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Section 23 65 00 Cooling Tower

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Section 23 65 00 Cooling Tower

    02-10

    SECTION 23 65 00

    COOLING TOWERS

    SPEC WRITER NOTES:

    1. DELETE BETWEEN //---// if not

    applicable to project. Also delete any

    other item or paragraph not applicable

    in the section and renumber the

    paragraphs. Specify packaged cooling

    towers except in the rare cases where

    field assembled type has been selected.

    PART 1 - GENERAL

    1.1 DESCRIPTION

    A. Packaged, //induced draft //forced draft //open circuit cooling tower//

    closed circuit fluid cooler//complete with fill, fan, //inlet louvers

    //and associated accessories and equipment.

    1.2 RELATED WORK

    A. Section 03 30 00, CAST IN PLACE CONCRETE: Requirements for concrete

    inertia bases.

    //B. Seismic Restraint for Equipment: Section 13 05 41, SEISMIC RESTRAINT REQUIREMENTS FOR NON-STRUCTURAL COMPONENTS.//

    C. Section 23 05 11, COMMON WORK RESULTS FOR HVAC and STEAM GENERATION:

    General mechanical requirements and items, which are common to more than

    one item.

    D. Section 23 05 12, GENERAL MOTOR REQUIREMENTS FOR HVAC and STEAM

    GENERATION EQUIPMENT.

    E. Section 23 05 41, NOISE and VIBRATION CONTROL FOR HVAC PIPING and

    EQUIPMENT: Requirements for vibration isolation.

    F. Section 23 21 13, HYDRONIC PIPING: Requirements for water piping and

    fittings.

    G. Section 23 25 00, HVAC WATER TREATMENT: Requirements for condenser water

    treatment.

    H. Section 23 31 00, HVAC DUCTS and CASINGS: Requirements for sheet metal

    ductwork.

    I. Section 26 29 11, LOW-VOLTAGE MOTOR STARTERS.

    1.3 QUALITY ASSURANCE

    A. Refer to Article, QUALITY ASSURANCE, in specification Section 23 05 11,

    COMMON WORK RESULTS FOR HVAC and STEAM GENERATION.

    B. Design Criteria:

    1. Design to withstand ______Pa (___ psf) wind load.

    2. Free water drift loss shall not be greater than five hundredths of

    one percent (0.005) of the water circulated to tower.

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    SPEC WRITER NOTE: Specify dB(A) level

    based on the project specific acoustic

    analysis and local ordinance.

    3. Sound levels at 1.5 meters (5 feet) and 17 meters (55 feet) in any

    direction from the tower shall not exceed _____dB (A) and _____dB

    (A), respectively. Select “low Noise” model cooling towers, where

    available. Provide sound attenuators if necessary to meet the noise

    criteria.

    C. Performance Criteria:

    1. Manufacturer shall certify that performance of cooling towers will

    meet contract requirements, stating entering air wet bulb

    temperature, entering and leaving condenser water temperatures, water

    flow rates, fan kW (horsepower) //and pump head at base of tower//.

    Certification shall be made at the time of submittal.

    SPEC WRITER NOTE: CTI certification under

    Standard 201 applies only to selections

    with entering water temperature of 51.7

    degrees C (125 degrees F) or less,

    temperature ranges of 2.2 degrees C (4

    degrees F) or more, temperature approaches

    of 2.8 degrees C (5 degrees F) or more,

    and wet bulb between 15.5 degrees C to

    29.5 degrees C (60 degrees F to 85 degrees

    F).

    2. Cooling Technology Institute (CTI) Certified Towers: These towers

    shall have been tested, rated, and certified in accordance with

    Cooling Technology Institute (CTI) Standard 201, and shall bear the

    CTI certification label, and shall be listed in the CTI directory of

    certified cooling towers.

    3. The alignment and balancing of the fans, motors and drive shaft as

    installed shall operate within the vibration tolerance specified in

    specification Section 23 05 41, NOISE and VIBRATION CONTROL FOR HVAC

    PIPING and EQUIPMENT.

    1.4 SUBMITTALS

    A. Submit in accordance with specification Section 01 33 23, SHOP DRAWINGS, PRODUCT DATA, and SAMPLES.

    B. Shop Drawings

    1. Sufficient information, clearly presented, shall be included to

    determine compliance with drawings and specifications. 2. Include rated capacities, pressure drop, fan performance and rating

    curves, dimensions, weights, mounting details, front view, side view,

    equipment and device arrangement.

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    3. Include electrical rating, detail wiring for power, signals and

    controls.

    //4. Pump characteristic curve for the closed circuit fluid cooler. // 5. Sound curves and characteristics of sound attenuators if required to

    meet the noise criteria.

    SPEC WRITER NOTE: If the scope of work

    involves, total building commissioning,

    coordinate all documentation requirements

    with the commissioning efforts.

C. Certification:

    1. Submit four copies of performance curves, for CTI certified cooling

    towers, showing compliance with actual conditions specified, to the

    Resident Engineer two weeks prior to delivery of the equipment. 2. Two weeks prior to final inspection, submit four copies of the

    following to the Resident Engineer:

    SPEC WRITER NOTE: Specify the seismic

    design category for the project so the

    cooling tower manufacturers can

    check/design seismic strength of their

    equipment. Delete the following paragraph

    if the seismic design category is A or B.

    a. Certification from the manufacturer that the cooling tower(s),

    accessories, and components are suitable for seismic design

    category ___ installations and that the unit will be fully

    operational after the seismic event at the project site.

    b. Certification by the manufacturer that the cooling towers conform

    to the requirements of the drawings and specifications.

    c. Certification by the Contractor that the cooling towers have been

    installed, adjusted, and tested.

    1.5 APPLICABLE PUBLICATIONS

    A. The publications listed below form a part of this specification to the extent referenced. The publications are referenced in the text by the basic designation only.

    B. American National Standard Institute (ANSI/ASSE)

    A10.18-2007.............Safety Requirements for Temporary Floors, Holes,

    Wall Openings, Stairways and Other Unprotected

    Edges in Construction and Demolition Operations C. American Society of Mechanical Engineers (ASME):

    PTC 23-03...............Performance Test Codes on Atmospheric Water

    Cooling Equipment

    D. American Society for Testing Materials (ASTM):

    23 65 00-3

    02-10

    A385-08.................Standard Practice for Providing High-Quality

    Zinc Coatings (Hot-Dip)

    B117-07a................Standard Practice for Operating Salt Spray (Fog)

    Apparatus

    B209-07.................Standard Specification for Aluminum and

    Aluminum-Alloy Sheet and Plate

    E84-08a.................Standard Test Method for Surface Burning

    Characteristics of Building Materials

    E. Cooling Technology Institute (CTI):

    ATC-105-00..............Acceptance Test Code for Water-Cooling Towers

    (CTI Code Tower Standard Specifications)

    ATC-105S-Rev. July 2004.Acceptance Test Code for Closed Circuit Cooling

    Towers (CTI Code Tower Standard Specifications)

    201-02 (Rev. 04)........Standard for Certification of Water Cooling

    Tower Thermal Performance (CTI Code Tower

    Standard Specifications)

    F. National Electrical Manufacturers Association (NEMA):

    MG 1-2006 Includes......Motors and Generators (ANSI)

    250-03..................Enclosures for Electrical Equipment (1000 Volts

    Maximum)

    G. National Fire Protection Association (NFPA):

    70-08...................National Electrical Code

    PART 2 - PRODUCTS

    SPEC WRITER NOTE: Induced draft open

    circuit cooling towers should be used on a

    majority of projects. In general, cross-

    flow type shall be used, where winter

    operation is required, specify counter-

    flow type.

    2.1 INDUCED DRAFT OPEN CIRCUIT COOLING TOWER:

    A. Cooling tower shall be a factory assembled, induced draft, //cross-flow

    //counter-flow // type with a vertical discharge configuration.

    DESIGNER NOTE: Use stainless steel for all

    principal panels and structural elements,

    hot and cold water basins, fan deck, etc.

    for the High-Humidity locations listed in

    the VA HVAC Design Manual

    B. Casing: Heavy gage (minimum 16 gage)// Galvanized Steel// Stainless

    Steel // Fiberglass Reinforced Plastic (FRP) with UV inhibitors. // //1. Galvanized Steel: Hot-dip galvanized steel complying with ASTM

    A653/A653M, and having G235 (Z700) coating. //

    23 65 00-4

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    //2. Stainless Steel: ASTM A666, Type 304. //

    //3. Fiberglass Reinforced Plastic: FRP with maximum flame spread rating

    of five according to ASTM E84 and with UV inhibitors. // 4. Fasteners: Zinc or cadmium coated bolts or tapping screws for

    assembly. Use stainless steel washers with neoprene backing where

    required for preventing leaks.

    5. Joints and Seams: Sealed watertight.

    6. Welded connections: Continuous and watertight.

    C. Framing: //Rolled structural steel shapes, hot-dip galvanized after fabrication or structural shapes cold formed from galvanized steel sheets or plates, complying with ASTM A653/A653M, and having G235 (Z700) coating. //Rolled or formed structural stainless steel conforming to ASTM A666, Type 304. //

    D. Louvers:

    1. Spaced to minimize air resistance and prevent splash out. Louver

    materials shall be similar to the casings or may be polyvinyl

    chloride (PVC) if formed integral with the fill material. //2. 25 mm (1 inch) inlet screen, hot dipped // galvanized steel or copper

    // stainless steel. // Attach the screen securely to air intakes. E. Fill: // PVC // FRP // resistant to rot, decay and biological attack; with a maximum flame spread rating of five per ASTM E84 and fabricated, formed and installed by manufacturer to ensure that water breaks up into droplets.

    F. Drift Eliminators: Same as fill material. Effectively trap water droplets entrained in discharge air stream and limit drift loss to less than 0.005 percent of the total water circulated. Sections shall be assembled into easily removable racks of the same material as the casing. Eliminators can be PVC neoprene honeycomb type.

    SPEC WRITER NOTE: Eliminate the

    combustible materials when cooling tower

    is located 12 meters (40 feet) or closer

    to hazards such as chimneys, and

    incinerators, or when roof mounted.

    G. Hot Water Distribution System: Open basin, flume and troughs, or a pipe system with nozzles spaced for even distribution of water over fill material. Provide access door. System shall be self-draining and non-clogging. Spray nozzles, if used, shall be cleanable stainless steel, bronze or high impact plastic, non-clog, removable type properly spaced for even distribution. Provide cover for entire nozzle area or flume/trough area. // Provide manufacturer's standard pre-strainer

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    assembly and butterfly or globe valve, for cross flow tower, to balance the water flow to each basin. //

    H. Cold Water Collection Basin: Heavy gauge, zinc-coated or hot-dip galvanized steel, same as the casing // stainless steel // FRP with UV inhibitors //. Overflow, drain not less than DN (Deutsches Normung) 50 (NPS (Nominal Pipe Size) 2), and a 304 stainless steel strainer assembly with openings smaller than nozzle orifices and with built-in vortex baffling to prevent cavitation and air entrainment in the water basin circulating pump.

    I. Accessories: Make-up water, overflow and drain connections//; Equalizer connection (multiple cooling tower systems)//; Flume plate between adjacent cells (multi-cell units only)//.

    SPEC WRITER NOTE: On large multiple tower

    systems, on small systems with a single

    tower 50 tons or larger, or on systems

    requiring remote level indication/alarm

    capability, provide electronic level

    control. Locate the sensor in the

    equalization line on multiple tower

    systems.

    J. Collection Basin Water Level Control: // Mechanically operated bronze adjustable make-up water float valve. // Electronic operated with slow closing 120V solenoid valve and NEMA MG 1, Type 4x enclosure. Solid state controls with stainless steel electrode probes and relays factory wired to a terminal strip to provide control of makeup valve, low and high level alarms and output for shutoff of pump on low level//.

    K. Fans: Heavy duty axial flow type, //belt//gear// driven and balanced at the factory after assembly, with //cast aluminum or aluminum alloy //FRP // blades. Fans shall be driven by // single speed // variable speed // motor. The fan drive and moving parts shall be completely enclosed by removable hot-dip galvanized screens and panels complying with OSHA regulations. Fan shaft bearings of the self aligning, grease-lubricated ball or roller bearings with moisture proof seals and premium, moisture-resistant grease suitable for temperatures between minus 29 and 149 degrees C (minus 20 and plus 300 degrees F). Bearings designed for an L-10 life of // 40,000 // 50,000 // hours and with extended lubrication lines to an easily accessible location outside of the wet air stream. Provide access doors for inspection and cleaning.

    L. Motors and drives:

    1. The alignment and balancing of the fans, motors and drive shaft as

    installed shall operate within the vibration limits specified in

    23 65 00-6

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    specification Section 23 05 41, NOISE and VIBRATION CONTROL FOR HVAC PIPING and EQUIPMENT.

    2. In addition to the requirements of specification Section 23 05 11, COMMON WORK RESULTS FOR HVAC and STEAM GENERATION, the following shall apply:

    a. Motors: Totally enclosed or epoxy encapsulated NEMA MG 1. Protect

    fan, bearings, and appurtenances from damage by weather,

    corrosion, water spray and grit. Provide motors with severe duty

    rating with the rotor and stator protected with corrosion-

    inhibiting epoxy resin, double shielded, vacuum-degassed bearings

    lubricated with premium moisture-resistant grease suitable for

    temperatures between minus 29 and plus 149 degrees C (minus 20 and

    plus 300 degrees F), and an internal heater automatically

    energized when motor is de-energized. Provide an adjustable motor

    base or other suitable provision for adjusting belt tension. b. Fans for towers of 350 kW (100 tons) and less shall be belt

    driven. For towers larger than 350 kW (100 tons), fan shall be

    driven through a gear reducer, or driven by a V belt.

    1) Gear reducer drive: Specially designed for cooling tower

    operation, with dynamically balanced drive shaft assembly or

    shock absorbent flexible coupling requiring no lubrication,

    cast iron case with readily accessible oil drum and fill, and

    self-contained oil reservoir sealed against water entrance.

    2) V Belt Drive: Fan shall be driven by a one-piece,

    multi-groove, neoprene/polyester belt, where this is the

    manufacturer’s standard. Belt drives shall be "V" type as

    specified in specification Section 23 05 11, COMMON WORK

    RESULTS FOR HVAC and STEAM GENERATION. Belt driven fan and

    motor shafts shall have taper-lock sheaves fabricated from

    corrosion resistant material.

    SPEC WRITER NOTE: Coordinate motor and

    starter requirements with ELECTRICAL.

    c. Motor Controllers: Provide variable speed motors and controllers,

    if shown on drawings for cooling tower fans. See specification

    Section 23 05 11, COMMON WORK RESULTS FOR HVAC and STEAM

    GENERATION.

    d. Lubrication fittings shall be readily accessible outside the wet

    air stream. Provide access doors for inspection and cleaning. e. The alignment and balancing of the fans, motors and drive shaft as

    installed shall operate within the vibration tolerance specified

    23 65 00-7

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    in specification Section 23-05-41, NOISE and VIBRATION CONTROL FOR

    HVAC PIPING and EQUIPMENT.

    M. Fans over 1500 mm (60 inches) in diameter include a vibration cutout switch located in a protected position to effectively monitor fan vibration. Vibration switch shall be solid-state with adjustable time delay in NEMA 250, Type 4 enclosure. It shall stop fan motor under excessive fan vibration. //Interface the vibration cut-out switch with the DDC control system to provide an alarm in the event the fans stop due to excessive vibration.//

    SPEC WRITER NOTE: Designer shall show

    handrails, ladders, and platforms required

    for maintenance of cooling towers on

    drawings. The design shall comply with

    OSHA Standards. Coordinate with

    manufacturer’s requirements for

    maintenance access.

    N. Safety: Provide fan guards, ladders, handrails and platform in conformance with the ANSI A10.18 as follows:

    1. Fan Guard: Removable fan discharge with a rigid framed screen guard,

    installed over the fan cylinder.

    2. Ladders: Vertical hot-dip galvanized steel or aluminum ladder for

    each tower located outdoors. Ladders higher than 3.6 meters (12 feet)

    shall have safety cage. Ladders shall extend to within 300 mm (one

    foot) of the grade or the roof deck surface.

    3. Hand Railing: Steel or aluminum hand railings not less than 1070 mm

    (42 inches) high around perimeter of each fan-deck, or working

    surface 3.6 meters (12 feet) or more above ground, roof or other

    supporting construction. Handrails shall meet OSHA Standards. 4. Platform: Galvanized steel with a bar grating floor.

    SPEC WRITER NOTE: Delete paragraph O and P

    when winter operation is not required.

    O. Electric Basin Heater: Furnish stainless steel electric immersion heater installed in a threaded coupling on the side of the basin and with watertight junction boxes mounted in the basin with sufficient capacity to maintain plus 4 degrees C (40 degrees F) water in the basin at ___degrees C (___degrees F) ambient. Provide a NEMA 250, //Type 3R // Type 4 // Type 4X// mounted on the side of each cooling tower cell with magnetic contactors controlled by a temperature sensor/controller to maintain collection basin water-temperature set point. Provide a water-level probe to monitor cooling tower water level and de-energize the heater when the water reaches low-level set point. Provide a control-

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    circuit transformer with primary and secondary side fuses, terminal blocks with numbered and color-coded wiring to match wiring diagram, Single-point, field-power connection to a // fused disconnect switch // nonfused disconnect switch // circuit breaker// and heater branch circuiting complying with NFPA 70. Provide a Metal raceway for factory-installed wiring outside of enclosures, except make connections to each electric basin heater with liquid tight conduit.

    SPEC WRITER NOTE: Specify electric heat

    tracing if cooling tower is specified

    independent of HVAC Piping Systems.

    P. Electric Heat Tracing: Provide in specification Section 23 21 13, HYDRONIC PIPING.

    SPEC WRITER NOTE: Specify discharge hood,

    if necessary, to increase leaving air

    velocity to avoid recirculation.

    //Q. Discharge Hood: // Tapered // Straight// // Hot-dip galvanized steel, // stainless steel, //same as the casing with factory installed access door. //

    SPEC WRITER NOTE: Forced draft open

    circuit cooling towers should be used on

    projects where the tower is indoors,

    requires ductwork, or is operated in the

    winter.

    2.2 FORCED DRAFT OPEN CIRCUIT COOLING TOWER:

    A. Cooling tower shall be a factory assembled, forced draft, counter-flow type with a vertical discharge configuration.

    DESIGNER NOTE: Use stainless steel for all

    principal panels and structural elements,

    hot and cold water basins, etc. for the

    High-Humidity locations listed in the VA

    HVAC Design Manual.

    B. Casing: Heavy gage (minimum 16 gage) // Galvanized Steel // Stainless Steel // Fiberglass Reinforced Plastic (FRP) with UV inhibitors. // //1. Galvanized Steel: Hot-dip galvanized steel complying with ASTM

    A653/A653M, and having G235 (Z700) coating. //

    //2. Stainless Steel: ASTM A666, Type 304. //

    //3. Fiberglass Reinforced Plastic: FRP with maximum flame spread rating

    of five according to ASTM E84 and with UV inhibitors. // 4. Fasteners: Zinc or cadmium coated bolts or tapping screws for

    assembly. Use stainless steel washers with neoprene backing where

    required for preventing leaks.

    5. Joints and Seams: Sealed watertight.

    23 65 00-9

    02-10

    6. Welded connections: Continuous and watertight.

    B. Framing: //Rolled structural steel shapes, hot-dip galvanized after fabrication or structural shapes cold formed from galvanized steel sheets or plates, complying with ASTM A653/A653M, and having G235 (Z700) coating. //Rolled or formed structural stainless steel conforming to ASTM A666, Type 304. //

    C. Fill:// PVC // FRP // resistant to rot, decay and biological attack; with a maximum flame spread rating of five per ASTM E84 and fabricated, formed and installed by manufacturer to ensure that water breaks up into droplets.

    D. Drift Eliminators: Same as fill material. Effectively trap water droplets entrained in discharge air stream and limit drift loss to less than 0.005 percent of the total water circulated. Sections shall be assembled into easily removable racks of the same material as the casing. Eliminators can be PVC neoprene honeycomb type.

    SPEC WRITER NOTE: Eliminate the

    combustible materials when cooling tower

    is located 12 meters (40 feet) or closer

    to hazards such as chimneys, and

    incinerators, or when roof mounted.

    E. Hot Water Distribution System: Open basin, flume and troughs, or a pipe system with nozzles spaced for even distribution of water over fill material. Provide access door. System shall be self-draining and non-clogging. Spray nozzles, if used, shall be cleanable stainless steel, bronze or high impact plastic, non-clog, removable type properly spaced for even distribution. Provide cover for entire nozzle area or flume/trough area. // Provide manufacturer's standard pre-strainer assembly and butterfly or globe valve, for cross flow tower, to balance the water flow to each basin. //

    F. Cold Water Collection Basin: Heavy gauge, zinc-coated or hot-dip galvanized steel, same as the casing // stainless steel // FRP with UV inhibitors //. Overflow, drain not less than DN (Deutsches Normung) 50 (NPS (Nominal Pipe Size) 2), and a 304 stainless steel strainer assembly with openings smaller than nozzle orifices and with built-in vortex baffling to prevent cavitation and air entrainment in the water basin circulating pump.

    G. Accessories: Make-up water, overflow and drain connections, Equalizer connection (multiple cooling tower systems) Flume plate between adjacent cells (multi-cell units only).//

    SPEC WRITER NOTE: On large multiple tower

    systems, on small systems with a single

    23 65 00-10

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