local requirements.
2. Submittals: Complete fabrication and assembly drawings, together with detailed specifications and data covering materials, parts, devices, and accessories forming a part of the equipment furnished, shall be submitted in accordance with the submittals section. The data and specifications for the Control Panel and Components shall include, but not be limited to, the following:
- Name of manufacturer
- Type and model
- Enclosure rating
- Dimensions of complete panel
- Electrical schematics and wiring diagram
- Liquid level sensors with mounting details and cable lengths, and pump controls
- Published descriptive data on each item of equipment and all accessories, indicating all specific characteristics and options.
3. NEMA 3R Enclosure: The Control Equipment Enclosure shall be a NEMA type 3R and be of suitable size to house all components. A locking hasp shall be provided in addition to screw clamp type latches. Enclosure shall be fabricated from 14 gauge steel. The top of the enclosure shall serve as a drip shield and the seam free sides shall prevent rain and sleet from entering. Inner panel shall be made of 12 gauge steel and shall be painted white. The enclosure and interior panel shall be painted with heat fused modified polyester powder, electrostatically applied over a phosphatized base. Enclosure shall be ANSI/ASA 61 grey.
4. Hinged Inner Door: An inner door shall be furnished. Overload reset push buttons, circuit breakers, switches and pilot lights shall be the only components accessible with door closed. Door shall be hinged and may be opened when service is required.
5. Line Terminal Block: A terminal block shall be furnished with properly sized line lugs to accept the main power source entering the control panel. Load lugs shall be adequate to accept all required load side wiring requirements. All live parts shall be fully shielded.
6. Motor Circuit Breaker (440-480 VAC): A properly sized, molded case, hydraulic-magnetic circuit breaker shall be provided for each pump motor. Line and load sides shall be equipped with lugs properly sized for the horsepower and current rating of the motor(s). The interrupting rating shall be 5,000 RMS symmetrical amps.
7. Transformer Primary Circuit Breaker: A properly sized, two pole, molded case circuit breaker shall be furnished ahead of the control power 120-VAC power transformer for short circuit protection and disconnecting power to the transformer. The circuit breaker shall conform to the specifications for the motor circuit breaker(s).
8. Control Power Transformer: An industrial quality control transformer shall be furnished to provide control voltage. The transformer shall be furnished to provide adequate KVA rating to provide 120-VAC power for all items required in the control and alarm circuits. Transformer shall be protected in its secondary by properly sized fuse and/or circuit breaker(s).
9. Magnetic Contactors and Overload Relays: A magnetic contactor shall be furnished for each motor. A separate, panel mounted, 3 leg (three phase) overload relay shall be supplied for each motor. Each leg of the overload relay shall be equipped with a properly sized overload heater. Contactor and overload relay shall be properly sized for the required horsepower, voltage and phase.
10. Elapsed Time Meters: Six digit, non-resetable elapsed time meters shall be mounted in the control panel enclosure to record the running time of each pump.
11. Condensation Strip Heater With Thermostat: A strip heater shall be furnished to prevent condensation within the control panel enclosure. The heater shall be controlled by a panel mounted, adjustable thermostat.
12. Phase & Voltage Monitor: A phase failure, reversal and under voltage monitor shall be supplied to prevent the motors from running under low voltage, phase loss, or phase reversal conditions. The monitor shall lock out the control circuit until the problem is corrected and automatically reset.
13. Lightning Arrestor: Suitable lightning arrestors shall be provided to protect motors and control equipment from lightning induced line surges.
14. Thru - Door Overload Reset Push Buttons: Overload reset push buttons shall be provided for each overload relay. Push buttons shall be mounted so that with inner door closed, overload relays may be reset without entering high voltage compartment.
15. Switches: Heavy-duty industrial grade oil-tight switches shall be provided for each pump for "Hand/Off/Automatic" operation selection. All switch components shall be made of corrosion resistant metals and polyesters. Contact blocks shall be made of see-through polycarbonate for simplified inspection of contacts. Cams and strokers shall be Teflon impregnated for abrasion free service without lubrication. The switches required shall be as follows:
|
Switch Function |
Voltage |
|
(Name Plate) |
|
|
HOA |
120 VAC |
16. Pilot Lights: Full voltage heavy-duty industrial grade oil-tight pilot lights shall be provided. All pilot light components shall be made of corrosion resistant metals and polyesters. An insulated socket shall be furnished to eliminate the possibility of shock during bulb change. Lens shall be made of lexan. The pilot lights required shall be as follows:
|
Pilot Light Function |
Voltage |
Lens Color |
|
(Name Plate) |
|
|
|
PUMP 1 |
120 VAC |
GREEN |
|
PUMP 2 |
120 VAC |
GREEN |
17. Seal Fail Alarm Circuit With Test Push Button (Required For Submersible Pumps and Motors): The control panel shall be equipped with a conductance actuated control relay that shall respond to current from a moisture sensor in the pump seal chamber. Relay contacts shall be rated at 16 amps minimum. All molded structural parts shall be of high mechanical and dielectric strength, structural dimensionally stable, arc resistant, thermosetting plastic. Base plate shall be high strength, diecast aluminum alloy. Solid state type relays shall not be considered acceptable for seal fail monitoring applications. An amber alarm pilot light shall illuminate upon alarm condition. Each pilot light shall include contacts that shall allow testing of the seal failure circuit and pilot light bulb by pushing.
18. Seal Failure Circuit Test Push Button (Illuminated): Heavy-duty industrial grade oil-tight push buttons shall be provided for each submersible pump motor. All push button components shall be made of corrosion resistant metals and polyesters. Contact blocks shall be made of see-through polycarbonate for simplified inspection of contacts. An insulated socket shall be furnished to eliminate the possibility of shock during bulb change. Lens shall be made of lexan. The push buttons required shall be as follows:
|
Push Button Function |
Voltage |