EVAPCO LRT FORCED DRAFT COUNTERFLOW COOLING TOWER
Part 1 General
1.01Cooling Tower
Furnish and install as indicated on drawings and schedules, and by requirements of this section, (1) packaged forced draft counterflow cooling tower(s).
1.02Codes 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.
1.03Warranty
The entire motor and drive system shall be covered by a five year manufacturer's warranty including the fan(s), bearings, sheaves, shafts, mechanical equipment supports, and fan motor(s).
Part 2 Product
2.01Acceptable Manufacturers
Evapco LRT or approved equal.
2.02Manufactured 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.
2.03Mechanical Equipment
A.Fan Motor
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 mounted on adjustable base.
B.Centrifugal Fans and Drives
The complete drive system, including the fan housing, electric motor, belts, bearings, and drives shall be completely enclosed by a protective housing which cover the drive system and provides sound reduction.
Fans shall be forwardly curved centrifugal type of hot-dipped galvanized construction. The fans shall be factory installed, statically balanced for vibration free operation. The fans shall be mounted on either a solid steel shaft or a hollow steel foamed filled shaft with forged bearing journals. The fan shaft shall be supported by heavy-duty, self-aligning ball bearings with cast iron housings and lubrication fittings for maintenance. The fan drive shall be V-Belt type adjustable from outside the unit, with taper lock sheaves designed for 150% of the motor nameplate horsepower. Drives are to be mounted and aligned at the factory. A belt adjustment device shall be provided as standard.
2.04Fill, 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 have special drainage tips to allow high water loading and low pressure drop. The fill section shall be easily removed from the cooling tower casing section. 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.
B.Drift Eliminators
The eliminators shall be constructed entirely of inert polyvinyl chloride (PVC) that has been specially treated to resist UV degradation. Assembled in easily handled sections, the eliminators 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.
2.05ColdWaterBasin
The complete cold water basin shall be constructed of 304 stainless steel for long life and durability. Standard cold water basin accessories shall included 304 stainless steel overflow, drain, anti-vortexing hood, strainers, and brass make-up valve with unsinkable, foam filled plastic float. A circular access door shall be located above the basin to allow easy access to the pan interior. Fiberglass basin liners and epoxy coated galvanized support structures will not be acceptable.
The outlet shall be 304 stainless steel grooved for a mechanical coupling and beveled for welding or a threaded connection.
2.06Casing and Fan Section
The casing and fan section shall be constructed of G-235 hot-dip galvanized steel as standard for long life and durability. Fan section shall include fans, motors and drives. The entire drive system (including fans, motors, sheaves and belts) shall be located in the dry entering air stream.
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2.07Water 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.
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.ColdWaterBasin 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
3.01Installation
A.General
Install cooling tower(s) where indicated in the plans, in accordance with equipment manufacturer’s written instructions.