Section 236500
Cooling Towers
	PART 1 GENERAL
1.01	SECTION INCLUDES
A.	Closed circuit, induced draft, crossflow cooling towers with hybrid operation. 
1.02	REFERENCE STANDARDS
A.	ASHRAE 90.1-2019 – Energy Standard for Buildings Except Low-Rise Residential Buildings.
B.	ASME B31.5 - Refrigeration Piping and Heat Transfer Components 2016.
C.	ASME Section VIII Boiler and Pressure Vessel Code.
D.	ASTM A123/A123M - Standard Specification for Zinc (Hot-Dip Galvanized) Coatings on Iron and Steel Products 2017.
E.	ASTM A653/A653M - Standard Specification for Steel Sheet, Zinc-Coated (Galvanized) or Zinc-Iron Alloy-Coated (Galvannealed) by the Hot-Dip Process 2018.
F.	ASTM B117 - Standard Practice for Operating Salt Spray (Fog) Apparatus 2018.
G.	ASTM E84 - Standard Test Method for Surface Burning Characteristics of Building Materials 2018b.
H.	ASTM D2794 - Standard Test Method for Resistance of Organic Coatings to the Effects of Rapid Deformation (Impact).
I.	ABMA STD 9 - Load Ratings and Fatigue Life for Ball Bearings 2015.
J.	ABMA STD 11 - Load Ratings and Fatigue Life for Roller Bearings 2014.
K.	CTI STD-201 OM - Operations Manual for Thermal Performance Certification of Evaporative Heat Rejection Equipment 2017.
L.	CTI STD-201 RS - Performance Rating of Evaporative Heat Rejection Equipment 2017.
M.	ISO 9001 - Quality management systems -- Requirements 2015.
N.	NEMA MG 1 - Motors and Generators 2017.
O.	ASCE/SEI 7 - Minimum Design Loads and Associated Criteria for Buildings and Other Structures.
1.03	SUBMITTALS
A.	Product Data: Provide rated capacities, dimensions, weights and point loadings, accessories, electrical requirements and wiring diagrams, and location and size of field connections. 
B.	Shop Drawings: Indicate suggested structural steel supports including dimensions, sizes, and locations for mounting bolt holes.
C.	Manufacturer's Certificate: Certify that cooling tower performance, based on CTI STD-201 meets or exceeds specified requirements and submit performance curve plotting leaving water temperature against wet bulb temperature.
D.	Manufacturer's Instructions: Submit manufacturer's complete installation instructions.
E.	Operation and Maintenance Data: Include start-up instructions, maintenance data, parts lists, controls, and accessories.
F.	Warranty: Submit manufacturer's warranty and ensure forms have been filled out in Owner's name and registered with manufacturer.
1.04	QUALITY ASSURANCE
A.	Manufacturer Qualifications:  Company specializing in manufacturing the type of products specified in this section, with minimum 20 years of documented experience and ISO 9001 certification.  
B.	Installer Qualifications: Company specializing in performing the type of work specified in this section with minimum 20 years of experience and approved by manufacturer.
C.	Product Performance: 
1.	Cooling tower must have a minimum energy rating of [_____] per ASHRAE 90.1, 189 and CA Title 24.
2.	Structural and Seismic Performance: The structure will be designed, tested and certified in accordance with IBC regulations to meet a minimum unrestricted seismic design SDS = ___ g with an Importance Factor of ___ and wind load of __ psf.  Units not provided with a certificate of IBC compliance will not be an acceptable alternative.
1.05	DELIVERY, STORAGE, AND HANDLING
A.	Equipment will be factory-assembled, including cold water basin, heat transfer section, water distribution, fan drive system, and casing panels. For shipping, disassemble into as large as practical sub-assemblies so that minimum amount of field work is required for re-assembly. 
B.	Comply with manufacturer's installation instructions for rigging, unloading, and transporting units.
1.06	WARRANTY
A.	One-year warranty after start-up, or eighteen months from date of shipment, whichever occurs first. Warranty to include coverage for defects in material and workmanship.
B.	Fans, fan shafts, bearings, sheaves, gearboxes, drive shafts, couplings, and mechanical equipment support must be warranted against defects in materials and workmanship for a period of five (5) years or seven (7), if motor space heater is properly wired.
	PART 2 PRODUCTS
2.01	MANUFACTURERS
A.	Closed Circuit, Induced Draft, Crossflow Cooling Towers with Hybrid Operation:
1.	Basis of Design: Baltimore Aircoil Company; HXV: www.baltimoreaircoil.com #BAC
2.02	MANUFACTURED UNITS
A.	Provide units suited for outdoor use, factory-assembled, induced draft with vertical air discharge, dry and wet coils for hybrid operation, and fan assemblies built into casing.
2.03	COMPONENTS
A.	Cold Water Basin:
1.	 Constructed with a minimum of 14-gauge galvanized steel with access doors at both ends of tower to air plenum. A removable anti-vortexing hood will be provided to prevent air entrainment. Large area lift out strainers will be provided with perforated openings sized smaller than the water distribution system nozzles. Provide sloped basin with drain/clean-out connection
----- ALTERNATE for TriArmor -----
1.	Tri-layer protection system consisting of G-235 galvanized steel, a thermosetting hybrid polymer, and a polyurethane liner factory applied to all submerged surfaces. A Removable anti-vortexing hood will be provided to prevent air entrainment. Large area lift out strainers will be provided with perforated openings sized smaller than the water distribution system nozzles. Sloped with depressed section with drain/clean-out connection. A welded Type 316 stainless steel basin is an acceptable alternative.
----- ALTERNATE for 304 Stainless Steel -----
2.	Type 304 welded stainless steel panels and structural members. A Removable anti-vortexing hood will be provided to prevent air entrainment. Large area lift out strainers will be provided with perforated openings sized smaller than the water distribution system nozzles. Sloped with depressed section with drain/clean-out connection. Basins with bolted seams or constructed of 301 stainless steel are not acceptable.
----- ALTERNATE for 316 Stainless Steel -----
3.	Type 316 welded stainless steel panels and structural members. A Removable anti-vortexing hood will be provided to prevent air entrainment. Large area lift out strainers will be provided with perforated openings sized smaller than the water distribution system nozzles.  Sloped with depressed section with drain/clean-out connection. Basins with bolted seams or constructed of 301 stainless steel are not acceptable.
B.	Casing Panels and Framework:
-----Thermosetting Hybrid Polymer Panels-----
1.	Casing panels: Galvanized steel protected by a thermosetting hybrid polymer. The polymer to consist of G-235 (Z700 metric) hot-dip galvanized steel prepared in a four-step (clean, pre-treat, rinse, and dry) process with an electrostatically applied, thermosetting, hybrid polymer fuse-bonded to the substrate during a thermally activated curing stage and monitored by a 23-step quality assurance program. Other coatings must be submitted to the engineer for pre-approval. Approved equals must have undergone testing, resulting in the following results as a minimum:
a.	When X-scribed to the steel substrate, unit to withstand 6000 hours of 5 percent salt spray per ASTM B117 without blistering, chipping, or loss of adhesion.
b.	When X-scribed to the steel substrate, unit to withstand 6000 hours of exposure to acidic (pH=4.0) and alkaline (pH=11.0) water solutions at 95 degrees F (35 degrees C) without signs of chemical attack.
c.	Unit to withstand impact of 160 in-lbs per ASTM D2794 without fracture or delamination of the polymer layer.
d.	Unit to withstand 6000 hours of ultraviolet radiation equivalent to 120,000 hours of noontime sun exposure without loss of functional properties.
e.	Unit to withstand 200 thermal shock cycles between minus 25 degrees F and 180 degrees F (minus 32 degrees C and 82 degrees C) without loss of adhesion or other deterioration.
f.	Unit to withstand 6000 hours of exposure to 60 psi (42,184 kg/m^2) water jet without signs of wear or erosion.
g.	Type 304 stainless steel may be supplied as an equal to eliminate the need for passivation, minimize maintenance requirements, and prolong equipment life.
----- ALTERNATE for Galvanized Steel Panels-----
2.	Casing panels and framework will be constructed of G235 galvanized steel.
----- ALTERNATE for 304 Stainless Steel Panels-----
3.	Casing panels, framework, and fasteners will be constructed of Type 304 stainless steel. Type 301 stainless steel is not an acceptable alternative.
----- ALTERNATE for 316 Stainless Steel Panels-----
4.	Casing panels, framework, and fasteners will be constructed of Type 316 stainless steel. Type 301 or 304 stainless steel is not an acceptable alternative.
C.	Fans:  Multi blade, axial type. Fans must factory test-mounted, balanced, and aligned to ensure reliable operation and ease of maintenance. Fan type will be selected to meet sound ratings published on equipment schedule. 
D.	Motors and Drives:
1.	Single speed (1800 rpm) premium efficiency, cooling tower duty motor mounted on adjustable steel base. Fan motors will be inverter duty type designed per NEMA Standard MG1, Section IV Part 31. Motors will include an internal space heater that can be wired to remove condensation when motor is not in use. 
2.	Fan Drive System: Belt drive designed for minimum 150 percent motor nameplate power. Fan and motor sheave(s) will be fabricated from corrosion-resistant materials to minimize maintenance and ensure maximum drive and powerband operating life. Bearings must have a minimum L-10 life of 80,000 hours per ABMA STD 11. Belt tension must be easily adjusted in the field. 
(Optional) Extended Grease Fittings: Extended grease lines are supplied that reach from the bearing to fittings on the exterior casing near the access doors. This facilitates easy periodic bearing maintenance without entering the tower. 

E.	Fan Guard: 
1.	Welded steel rod and wire guard, hot dipped galvanized after fabrication. Installed over fan discharge. 
-----ALTERNATE for Stainless Steel Fan Guard-----
2.	Welded stainless steel rod and wire guard, placed over fan discharge. 
F.	Motor Removal Davit (Optional): The unit will be equipped with a mechanical equipment removal davit. The motor will lower from the mechanical equipment supports down to grade. Davit will attach to the unit without the need for tools. If tools are required for davit installation or removal, provide (1) davit for each motor provided.
G.	Heat Transfer Coils:
1.	Wet Coils:
a.	Galvanized Steel: The coil will be constructed of continuous serpentine all prime surface steel, be pneumatically tested at 375 psig (2,685 kPa), and be hot-dip galvanized after fabrication. The coil will be designed for free drainage of fluid and will be ASME B31.5 compliant. Maximum allowable working pressure will be 300 psig (280 psig for coils supplied with a CRN).
----- Alternate for 304 Stainless Steel Coil -----
b.	304 Stainless Steel: Coil(s) will be constructed of type 304 stainless steel serpentine tube. Tubes will be sloped for free drainage and coil assembly will be pneumatically tested at 375 psig (2,685 kPa). Coil(s) will be ASME B31.5 compliant.
2.	Dry Coils:
a.	Copper coil material with aluminum fins. Coated to resist corrosion. Tubes will be sloped for complete drainage of coil and pneumatically tested at 320 psig.
H.	Water Distribution System: 
1.	Water will be distributed evenly over the coil at a flow rate sufficient to ensure complete wetting of the coil at all times. Large diameter, non-clog, 360° plastic distribution nozzles will utilize a two-stage diffusion pattern to provide overlapping, umbrella spray patterns that create multiple intersection points with adjacent nozzles. The branches and spray nozzles will be held in place by snap-in rubber grommets, allowing quick removal of individual nozzles or complete branches for cleaning or flushing. Distribution system must be able to be inspected while the unit is in operation. 
2.	Spray Water Pump: The closed circuit cooling tower will include an appropriate number of close coupled, bronze-fitted centrifugal pump and motor assemblies equipped with mechanical seal, and piped from the suction connection to the water distribution system. The pump motor(s) will be the totally enclosed fan cooled (TEFC) type, premium efficiency suitable for _____ volts, ___ phase, and ____ hertz electrical service. The system will include a metering valve and bleed line to control the bleed rate from the pump discharge to the overflow connection.
3.	(Optional) Redundant Spray Water System: The closed circuit cooling tower will include (2) two close coupled, bronze-fitted centrifugal pump and motor assemblies piped from the suction connection to the water distribution system, with each pump sized for 100% redundant spray water flow. This system includes all piping and isolation valves that allow for pump service while the equipment remains in operation. Bypass valves with tubing are factory-installed to avoid stagnant water in the piping system.  Each isolation valve handle can be removed in the future and replaced with actuators and controls for automatic lead /lag operation and pump exercising in the field via BAS.  The system will also include a metering valve and bleed line to control the bleed rate from the pump discharge to the overflow connection.
I.	Fill:
1.	The fill and integral drift eliminators will be formed from self-extinguishing (per ASTM-568) polyvinyl chloride (PVC) having a flame spread rating of 5 per ASTM E84 and will be impervious to rot, decay, fungus and biological attack. The fill is suitable for entering water temperatures up to and including 130°F (54.4°C). The fill must be manufactured, tested and rated by the cooling tower manufacturer and are elevated above the cold water basin floor to facilitate cleaning.  If louvers are attached to fill, a spare set of fill sheets are required in case of icing and scaling damage. 
----ALTERNATE for High-Temp Fill----
2.	The fill and integral drift eliminators will be formed from self-extinguishing (per ASTM-568) chlorinated polyvinyl chloride (CPVC) having a flame spread rating of 5 per ASTM E84 and will be impervious to rot, decay, fungus and biological attack. The fill is suitable for entering water temperatures up to and including 140°F (60.0°C). The fill must be manufactured, tested and rated by the cooling tower manufacturer and are elevated above the cold water basin floor to facilitate cleaning.  If louvers are attached to fill, a spare set of fill sheets are required in case of premature icing and scaling. 
J.	Drift Eliminators: Three-pass design made of PVC material. Primary eliminators will be integrated into the fill media.
K.	Basin Water Level Control: 
1.	Corrosion resistant PVC make-up valve with plastic float for easy adjustment of operating water level.
----- ALTERNATE for Electric Water Level Controller-----
2.	Electric water level control with NEMA 4 enclosure, solid state controls, LED status light, and stainless steel water level sensing electrodes. Number and position of probes provided to sense the following: high water level, low water level, high water alarm level, low water alarm level, heater safety cutout, and automatic solenoid valve. Include all necessary mounting hardware. 
	2.04	ACCESSORIES
A.	(Optional) Electric Immersion Heaters: In pan suitable to maintain temperature of water in pan at 40 degrees F (4.4 degrees C) when outside temperature is 0 degrees F (-17.7 degrees C) [OR -20 degrees F (-28.9 degress C)] and wind velocity is 15 mph (25 kph); immersion thermostat and float control operate heaters on low temperature when the pan is filled. Heaters will be constructed of copper.
B.	(Optional) Basin Sweeper Piping: The cold water basin of the cooling tower will be equipped with PVC sump sweeper piping with plastic eductor nozzles. The piping must be designed specifically for the size and shape of the basin to ensure full agitation.
C.	Vibration Switch:
1.	Provide a mechanical local reset vibration switch. The mechanical vibration cutout switch will be guaranteed to trip at a point so as not to cause damage to the cooling tower. To ensure this, the trip point will be set in a frequency range of 0 to 3,600 RPM and a trip point of 0.2 to 2.0 g’s.
----- ALTERNATE for Electronic Vibration Switch----- 
2.	Provide an electronic remote reset vibration switch with contact for BAS monitoring. Wiring will be by the installing contractor. The electronic vibration cutout switch will be set to trip at a point so as not to cause damage to the cooling tower. To ensure this, the trip point will be set in a frequency range of 2 to 1000 Hertz and a trip point of 0.45 in/sec (0.0114 m/sec).
D.	Access Packages: See submittal documents for access package requirements. Platforms and ladders must ship assembled from cooling tower manufacturer.
1.	Plenum Access: Two hinged access doors must be provided for access into the plenum section. Include an internal walkway for inspection and maintenance. All working surfaces will be able to withstand 50 psf (244 kg/m^2) live load or 200 pound (90.7 kg) concentrated load. Other components of the cooling tower, i.e. basin and fill/drift eliminators, will not be considered an internal working surface. Cooling tower manufacturers that promote these surfaces to be used as a working platform will provide a two-year extended warranty to the Owner to repair any damage to these surfaces caused during routine maintenance.
2.	(Optional) Louver Face External Platforms: Easy access to the hot water basins for inspection of spray water distribution, even during tower operation, will be provided by external platforms at the louver face. Fan deck ladders and handrails, which add to the overall height of the tower, are not acceptable. Platforms and ladders must ship assembled from cooling tower manufacturer.0 degrees F (-17.7 degrees C)
3.	(Optional) Internal Platform: An internal platform will be provided in the plenum section to provide for inspection and maintenance. All working surfaces will be able to withstand 50 psf (244 kg/m^2) live load or 200 pound (90.7 kg) concentrated load. Platforms and ladders must ship assembled from cooling tower manufacturer.
4.	(Optional) Access Door Platform: An external galvanized steel access platform at the access door of the unit(s) provides access to the spray distribution system or internal plenum. An aluminum ladder and 1-1/4 inch (32 mm) galvanized steel pipe safety railing is included with the platform. This option meets pertinent OSHA standards. Platforms and ladders must ship assembled from cooling tower manufacturer.
5.	(Optional) Safety Gates: All handrail access openings will be provided with a self-closing safety gate for increased safety. 
E.	(Optional) Sound Attenuation: 
1.	Intake Sound Attenuation: The unit will be equipped with attenuation at the unit’s air intake. Sound absorbing fiberglass acoustical baffles will reduce sound levels from the air intake side of the unit.
	PART 3 EXECUTION
3.01	INSTALLATION
A.	Install in accordance with manufacturer's instructions.
B.	Provide the services of the manufacturer's field representative to supervise rigging, hoisting, and installation, allowing for minimum of one eight-hour day per tower.
C.	Install tower on structural steel beams as instructed by manufacturer.
D.	Connect condenser water piping to tower. Pitch condenser water supply to tower and condenser water suction away from tower. 
E.	Connect make-up water piping to tower. Pitch to tower. 
F.	Connect overflow and drain to acceptable discharge point as required by jurisdiction.
3.02	FIELD QUALITY CONTROL
A.	See Quality Requirements, for additional requirements.
B.	Provide the services of the manufacturer's field representative to inspect tower after installation and submit report prior to start-up, verifying installation is in accordance with specifications and manufacturer's recommendations.
3.03	SYSTEM STARTUP
A.	Start-up tower in presence of and instruct Owner 's operating personnel.
3.04	SCHEDULES
A.	Closed Circuit Cooling Towers with Hybrid Operation
1.	Unit must have the capability to pre-cool incoming air to enhance dry coil heat transfer.
2.	When equipped with a 3-way valve (coordinated with other disciplines), the unit will have three modes of operation:
a.	Wet operation: Utilizes dry coil, primary coil, and fill media for maximum energy savings.
b.	Adiabatic Mode: Utilizes dry coil and fill media to precool incoming air for increased capacity over dry operation.
c.	Dry operation: Utilizes primary coil and dry coil to maximize water savings when ambient or load conditions allow.
3.	Drawing Code:
4.	Location:
5.	Manufacturer:
6.	Model Number:
7.	Cooling Capacity
a.	Water Flow Rate:
b.	Entering Water Temperature:
c.	Leaving Water Temperature:
8.	Entering Air WB Temperature:
9.	Entering Air DB Temperature Switch point: 
10.	Number of Fan Motors:
11.	Motor Size:
12.	Heaters No. and Type:
a.	END OF SECTION