summer 2006 (pdf)

CTI Journal, Vol. 27, No. 2 1

The CTI Journal(ISSN: 0273-3250)

PUBLISHED SEMI-ANNUALLYCopyright 2006 by The CoolingTechnology Institute, PO Box 73383,Houston, TX 77273. Periodicalspostage paid at FORT WORTH, Texas.

MISSION STATEMENTIt is CTI’s objective to: 1) Maintain andexpand a broad base membership ofindividuals and organizationsinterested in Evaporative HeatTransfer Systems (EHTS), 2) Identifyand address emerging and evolvingissues concerning EHTS, 3) Encour-age and support educationalprograms in various formats toenhance the capabilities andcompetence of the industry to realizethe maximum benefit of EHTS, 4)Encourge and support cooperativeresearch to improve EHTS Technologyand efficiency for the long-termbenefit of the environment, 5) Assureacceptable minimum quality levelsand performance of EHTS and theircomponents by establishing standardspecifications, guidelines, andcertification programs, 6) Establishstandard testing and performanceanalysis systems and prcedures forEHTS, 7) Communicate with andinfluence governmental entitiesregarding the environmentallyresponsible technologies, benefits,and issues associated with EHTS, and8) Encourage and support forums andmethods for exchanging technicalinformation on EHTS.

LETTERS/MANUSCRIPTSLetters to the editor and manuscriptsfor publication should be sent to: TheCooling Technology Institute, PO Box73383, Houston, TX 77273.

SUBSCRIPTIONSThe CTI Journal is published inJanuary and June. Complimentarysubscriptions mailed to individuals inthe USA. Library subscriptions $20/yr.Subscriptions mailed to individualsoutside the USA are $30/yr.

CHANGE OF ADDRESSRequest must be received atsubscription office eight weeks beforeeffective date. Send both old and newaddresses for the change. You mayfax your change to 281.537.1721 oremail: [email protected].

PUBLICATION DISCLAIMERCTI has compiled this publicationwith care, but CTI has not Investi-gated, and CTI expressly disclaimsany duty to investigate, any product,service process, procedure, design,or the like that may be describedherein. The appearance of anytechnical data, editorial material, oradvertisement in this publicationdoes not constitute endorsement,warranty, or guarantee by CTI of anyproduct, service process, procedure,design, or the like. CTI does notwarranty that the information in thispublication is free of errors, and CTIdoes not necessarily agree with anystatement or opinion in thispublication. The entire risk of the useof any information in this publicationis assumed by the user. Copyright2006 by the CTI Journal. All rightsreserved.

ContentsFeature Articles10 A Performance Comparison of Counterflow Reduced

Fouling FillsToby L. Daley, P.E.

34 Large Scale Mechanical Equipment Replacement - SimpleSteps for SuccessDavid M. Suptic P.E. LLC

44 Roulette And Mechanical Vibration Switches: What AreYour Odds?Gene Ort

60 Improving Localized Corrosion in a Complex CoolingWater SystemMichael H. Dorsey,Kevin Daigle,and A.F. Brunn

Special Sections68 CTI Licensed Testing Agencies70 CTI ToolKit

Departments02 Meeting Calendar04 View From the Tower06 Editor’s Corner08 Data Sheet

see...page 44see...page 16

see...page 38

CTI Journal, Vol. 27, No. 22

CTI JournalThe Official Publication of The Cooling Technology Institute

Vol. 27 No.2 Summer 2006

Journal CommitteePaul Lindahl, Editor-in-ChiefArt Brunn, Sr. EditorVirginia Manser, Managing Editor/Adv. ManagerDonna Jones, Administrative AssistantGraphics by Sarita Graphics

Board of DirectorsSteve Chaloupka, PresidentThomas Bugler, Vice PresidentRich Altice, SecretaryDennis (Denny) P. Shea, TreasurerRobert (Bob) Giammaruti, DirectorRichard (Rich) Harrison, DirectorJames Kanuth, DirectorKen Kozelski, DirectorTerry Ogburn, DirectorMark Shaw, Director

Address all communications to:Virginia A. Manser, CTI AdministratorCooling Technology InstitutePO Box 73383Houston, Texas 77273281.583.4087281.537.1721 (Fax)

Internet Address: http://www.cti.org

E-mail: [email protected]

FUTURE MEETING DATESCommittee AnnualWorkshop Conference

July 9-12, 2006 February 4-7, 2007Sheraton Sand Key Resort Omni Corpus Christi Hotel

Clearwater, FL Corpus Christi, TX

July 8-11, 2007 February 3-7, 2008The Westin La Cantera The Westin Galleria

San Antonio, TX Houston, TX

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Member


View From The Tower

Steven ChaloupkaPresident

I want to thank all attendees and participants tothe 2006 Annual Conference for making it the bestmeeting we have had in a long time. Continuingeducation, fellowship, networking, progress withstandards and codes; all accomplished at the con-ference! When evaluating personal time spent vs.cost of participation, I think CTI is offering a pre-mier value to our industry.Time flies, and if I read my calendar correctly,July 9th is rapidly approaching. You might ask

to keep pace with technology advancements. Ihope to see you at this upcoming meeting.Speaking of the Summer Committee Workshop,I would like to personally invite any and allowner/operators to attend this meeting. We needyour input into the CTI codes and standards.After all, these are for your ultimate benefit. Ifyou are not able to attend the meeting, but wouldlike to participate in committee work, please letme know and I will be happy to get you con-

“What happens on July 9th?” Well, that is the beginning ofthe CTI Summer Committee Workshop being held from July9th through July 12th at the Sheraton Sand Key Resort inClearwater, Florida. This is the meeting in which the threestanding committees of Performance & Technology, WaterTreating and Engineering Standards & Maintenance are ableto review progress on standards and codes. This is truly thebackbone of CTI and the means in which new standardsand codes are created, plus updating our existing documents

nected with the right people that match your interests andexpertise.I want to personally welcome Cleanair Engineering, Inc. andMcHale & Associates, Inc. as our two newest CTI licensedtesting agencies. These two new additions bring the CTIofficial licensed testing agencies to four, joining existing com-panies of Cooling Tower Technologies, Pty., Ltd. and CoolingTower Test Associates, Inc. I encourage all owner/opera-tors to use these CTI licensed agencies for performance and

drift code verification on any new or rebuilt cool-ing towers. By using these licensed agencies,you are assured of accurate data for adherenceto codes and standards. Just one more way CTIcan help owners and operators maximize the per-formance of their cooling towers.If you have any ideas, suggestions or concernsabout CTI that you would like to discuss withme, please feel free to contact me. I would bevery interested in discussing anything that mightimprove the offerings of CTI.

Steven Chaloupka,CTI President


Editor’s Corner

Paul LindahlEditor-In-Chief

Dear Journal Readers,Another year’s thermal testing results were pre-sented at CTI’s 2006 Annual Meeting, providinganother opportunity to consider the issue and itsimpact on our industry. The report by the Multi-Agency Testing Chair, Mark Shaw, is available forfree from the CTI office.The overall average is up a bit, influenced by a fewvery high results, likely for tests with parameterswell outside of code. There are, again, a significantnumber of tests below 100%, with too many below90%.During discussions of the report at the CTI Boardmeeting, it was suggested that the average of testsbelow 97%, and the percentage of tests below 97%be reported and presented during the Annual Conference inthe future. Field testing is generally considered to be approxi-mately within ± 3%, so a 97% threshold is arguably a fullyperforming tower. Increasing visibility of these numbers in theindustry is important for our future. The results should becarefully scrutinized in next year’s report.The Board of Directors also received a report from a committeeappointed to consider the issue. The committee recommendedopening a task group in P&T to revitalize STD-202, the existingstandard for publication of performance results for field erectedcooling towers by manufacturer name. The goal is to reducethe negative aspects of the standard that led to only one com-

pany actually joining the program.The Certification program for smaller, usually standard-ized factory assembled towers, has been very success-ful. The ranks of member companies have grown sig-nificantly over the last few years, indicating the per-ceived value of Certification of products by custom-ers. Certification of field erected towers, which aremainly custom designs to suit a particular customerneed, has been deemed impractical each time it hasbeen considered in the past. The publication of test-ing results via the STD-202 standard can at least takeus part way toward achieving the industry credibilityassociated with CTI Certification.Poorly performing cooling towers cost customers

money in process inefficiency and energy consumption every singlehour of operation. Tower owners and operators are needed toparticipate on the new task group in P&T. It is in your best interestto participate in moving this valuable program forward.Please contact me or the P&T leadership if you are interested inparticipating.

Respectfully,Paul LindahlCTI Journal Editor


Performance and Testing Program(Accoustical - Drift - Thermal Testing Agencies)

A hearty welcome to our two newest Multi-Agency Testing Companies, Clean Air Engineering and McHale & Associates,Inc. Here is an introductive discription for both companies to help you get acquainted with each.

Clean Air Engineering, Powell, Tennessee - Clean AirEngineering is proud to continue the relationship that its staff

Thermaland

Drift

Data Sheet:

McHale & Associates, Inc. - is pleased to announce the addition of the CTI Licensefor Drift Testing to our CTI License for Thermal Testing which was established earlierthis year.McHale is a specialized engineering group providing high quality measurement and

consulting services in plant performance evaluations for cooling towers and BOP testing, audits, monitoring, and optimizationsas well. McHale is the industry leader in supplying cost effective solutions, professional and innovative staff, and quality,

precision, calibrated equipment for your testing program.McHale is the successor of the past Environmental Systems CorporationPerformance Services Division (formerly PGT) and has assumed many oftheir outstanding contracts and potential opportunities. McHale haspurchased all of the ESC testing equipment, and technical and intellectualassets, including the entire calibration facility, to supplement our testingservices capabilities. Our new 7000 sq. ft. facility inKnoxville is ready to calibrate and stage the equipmentneeded for all of your testing requirements.The McHale cooling tower testing program is being leadby Mr. Gene Culver. Gene has more than 27 years of

experience working in the cooling tower industry, has been an active member of a number of CTI technicalcommittees, and is a highly skilled CTI test representative through his significant experience in providingdrift, plume, and thermal testing services.

Please note the following contact information and let us quote your next testing project:McHale & Associates, Inc. (Knoxville Offices) Thomas Wheelock, P.E. Gene Culver6430 Baum Drive Director of Testing Services Sr. Engineer - Cooling Tower ServicesKnoxville, TN 37919 [email protected] [email protected]. (856) 588-2654

Thermaland

Drift

condensers. CleanAir’s other five offices perform emissionstesting, and modeling of ESPs and SCRs for performanceoptimization. CleanAir also rents or sells calibrated testinstrumentation for thermal performance and emissions testing.The Powell, TN office can be reached at (800) 208-6162,fax (865) 938-7569, or at www.cleanair.com. Their mailingaddress is: 7936 Conner Rd., Powell, TN 37849

See advertisement on page 41

See advertisement on page 31

has had for yearswith the CoolingT e c h n o l o g yInstitute. ThePowell, Tennesseeoffice is focusedon performancetesting and coolingtower thermal and

drift tests across a broad array of industries. Within the powerindustry, the Plant Performance group routinely conductscomponent tests including evaluations of gas turbines, steamturbines, HRSGs, boilers, cooling towers and steam


Toby L. Daley, P.E.T Daley & Associates, Inc

AbstractThis paper will present the recent testing results ofcounterflow film and splash type reduced foulingfill configurations. It will present a comparison ofthe relative performance of the fills. This recent test-ing program provides a today’s performance per-spective of the most commonly used fills of thistype.

IntroductionSince the introduction of Poly Vinyl Chloride (PVC)counterflow film fills there has been a continuing

Fill Media TestedThe fill media that were tested represent a mix ofreduced fouling fills for various water quality ap-plications.These are:

· FB20· FC18· SNCS· AAFNCS· RF20· DF254· Spaced Tile

A Performance Comparison ofCounterflow Reduced Fouling Fills

effort to reduce the fouling characteristics in fouling potential ap-plications. Physical characteristics of high efficiency film fills suchas close flute spacing, cross corrugation and cross stacking ofpacks are all negatives when considering their use in fouling po-tential applications.Early applications of these high efficiency fill media in potentialfouling applications in the 1980’s were met with failure due to a lackof understanding of its behavior in the environment. It was notuncommon to hear stories of towers which routinely became pluggedafter a short period of service. It became accepted to repack a towerevery so many years to maintain the As-New thermal performance.Thus, the goal of designing a new reduced fouling fill media be-came how to reduce the fouling potential while trying to maintainthe heat transfer characteristics of a high efficiency fill media. Asthese new generations of reduced fouling fills became available itwas apparent that this goal was not going to be easily achieved. Inmost applications the solution to scheduled repacking of high effi-ciency fill media was the installation of a reduced fouling fill mediawith a substantial reduction in tower performance.However, over the last 15 years fill manufacturers have continuedto reduce the fouling potential and increase the thermal efficiency.There is a physical limit in achieving this combination that is verydependent upon the quality of the circulating water, water treat-ment and environment.This paper will present the results of recent testing of some of themost common types of these fills. Basic thermal capability compari-sons will then be performed to provide the user with an under-standing of fill selection impact versus performance. It is not theintent to provide water quality guidelines for applying the fills.There have been several quality technical papers previously pre-sented to the industry on this subject.An additional fill is included that is not a PVC film fill but is aSplash-Film fill known as “Tile Fill” which was created by CeramicCooling Tower in the late 1940’s. This fill has also been classified asa non-fouling fill.

The testing was performed at the SPX Cooling Technologies De-velopment Center over a period from 2002 thru 2005. The raw testdata was provided by SPXCT and the author performed the datareduction and analysis using custom developed software whichincludes the Cooling Technology Institute (CTI) Merkel and Psy-chrometric methods.The configuration of the test cell and testing protocol has beenpreviously described in the CTI Technical Paper TP88-05 “Com-parative Evaluation of Counterflow Cooling Tower Fills”, authoredby Bob Fulkerson.

Fill ConfigurationThe following table presents the fill configuration for each fill tested.

Fill Nozzle Type Nozzle Nominal Fill Spray HeightSpacing, Height

inchesFB20 NS5A X 12 26 X 36 4, 6, 8 Ft. 26" C/L branch to

top of fillFC18 NS5A X 12 26 X 36 4, 6, 8 Ft. 26" C/L branch to

top of fillSNCS NS5A X 12 26 X 36 1, 1.5, 2 M 26" C/L branch to

top of fillAAFNCS NS5A X 12 26 X 36 1,1.5, 2, 2.5 M 26" C/L branch to

top of fillRF20 NS5A X 12 26 X 36 1.5, 2, 2.5 M 26" C/L branch to

top of fillDF254 NS5A X 12 26 X 36 2.5, 5, 7.5 Ft. 26" C/L branch to

top of fillSpaced NS5A X 12 26 X 36 3.25, 6.0 Ft. 26" C/L branch tTile top of fill

Data AnalysisThe data was received in text file format and converted to a spread-sheet format. Using the analysis software, written by the Author, aCTI Merkel KaV/L was then determined for each test L/G, fill typeand height. A multiple regression curve fit analysis was performedto determine the coefficients and the proper equation form to math-ematically represent the L/G and KaV/L relationship.This same analysis process was performed for each fill velocity andwater loading or Q/A (gallons per minute per square foot of fill plan

Toby L. Daley, P.E.


area) to determine the fill static pressure equation form and coeffi-cients characteristics.The resulting L/G vs. KaV/L characteristics and Velocity vs. StaticPressure for water loadings of Q/A = 4, 6, and 8 are presented incurve form in Appendix A. The equations and coefficients are con-sidered proprietary.The L/G vs. KaV/L curves are presented for a hot water temperatureof 100 F.The Velocity vs. Static Pressure curves are presented at .070 den-sity (lb dry air/ft^3 mix).

Performance Comparison ModelsThe typical goal for a thermal selection is to determine the mostefficient and economical tower to satisfy a required thermal duty,horsepower, and space available. In clean water applications this isusually straight forward and involves a traditional high efficiencyfill. However, when an installation involves a water quality and/orenvironment which could interact with the fill and produce foulingthen fill selection process involves other considerations. Theseconsiderations might be hot water temperature, fill velocity, waterloading per square foot, etc.Thus, the need for thermal performance equivalence usually arises.The following questions generally occur.

· If I leave the cell size and horsepower the same, what is theperformance capability if I change to a different fill but keepthe same fill height? (Especially true in an existing tower.)

· If I change the cell size and the fill height, how much larger inplan area is required at the same horsepower?

There can be and usually are many more questions. The answerinvolves much more that just changing the fill selection. How doesit affect the air inlet heights, fan size, gear reducer, plenum, etc? It isnot the intent to provide these answers herein since there are varia-tions in proprietary rating systems and methodology. However, afill only performance comparison can be performed by using the fillthermal characteristics and static pressure curves.The performance comparison models involved the following;

· Defining three thermal duties which utilize L/G’s boundingthe characteristic line. This included a varying approach,water loading, fill velocity for a WBT = 78 F.

· Creating a normalization process to reflect % change in ther-mal capability or % change in required plan area.

The following table shows the duties used to create the compari-sons.

Duty Range, F App, F Q/AA 10.0 6.0 3.5B 10.0 10.0 6.0C 10.0 14.0 8.0

The normalization and comparative process consisted of the fol-lowing;

· A 4 Ft. fill height of FB20 was used as the base fill, plan area,and horsepower. All other fills were then compared to it.

· Holding the FB20 plan area constant – % of Capability wascompared.

· Holding the FB20 horsepower constant – Required % planarea was compared on a normalized basis.

Fill velocities ranged from 300 to 700 feet per minute.

Performance ComparisonsThe results of the performance models are presented in two graphi-cal forms. One for the capability comparison and second graph forthe percent adjusted plan area comparison. Each graphical form isplotted against nominal fill height in feet.All comparison graphs are at HWT = 100 F.The following graphs are presented in Appendix A:Holding the FB20 plan area constant – % of Capability was com-pared.

· Figure A1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F· Figure A2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F· Figure A3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

Holding the FB20 horsepower constant – Required % plan areawas compared on a normalized basis.

· Figure B1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F· Figure B2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F· Figure B3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

% of Capability Comparison - Example

Figure A-1 reflects that as compared to 4 Ft. of FB20 in the same fillplan area it would require the following fill heights or greater toachieve the 100% capability.

Fill Minimum Equivalent Fill Height – Duty AFB20 4 Ft. (Base)FC18 6 Ft.SNCS 1.5 MAAFNCS 1.5 MRF20 1.5 MDF254 5.25 Ft.Spaced Tile 4 Ft. = - 35% capability (Not Shown)


Required % Plan Area Comparison – Example

Figure B-1 reflects that as compared to 4 Ft. of FB20 to maintain thesame horsepower would require the following change in plan areato achieve the 100% capability.

Fill Required Minimum Equivalent Fill Plan Area,Ft^2 at Same Hp – Duty A

FB20 4.0 Ft. (Base)FC18 4 Ft. Requires 2.8% IncreaseSNCS 1 M Requires 6.2% IncreaseAAFNCS 1 M Requires 4.2% IncreaseRF20 1 M Requires 4.2% IncreaseDF254 4 Ft. Requires 2.8% IncreaseSpaced Tile 4 Ft. Requires 52.1% Increase (Not Shown)

ConclusionsIn concluding it can be seen from the figures in Appendix A thereare several options that exist in fill selections classified as ReducedFouling Fills. The continued efforts to improve the thermal charac-teristics of these types of fills have produced a varied selection tochoose from depending upon the quality of the circulating waterand the environment. However, in general the more reduced foulingeffective the fill is there is a performance trade off due to the physi-cal characteristics required to achieve this goal.APPENDIX A% of Capability Comparison

· Figure A1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F· Figure A2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F· Figure A3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 FRequired % Plan Area Comparison· Figure B1 Duty A R=10 F, A=6 F, Q/A = 3.5, WBT = 78 F· Figure B2 Duty B R=10 F, A=10 F, Q/A = 6.0, WBT = 78 F· Figure B3 Duty C R=10 F, A=14 F, Q/A = 8.0, WBT = 78 F

% of Capability Comparison


% of Capability Comparison continued Required % Plan Area Comparison


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Required % Plan Area Comparison cont’d

APPENDIX BFill Characteristic Curves

Curve No.1 FB20 4, 6, 8, Ft. Fill HeightsCurve No.5 FC18 4, 6, 8, Ft. Fill HeightsCurve No.9 SNCS 1, 1.5, 2 M Fill HeightsCurve No.13 AAFNCS 1, 1.5, 2, 2.5 M Fill HeightsCurve No.18 RF20 5, 6.5, 8 Ft. Fill HeightsCurve No.22 DF254 2.5, 5, 7.5 Ft. Fill HeightsCurve No.26 Spaced Tile 3.25, 6.0 Ft. Fill Heights

Fill Pressure Drop CurvesCurve No.2 FB20 4 Ft Fill Height Q/A = 4, 6, 8Curve No.3 FB20 6 Ft Fill Height Q/A = 4, 6, 8Curve No.4 FB20 8 Ft Fill Height Q/A = 4, 6, 8Curve No.6 FC18 4 Ft Fill Height Q/A = 4, 6, 8Curve No.7 FC18 6 Ft Fill Height Q/A = 4, 6, 8Curve No.8 FC18 8 Ft Fill Height Q/A = 4, 6, 8Curve No.10 SNCS 1 M Fill Height Q/A = 4, 6, 8Curve No.11 SNCS 1.5 M Fill Height Q/A = 4, 6, 8Curve No.12 SNCS 2 M Fill Height Q/A = 4, 6, 8Curve No.14 AAFNCS 1 M Fill Height Q/A = 4, 6, 8Curve No.15 AAFNCS 1.5 M Fill Height Q/A = 4, 6, 8Curve No.16 AAFNCS 2 M Fill Height Q/A = 4, 6, 8Curve No.17 AAFNCS 2.5 M Fill Height Q/A = 4, 6, 8Curve No.19 RF20 5 Ft Fill Height Q/A = 4, 6, 8Curve No.20 RF20 6.5 Ft Fill Height Q/A = 4, 6, 8Curve No.21 RF20 8 Ft Fill Height Q/A = 4, 6, 8Curve No.23 DF254 2.5 Ft Fill Height Q/A = 4, 6, 8Curve No.24 DF254 5 Ft Fill Height Q/A = 4, 6, 8Curve No.25 DF254 7.5 Ft Fill Height Q/A = 4, 6, 8Curve No.27 Spaced Tile 3.25 Ft Fill Height Q/A = 4, 6, 8Curve No.28 Spaced Tile 6.0 Ft Fill Height Q/A = 4, 6, 8


David M. Suptic P.E. LLC

Abstract:Faced with multiple gear reducerfailures on two large cooling tow-ers, an international power genera-tion facility replaced 28 sets of rearreduction drives and supportingstructure with new, upgraded equip-ment. A description of the uniquenature of this large scale equipmentreplacement project provides thereader with several key steps to

ness, bolt hole locations, and details of the gear reducer loca-tion relative to existing support beams. (Figure 1)

Large Scale Mechanical EquipmentReplacement - Simple Steps for Success

insure success on construction products of a similar nature.

Introduction:After less than two years of operation a new power genera-tion facility located in western Turkey experienced a seriesof cooling tower gear drive failures. The new cooling towerswere two large counterflow units, each with 14 cells of backto back 10 Meter diameter fan drives. The cooling towersprovided heat removal for a four unit-1650 megawatt gasfired cogeneration plant. The cooling towers were constructedof pultruded fiberglass and circulated sea water for cooling.Replacement of the failing gear drives was necessary to pre-vent the loss of power generation capacity. Mechanical fail-ures and replacements are not uncommon on large industrialcooling towers, however, such replacements are usually per-formed on one or two cells with limited plant impact. Theurgency of this particular replacement and the large numberof units to be replaced created the need to apply successfulproject management and field construction techniques in anenvironment of language and cultural diversity, to say the least!The writer served as a technical advisor to the project man-ager for the 28 cell mechanical equipment replacement project.

Background:The project was divided into three distinct phases; initial fieldmeasurement and verification, trial installation, and final in-stallation. Accurate field measurement of existing mechani-cal support beams was considered critical to insure the properdesign and fabrication of new mechanical supports. Sevenmonths before actual equipment installation, the writer per-formed field measurements of beam sizes, elevations, level-

Figure 1The condition of the supporting wide flange beams was satis-factory even though their material was galvanized steel, butthere was considerable corrosion of the 10" square tube sup-porting the old mechanical system. (Figure 2)

Figure 2A trial installation of two gear reducers with torque tube typesupports was scheduled one month prior to final installation.While domestic projects of this type may not require this ex-tra step, the logistics of shipping a large number of units acrossthe Atlantic Ocean made it more important to perform thistrial installation. A construction process could also be cre-ated that would be reviewed and approved by power plant

David M. Suptic


managers. The local workers would also have an opportunityto learn the process of cooling tower construction before fullscale installation.Final installation was planned for July 2005. Unfortunatelythe weather during July in western Turkey is very hot, up to40 degrees C (104 degrees F). This hot temperature wouldimpact the construction schedule but worker safety was veryimportant. The work crew consisted of 17 Turkish carpen-ters and one construction foreman who was experienced withpower plant construction. None of the workers spoke En-glish or were able to read drawings. The foreman spokebroken English and was able to instruct workers on the propercooling tower construction methods. Two plant engineersassisted with communication and coordination with plant op-erations personnel. The engineers spoke fluent English.Two 50 Ton cranes were used in the final construction phase,one at each cooling tower. The work crews were split evenlybetween the two towers. Only one cell on each tower couldbe shut down at a time to keep the plant on line. Work wasinitially scheduled for 12 hours per day, six days per week.The high heat forced the schedule be relaxed to nine hourdays. The project manager believed the total project could becompleted within 18 working days. A construction processwas needed that would produce a safe job with a minimum ofdelays.

The Process:Since the gear reducer model and manufacturer were to bechanged, the support system design was also revised. Thenew structural support and gear reducer would raise the fanheight by approximately 15.25 cm (6 inches). It was impor-tant to verify the existing motor power wiring could be usedwith the new mechanical system. Although the wire couldnot be lengthened, the conduit system had enough play toaccommodate the additional equipment height. (Figure 3)

Figure 3

During the initial trial installation, the complete motor seg-ment of the fan cylinder was to be removed. This work provedto be very time consuming for the work crews to erect scaf-folding and unbolt the segment. There was also concern forthe structural integrity of the remaining fan cylinder segments.So, for subsequent construction a large square opening wouldbe cut around the motor and support to allow removal of theold torque tube assembly. (Figure 4)

Figure 4This opening would later be resealed with the old segmentparts bolted together with fiberglass bands.The area under the mechanical equipment was completelycovered with scaffold planks and surrounded with a guardrail. With this level of fall protection in place, no climbingharnesses were required by the workers as they worked inthe fan cell.During trial installation, individual mechanical componentswere removed and reinstalled by crane hoist. This processwas time consuming but helped the work crew learn how tohandle the mechanical components individually. Each old gearreducer and fan hub was removed as an assembly and takento the plant’s machine shop where a torch, hub puller, andhydraulic jack were used to separate the hub components.Figure (5)

Figure 5


The galvanized fan hub plates were reconditioned by sand-blasting and painting with Urethane paint. Epoxy paint wouldhave been preferred but was not available. There was con-siderable galvanic corrosion between the Aluminum fan bladeclamps, galvanized steel fan blade shanks, and the galvanizedhub. The use of Aluminum fan blade clamps for sea water dutycooling towers is not generally recommended. Additional corro-sion was also observed on the blade skin attachment bolts whichcould lead to eventual blade failure. Correction of this deficiencywill be addressed in the future. (Figure 6).

filling the gear reducer with oil, fabricating and installing thefan shroud closure, rewiring the motor and checking rotationdirection, installing a new anti-rotation device to prevent back-ward fan rotation, and finally clearing the cell of fall protec-tion equipment, closing the access door, and operating thefan.The trial installation of two cells helped the work crew andproject managers fully understand the many steps that mustbe sequenced and performed properly to insure the best pos-sible installation. The new mechanical equipment operatedperfectly but the two trial installations had taken 36 workhours to complete with a crew of seven men.

Final Installation Project:26 new gear reducers, torque tube supports and associatedmaterial arrived at the power plant in time for a project startdate of July 20. The construction process was closely re-viewed for any potential time saving adjustments. Twochanges were proposed that would drastically reduce overalltime to complete each mechanical system change out.First, the mechanical equipment would be preassembled onthe ground next to the cooling tower and the complete as-sembly hoisted on to the tower. This process is used suc-cessfully in the United States and with some rigging adjust-ments; the Turkish crew became comfortable with the hoist-ing process. (Figure 8)

Figure 7

Figure 6

New split taper bushings were supplied to reinstall the fans,and the steel center hub was sandblasted and repainted withUrethane paint. The original fan assembly bolts were re-used after careful cleaning. These stainless steel bolts weretorqued to appropriate values without bolt lubricant. As thetrial installation progressed the new torque tubes were set inplace. The position was measured to insure the fan wouldbe centered with the fan shroud. Hold down hole positionswere marked using the torque tube as a template. The torquetube was removed with a crane hoist and new holes weredrilled in the existing support beams using a magnetic basedrill.The torque tube was hoisted and bolted to the support beams.Then the old motor, gear reducer, and drive shaft were rein-stalled on the torque tube. The first drive shaft alignmentwas performed by a senior millwright from the power plantstaff. Special steel adaptor rings for holding the dial indica-tor were fabricated in the plant. (Figure 7 ).Since the workers had little experience with cooling towerconstruction it was very interesting observing the trial anderror process used to shim, bolt down, measure alignment,and do again until correct alignment was achieved. Severaladditional steps would be required to finish the installationincluding, fan blade installation, oil and vent line installation, Figure 8


By hoisting the completed “power-pack” all the new gearreducers could be pre mounted to the torque tubes at groundlevel. The, as each old motor and drive shaft became avail-able during the disassembly phase, the power pack assemblycould be completed including initial drive shaft alignment.One key to success when replacing multiple sets of mechani-cal equipment is to perform as much work as possible on theground. This is especially valid in hot weather because thework is much more difficult inside the fan shroud with 100%cooling tower humidity surrounding the workers. Workersinside the fan cell required frequent breaks to prevent heatexhaustion.Additional time saving steps were incorporated as the newpower packs were being installed in the fan cell. The powerpack was carefully positioned on the existing support beamsand then centered by measuring the radius from the fan hubbushing flange to the inside surface of the shroud. By mea-suring in four places the power pack assembly could be movedand centered very accurately (within +/- 5 millimeters). (Fig-ure 9). The hold down hole locations were marked using the

cause of the time required to sandblast, paint, and cure thehub plates. Fortunately, the plant had two spare hub platesthat were cycled into the process. This ensured two com-pleted plates were available as soon as the rest of the fan hubreconditioning was complete. Fan blade shanks and alumi-num blade clamps were cleaned up with emery cloth by thework crew as slack time permitted.The fiberglass shroud openings were cut with angle grinderswhich made quick work of shaping the fiberglass parts to fit.Custom closures for holes in the old shroud were fabricatedby hand and shaped with the grinders too. Workers werealways careful to observe safety precautions when grindingon the fan deck. Fire extinguishers and a fire hose were athand for any unexpected sparks.It was very important for the work crew to coordinate ef-forts with the plant operation and maintenance personnel.Plant personnel coordinated and performed the fan hub re-furbishment and provided electricians to disconnect and re-connect the motors and install new vibration switches. Lockout/tag out of the fan motors was performed by plant engi-neers when any motor was taken out of service or the newcell was started up. The plant painter was required to applyepoxy touch up paint to the torque tube and gear reducersbefore they were put into service.Before each new cell was put back into service the fan bladepitch was adjusted to 10 1/2 degrees to achieve optimum motoramperage. Adjusting the pitch was necessary because ofslightly different fan speed and the increased fan elevationwithin the fan cylinder. Vibration on the fan shroud had in-creased, compared to original uncut stack, but remained withinacceptable levels.

Conclusion:The time required to deconstruct and reinstall each fan cellwas reduced from 16 -18 hours per cell to less than 12 hours

Figure 10

Figure 9

torque tube as a template. To save even more constructiontime the power pack was hoisted and moved aside with themotor sticking through the fan shroud access door. Holeswere drilled in the support beams and the power pack wasquickly moved back in place and bolted down tight. Driveshafts were aligned to final tolerances after the power packwas bolted in place.Another helpful time saver was to preassemble the stainlesssteel oil lines and vent lines on the ground. All 26 units werepreassembled when workers had any slack time. They wereeasily hoisted into place through the top of the fan shroud andquickly connected to the power pack assembly. (Figure 10)The turnaround time for removal and refurbishing the old fanhubs became the bottleneck in the construction process be-


per cell by employing the time saving techniques described inthis paper. The Turkish construction crew was able to quicklylearn and effectively apply common cooling tower construc-tion practices without the aid of detailed construction draw-ings or specifications. Each technique was described to plantengineers and the construction superintendent who taught theworkers everything the needed to complete the job.Worksite material control is always a problem at constructionsites. It is especially important to maintain tight material con-trol when the jobsite is overseas because of the difficulty inobtaining replacement parts. Hardware is particularly diffi-cult to control, and the large stainless steel mechanical holddown bolts were prone to seizing under repeated tightening.Several bolts were lost to seizing and were replaced throughlocal supply. Additional small bolts were discovered missinglate in the project and had to be replaced. All of the jobmaterial had been stored in open crates adjacent to eachtower. Workers had free access to the material as neededon the job. Had all the hardware been separated, counted outper cell, and issued to the site as each cell was started, thematerial shortages would have been identified earlier andcontrolled better.The 28 cell installation was completed in 20 – nine hour workdays with a crew of 17 men and two cranes. The two trialinstallation cells had to be reworked because of paint defi-ciencies that were corrected at the plant. Success wasachieved in a difficult work environment because of the cre-ativity and work ethic of the Turkish crew and supportingplant personnel.By applying key time saving construction techniques and pay-ing close attention to the process bottleneck, impact to thepower plant was minimized and satisfaction of the plant man-agement was achieved. 21 steps to success are summa-rized:

1. Stop the fan motor. Lockout / tagout at the MCC.2. Scaffold and plank area under the fan and mechani-

cal equipment.3. Unbolt and unwire motor. Disconnect old vibration

switch. Lower motor to ground with crane.4. Motor is placed on torque tube and gear reducer is

mounted to “power pack” on grade.5. Drive shaft is removed and lowered to power pack

at grade.6. Drive shaft hub and hardware is placed on gear re-

ducer input shaft along with anti-rotation device.7. Power pack of new mechanical equipment and old

motor/drive shaft is completed including drive shaft

alignment. New fan hub bushing is mounted on fanshaft. Plugs are glued into torque tube openings.

8. 10 Meter diameter fan blades are removed from hub.Old gear box hold-down bolts are removed. Cranelowers gear box and fan hub to grade. Unit is movedto plant workshop.

9. Mechanical support hold-down bolts are removed andsupport is lowered to grade with crane.

10. Old fan hub is removed from old gear box with torchand hydraulic jack. Old hub plates are sand blastedand repainted. Fan center hub is cleaned by handand painted with enamel paint.

11. Power pack is lifted to the fan cell and gently posi-tioned on old structural beams.

12. Fan bushing mounted on gear reducer shaft is usedto center the power pack in the fan cell. When cen-tered, holes in torque tube feet are used to mark sup-port beams for drilling.

13. Power pack is moved aside and supported with crane.Holes drilled in support beams with a magnetic basedrill.

14. Power pack is reset in place and bolted down tight.Any spots with gaps between the torque tube feetand support beams are shimmed with stainless steelshims.

15. Motor is rewired, new vibration switch is mountedon torque tube support

16. Fan is reassembled on new gear reducer. Bladesare pitched as specified with digital inclinometer. Tipclearance is checked around fan circumference.

17. Oil line and vent line that have been previously as-sembled at grade are lifted by crane and assembledonto torque tube.

18. New closure pieces are fitted around torque tube open-ing. Backing plates are bolted across the cut madewhen fan cylinder segment was removed. Couplingguard is modified to fit fan cylinder and screwed intoplace.

19. Gear reducer is filled with mineral oil and external oillevel placard is set at the full level. All mechanicaland structural bolting is checked for proper torque.

20. Scaffolding is cleared from the fan cell. Final checkis made for material removed from cell.

21. Door is closed and fan started. Vibration switch setat 0 .3 in/sec trip level. Motor amperage is mea-sured.


By Gene Ort, Internet Marketing JV

AbstractYou have a better chance of winning at roulettethan protecting your cooling towers with mechani-cal vibration switches. The odds at roulette arerelatively straight forward. There are 36 numberswith which you might win plus two sure-loss“house numbers”: 0 & 00. If you play just num-bers with a payoff of 35 to 1 for a win, long-term,you probably lose 5.26% of your money. That’slike a mortgage without the house.The odds of protecting your cooling towers withmechanical vibration switches from excessive vi-bration are more difficult to calculate. But theyare so poor, precision isn’t necessary to make thepoint. It is tempting to para-phrase the old say-

It’s the old 80-20 rule but in reverse: 80% of theswitches handle 20% of the problems. The restof the time, they are clueless. Why do youthink we call them “earthquake switches”?

The Nature of the ProblemIn many plants, cooling towers are still consid-ered BOP (Balance of Plant) meaning they de-serve less investment and attention than morecritical machines: a legacy from the times ofless plant efficiency and substantial excesscooling capacity. Now, there is greater produc-tion efficiency and less capital spent on cool-ing towers. Excess cooling capacity has dimin-ished. In many plants, if you lose a cooling

Roulette And Mechanical VibrationSwitches: What Are Your Odds?

ing, “Close only counts in horseshoes, hand grenades, and me-chanical vibration switches”, but that does a disservice to horse-shoes.In many plants, cooling towers are no longer balance of plant (BOP)equipment worthy of only “symbolic”, minimal, or lowest cost pro-tection from excessive vibration. Losing a cell in the heat of sum-mer can reduce production throughput. With their increasing sig-nificance, cooling towers require better protection than affordedby mechanical vibration switches. With any reasonable definitionof “protection”, a case will be made that mechanical vibrationswitches, called “earthquake switches” in the trade, may offer noprotection at all from the excessive vibration of the rotating equip-ment in your cooling towers. Mechanical vibration switches dosense shock. They sense vibration at very high levels or high rpmand may give notice that a disastrous failure has just occurred.Better solutions will be listed with pros and cons.Introduction: It’s Your Choice- Effective Cooling Tower Protectionor Disaster ConfirmationFigure 1 is a greatly simplified nomograph based on physics andthe generally accepted values of the condition of rotating equip-ment. It represents the accumulated knowledge of decades of thevibration instrumentation industry. It is developed in detail at thepaper’s end (see figs. 1a-1d). In log scale and at a typical 1 Gacceleration switch setting at 1800 rpm driver speed, the sensitiv-ity area for mechanical vibration switches in Fig. 1 begins at over4 times the level designated as “BAD”: at the lower fan speeds, itis over 20 times!

The 80-20 Rule for Earthquake SwitchesWith any reasonable definition of “protection”, a case can be madethat mechanical vibration switches, derisively called “earthquakeswitches” in the trade, offer little or no protection for rotatingequipment from excessive vibration in cooling towers.

Fig. 1tower in the heat of summer, cooling capacity drops below 100%,production is decreased and cooling towers are Not BOP AnymoreIf plant managers and underwriters do not know, vibration analystsdo know that cooling towers present a particularly challenging situ-ation for monitoring its vibration. The train includes an electricmotor drive, usually at 1800 rpm, long jack-shaft, right angle speedreduction gearbox to approximately 100 to 300 rpm, and large diam-eter fans (fig. 2). This machine is large, complex, production depen-

Gene Ort

Fig. 2


dant and may be the last machine in your plant on which you wanta mechanical vibration switch. But 15,000 to 20,000 mechanicalvibration switches go into service every year: most on cooling tow-ers.

The Scope of the ProblemThere could be over a quarter-million mechanical vibration switchesout there. There are three major manufacturers of mechanical vibra-tion switches which are typically sold to cooling tower manufactur-ers (OEMs) in substantial volume. One switch manufacturer claimedon their web site that 125,000 switches have been installed. Thereare likely over 15-20,000 new switches going into service everyyear. In addition, there is also a switch that uses a pedestal and ballwith a chain to a switch. If the tower shakes enough, the ball fallsoff the pedestal to initiate the switch action, to be reset by hand.

TerminologyIn the development of figure 1 and the basic vibration informationthat follows, four terms are used:

1. frequency (in cpm= cycles per minute or RPM = cycles atrunning speed)

2. acceleration (in Gs)3. velocity (in ips = inches per second)4. displacement (in mils peak to peak)

They refer to the movement of points on the machine and are re-lated by physics. Given frequency and one point, the other two canbe calculated and shown on the graph.

Accepted Use of These TermsBy their design, mechanical vibration switches are sensitive to ac-celeration only. There is no signal from which to generate moremeaningful information about a machine’s operating condition andgenerate meaningful alarm levels.Electronic switches and monitors use an accelerometer to producea “dynamic signal” containing all the significant contributors ofinterest. This signal can be used with instrumentation to:

1. Develop overall vibration (not shock values)a. In terms of accelerationb. Be integrated to show overall vibration in velocityc. Be integrated again to show overall vibration in

displacement (not recommended)2. Use the “waveform” (complex signal) for analysis3. Develop spectra of the various contributors to vibration

for analysis.

Debunking Eight MythsBy misusing the terminology above, some myths developed overthe years about the design, suitability for the purpose and accuracyof mechanical vibration switches, especially as they relate to cool-ing tower protection.

Myth #1- Use acceleration, not velocity or displacementTo place mechanical vibration switches as solutions for monitoringcooling towers, vendor’s marketing “promotes” the term accelera-tion over the other, more relevant terms used for that purpose.Examples:

1. Acceleration is your best solution for monitoring coolingtowers

2. Displacement is for deformation or bending (inferring notmachine vibration)

3. Velocity is most useful for sound (again, inferring not ma-chine vibration)

Fact: Velocity and displacement are used to monitor vibration inthe overwhelming majority of rotating equipment in the world. Theclaims of mechanical vibration switch vendors fly in the face of allaccepted practice of vibration monitoring whether for protection oranalysis; for cooling towers or most of the other machines in theworld. Remember, acceleration is all that these vendors have.

Myth #2- Design & Suitability for PurposeClaims are made that a mechanical vibration switch is effective for“slow to medium speed machines”, or “0 to 3600 rpm”. (Right of thewebsite)Fact: “It depends on what the definition of is is.” It depends moreon what the definition of effective is. Take a quick look at Figure 1again. That claim is simply not true for vibration or any reasonabledefinition of effective.

Myth #3- Acceleration is KINGReference by proponents is made to Newton’s Law F=MA. Incontext, it is meant to leave the impression that acceleration isessential and by their absence that displacement & velocity arenot. F=MA is appropriate if you want to launch your cooling tower,and occasionally they do; likely with their mechanical vibrationswitch.

Myth #4- Unique Terminology used for MechanicalVibration SwitchesTerms are used by proponents of mechanical vibration switchessuch as “acceleratory vibration” and “acceleratory shock”. Thislooks and sounds good: highly technical.Fact: An Internet search for acceleratory vibration” brings up onepage and it’s the vendor’s. When is the last time you got a onepage hit for any search? “Acceleratory shock” gets 20 hits, but allrelated to sites promoting mechanical vibration switches with noother reference in the world of internet searches.

Myth #5- Set Point AccuracySome manufacturers claim accuracy of set point adjustment.Fact: These are very crude devices. Do you know how to check tosee if the switch is set for 1 G? Pick it up and rotate the switch 90°(on its side). If you hear the mechanism “click”, you’re set forapproximately 1 G. If you can rotate the switch 180° (upside down)before you hear the “click”, the switch is set for approximately 2 Gs.Note there was no vibration involved.Further, this is likely how production sets the unit prior to ship-ping to the OEM or end user since it is quick and less costly thansetting the units on the huge shakers necessary for the switches’large mass. You can also get the “click” if you hit it hard enoughwith a big enough hammer. In real life, if the cooling tower hassubstantial shock or “bump” on startup and the switch activates,the solution is to “crank it up” until “it doesn’t bother you” any-more. That higher setting is unknown and likely quite high, furtherlimiting the switch sensitivity in the cooling tower vibration levelsof interest.


Myth #6- Range AccuracyIn most instrumentation, you match the instrument range to ex-pected values in operation preferring not to operate too near thebottom or top of the range. Some mechanical vibration switchproduct lines show multiple ranges leaving it up to you to drawwhatever conclusions you wish about the accuracy and suitabilityfor your use. It’s not clear how one chooses between 2, 4.5, 5, or 10g models.Fact: It is likely that all the mechanisms of one manufacture are thesame but different ranges are claimed. Inquiry of your vendor isappropriate. If it is true in your case, the 2 G switch you boughtthinking you have “narrower range with finer adjustment” is reallyas course as a 10 G switch.

Myth #7- CostLegacy issues include the perception that mechanical vibrationswitches are cheap and do the job.Fact: There are some cheap switches available in the $200-$300range. Prices off the Internet can go from $200 to over $700 forsome models. But if they are unsuitable to protect your coolingtowers, any price is too high. For similar prices, there are muchbetter solutions available.The OEMs that buy mechanical vibration switches in quantity, dobuy for substantially less unit cost. It’s up to the user to specifybetter solutions and possibly pay a little more for better protectionof this valuable plant asset.What is the cost of lost production? What does it cost to replacea gearbox or repair the damage to the cell if the fan throws a blade?Or worse? Is saving just one of those disasters worth $200 to$500?

Very Basic Applied VibrationVibration is a symptom of underlying machine component condi-tion and the overall function of the machine. To better understandthe statements of this paper and the claims of mechanical vibrationswitch manufacturers, only the basics of vibration needs to beunderstood; essential to make your own informed judgment. Thefollowing analogies support this abbreviated vibration primer:Analogies: Overall Values vs. Complex

LightWe think of light in overall terms as intense, bright, soft, or dim.We’ve all been fascinated as kids to find that sunlight separatesinto its different colors (frequencies) by use of a prism or as anexplanation for what makes a rainbow.

SoundWe know that the sound we hear can be thought of as loud or faintand yet it too is complex. Submariners can tell the class and nameof Russian submarines from their complex and unique “signatures”.Even without the fancy instrumentation, humans are wonderfulsound analyzers. A song no sooner starts and you know if it Bingor Sting, Minnelli or Bocelli. Your phone rings, you answer, andwithin two words, you know it’s your wife and whether or not youare in trouble.

VibrationOverall vibration levels can be high or low, but like sound and light,

are very complex. Basic machine vibration is made up of a varietyof vibrations contributed by the machine components, its mount-ing, blade aerodynamics, and other process & environmental fac-tors. In the case of cooling towers, the overall vibration, high orlow, is comprised of the summation of all vibration contributions atvarying frequencies and amplitudes from:

1. the electric motor drivea. mechanical imbalance, electrical imbalance, misalignment,bearing frequencies, soft motor mounting and more; a func-tion of driver RPM.

2. the gearboxa. mechanical imbalance, misalignment, bearing frequencies,and gear mesh frequencies; a function of driver RPM andfan RPM.

3. the fan

a. mechanical imbalance, misalignment, and aerodynamic con-tributions; a function of fan RPM, the number of blades andother factors.

4. Other cells (propagation) and the environment (such as trainsgoing by in close proximity)

The most destructive energy on any machine is imbalance andmisalignment. Their energy level at frequencies of one or two timesrunning speed is so large a part of overall vibration, it usuallymasks the other higher frequency contributions depending uponwhere the measurement is taken and for what purpose. Overallvibration is measured by the electronic vibration switch and ismost effected by imbalance and misalignment. Only your analystcan give you the details of the condition of the machine by estab-lishing baselines and watching over time to see how the variousfrequencies change. Your GP may tell you if you are in good healthor not, but you wouldn’t go into open heart surgery without acardiologist and at least results from your electrocardiogram.

Likely causes of vibration in cooling towersIn cooling towers, there are many contributors to vibration butlikely causes of vibration include:

1. Plugging weep holes in a fan blade is a source of greatimbalance as condensate builds within only one of sev-eral blades.

2. The aerodynamic performance of the fan blades can besignificant. One reported case had blades getting a lift asthey passed over the jackshaft. That would show us assignificant imbalance at a frequency equal to the numberof blades times running speed.

3. Misalignment of motor to gearbox at the end of the longjackshaft can be significant at one or two times runningspeed.

4. Gearboxes in early stages of degradation offer dramaticdynamic signals but show little effect on overall vibrationreadings. In later stages, their contribution to overall vi-bration gets significant.

5. The same can be said of rolling element bearings in thegearbox or motor. An interesting side note to this is thatrolling element bearings often appear to get “better” justbefore complete failure.


6. Electric motors can contribute to imbalance due to softfoot mounting which shows up at two times running speed.The effects of broken rotor bars show up at “runningspeed” in normally taken data. Before you start a balanc-ing procedure, make sure you know the source. A vibra-tion analyst can set up to take readings with greater reso-lution than normal to ”separate” the motor running speedfrom the 50 or 60 Hz driving frequency. They are close butnot exactly the same due to slip. Broken rotor bars are amajor contributor to electrical imbalance.

Simple Vibration MeasurementsA very simple sinusoidal vibration signal looks like that shown infig. 3 and is measured in velocity, displacement & acceleration at itsfrequency.

Figure 3Machine Vibration MeasurementsAll components of a machine generatedifferent frequencies andenergy levels which contribute to the overall vibration measured.For illustration purposes only, these various frequencies are shownin fig. 4 on a spectrum plot of a fan with significant imbalance and“looseness”.

arrangement may vary but in principle, it is represented by fig. 5.

Figure 4

They are sensitive to acceleration only and can be activated byshock, position, or high levels of vibration inappropriate for ad-equate cooling tower protection.There is another even simpler version of a mechanical “vibration”switch. It is referred to as a “ball & pedestal” type. See fig. 6.Shake the tower enough and the ball comes off of the pedestalactivating the switch. Resetting is manual.

Figure 5

Principle of Operation of a Mechanical VibrationSwitch (MVS)Why do Mechanical vibration switches sense only accelerationand none of the other measurements of vibration? Take a look attypical construction of the mechanism. Most MVSs consist ofsprings, magnets, a lever arm, and 1 or 2 snap action switches. The

Figure 6

Alternatives to Mechanical Vibration SwitchesThey include:

1. Accelerometer mounted on gearbox (see fig. 7) With acable run to a box outside the cell.

Figure 7


This is not protection 24/7 but a complement to aninstalled vibration switch.

2. Electronic vibration switch mounted on the gearbox3. Vibration transmitter mounted on the gearbox4. Single channel monitor mounted outside the cell using an

accelerometer on the gearbox.5. Dual path monitor using a single installed accelerometer6. A multi-channel monitor with single or double accelerom-

eters installed per machine train.Alternatives 2 through 6 offer a substantially superior solutionfor protecting cooling towers than do mechanical vibrationswitches. They share one thing in common: they use an acceler-ometer and electronic circuitry to capture the relative dynamic vi-bration signal and process it to meaningful & useful overall vibra-tion levels or for analysis when needed.The electronic switch uses an internal accelerometer and is installedas a unit. The monitor solutions use external accelerometers mountedon the gearbox with instrumentation outside the cell.Are there advantages of electronic switches over mechanical vi-brations switches? Yes. As standard or optional features, you get:

1. Accurate sensing of the vibration found in the rotatingequipment in cooling towers

2. More precise and relevant alarm and shutdown set-pointadjustability

3. Adjustable time delay to ride through transient eventseliminating the need to run at set points higher than thoseneeded for prudent protection levels

4. Smaller size that is more appropriate for mounting on thegearbox directly

5. Easy access to the dynamic signal needed for analysisand quicker turn around on repairs

6. Valuable cooling tower information to trend and displayon your DCS operator interface.

Important Notes:a. REPLACEMENT OF MVS: If you are going to replace a

mechanical vibration switch, do not remove or disconnectit before your alternative solution is installed and opera-tional.

b. LEAVE THE MVS INSTALLED: Consider leaving the me-chanical vibration switch installed in a “belt and suspend-ers” approach to protecting a cooling tower: you havealready paid for it. Mechanical switches do sense shockwhereas electronic vibration switches sense vibration andshould have adjustable 3 to 5 second time delays built into override short-term episodes. Failure of some compo-nent might occur without vibration being a precursor.

c. MOUNTING A VIBRATION SWITCH: As seen in figure8, both mechanical and electronic vibration switches canbe mounted in a poor or totally ineffective position. Thiselectronic switch is mounted on an extension of thestructure’s frame. Its axis of sensitivity is parallel to thejack shaft with its mounting negating most if not all thebenefits of the electronic vibration switch. Consult some-one who knows this application about the mounting ofyour current switch or its replacement. If you like, attach

a digital image of the switch installation to an e-mail andsend it to me at [email protected] for comment. Iwould be glad to help.

d. SET POINT FOR ALARM OR SHUTDOWN: How dooperators know what cooling tower vibration levels arenormal or tolerable and what levels are dangerous? Thatis a good question. It is addressed in general terms on thenomograph overlays of “Good” to “Bad”. See fig. 1C.There is no one answer but 0.5 ips velocity is high in mostapplications. But this is only a reference and not a rec-ommendation for any specific machine. Of the many callsI have received over the years with this question, I ask,“What does your vibration analyst say?” The answer alltoo often is, “I don’t know. I didn’t ask.” Check with youranalyst or if you use a contract analyst, ask them. Theyare a good source of this information. The reason is thatit is important to know the baseline levels, current levelsand performance of the cooling tower in the past. It de-pends on the vibration sensing device, where it is mounted,how it is mounted and your analyst can answer with thatin mind. Often, the levels are “negotiated” between op-erations and maintenance for practical plant/machine re-lated issues.

Some application issues for each electronic vibra-tion switch solution include:

1. Mounting an accelerometer on gearbox (see fig. 7)Using an accelerometer and running the cable to a boxoutside the cell is a partial solution. In itself, it is notinstalled “protection” but is used by many to manuallymonitor a tower periodically. It gets the dynamic vibra-tion signal into an area more easily and safely accessedby an analyst collecting the data for long-term trending ortrouble shooting. It is data you should get regardless ofyour protection solution. If done well, it will complementvibration switches by giving early warning of problemsand likely pin-point the source for quicker repairs. If it isalready installed, install an electronic vibration switch forthe 24/7 protection of the machine as soon as possible.

2. Electronic vibration switch mounted on the gearboxThis is a common replacement tactic offering the advan-tages of an internal accelerometer, relatively moderate cost,

Figure 8


but if replacing a mechanical vibration switch, requirespower be run to the unit and with some added cost. If theswitch is mounted on the gearbox, it still leaves the ques-tion of getting that important dynamic signal out to thevibration specialist.ADVANCED NOTICE: By the time this paper is distrib-uted, there will be on the market (or soon to be on themarket) an inexpensive two-wire electronic switch de-signed specifically to replace mechanical vibration switcheswithout the sometimes high cost of running added powerlines to new powered electronic vibration switches. Justpull the mechanical switch and install the electronic switch.It will run off of the same line and you get all the benefitsof an electronic switch.

3. Vibration transmitter mounted on the gearboxWhile not common in use on cooling towers, a vibrationtransmitter mounted on the gearbox, can be used in con-junction with a PLC or DCS trending the 4-20mA signaland giving relay action based on preset alarm and shut-down levels. Some offer 4-20 mA signal and the dynamicsignal which can be run to a box with a BNC jack for theanalyst although the full range of frequencies for appro-priate analysis may not be available to the analyst. Cau-tion is suggested.

4. Single channel monitor mounted outside the cellUsing an existing installed accelerometer or install oneand add a single channel monitor outside the cell. Makesure the dynamic signal is available for the vibration ana-lyst. Note the terminology in the industry: A single chan-nel monitor may be called an electronic vibration switchwith a remote accelerometer. The terms are interchange-able. The device does the same job.

5. Dual path monitorThis is a solution using a single installed accelerometerto a monitor that splits the signal and processes it forboth velocity (for the driver speed) and displacement(for the low speed fan). At 1800 rpm, velocity is the bestchoice. For 100 to 600 rpm, displacement is a betterchoice. The problem with this solution is that the signalfrom the accelerometer is integrated once to get velocitywhich is standard industry practice. Double integrationof the signal is required to get displacement and thisgives signals with high noise to signal ratios. This canbe problematic so caution is advised. Worst case: iftried and problems arise, you can ignore displacementand still have a full functioning electronic vibrationswitch with all of the advantages over mechanicalvibration switches.

6. Multi-channel monitorGiven that multiple cooling tower cells are in a commonstructure, there can be advantage to running the signalsfrom installed accelerometers to a common instrument forprocessing. This depends on a comparison of total in-stalled costs.

Some Notes About VendorsThere are many vendors of electronic vibration switches with goodproducts that will outperform mechanical vibration switches. Thosewho supply both may have compromised their credibility in themanner in which they market their mechanical offerings. That judg-ment is yours to make. You are welcomed to contact me [email protected] or call my cell at 979-739-7279 to find outmore about products and services available to meet your coolingtower monitoring needs.Bio: Gene Ort is a thirty year resident of southeast Texas with amechanical engineering degree & holds two patents. Employmenthistory includes working for a major gas turbine and AC motormanufacturer, and major manufacturers of instrumentation for vi-bration monitoring of rotating equipment including cooling towers.He has had the training for vibration analyst. Gene successfullyled a project that outfitted an entire grassroots refinery in Thailandwith all of the installed vibration monitoring instrumentation aswell as the portable vibration data-loggers and analysis software.He has spoken to many audiences interested in the protection ofrotating equipment including the Saudi Arabian Chapter of the Vi-bration Institute.

Vibration Nomograph SimplifiedThe “vibration nomograph” referred to in figure 1 at the papersbeginning, is a standard representation of the relationship amongfrequency, acceleration, velocity and displacement. It is basedupon physics and I have used it since the early seventies. It isused in vibration analysis courses as well as by most vibrationinstrument manufacturers for the practical application of their prod-ucts. The only arbitrary data shown are the superimposed lineslabeled from “Good” to “Bad”. This represents the accumulatedknowledge and consensus of what constitutes acceptable vibra-tion levels for most machines. Example of the conservative natureof these values. “Bad” is over 0.5 inches/second (ips) velocity.For the purpose of this paper and its relatively narrower scope, thegraph is simplified in steps illustrated in figures 1a through 1d thatfollow. If you are familiar with the subject, reading further on is notnecessary. If you are not familiar with the subject, it does not takegreat study to see the logic of the argument.

Continued on page 56


Fig. 1a is the nomograph with all the lines designating:· Frequency in terms of machine speed (vertical)· velocity (horizontal)· displacement (diagonal bottom left to upper right)· acceleration (diagonal bottom right to upper left)

This is a complex graph, log based, and difficult to use for novices:simplification is in order.

Fig. 1b is the “skeleton” of the nomographThis shows only the lines for frequency, displacement, velocityand acceleration of interest for cooling tower rotating equipment

Fig. 1a

Figure 1b

Continued on page 58


Fig. 1c shows the superimposed values of Good to BadThese are the commonly accepted vibration levels for machinesrunning at various speeds.

Figure 1c

Fig. 1d is figure 1 at the paper’s beginning with the 1 Glevel added for reference

Greatly simplified, it assumes likely set-points for mechanical vibra-tion switches at 1 G (though likely higher), cooling tower drive at1800 rpm, and accepted vibration levels of a cooling tower.


IntroductionHistorically, water systems in industry have notreceived the same attention as process systems.Until a problem or failure occurred, water sys-tems were typically considered a cost centerwhereas the process systems were a profitcenter. As a result, many water systemsevolved into applications that in today’s stan-dards would not be considered a viable optionfor new construction. One such system existsat DuPont Sabine in Orange, Texas. The pur-

built and different heat transfer metallurgieswere introduced, the need for better qualitywater became apparent. A pond system wasdeveloped for additional cooling. It consistedof a 500,000,000 gallon natural bottom pondfor cooling; a water distribution and return sys-tem, with entry into the pond system well awayfrom the pumping station (Figure 1.0). Waterwas taken from the Sabine River about 30 milesupstream from the plant. The water was sup-plied to the plant-site via the Sabine River Au-

Improving Localized Corrosion in aComplex Cooling Water SystemMichael H. Dorsey, E.I. DuPont de Nemours & Co.Kevin Daigle, ChemTreat, Inc.A.F. Brunn

pose of this paper is to document how this large, multifunc-tional, cooling water system has been revised to meet theplant cooling requirements while maintaining acceptable cor-rosion and deposition control.

BackgroundThe first production units at DuPont’s Sabine River Workswere placed into operation in the mid-1940’s. Although noneof the original production units are still operational, the basiccooling water system that developed over time remains oneof the primary sources of heat removal at the site. Initially,water was taken from Adams Bayou, adjacent to the plant,and circulated once through for production areas in the com-plex. The plant is about 30 miles upriver from the Gulf ofMexico and during times of dry weather Adams Bayou wassubject to chloride intrusion. As new production units were

thority (SRA) canal system and not subject to chloride intru-sion. Supply water temperature was achieved by surfaceevaporation in the pond plus enough water was dischargedfrom the pond and replenished with cooler SRA water. Inreality the system was just slightly better than once through.The site currently has nearly a dozen different operating ar-eas with an extremely complex site cooling water system.After the mid-1960’s new production units installed their ownrecirculating cooling tower systems for process cooling sincethe existing systems had reached their full heat rejection ca-pacity.During the late 1980’s and early 1990’s there was a strongpush to lower the amount of water discharged to the river.The two most obvious high flow sources were the oncethrough water and the discharge from the pond system. Fromthe various options available, it was decided to enclose thepond circulating water system and eliminate the once throughwater from Adams Bayou.

Operation ConditionsThe current system circulates between 100,000 and 130,000 gpm.Fluctuations in flow are due to varying heat loads in the dif-ferent process units and to some degree seasonal changes.Since radiation from the pond would no longer provide thenecessary supply water temperature to the process units, a125,000 gpm cooling tower with a 25OF temperature differ-ential was erected at the edge of the pond. Return waterfrom the plant is pumped across the cooling tower and dis-charged directly into the pond. Suction for the site closedcooling water system is taken at a point about 200 yards fromthe cooling tower (west loop) and a second pumping stationabout 400 yards from the pumping station (east loop). Thesystem is supplied by 65,000 gpm off the East lift station and

Michael H. Dorsey

Figure 1.0 – DuPont Sabine Site ClosedCooling Water System


35,000 gpm from the West lift station. Return water from thewest side of the plant (about 70,000 gpm at this time) crossesthe cooling tower; return water from the east side of theplant (about 30,000 gpm) is sent through a ditch system to thefar southwest end of the pond system to obtain maximumnatural cooling.Return water to the cooling tower from the west side of theplant was directed through a wood lined ditch system thatexisted in the past and discharged into the river. In fact, theentire wood lined ditch return was re-directed to the coolingtower. This included demineralizer regenerant waste, filterbackwash, boiler blowdown, cooling tower blowdown, pro-duction area washdown water, rain water runoff from thesite production areas, runoff from the site parking lot, somerunoff from the state highway in front of the site, and eventhe runoff from the company golf course across the roadfrom the plant. All of this water was returned to the siteclosed cooling water system across the cooling tower.Initially, it was thought that the golf course and runoff fromthe roadway was a major contributor to many of the prob-lems seen in the site cooling water system. Analyses takenfor some time after this was discovered have never shown asignificant contribution of contamination.Cooling water is used for a wide variety of process heat re-duction methods from jacket cooling of high pressure extrud-ers to in-column, direct cooling of process gases to standardheat exchangers. There is a wide variety of metallurgy in thesystem, from carbon steel and copper bearing metals to asignificant number of various stainless steels.Before the cooling tower was installed and the system closed,treatment consisted of chlorination of the circulating water atthe pump suctions. Target control was approximately 1 mg/l free chlorine, but the capacity of the chlorination systemcould not always achieve this residual. Lack of attention tothe chlorine feed system was also a factor in the overall op-eration of this system. This continued into the initial stages ofthe system being closed. Although there is no historical data,it has been reported that corrosion rates on carbon steel werein the 20 to 30 mils per year range.

Chemical Treatment HistoryWhen the cooling tower started up in late 1994 the oncethrough river water circulating system was integrated intothe pond system, the Adam’s Bayou water abandoned, andthe discharge to the river significantly reduced. Makeup tothe system was untreated SRA water, a low hardness, lowalkalinity, low silica, low solids water. However, during highrain periods the organic content and suspended solids contentof the raw water increases dramatically. The system appar-ently operated without too many problems for the first twoyears although there is a lack of historical data to totally sup-port that supposition. During periods of high organic intru-

sions, generally in the late fall and winter, it was impossible tomaintain a free chlorine residual in the system.In early 1996 there was a perception that corrosion in thesystem was increasing. Corrosion coupon racks (Figure 2.0)were set up in a number of operating areas and the resultswere, at best, very poor. Carbon steel corrosion rates on 30

Figure 2.0 – Typical Corrosion Rack

day coupons of 20 to 40 mpy were not uncommon and up to80 mpy was recorded. There was a significant pitting prob-lem on the unheated coupons as well. A review of the sys-tem showed the chlorine feed to satisfy the demand was highenough to drop the pH of the system water well under neu-tral, sometimes below pH 5. A caustic feed system was in-stalled to overcome the pH suppression and increase alkalin-ity on both the east and west loops in the fall of 1999. ORPcontrol of chlorine feed and pH control of caustic feed wasinitiated at this time. Although chlorine feed is controlled byORP on the supply water downstream of the injection point,water being returned to the ditch system is regularly checkedfor free chlorine. These changes brought the pH back undercontrol and increased the almost negligible alkalinity back intoa somewhat reasonable range.Corrosion rates, although much lower, still remained wellabove the target 5 mpy on carbon steel (Figure 3.0). Even

Figure 3.0 - Corrosion Rates (mpy)


with the lower corrosion rates, the pitting ofcarbon steel continued at a higher than desir-able rate. In addition, under deposit corrosionon 304L and 316L stainless steel tubing oc-curred in a number of exchangers resulting inequipment failure and unplanned productionarea shutdowns.Other 304L and 316L stainless exchangers haveoperated without significant problems since thecooling water system was closed in 1994. Stain-less steel corrosion coupons in the system gener-ally showed excellent corrosion rates, usually lessthan 0.01 mpy and little to no pitting on the cou-pons, although there has been an occasional cou-pon that did show pitting and indication of mi-crobiologically influenced corrosion (MIC). Thefailed tubing was replaced and inspected for pos-sible feeling that MIC had been the cause of thetubing failures. Some analyses of deposits fromthe failed tubes showed the presence of manga-nese and there has never been a consensus as tothe exact cause of the failures.In early 2000 a program was established todetermine microbiological activity both by as-sessing the sessile and planktonic bacteriacounts in various locations served by theclosed cooling water system. In general,counts of both were very low when chlorina-tion was maintained properly. These countsran between 102 and 104 with averages around103. There has been an inherent problem withthe chlorination in the summer months. Therehave been many times when the demand ex-ceeds the capacity of the chlorine deliverysystem to provide sufficient chlorine to main-tain the desired residual. This situation is be-ing addressed with a proposed project to in-crease the pressure of the motive water byadding booster pumps in the chlorination educ-tion system.The plant also started a formal chemical treat-ment program is early 2000. Because of en-vironmental concerns, several treatment chemistries were notconsidered an option. Use of zinc as a cationic inhibitor wasrecommended, but site environmental concerns precluded theuse of zinc until all other avenues were investigated. Usingwater from the pond system, laboratory spinner bath studieswere performed to determine which treatment program wouldprovide the best return for the chemical investment.The initial program consisted of an ortho phosphate, organicphosphate, and a dispersant (Figure 4.0). It took nearly twomonths for the system to stabilize because of its large sizeand mud bottom in the pond. In June of 2000, sodium

hexametaphosphate was added to the system to evaluate thebenefits of polyphosphate. In July, 2001, due to a pH of over8.0 and sometimes approaching 8.5, the oxidizing biocide treat-ment was modified to include a bromine component. Theaddition of bromide was justified based on the high systempH. Tripolypotassium phosphate feed replaced thehexametaphosphate in an attempt to reduce reversion to or-thophosphate and maintain a higher polyphosphate residual inthe system. Treatment modifications each resulted in slightimprovement of carbon steel corrosion rates, but the successwas always questionable due to inconsistencies in the newer


corrosion data. Later review of the data indicated that someof the flucuations could have been the result of seasonalchanges that impact the system. However, there are evensome inconsistencies with that assumption. Figure 4.0 pro-vides a timetable of the treatment chemistries used in varioustrials at the site. It does not include chlorine and causticsince they have continuously been used.Even when corrosion rates were lowered, the pitting rate oncarbon steel remained at an unacceptable high level.

would not exceed the zinc limitations at the outfall. It wasanticipated that there would be some insoluble zinc in thesystem which proved to be correct. Curves had been devel-oped by the water treatment supplier to show a direct rela-tionship between zinc concentration, orthophosphate concen-tration, and pH. This data indicated that the best pH rangefor operation without excessive zinc precipitation would be inthe range of 7.5 or under. There have been some periodswhen insoluble zinc residuals were higher than normal, butgenerally these are periods are when the pH in the system issomewhat high.Zinc residuals have been closer to 0.2 – 0.3 ppm, but as canbe seen from Figure 5.0 corrosion rates have improved. Or-thophosphate has been controlled between 5 to 7 ppm. ThepH has been a little harder to control. Although the totalalkalinity was lowered from about 70 ppm to 20 to 30 ppm,the summer months saw pH increases from during daylighthours of 1.0 to 1.5 units. The automatic pH system cut thecaustic feed off when the pH increased above the set point,

Figure 4.0 – Timetable of Treatment Chemistries

Numerous studies were conducted in the laboratory in aneffort to get a better handle on the microbiological compo-nent in the overall problem. Various on-line, real time analyz-ers were studied to determine if the claims that they couldpredict microbiological fouling were overstated. Although insome cases there were somewhat positive results the overallresult was not as definitive as we had hoped. The results ofthese tests have been reported elsewhere.In 2005 it was decided to review the possible use of zinc as acathodic inhibitor into the system. The environmental con-cerns were overcome by agreeing that zinc concentrations inthe outfall would be held well below the allowable limits asestablished by the NPDES permit. There was concern thatthe mud bottom of the pond would adsorb a great deal of thezinc, but the decision was made to give the program a try andevaluate the results. The program would be initiated in foursteps. First, zinc would be added to the system and withremaining controls held in place. Next the pH would be re-duced to 7.5 to maintain solubility of zinc, and then the bro-mine component would be eliminated since the pH would belowered to a range where bromine did not improve the effec-tiveness of the oxidizing biocide program. Finally, the chlo-rine injection points would be changed with the addition ofhigher motive pressure for chlorine induction and the abilityto inject the chlorine solution into a pressurized line.Zinc feed was initiated in mid-January, 2005. The controlrange for soluble zinc was targeted to be 0.5 to 0.75 ppm and

Figure 5.0 – Corrosion Rate Improvements (mpy)

but the pH continued to rise during daylight. Based on expe-rience from other DuPont sites, we attribute this to algaeactivity during the hot, sunny days that feeds on free carbondioxide in the circulating water. Addition of sulfuric acid isbeing considered and would be used during these periods tocontrol the pH below 7.5. Table 1.0 shows this data.Figure 6 provides a wider look at corrosion rates. This figureshows corrosion rates at the same four locations since 1998.Corrosion rates have decreased based on corrosion coupondata.The plant has now had nearly a year of service on the zinc/polyphosphate/quad polymer program and the average cor-rosion rate remains approximately 5-9 mpy with periodic in-creases at individual units. Pitting can still be seen on thecarbon steel coupons, but it is also significantly less than wasfound previously.


It will take a much longer period to determine if the MICproblems have also been alleviated. In 2000, additional localtreatment for several production areas containing the 304 stain-less steel reactor tubes was initiated. This supplemental treat-ment included sodium hypochlorite to be sure there is alwayscontrolled free chlorine residual in that production area. Thestainless steel reactor tubes have been again repaired be-cause of leaks occurring in 2004 and only time will tell whetherthis situation is also under control.

SummaryThere are times when people have questioned the continuedviability of this system. There have been many, some expen-sive, problems with this system. We continue to look at costeffective improvements that can be made to reduce theseproblems as they develop. However, the goal of reducing theenvironmental problems that the plant experienced during thepre-1995 days has been met.This system is complex and expensive to treat with chemi-cals. It requires a substantial amount of operator, technical,and management time to be sure the system is controlledvery closely. Faced with the reality of having a large, com-plex system with many of its shortcomings not recognized in

Figure 6.0 – Historical Corrosion Coupon Data

the initial installation, the resulting problems have been ad-dressed and significantly improved with the assistance of acommitted management, concerned operating group, and in-terested technical assistance.


Table 1.0 - Analytical Data pH FreeHalogen Filtered Zinc Unfiltered Zinc M Alkalinity Filtered Phosphate Unfiltered Phosphate

Date East West East West East West East West East West East West East West31-Oct-05 7.38 7.34 0.28 0.35 0.23 0.22 0.26 0.25 26 26 3.8 3.8 3.8 3.917-Oct-05 7.19 6.90 0.31 1.67 0.31 0.62 0.33 0.63 24 24 3.0 3.1 3.0 3.216-Sep-05 7.08 7.13 0.46 0.78 0.22 0.38 0.26 0.42 24 24 5.6 5.7 5.8 5.829-Aug-05 7.55 7.44 0.36 0.71 0.25 0.40 0.29 0.46 34 30 5.2 5.1 5.3 5.219-Aug-05 7.30 7.29 0.19 0.27 0.26 0.30 0.29 0.34 24 24 4.9 4.9 5.0 5.008-Aug-05 7.15 7.50 0.20 0.41 0.20 0.26 0.24 0.31 22 28 5.4 5.1 5.6 5.225-Jul-05 7.74 7.65 0.15 0.20 0.15 0.20 0.20 0.24 28 24 5.2 5.0 5.3 5.015-Jul-05 7.58 7.43 0.19 0.30 0.13 0.18 0.19 0.24 28 26 4.3 4.9 4.6 4.928-Jun-05 8.37 8.39 0.22 0.28 0.14 0.28 0.22 0.35 84 86 5.2 5.0 5.4 5.017-Jun-05 7.30 7.39 0.39 0.52 0.13 0.26 0.19 0.31 34 34 5.8 5.8 5.9 5.806-Jun-05 7.71 7.59 0.38 0.39 0.15 0.31 0.20 0.38 46 35 5.7 5.7 5.9 5.926-May-05 7.51 7.40 0.56 0.67 0.16 0.27 0.20 0.32 5.7 6.0 5.8 6.213-May-05 8.10 7.59 0.41 0.76 0.15 0.27 0.25 0.36 82 78 5.0 4.9 5.5 5.006-May-05 9.06 8.81 0.22 0.15 0.12 0.16 0.21 0.30 100 100 5.1 5.3 5.3 5.627-Apr-05 7.78 7.80 0.46 0.72 0.17 0.22 0.22 0.27 78 78 6.1 6.2 6.3 6.318-Apr-05 8.02 8.04 0.41 0.52 0.22 0.21 0.25 0.26 78 76 6.0 6.1 6.3 6.308-Apr-05 7.86 7.79 0.27 0.90 0.24 0.30 0.33 0.38 68 68 5.9 5.9 6.1 6.001-Apr-05 7.85 7.73 0.27 0.84 0.29 0.37 0.42 0.52 68 68 5.9 5.9 6.0 6.023-Mar-05 7.95 7.80 0.18 0.91 0.30 0.40 0.39 0.54 68 68 6.0 5.8 6.1 5.916-Mar-05 8.00 8.00 0.35 0.52 0.22 0.43 0.35 0.43 70 69 6.3 6.1 6.4 6.309-Mar-05 8.00 7.92 0.52 0.65 0.24 0.31 0.40 0.48 62 64 6.0 6.3 6.0 6.502-Mar-05 7.73 7.95 0.51 0.75 0.27 0.34 0.34 0.40 68 68 7.1 7.1 7.2 7.323-Feb-05 7.79 7.71 0.41 0.74 0.20 0.25 0.29 0.34 68 66 6.6 6.5 6.8 6.616-Feb-05 8.02 8.01 0.35 1.04 0.20 0.26 0.32 0.38 7.1 7.3 7.2 7.511-Feb-05 7.44 7.49 0.39 0.98 0.20 0.29 0.22 0.32 7.3 7.3 7.5 7.608-Feb-05 8.01 8.08 0.51 0.48 0.20 0.25 0.22 0.26 7.7 7.7 7.9 7.903-Feb-05 7.72 7.68 0.66 0.86 0.20 0.22 0.25 0.33 8.2 8.214-Jan-05 8.21 7.89 0.42 0.29 0.07 0.11 0.07 0.15 84 72 8.5 8.4 7.5 7.7


Cooling Technology InstituteLicensed Testing Agencies

For nearly thirty years, the Cooling Technology Institute hasprovided a truly independent, third party, thermal performancetesting service to the cooling tower industry. In 1995, the CTIalso began providing an independent, third party, driftperformance testing service aswell. Both these services areadministered through the CTIMulti-Agency Tower Perfor-mance Test Program and providecomparisons of the actual operat-ing performance of a specifictower installation to the designperformance. By providing suchinformation on a specific towerinstallation, the CTI Multi-Agency Testing Program standsin contrast to the CTI CoolingTower Certification Programwhich certifies all models of aspecific manufacturer's line of cooling towers perform inaccordance with their published thermal ratings.To be licensed as a CTI Cooling Tower Performance Test

Licensed CTI Thermal Testing AgenciesLicense Agency Name Contact Person TelephoneType* Address Website / Email Fax

A,B Clean Air Engineering Kenneth Hennon 800.208.61627936 Conner Rd www.cleanair.com 865.938.7569

Powell, TN 37849 [email protected]

A, B Cooling Tower Technologies Pty Ltd Ronald Rayner 61 2 9789 5900PO Box N157 [email protected] 61 2 9789 5922

Bexley North, NSW 2207AUSTRALIA

A,B Cooling Tower Test Associates, Inc. Thomas E. Weast 913.681.002715325 Melrose Dr. www.cttai.com 913.681.0039

Stanley, KS 66221-9720 [email protected]

A, B McHale & Associates, Inc Thomas Wheelock 865.588.26546430 Baum Drive www.mchale.org 425.557.8377

Knoxville, TN 37919 [email protected]

* Type A license is for the use of mercury in glass thermometers typically used for smaller towers. Type B license is for the use of remote data acquisition devices which can accommodate multiple measurement locations required by larger towers.

Licensed CTI Drift Testing AgenciesAgency Name Contact Person Telephone

Address Website / Email Fax

Clean Air Engineering Kenneth Hennon 800.208.61627936 Conner Rd www.cleanair.com 865.938.7569

Powell, TN 37849 [email protected]

McHale & Associates, Inc. Thomas Wheelock 865.588.26546430 Baum Drive www.mchale.org 425.557.8377

Knoxville, TN 37919 [email protected]

Agency, the agency must pass a rigorous screening process anddemonstrate a high level of technical expertise. Additionally, itmust have a sufficient number of test instruments, all meetingrigid requirements for accuracy and calibration.

Once licensed, the Test Agenciesfor both thermal and drift testingmust operate in full compliancewith the provisions of the CTILicense Agreements and TestingManuals which were developedby a panel of testing expertsspecifically for this program. In-cluded in these requirements arestrict guidelines regarding conflictof interest to insure CTI Tests areconducted in a fair, unbiasedmanner.Cooling tower owners and manu-facturers are strongly encouraged

to utilize the services of the licensed CTI Cooling TowerPerformance Test Agencies. The currently licensed agencies arelisted below.


Albemarle 67Aggreko Cooling Tower Services 36, 37AHR Expo 69Amarillo Chittom AirFlo 55Amarillo Gear Company IBCAmcot Cooling Tower Corporation 23American Cooling Tower, Inc. 15, 51AMSA, Inc. 25, 57Bailsco Blades & Castings, Inc. 56Bedford Reinforced Plastics 17Beetle Plastics, LLC 21Brentwood Industries, Inc. 9ChemTreat, Inc. 13Clean Air 41Cooling Tower Resources, Inc. 33CTI License Test Agencies 68CTI ToolKit 70, 71Dynamic Fabricators, LLC 7Engelhard Corporation 35Gaiennie Lumber Company 2Goodway 63Howden Cooling Fans 5Hudson Products Corporation 29Industrial Cooling Tower 58,IFCKIMCO 45LaMotte 6McHale and Associates 31Metrix 61Midwest Towers, Inc. 53Moore Fans 47Multi-Wing America, Inc. 49Myron L Company 4Paharpur Cooling Towers Ltd. 39Rexnord 3C.E. Shepherd Company, L.P. 27SPIG 59Spraying Services, Inc. 11SPX Cooling Technologies OBCStrongwell 19Swan Secure Products, Inc. 65Tower Performance, Inc. 72Vangd 18

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