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EVAPCO AT INDUCED DRAFT COUNTERFLOW COOLING TOWER WITH STAINLESS STEEL BASIN Part 1 General 1.01 Cooling Tower Furnish and install as indicated on drawings and schedules, and by requirements of this section, (1) packaged induced draft counterflow cooling tower. Crossflow type towers shall not be acceptable. 1.02 Codes and Standards A. CTI Compliance: Provide capacity ratings for cooling tower in accordance with CTI Certification Standard CTI-201. B. UL and NEMA Compliance: Provide electrical motors and electrical components required as part of the cooling tower, which have been listed and labeled by UL, and comply with NEMA standards. C. NEC Compliance: Install cooling towers in accordance with NFPA 70. 1.03 Warranty The entire structure shall be covered by a five year manufacturer's warranty including belt(s), bearing(s), fan(s), fan shaft(s), drive sheave(s), gear box, flexible coupling(s), driveshaft(s), and fan motor(s). Part 2 Product 2.01 Acceptable Manufacturers Evapco AT or approved equal. 2.02 Manufactured Units Provide units for outdoor use, factory assembled, sectional, counterflow industrial duty cooling tower, with sump, fan, surface sections, drift eliminators, and motor situated as shown in plans. Each cell shall be CTI certified to cool ____ GPM of water from 95ºF to 85ºF at 80ºF EWB. Overall tower dimensions shall not exceed: ___ L x ___ W x ___ H. Operating weight shall not exceed _____ lbs. 2.03 Mechanical Equipment A. Fan Motor Totally enclosed air over (TEAO) or totally enclosed fan cooled (TEFC), 460 volt, 3 phase, 60 cycle ball bearing fan motor(s) with 1.15 service factor shall be furnished suitable for cooling tower service. Motor(s) shall be accessible from the outside of the unit for service. Horsepower shall not exceed ___ HP per cell. B. Axial Propeller Fans Fans shall be heavy duty axial propeller type statically balanced. The fans shall be fabricated by the cooling tower manufacturer for single source responsibility and reliability. The fans shall be constructed of extruded aluminum alloy blades, installed in a closely fitted cowl with venturi air inlet for maximum fan efficiency. Each fan blade shall be individually adjustable. Fan cowl shall be covered with a heavy gauge hot dip galvanized wire fan guard. Optional Low Sound Fan Units shall be provided with Low Sound Fan in order to assure a maximum sound pressure level of 79 dB measured at 5ft above the fan discharge cylinder during full speed operation. Fans shall be high efficiency axial propeller type with aluminum wide chord blade construction. Each fan shall be statically balanced and installed in a closely fitted cowl with venture air inlet for maximum fan efficiency. The fan cowl shall be covered with a heavy gauge hot dipped galvanized steel fan guard. There shall be no performance derate when utilizing the Low Sound Fan. C. Fan Shaft Bearings Fan shaft bearings shall be heavy duty self-aligning ball type with grease fittings extended to the outside of the unit. Bearings shall be designed for a minimum L- 10 life of 75,000 hours. D. Drive The fan drive shall either be belt or gear driven. Belt driven units shall be a multigroove, solid back V-belt type with taper lock sheaves designed for 150% of the motor nameplate horsepower. The belt material shall be neoprene reinforced with polyester cord and specifically designed for cooling tower service. Fan sheave(s) shall be aluminum alloy construction. The fans and fan sheaves shall be mounted on the shaft with a specially plated bushing to provide maximum corrosion protection. Belt adjustment shall be accomplished from the exterior of the unit. Bearing lube lines shall be extended to the exterior of the unit for easy maintenance. All sheaves located in the airstream shall be constructed of aluminum alloy, vented guards shall be not acceptable. If internal belt adjustment is necessary, an internal working platform and ladder is required to access the drive system. Gear reducers shall be an industrial grade, single-reduction right-angle gear reducer with a minimum 2.0 service factor. The gear housing shall be a single piece design to eliminate split line seals and assure permanent alignment of bearings and gears. All gears shall be precision machined from nickel alloy steel, case hardened, and finish ground to class 10 tolerances. Continuous oil circulation is assured in either directions of operation or at half speed through the location of channels and baffles within the gear casing and the use of an oversized slinger on the input shaft. Gear design shall meet or exceed minimum applicable AGMA and CTI standards. A gear breather vent is piped to external ambient air. The oil fill and drain connections will be extended from the side of the gear to the outside of the unit. 2.04 Fill, Louvers and Drift Eliminators A. Fill The cooling tower fill shall be PVC (Polyvinyl Chloride) of crossfluted design for optimum heat transfer and efficiency. The crossfluted sheets shall be bonded together for strength and durability. The fill shall be fabricated, formed, and installed by the cooling tower manufacturer and shall be elevated a minimum of 6" above the floor of the cold water basin to facilitate cleaning. The fill shall be suitable for use as a working platform. The PVC fill shall be self-extinguishing for fire resistance with a flame spread rating of 5 per ASTM E84-81a. It shall also be resistant to rot, decay, or biological attack. The fill shall be able to withstand a water temperature of 130ºF. B. Air Inlet Louver Screens The air inlet louver screens shall be constructed from polyvinyl chloride (PVC) and mounted in easily removable Stainless Steel frames on all four sides of the cooling tower for access to the entire basin area for maintenance. The removable louvers shall have a minimum of two changes in air direction to prevent splashout, block direct sunlight from entering the basin, and shall have either a maximum 3/4" opening or stainless steel inlet screens to prevent debris from entering the basin. C. Drift Eliminators The eliminators shall be constructed entirely of inert polyvinyl chloride (PVC) in easily handled sections and be completely separate from the fill section for maximum efficiency. The eliminator design shall incorporate three changes in air direction to assure complete removal of all entrained moisture from the discharge air stream. Maximum drift rate shall be less than 0.001% of the circulating water rate. 2.05 Cold Water Basin The basin shall be constructed of Type 304 Stainless Steel for long life and durability. The basin area shall include all steel components from the base of the unit to the top of the air inlet louver screens. Standard basin accessories shall include overflow, drain, anti-vortexing hood, Type 304 Stainless Steel strainers, and brass make-up valve with plastic float. The entire basin area shall incorporate a stepped configuration for reduced water volume, lower operating weight and easier basin maintenance. Depressed side outlet sumps which are not an integral part of the basin shall not be acceptable. Fiberglass basin liners and epoxy coated galvanized support structures will not be acceptable. 2.06 Casing The casing shall be constructed of G-235 hot-dip galvanized steel as standard for long life and durability. The casing panels shall totally encase the sides of the fill section to protect the surface from direct atmospheric contact. 2.07 Water Distribution System The spray header and branches shall be constructed of Schedule 40 polyvinyl chloride (PVC) pipe for corrosion resistance. The connection to attach the external piping shall be galvanized steel. The spray header and branches shall be removable for cleaning purposes. The water shall be distributed over the fill by precision molded ABS spray nozzles with large 3/8 by 1 inch orifice openings and integral sludge ring to eliminate clogging. The nozzles shall be threaded into the water distribution piping to assure positive positioning. If open type gravity distribution pans are used, they shall include basin covers and both shall be constructed of galvanized steel. 2.08 Accessories A. Electric Pan Heaters Electric pan heater package consists of electric immersion heaters, heater thermostat and low water cutout, all installed in pan. The heaters are sized to maintain +40°F pan water temperature with the fans off. Heaters are controlled by the thermostat, and the low water cutout prevents the heaters from cycling on unless they are completely submerged. Contractor shall provide and field install heater contactor, transformer, circuit breaker, disconnect and wiring in conduit for complete installation as per manufacturer’s recommendations. B. External Service Platform with Access Ladder Cooling towers will be provided with an external service platform with sloped aluminum vertical ladder extending to the base of the tower. The platform and ladder will allow servicing of the electric motor, fan drive, mechanical equipment and water distribution systems. On units with gravity type hot water basins, the top of the tower shall also be equipped with a sturdy handrail, complete with kneerail and toeboard, designed according to OSHA guidelines. An aluminum ladder shall extend from the mechanical platform to the top of the perimeter handrail. C. Control Panel Each cell shall include a UL listed control panel complete with NEMA 4X fiberglass enclosure, single speed fan motor starters, temperature control, control voltage transformer, H-O-A switches, and door mounted disconnect switch. Panel is to ship loose for field installation by installing contractor. D. Non-Chemical Water Treatment System Each cooling tower shall include a non-chemical water treatment system as manufactured by Clearwater Systems, Dolphin Series. The Clearwater System is to include a coil pipe assembly and transformer panel mounted in NEMA 3R panel. The panel shall include a Form C dry contact for remote monitoring. System to ship loose for field installation by others. E. Cold Water Basin Sand Filter System Each cell shall include sump sweeper piping factory mounted by cooling tower manufacturer. Skid mounted filter system to ship loose for field installation and connection to factory sump sweeper piping. Skid mounted system shall include the following: epoxy coated/lined vessel rated for 100 PSI, automatic air relief valve, (2) bronze 3-way control valves, close coupled pump with integral pre- strainer, automatic controls with NEMA 3R panel with door disconnect, backwash timer, 24 hour backwash clock, differential pressure switch, and electric valve actuator. Filter shall have single electrical hook-up point. F. Sentinal Monitoring System Cooling tower shall be supplied with Sentinal Monitoring System capable of monitoring the following: pan water temperature, water pressure across the spray header, pan water conductivity, pan water PH, pan water level, vibration of the drive system, fan motor current, and fan motor run time. The monitor and alarm panel shall have the following features and capabilities: integrated LCD for display of the current status and alarms, front panel LED alarm indicators, programmable alarm limits for each measured value, logging of all measured values, logging of all alarms, interface to BMS via BACnet MSTP or Modbus RTU. Part 3 Execution 3.01 Installation A. General Install cooling tower(s) where indicated in the plans, in accordance with equipment manufacturer’s written instructions.
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