Section 8 — Heat Transfer Equipment

Cooling Towers

IPE Engineering Practice IPE-EP-8-4-1

Document number: IPE-EP-8-4-1 · Section: 8 — Heat Transfer Equipment

SCOPE

This Practice covers the design fabrication and inspection of mechanical draft cooling towers.
Documentation required for fire protection systems constructed in accordance with this Practice is given in Table 2.
Any deviation from this Practice, or Practices referenced herein, must be approved by the procedure described in EP 1–1–3.
An asterisk (*) indicates that a decision by the Owner or Owner’s Engineer is required or that additional information is furnished by the Purchaser.
A revision bar indicates all changes made to this Practice.

2.0 REFERENCES

The latest edition of the following standards and publications are referred to herein.

STANDARDS AND PUBLICATIONS

IPE Engineering Practices
EP 1–1–3 Deviations to IPE Engineering Practices EP 3–5–2 Firewater Systems EP 4–1–1 Design Criteria and Loads for Structures EP 4–5–3 Auxiliary Structures for Operation and Maintenance EP 5–9–1 Design and Installation of Non–Metallic Piping EP 8–4–1 DS Cooling Towers Data Sheet EP 10–3–1 Shop Painting EP 13–2–1 Electrical Detail Design and Construction Practice EP 13–3–1 Induction Motors NEMA Frame EP 13–3–1 DS Induction Motors NEMA Frame Data Sheet EP 13–3–2 Induction Motors Above 200HP EP 13–3–2 DS Induction Motors Above 200HP Data Sheet
ANSI Standard
S2.19 Balance Quality of Rotating Rigid Bodies
APl Standard
RP 500 Classification of Location for Electrical Installations at Petroleum Facilities Std 605 Large Diameter Carbon Steel Flanges
ASME/ANSI Standard
B16.5 Pipe Flanges and Flanged Fittings

STANDARDS AND PUBLICATIONS (CONT.)

ASTM Standards
A106 Seamless Carbon Steel Pipe for High–Temperature Service A123 Zinc (Hot–Galvanized) Coatings on Products Fabricated from Rolled, Pressed, and Forged Steel Shapes, Plates, Bars, and Strip A153 Zinc Coating (Hot–Dip) on Iron and Steel Hardware A181 Forgings, Carbon Steel, for General–Purpose Piping A536 Ductile Iron Castings B96 Copper–Silicon Alloy Plate, Sheet, Strip, and Rolled Bar for General Purposes B98 Copper–Silicon Alloy Rod, Bar, and Shapes B99 Copper–Silicon Alloy Wire for General Purposes B179 Aluminum Alloys in Ingot Form for Sand Castings, Permanent Mold Castings, and Die Castings C150 Portland Cement E84 Test Method for Surface Burning Characteristics of Building Materials
CTI Standards
ATC–105 Acceptance Test Code for Water–Cooling Towers STD–103 Redwood Lumber STD–111 Gear Speed Reducers STD–114 Douglas Fir Lumber STD–118 Inquiry and Bid Form STD–131 Fiberglass WMS–112 Pressure Preservative Treatment of Lumber
National Institute of Standards and Technology
PS 1–83 U.S. Product Standard for Construction and Industrial Plywood with Typical APA Trademarks
NEMA
MG–1 Motors and Generators
NFPA Standard
214 Water–Cooling Towers

DEFINITIONS

Contractor – Company or business that agrees to furnish materials or perform specified services at a specified price and/or rate to the Owner.

Inspection – An activity to check that design, materials, fabrication, and testing comply with the requirements of the specification.

Manufacturer – The recipient of a direct or indirect purchase order for materials and/or equipment. In this context, a direct order is one issued to a Manufacturer by a Contractor or the Owner. An indirect order is one issued to a Manufacturer by a vendor (recipient of a direct order) for materials, fabricated components, or subassemblies.
Owner – Inflection Point Engineering, LLC.
Owner’s Engineer – A Inflection Point Engineering, LLC appointed engineer.
Purchaser – The party placing a direct purchase order. The Purchaser is the Owner’s designated representative.

DESIGN

General
The equipment shall be free from defects in material and workmanship.
The mechanical equipment shall be designed specifically for cooling tower use. The Manufacturer shall be responsible for mechanical equipment design and shall insure that replacement parts will be readily available from domestic stock.
The tower shall be designed by the Manufacturer to permit the future installation of additional cells.
Framework
Bolted construction shall be used for tower framework. Non–framework members, such as fill, sheathing, and louvers shall not be considered as providing part of the structural strength of the tower.
Structural support columns shall have their bases trimmed to seat flush and without overhang on anchor plates on top of the basin wall or piers. Anchor plates shall be seated solidly by use of grout fill. Shims shall not be used for seating the anchor plates or columns.
All exterior unanchored columns shall be shop fabricated and of sufficient length to permit extension below the curb. Interior columns shall be extended and field fitted to the basin floor.
The main framing members shall be carefully fitted and bolted at each of their connections. Nails are not permitted at these points. Suitable bearing shall be provided by the use of side hill washers, structural castings, or similar attachments.
All structural members shall be designed to withstand combined live, dead, ice, seismic and wind loads in accordance with EP 4–1–1.
The tower shall be designed with no structural load being transferred to the tower walls, casing or partitions. Loads originating in any portion of the tower structure shall be transferred through the main columns to the foundation.
Casing

The external walls shall be constructed of corrugated FRP (fiberglass reinforced polyester) with a minimum weight of 12 oz/sq. ft. Horizontal seams shall have a minimum lap of 4 inches. The FRP casing shall be opaque.
Leakage shall not be permitted through the casing. All seams shall be sealed using a non– hardening oil proof and waterproof compound.
The casing shall be pre–drilled. Lag screws with washers shall be used for attachment to the tower columns.
External walls made of FRP (fiberglass reinforced polyester) shall have a flame spread rating of 25 or less and shall be resistant to aging by sunlight.
Louvers
(*) Air inlet louvers shall be provided and shall be fabricated from corrugated 16 oz./sq. ft. FRP (fiberglass reinforced polyester) or an alternate material approved by the Owner’s Engineer. Louver assemblies shall be designed to prevent warping, sagging, and water splash to outside of tower. The maximum span between braces shall not exceed 4 feet.
Louvers made of treated lumber shall be a minimum 3/4 inch thick supported by bracing with a maximum center to center span of 3 feet.
Towers that may be subject to icing conditions shall have retainer bars on the louvers to prevent damage to the fill from sliding ice.
Louvers shall be self–draining so as not to contribute to the formation of ice on the louvers or supports.
Tower Fill
Fill shall consist of individual removable assemblies designed to prevent warping or sagging. The maximum deflection in the span shall not exceed 1/4 inch under operating conditions. Fill shall be installed and attached per the Manufacturer’s documented recommendations. Fill shall be secured to prevent vibrations or movement during operation.
PVC splash type fill shall have a minimum thickness of 50 mil and film–type fill will be a minimum thickness of 15 mil thickness per sheet after forming.
The minimum nominal thickness of wood fill shall be 1/2 inch.
The fill in counterflow towers shall be designed to withstand ice load and a minimum live load of 25 lb./ft 2.
Fill made of PVC (Polyvinyl Chloride) shall have a flame propagation index of 25 or less per ASTM E84. The PVC and its installation shall be Factory Mutual approved.
All fill material shall be capable of floating in water.
High efficiency fill should not be used in towers that have high bacterial fouling tendencies. Caution should be used when specifying high efficiency fill in once through cooling systems.
Partitions
Towers consisting of two or more cells shall be provided with transverse partition walls. The walls shall extend from the normal water level to the fan deck to permit each cell to be taken out of service without affecting the operation or capacity of the other cells. The partition walls shall be tongue–and–groove type 1 inch nominal thickness wood or fiberglass reinforced polyester (FRP) with a minimum weight of 12 oz./sq. ft. Where FRP is used, it shall be supported every 3 feet with 2 inch by 4 inch crossbraces.
Individual water cells serviced with two or more fans shall be provided with partition walls. The walls shall be centered between fans and shall extend from the fan decks to the operating water level to avoid recirculation of air when one or more fans are not operating.
For counterflow towers, individual cells serviced by one fan and individual cells having more than one louver face shall be provided with a partition wall. The partition wall shall extend from the normal water level in the basin to the elevation of the top of the air inlet louvers and shall be located to prevent air from blowing from one louver face through the other louver face.
Partitions shall be adequately braced to prevent vibration and to prevent sagging of tower parts due to water temperature involved.

Drift Eliminators
(*) The maximum allowable drift loss shall be 0.05 percent of the design water circulation rate for fresh and saltwater towers. Supportive test data for proposed drift eliminators shall be provided by the Manufacturer. Drift tests using an approved test firm and approved methods may be performed as a function of the performance testing where all guarantees therein apply.
Drift eliminators shall be easily removable to permit maintenance. Eliminator sections shall be arranged to permit easy handling and removal from the tower.
For counterflow towers, drift eliminators shall be designed with a removable section to allow easy access to distribution system headers, laterals, and nozzles. Sections shall be designed to withstand a minimum live load of 25 #/ft 2. For crossflow towers, a removable section shall be provided for easy access to the fill area.
Drift eliminators made of wood shall have at least two passes. Drift eliminators made from other materials shall have a cellular type configuration providing a minimum depth of 5 inches parallel to the air flow. The leaving air shall make at least two compound directional changes within the pack to eliminate entrained water droplets.
Eliminator packs for counterflow cooling towers shall be supported at 6 foot vertical centers by drain board supports designed to drain the collected water back into the cold water basin. Eliminator packs for crossflow cooling towers shall be supported on 2 foot horizontal centers.
Decks and Stacks
Fan decks and water distribution decks shall be designed for a live load of 60 lb./ft 2, and shall be reinforced for any concentrated or distributed dead loads such as fans or drivers, and the maintenance equipment required to service and handle them. Decking shall be tongue–and groove type wood having a minimum nominal thickness of 1–1/2 inches, or plywood having a minimum thickness of 1 inch.
Fan stacks shall have a minimum height of 6 feet. The stack design shall incorporate, or provide for, a modified venturi fan throat.
Each stack higher than 6 feet shall be provided with an inspection port located near the fan blade elevation. The port opening shall be 3–inch diameter, minimum, and shall be provided with a hinged cover. The opening shall be located so that the coupling at the reduction gear can be observed.
The fan deck shall be surrounded by a treated handrail with intermediate knee rails and toe boards designed in accordance with OSHA Standards.
Each fan cylinder shall be provided with an access panel large enough for mechanical equipment removal.
Water Distribution System
The central header pipe shall terminate 12 inches outside the tower wall with an ASME/ANSI B16.5 Class 150 steel raised face flange, ASTM A 181 Grade 1 or 2. For diameters larger than NPS 24 inch, the flange shall be per ASME B16.47. Counter flow towers shall have a separate central header for each cell. Plastic distribution systems shall terminate inside the cooling tower with a flanged connection. A coated carbon steel Schedule 40 spool piece extended through the tower casing shall be used to attach the internal distribution piping to the outside header piping.
The distribution piping shall be protected with a standpipe or other pressure relief system to protect against excessive pressure or surges.

Crossflow cooling towers shall have waste distribution basins constructed of 1–1/2 inch nominal thickness tongue–and–groove type wood or 1–inch minimum thickness plywood. The outer basin walls shall be a minimum of 2 inches higher than the transverse walls.
Water distribution basins for crossflow towers shall be covered to exclude sunlight. Covers shall be removable to permit access and periodic inspection. The distribution pans or basins shall be designed to be self–draining and non–clogging.
Crossflow cooling towers shall have in each cell a cast iron flow control valve for each water distribution basin. These valves shall be mounted external to the distribution header.
Spray nozzles shall be self–draining, non–clogging type and shall be spaced to provide an even distribution of water over the top layer of fill. Nozzles shall be manufactured from polypropylene polyethylene, polyvinyl chloride, or phenolic resins. Material selection shall depend upon temperature condition.
(*) Nozzles shall be replaceable from the top side of the water distribution deck. The nozzle design shall be approved by the Owner’s Engineer.
Headers and laterals shall be provided with cleaning access or flush–out facilities.
Where an extended fan deck is used, water distribution basins for crossflow towers shall be covered with 12 oz./sq. ft. corrugated fiberglass reinforced polyester or 1/2 inch thick plywood, fastened with approved hardware. At least one 2 foot by 3 foot section per basin shall be removable.
(*) A hot water by–pass shall be provided when specified by the Owner’s Engineer.
The primary supports for the water distribution system shall be bolted to the framework.
Access
Additional requirements for access to cooling towers shall be per EP 4–5–3.
Cranes or davits (if specified) shall be located on the fan deck, and shall be capable of handling the largest and heaviest items of tower equipment.
Lighting shall be installed to give safe access to the interior, exterior, and top of the tower for servicing of the fan motors. General lighting details are covered in EP 13–2–1 and shall be followed.
A stairway shall be provided at both ends of the tower for access to the fan deck. The stairway shall be entirely bolted and provided with adequate handrails, knee rails and toe boards. The stairway shall be in accordance with EP 4–5–3.
Access shall be provided for each fan stack, the hot water basin, and each partition wall. Sufficient space shall be provided to allow complete access to all interior compartments. Access doors shall be man–sized, hung with a latch, commercially leak–proof, and easily operated. Interior partition doors may be lift–out type.
One access ladder from the fan deck to the top of the fill level shall be provided on each side of the tower for each cell.
Fan Blades, Drivers, and Transmissions
The fan rotating assembly shall have a minimum of six blades. A non–welded type hub design is preferred. Fan blades shall have a manual adjustment to vary the pitch. Each fan hub shall be dynamically balanced to ANSI Standard S2.19 Grade 6.3 or better. Each blade shall be set to the design pitch.
(*) The Manufacturer shall obtain approval from the Owner’s Engineer as to the proposed make of fans to be used.

If the Manufacturer does not furnish the motor driver, the driver half coupling shall be supplied to fit the driver shaft, finish bored, to the motor Manufacturer, as specified.
Motors, 200 HP and below, shall comply with EP 13–3–1. An Owner’s/Purchaser’s Data Sheet from EP 13–3–1 DS shall be completed and included in the purchase inquiry. The Manufacturer’s Data Sheet (see EP 13–3–1 DS) for the motor being offered shall be completed by the Bidder and returned with the bid.
(*) Unless specified otherwise on the motor Data Sheet, motors under 200 HP, as a minimum, shall have the following characteristics/requirements.
460 volt, 3 phase, 60 Hz
1.15 service factor
TEFC severe duty enclosure
Motors shall be energy efficient and meet or exceed NEMA MG–1.12.55 Table 12–6B.
Anti–friction bearings with Zirk fittings
Grounding on case and in terminal box for compression lugs
NEMA Code G
NEMA Torque Design B
Max. noise 85 dBA at 3 feet (maximum)
(*) Motors above 200 HP shall be medium voltage large frame motors in accordance with EP 13–3–2. A Data Sheet from EP 13–3–1 DS must be submitted with the proposal for approval by the Owner.
The service factor shall not be used when sizing the motor.
Couplings for induced draft towers shall have tubular shafts and non–lubricated flexible couplings. Pillow block bearing supports for shafts shall not be used. Coupling hubs and spacer and shafts shall be individually dynamically balanced to ANSI Standard S2.19 Grade 2.5 or better.
Shaft couplings for fan operating with an on/off temperature sensing control shall be rated for at least twice the normal torque requirement.
Safety guards shall be furnished on all moving equipment constituting a personnel hazard. Guards shall be provided at each end of the floating shaft to protect against shaft whip in the event of shaft failure. The minimum thickness of shaft whip guards shall be 1/2 inch.
Speed reducers shall have the following specifications:
Spiral bevel type gears with a service factor of 2.0 per CTI STD–111.
Gear reducers rated greater than 25 hp shall have integrally mounted anti–rotational devices.
Seals shall be provided with protection against moisture and leakage at the shafts.
Oil filling and level connections shall extend to outside the fan stack. Extension piping shall be stainless steel with a flexible connection to the gear reducer for vibration dampening.
(*) Unitized steel supports shall be provided to support the fan drive assembly. Design details for the support, including tolerances for parallelism and flatness of the mounting pads on the support for the motor and gearbox shall be provided to the Owner’s Engineer for approval.
The radial clearance between the fan tip and the fan cylinder shall not exceed 1/2 percent of the fan diameter or 1/2 inch, whichever is larger.
Speed reducers shall be self–lubricating with gears totally enclosed and running in oil.

Vibration Cutout Switch
A vibration protection alarm device shall be provided for each fan as specified to include:
A Nelson class 531, model TSBM vibration switch with separate alarm and trip contacts mounted in an approved enclosure. Ball–type gravity switches are not acceptable.
An external electrical reset and a set point adjustment capable of being set at some known, predetermined increment above the normal vibration level while the fan is operating.
When specified an adjustable time delay (0–15 seconds) within the motor control circuit that will prevent shutdown of the fan due to acceleration forces encountered during start–up.
Mounting of the device to the mechanical equipment assembly outside the fan ring.
Capability to actuate the Owner’s alarm.
(*) Detailed drawings and Manufacturer’s data will be provided to the Owner’s Engineer for approval before purchasing the machinery protection instrumentation.
Fan Braking Facilities
(*) An electronic braking device shall be provided by the Purchaser/Owner for each fan motor controller to prevent damage to the fan, motor, drive, and couplings during start–up or when changing speeds and/or direction of rotation. The cooling tower Manufacturer shall provide any recommendations on control schematics for starting and/or electronic brakes in the quotation.
The Manufacturer shall provide proven de–icing facilities if the design duty and specified winter wet bulb temperature indicate that tower icing problems will exist during winter operation. Acceptable deicing methods shall be as follows:
Multispeed fans.
Fan reversal.
Variable pitch hub.
Preheating the air inlet to the fill by hot water bypass.
Adjustable air inlet louvers.
Electrical
(*) Enclosures for motors and electrical equipment shall be appropriate for the specified area classification and environment. The classification of cooling towers used in hydrocarbon processing applications shall be classified as shown in API RP 500. The necessary detailed specifications for electrical items including deck lighting fixtures, shall be furnished by the Owner’s Engineer.
(*) Unless otherwise specified by the Owner’s Engineer, start/stop and reversing controls shall be provided at grade level and a local stop control shall also be provided.
Screens and Trash Racks

(*) The cooling tower Manufacturer (or others), as specified by the Purchaser, shall furnish screens and trash racks, as follows:

A pair of screens with a double track shall be provided for each basin division, such that one may be removed or inserted without removing the other. Screens shall be 5/8 inch by 5/8 inch mesh, using 0.135 inch diameter wire.
Trash racks shall be provided ahead of screens. Racks shall be designed with an element spacing of 1–1/2 inches.
A platform shall be provided adjacent to the screens and trash rack to provide access for maintenance. The screens shall be designed to be lifted by the Owner’s available mobile maintenance equipment, or shall be provided with a simple winch.
If a flume is used to bring water from basin divisions to the suction bay, a trash rack and a pair of screens shall be provided in the flume instead of in each division.

MATERIALS

(*) Material of construction and applicable standards are listed in Table 1. Where selection of materials is based on use of salt or brackish water, the Owner’s Engineer will so specify.
(*) Wood substitutes shall be submitted for approval to the Owner’s Engineer.
(*) All lumber shall be given a preservative treatment per CTI Standard WMS–112, as modified by Paragraph 6.1, using crecsote, ACC (acid copper chromate) or CCA (chromated copper arsenate) as specified. The plenum section for cross–flow cooling towers shall be constructed of redwood, unless approved by the Owner’s Engineer. All lumber shall be cut to dimensions, noted and drilled prior to preservative treatment.
(*) Pipe for central headers and laterals of the water distribution system shall be an acceptable plastic material. The specifications for plastic pipe shall be submitted for approval to the Owner’s Engineer. The design and installation of plastic pipe shall be in accordance with EP 5– 9–1.
All lumber used in the tower, including framework supports, flumes and distribution basins shall be dressed on four sides. Wood, when used for fill and drift eliminators, shall be furnished rough.

PRESERVATIVE TREATMENT

Preservative treatment of lumber shall be per CTI Standard WMS–112 modified as follows:

Moisture content of lumber prior to treatment shall be 19 percent for air–dried materials and 15 percent for kiln–dried materials.
(*) Deviations from the required penetration or retention, as determined from specimens representative of the condition and dimensions of the tower components to be treated, require approval of the Owner’s Engineer.
If waterborne salts are used, seasoning after treatment shall be continued for sufficient time to complete the chemical reaction within the wood.
(*) The stated responsibility of the treater regarding damage to lumber or nonconformance with penetration and retention requirements shall apply, unless modified by the Purchaser.
The referenced standards of AWPA for material, treatment, inspection, and handling pressure treated wood shall be considered mandatory.
Incising of lumber shall not be permitted.
(*) The Owner’s Engineer shall be furnished with a copy of pressure and temperature charts and treating reports covering the pressure treatment of each charge of lumber.

DOCUMENTATION

Proposal Information
Performance Curves: The Manufacturer’s proposal shall include three separate performance curve sheets, one each for 90 percent, 100 percent, and 110 percent of the design water quantity, showing tower temperatures versus ambient air wet bulb temperature. Curves shall cover cooling ranges corresponding to 60 percent, 80 percent, 100 percent, and 120 percent of design heat duty, at wet bulb temperature ranging from 10ºF below to 3ºF above of the design ambient wet bulb temperature. Performance curves shall be based on constant fan horsepower equal to the design horsepower.

Characteristic Curve: The Manufacturer’s proposal shall include a tower characteristic curve showing

and Bid Form: The Manufacturer’s proposal shall include a Data Sheet (EP 8–4–1 DS) containing all applicable information listed in the Cooling Tower Institute Inquiry and Bid Form CTI STD–118 and the following:
Percent recirculation (design).
Air temperature leaving the tower,_ºF.
Grade, dimensions, and other applicable specification for materials of construction.
Detailed description of de–icing facilities.
Cold water temperature when one cell is shut down and the design duty and flow are distributed between remaining cells.
Recommended spare parts based on two years of continuous operation.
A Data Sheet from EP 13–3–1 DS or EP 13–3–2 DS must be completed and included in the purchase inquiry when motor drives are specified. The Manufacturer’s Section from EP 13–3–1 DS or EP 13–3–2 DS for the motor being offered shall be completed by the Bidder and returned with the bid.
Supplemental Proposal Data: Supplemental data shall be submitted with proposals to include the following additional information:
Exceptions: Explain any exceptions to this Practice or other standards and Practices referenced herein. If there are no exceptions, it should be so stated.
Fan Data
State whether the fans are multispeed and, if so, give the air delivery per fan at all speeds, ACFM.
State whether the fans are reversible and, if so, give qualifications for operating the fans in the reverse direction.
Fan efficiency (including gear loss).
Proposal Substitutes to CTI Materials (Refer to Table 1)
A listing of comparative physical properties.
Grades of lumber to be used for the various tower parts.
Comparative chemical constituents of preservatives for lumber treatment.
Polypropylene, polyethylene, polyvinyl chloride, or similar plastics to be quoted as a base bid, unless an alternative is specified.
An outline drawing of the tower shall be submitted with the proposal. A drawing of a similar, typical cooling tower is acceptable, provided the differences between the typical tower and the one being offered are clearly noted.
Operating and Maintenance Manuals
(*) Prior to completion of a new or revamped tower, at least four sets of manuals shall be provided, unless otherwise specified. The manuals shall be delivered to the Purchaser.

All manuals shall be written specifically for the equipment being furnished and shall contain (but not be limited to) the following information:
Mechanical data on the fan, hub, coupling, and fan drivers, including the shaft bore and keyway dimensions, design pitch for fan blades, and types of lubricating oil to be used.
Sectional drawings of the fan, hub coupling, fan drivers, and gears showing location of parts, part numbers, and materials. The Manufacturers standard drawings are acceptable if corrected or supplemented as necessary to provide positive identification.
Instructions for installation, operation, and maintenance of the tower and mechanical equipment.
Instructions for fan hub and blade assembly and recommended procedures for field dynamic balancing of the installed fan.
One complete set of erection drawings to include structural details.
Instructions for the installation and removal of tower fill.

INSPECTION AND TESTING

Inspection
(*) Lumber inspection shall be made by a qualified inspector of an independent agency mutually agreed upon between the Owner’s Engineer and the Manufacturer. Lumber will be either group marked or individually grade marked, as specified.
(*) Grading Certificate: If the lumber has been treated with a preservative, a certificate of grading in lieu of physical grade markings shall be furnished to the Owner’s Engineer for approval.
If erection inspection is specified to be by the Inspector, the Manufacturer shall notify the Inspector at least 30 days in advance of the scheduled start of erection.
(*) All material and fabrication are subject to inspection by the Inspector. Rejections by the Inspector are final. The inspection or witnessing of tests by the Inspector does not relieve the Manufacturer of conforming to this Practice, or from the materials, apparatus, workmanship or performance guarantees.
Testing
(*) A performance test will be conducted by a third party which is approved by the Cooling Tower Institute (CTI) in the presence of the Owner’s Engineer. Testing will be performed when ambient conditions allow or the first summer after start–up. The initial CTI test will be paid for by the Owner. If the tower fails to meet 100 percent of the design performance as stated in the Owner’s Job Specification, the Manufacturer shall make the necessary modifications at his expense to obtain the Design Performance. The tower shall be retested by CTI representatives as before, but at the Manufacturer’s expense. If the tower performance is still below 100 percent, the Manufacturer shall reimburse to the Owner a percentage of the total purchase price (less freight and taxes). The final tower capability will be calculated from the Cooling Tower Institute ATC–105 Test as compared to the specified design performance criteria. The percentage of reimbursement to the Owner will be calculated as follows:

Reimbursement Price = [Design Performance (100%) – Final Tower Capability (%)] x Total Purchase Price (less taxes and freight).

(*) The locations, size, number, and orientation of connections for water flow and temperature measurements shall be as specified in the test procedure selected and agreed upon by the Manufacturer and the Owner’s Engineer prior to the test.

The fan driver power shall be determined as power input to the motor. Power input shall be determined by measurement of the voltage, current, and power factor, or by direct measurement of the kilowatt input. Where the guarantee is tied to the driver output, efficiencies as given by the Manufacturer of the driver may be used.

9.0 PERFORMANCE

The tower shall be guaranteed to perform as specified when tested and evaluated by the Cooling Tower Institute in accordance with CTI Bulletin ATC–105. The evaluation shall be based on the ambient air wet bulb temperature. This temperature shall be taken on the windward side of the tower at three locations, each at least five feet above the normal water level of the basin and not less than 50 feet nor more than 100 feet from the tower.

10.0 EQUIPMENT GUARANTEE

The tower and mechanical equipment shall be guaranteed by the Manufacturer against defective material, poor workmanship, and failure from normal usage for one year after being placed in service. Replacement of defective parts shall be made at the Manufacturer’s expense, including costs for delivery, erection, installation, or application at the job site.

Defective parts shall be returned at the Manufacturer’s expense.

FIRE PROTECTION

Fire protection for all cooling towers shall be in accordance with NFPA Standard 214 and the additional requirements as stipulated by the local fire protection specialist.
(*) The Owner’s Engineer will specify the extent of the fire protection facilities to be provided by the cooling tower Manufacturer or others.
Installation of fire protection equipment shall conform to EP 3–5–2 as applicable.
(*) Unless approved by the Owner, a continuous Hydrocarbon–in–water analyzer in the cooling water return shall be provided for re–circulating cooling water systems.

12.0 TABLES

TABLE 1

MATERIALS FOR COOLING TOWER COMPONENTS

COMPONENT	MATERIAL (1)(2)(5)	STANDARD	REMARKS
Framework: Structural	Redwood(5)	CTI STD – 103 CTI WMS – 112	Clear Heart Structural Grade, No Sapwood Allowed
	Douglas Fir	CTI STD – 114 CTI WMS – 112	Dense Select Structural Grade
	Concrete	—	Cement–ASTM C 150 – Type I or II
Fill	Polypropylene (3) Polyethylene (3) Polyvinyl Chloride (3)	—	15 Mil Min. (Film Type)
	Redwood	RIS(5) CTI WMS – 112	Clear Heart Structural
	Douglas Fir	CTI STD – 114 CTI WMS – 112	—
Casing and Partitions Louvers	Fiberglass Reinforced Polyester	CTI STD – 131	See paragraphs 4.3, 4.4 and 4.6
	Redwood	RIS (5) CTI WMS – 112	Clear Heart Structural Grade
	Douglas Fir	CTI STD – 114 CTI WMS – 112	Dense Select Structural Grade
Drift Eliminators	PVC*	—	Material Selection Requires Approval of Owner’s Engineer
	Redwood	RIS (5) CTI WMS – 112	Clear Heart Structural Grade
	Douglas Fir	CTI STD – 114 CTI WMS – 112	Dense Select Structural Grade

TABLE 1 (CONT.)

MATERIALS FOR COOLING TOWER COMPONENTS

COMPONENT	MATERIAL (1) (2) (5)	STANDARD	REMARKS
Fan Deck Flooring, Water Basins, Water Distribution System CIF	Redwood	RIS (5) CTI WMS – 112	Clear Heart Structural Grade
	Douglas Fir	CTI STD– 114	Dense Select Structural Grade
	Douglas Fir Plywood	UPS PS 1–83 CTI WMS– 112	Exterior Marine Type AA Plugged Two Sides
Water Distribution System Piping	PVC*	—	Material Selection Requires Approval of Owner’s Engineer
Fan Stack	Fiberglass Reinforced Polyester*	CTI STD – 131	Material Quality Must Be Approved by Owner’s Engineer
Stairways, Railings	Redwood	RIS (5) CTI WMS – 112	Clear Heart of Select Heart Grade
Ladders and Safety Cages	Douglas Fir	CTI STD – 114 CTI WMS – 112	Dense Select Structural Grade
	Carbon Steel	OSHA–Title 29	Galvanized per ASTM A 123 and coated per EP 10–3–1
Lag Screws, Nails, and Washers	Stainless Steel	—	Type 316 Washers, Neoprene Backed
Fan Blades	Fiberglass Reinforced Polyester or EpoxyAluminum–Cast (4)	ASTM B179	Alloy SG 70A
Fan Hub	Non–Welded Construction Cast Iron Ductile	ASTM A 536	Galvanized per ASTM A 153 and coated per EP 10–3–1
Fan Bolts and Hardware	Stainless Steel	—	Type 316 non–welded or 316L

TABLE 1 (CONT.)

MATERIALS FOR COOLING TOWER COMPONENTS

COMPONENT	MATERIAL (1)(2)(5)	STANDARD	REMARKS
Fan Shafts, Coupling Disk and Bolting	Stainless Steel	—	Type 316
	Composite*
Anchors and Structural Connectors	Fiberglass Reinforced Polyester	—	—
	Stainless Steel	—	Type 316
Nuts, Bolts, Washers, and Nails (Serrated)	Stainless Steel	—	Type 316
Mechanical Equipment Supports	Carbon Steel	—	Galvanized per ASTM A 123 and coated per EP 10–3–1
Guards	Stainless Steel	—	Type 316L or 316 non–welded
Screens and Trash Racks (Including Frames)	Stainless Steel	—	Type 316 (Fresh, Brackish, or Salt Water)

NOTES:

Material Indicated by an asterisk (*) requires approval by Owner’s Engineer as to use and material quality. Applicable standards and specific qualifications for any wood species from other than U.S.A. sources also require such approval.
Special material requirements for brackish and salt water cooling towers are listed below:
Fan blades shall be fiberglass–reinforced polyester only.
Fan hub shall be ductile cast iron galvanized per ASTM A 123, brush blasted and then prime with vinyl wash primer coat and top with coal tar epoxy.
Fan bolts shall be Type 316 stainless steel.
All carbon steel shall be white metal blast cleaned and coated with coal tar epoxy.
Bolts and connectors used from louver face to drift eliminators shall be silicon bronze with ends protected from corrosion/erosion by protective sheds or caps (polypropylene) or by an approved coating. Aluminum bronze (unprotected) may be used as an alternate. All other bolting, including anchor bolts, nuts and washers, lag screws and nails may be silicon bronze (unprotected).
Aluminum bronze, cupronickel, or monel may be used in place of silicon bronze material permitted.
Galvanized steel per ASTM A 123 shall be brush blasted and primed with vinyl wash primer and then have a top coat of aliphatic polyurethane paint.
Type II sulfate–resistant cement per ASTM C 150 shall be used in any cement structure.
Polypropylene, polyethylene, polyvinyl chloride, or similar plastic fill is preferred, and if supplied by the Manufacturer, shall be quoted as a base bid or as an alternative. Flame spread shall be 25 FSC or less for plastic. Film–type fill will be a minimum of 15 mil thickness per sheet after forming.
Fan blades of aluminum must be insulated from the iron hub to avoid galvanic corrosion.
RIS (Redwood Inspection Service), per CTI STD–103 references.

TABLE 2 DOCUMENTATION REQUIREMENTS

FOR COOLING TOWERS PER EP 8–4–1

Item	Description	Format	As–Built
1	Outline drawing.	See EP 2–5–2	Yes
2	Performance curves for 90, 100, and 110 percent of the design water quantity.	See EP 2–5–2	Yes
3	Tower characteristic curve.	See EP 2–5–2	Yes
4	Completed Tower Data Sheet (EP 8–4–1 DS).	See EP 2–5–2	Yes
5	Completed Motor Data Sheet EP 13–3–1 DS and EP 13–3–2 DS.	See EP 2–5–2	Yes
6	Fan data including fan speed(s), associated air delivery, fan efficiency, qualifications on reverse operation.	See EP 2–5–2	Yes
7	If substitutes to the CTI materials (see Table 3 of EP 8– 4–1) are chosen: a document listing comparative physical properties, the grades of lumber to be used for the various tower parts, and the comparative chemical constituents of preservatives for lumber treatment.	See EP 2–5–2	Yes
8	Operating and maintenance manuals.	See EP 2–5–2	Yes
9	Sectional drawings of fan, hub, coupling, fan drivers (in manual).	See EP 2–5–2	Yes
10	Erection drawings including structural details (in manual).	See EP 2–5–2	Yes
11	Performance guarantee.	See EP 2–5–2	Yes
12	Equipment guarantee.	See EP 2–5–2	Yes

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