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The CTI Journal (ISSN: 0273-3250) PUBLISHED SEMI-ANNUALLY Copyright 2015 by The Cooling Technology Institute, PO Box #681807 Houston, Texas 77268. Periodicals postage paid at Houston, Texas. MISSION STATEMENT It is CTIâ€™s objective to: 1) Maintain and expand a broad base membership of individuals and organizations interested in Evaporative Heat Transfer Systems (EHTS), 2) Identify and address emerging and evolving issues concerning EHTS, 3) Encourage and support educational programs in various formats to enhance the capabilities and competence of the industry to UHDOL]H WKH PD[LPXP EHQHÂ¿W RI (+76 4) Encourge and support cooperative research to improve EHTS TechnolRJ\ DQG HIÂ¿FLHQF\ IRU WKH ORQJ WHUP EHQHÂ¿W RI WKH HQYLURQPHQW $VVXUH acceptable minimum quality levels and performance of EHTS and their components by establishing standard speciÂ¿FDWLRQV JXLGHOLQHV DQG FHUWLÂ¿FDWLRQ programs, 6) Establish standard testing and performance analysis systems and prcedures for EHTS, 7) CommuniFDWH ZLWK DQG LQÃ€XHQFH JRYHUQPHQWDO entities regarding the environmentally UHVSRQVLEOH WHFKQRORJLHV EHQHÂ¿WV and issues associated with EHTS, and 8) Encourage and support forums and methods for exchanging technical information on EHTS. LETTERS/MANUSCRIPTS Letters to the editor and manuscripts for publication should be sent to: The Cooling Technology Institute, PO Box # 681807 Houston, TX 77268. SUBSCRIPTIONS The CTI Journal is published in January and June. Complimentary subscriptions mailed to individuals in WKH 86$ /LEUDU\ VXEVFULSWLRQV yr. Subscriptions mailed to individuals RXWVLGH WKH 86$ DUH \U CHANGE OF ADDRESS Request must be received at subscripWLRQ RIÂ¿FH HLJKW ZHHNV EHIRUH HIIHFWLYH date. Send both old and new addresses for the change. You may fax your change to 281.537.1721 or email: vmanser@cti.org. PUBLICATION DISCLAIMER CTI has compiled this publication with care, but CTI has not Investigated, and CTI expressly disclaims any duty to investigate, any product, service process, procedure, design, or the OLNH WKDW PD\ EH GHVFULEHG KHUHLQ The appearance of any technical data, editorial material, or advertisement in this publication does not constitute endorsement, warranty, or guarantee by CTI of any product, service process, SURFHGXUH GHVLJQ RU WKH OLNH &7, does not warranty that the information in this publication is free of errors, and CTI does not necessarily agree with any statement or opinion in this pubOLFDWLRQ 7KH HQWLUH ULVN RI WKH XVH RI any information in this publication is assumed by the user. Copyright 2016 E\ WKH &7, -RXUQDO $OO ULJKWV UHVHUYHG

Contents )HDWXUH $UWLFOHV 8

Hope Creek Circulating 144-inch Water Pipeline Carbon Fiber Upgrade Anna Pridmore, Ph.D. & Jim Melchionna

3URSRVHG 0HWKRGRORJ\ )RU &7, $7& 6RXQG &HUWLË‰FDLWRQ RI Factory Assembled Towers John Dalton & Larry Burdick

6DIHW\ ,Q &RROLQJ 7RZHU 0DLQWHQDQFH Magose Abraham Eju

$GYDQFHPHQWV LQ &OHDQLQJ DQG 3DVVLYDWLRQ RI &RROLQJ :DWHU 6\VWHPV Raymond M. Post, P.E., Prasad Kalakodimi, Ph.D., Je"rey Oâ€™Brien & Richard H. Tribble

0HFKDQLFDO %HKDYLRU RI 3RO\PHU )LOOV Nina Woicke, Ph.D., & Daniel Dierenfeld

ASHRAE Legionella Standard 188: Evidence-Based Interpretation and Application Janet E. Stout, Ph.D.

New York Legionella Regulations: Are They Missing The Boat? Sarah Ferrari

Special Sections 80 82

&7, &HUWLË‰HG 7RZHUV CTI Licensed Testing Agencies CTI ToolKit

Departments 2 2 4 6

Multi Agency Press Release Meeting Calendar View From the Tower Editorâ€™s Corner

...see page 17

...see page 34

...see page 54 ...see page 26

CTI Journal, Vol. 37, No. 2

...see page 44

CTI Journal

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FUTURE MEETING DATES Committee Workshop

Annual Conference

July 10-16, 2016 Pointe Hilton Tapatio Cliffs Phoenix, AZ

February 5-9, 2017 Sheraton New Orleans New Orleans, LA

July 16-19, 2017 Hilton Orlando â€“ Lake Buena Vista Lake Buena Vista, FL

February 4-8, 2018 Hilton Houston North Houston, TX

July 15-18, 2018 La Cantera San Antonio, TX

February 10-14, 2019 Sheraton New Orleans New Orleans, LA

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For Immediate Release Contact: Chairman, CTI Multi-Agency Testing Committee Houston, Texas 2-September-2016 Cooling Technology Institute, PO Box 681807, Houston, Texas 77268 â€“ The Cooling Technology Institute announces its annual invitation for interested thermal testing agencies to apply for potential Licensing as CTI Thermal Testing Agencies. CTI provides an independent third party thermal testing program to service the industry. Interested agencies are required to declare their interest by March 1, 2017, at the CTI address listed.

CTI Journal, Vol. 37, No. 2

View From The Tower Sixty six years of education. Sixty six years of These are what creates CTI’s solid foundation. So growth. Sixty six years of commitment. Sixty while at the summer workshop meeting in beautiful six years of setting the industry standards. Sixty Phoenix AZ, please join in, and take an ACTIVE role six years of fun. All this due to, sixty six years of in ensuring that CTI remains the fore-font leading CTI. Without the participation by all the attendees technical organization when it comes to all types over the many years, CTI would never be what it is of cooling technologies. It will be a time for a ton today. But let’s face it, without ACTIVE participaof fun in the hot hot sun! It will be a time to golf tion, CTI would be even less than it is today. I would (Sunday only though, time to roll up those sleeves like to thank the many ACTIVE volunteers of CTI for the balance of the meeting! ), a time to see old including all our board members over the years, all friends, meet new friends and have a drink or two the presidents over the years and all the committee in the hospitality suite after a long days work.It chairs and task group chairs and certainly even all will be a time when owner operators can network the task group participants over the years that have with other owner operators on trends and cooling helped create and update all our codes, standards and WHFKQRORJ\ VSHFL¿F WR WKHLU SODQWV DQG DSSOLFDWLRQV Bill Howard guidelines. By taking an ACTIVE role, both you and It will be a time when direct competitors can join your company are providing a valuable service to CTI, but equally hands (certainly not literally!) and be friends in the quest for a better important is the impact we are having on the world. CTI has numer- organization mostly it will be a time to: ous international members which we embrace and welcome to our “Ask not what CTI can do for you, rather ask what you can do CTI family. Over the past several years, this number has continued for CTI.” to grow and as can be seen by the attendance at our meetings, these CTI, “Join in, get involved, learn, educate others, parmembers are committing their time and efforts in helping to make ticipate and thrive!” CTI the world class technical organization that it is. The CTI staff continues to deliver the excellence that we all have come to ap- Sincerely and respectfully, preciate and a special thanks goes out to Vicki and her entire staff. Bill W. Howard, P.E. A technical organization is only as good as the documents and information they contain as well as the people within the organization.

CTI President

CTI Journal, Vol. 37, No. 2

CTI loses two of their best in 2016 Arthur â€œArtâ€? Brunn Jr. 1934 - 2016 Arthur Frederick Brunn, Jr., 81, of Beaumont, died Monday, March 21, 2016, at Harbor Hospice, Beaumont. He was born June 27, 1934, in Richmond Heights, Missouri, to Arthur Frederick Brunn, Sr. and Aileen Dorothy Rummel Brunn. They lived in Webster Groves, Missouri until 1939, when they moved to Kansas City, Missouri. The Brunn family moved to Memphis, Tennessee in 1950. Art graduated from Treadwell High School, where he was a member and president of the Key Club and a member of the National Honor Society. Art went to the University of Tennessee in Knoxville where he met Clarice Marie Tallent. They were married December 18, 1955. Art graduated with a Bachelor of Science degree in chemical engineering in August, 1956. Art and Marie moved to Milwaukee, Wisconsin ZKHUH $UW ZRUNHG IRU $OOLV &KDOPHUV 0DQXIDFWXULQJ &RPSDQ\ 7KHLU ÂżUVW VRQ 'DYLG $UWKXU ZDV ERUQ December 15, 1957. In February, 1958, Art, Marie and David moved to Houston, Texas, where Art did VDOHV DQG VHUYLFH ZRUN IRU $OOLV &KDOPHUV LQ WKH ÂżHOG RI ZDWHU WUHDWPHQW 7KHLU VHFRQG VRQ 0LFKDHO &KDUOHV ZDV ERUQ $SULO 1960 in Houston. In 1967 the family moved to Beaumont, Texas when Art started working for DuPont as a consultant in the ÂżHOG RI LQGXVWULDO ZDWHU WUHDWPHQW $UW ZDV DFWLYH ZLWK 1 $ & ( DQ LQWHUQDWLRQDO WHFKQLFDO RUJDQL]DWLRQ FRYHULQJ DOO SKDVHV RI corrosion. He became chairman of the Technical Practices Committee of N.A.C.E., a member of their Board of Directors, and received the Brannon Award for service to the organization. He was also active in the Cooling Tower Institute, where he was on the Board of Directors, treasurer, and president. Art was named an Honorary Life Member of CTI and remained active after UHWLUHPHQW IURP 'X3RQW $UW ZDV DQ DFWLYH PHPEHU RI 5HGHHPHU /XWKHUDQ &KXUFK +H KHOG WKH RIÂżFH RI WUHDVXUHU FKDLUPDQ RI the Voterâ€™s Assembly, Chairman of the Childrenâ€™s Center Board, and was active in many other phases of the church. Survivors include his wife, Clarice Marie Tallent Brunn of Beaumont; sons, David Brunn and his wife, Arlene; Michael Brunn and his ZLIH 6WDFH\ ERWK RI +RXVWRQ VLVWHU -XOLH 0RFKQDN RI /LYRQLD 0LFKLJDQ ÂżYH JUDQGFKLOGUHQ DQG IRXU JUHDW JUDQGFKLOGUHQ

Bruce Byron Brand Bruce Byron Brand, 88, passed away peacefully at home on Sunday, May 15, 2016, in Fort Worth. Bruce was born Sept. 27, 1927, in Kansas City, Missouri to Ella and Carl Brand. He graduated from high school at the age of 16, attended Virginia Military Institute for one year, spent time in the U.S. Army teaching cadets at West Point, then went on to the University of Missouri and graduated with a Bachelor of Science in Chemical I, Engineering. He was a lifetime member of Sigma Alpha Epsilon Fraternity. He married Ellie, his neighbor and sweetheart, in 1953. The couple began their life in Kansas City, Kansas and Prairie Village, Kansas. Over the next 11 years, the couple welcomed their four children into their home. His children remember him as a kind, gentle, smart but stubborn father who encouraged and aided them to pursue their goals. Bruce was an accomplished cooling tower engineer. He spent his early career with Havens Cooling Towers in Kansas City, Missouri. In 1973, he and Ellie picked up their four children and moved to Fort Worth were he started his new job at Ceramic Cooling Tower and remained there until he retired. Retirement did not slow him down, though; he became a consultant with Tower Engineering in Fort Worth and continued to â€œworkâ€? until just a few months before his passing. Outside of his work, he, Ellie and his children were avid sailors and members of the Fort Worth Boat club for many, many years. During this time, he amassed a room full of sailing trophies including some from the Lightning and Catalina 22 Nationals. When his children (crew) grew up and moved away, Bruce took up golf in his 50s and was an active member of the Ridglea Menâ€™s Golf Association where he played up to three rounds per week until he was age 87 and continued to play, when he could, until just a few months before his passing. He was an active member of Ridglea Country Club since 1975, and he and Ellie could be seen there almost every night enjoying dinner and friends. Bruce was preceded in death by his parents, Ella and Carl Brand of Kansas City, Missouri; and his daughter, Mary Elizabeth Tracy of Syracuse, Kansas. Survivors: Loving wife of 62 years, Eleanor Arnold Brand; children, Melanie Brand Tracy and her husband, Timothy Allen Tracy of Syracuse, Kansas, Thomas Marshall Brand of Forth Worth, Jeffrey Douglas Brand and his wife, Lindy Denise Brand of Austin, Texas; grandchildren, Liz and husband, Josh Porter of Ambridge, Pennsylvania, James Tracy of Wichita, Kansas, Whitney Tracy of Syracuse, Kansas, Jeffrey Brand Jr., Haley Rojas, Harper Brand and Matt Brand of Austin, Texas; and two great-grandchildren, Gabe Hrustic and Laney Porter of Ambridge, Pennsylvania. CTI Journal, Vol. 37, No. 2

Editorâ€™s Corner Dear Journal Reader, A new year for CTI started after the CTI Annual Meeting in February, 2016. Bill Howard of CTD,Inc., has started his two year term as President RI &7, 6HYHUDO RXWVLGH LQĂ€XHQFHV KDYH KDG DQ LPpact on CTI, and some new activities are moving, so the next few years should be interesting.

China Cooling Tower Institute: This organization has been growing in China, and has reached out to CTI to explore ways the two organizations can work together. Several meetings have occurred between the organizations, and we continue to work toward future cooperation.

Emerging Activities: CTI Research Update: A research grant was award2XWVLGH ,QĂ€XHQFHV ed to CleanAir to complete Pitot tip investigations to DOE Fan Rule: My last Editorâ€™s Corner made ÂżQG D UHSODFHPHQW IRU WKH QR ORQJHU FRPPHUFLDOO\ CTI Members aware that a Department of Energy available) Simplex tip, which has been the CTI water rulemaking is in progress with regard to fans, which Ă€RZ PHDVXUHPHQW VWDQGDUG &OHDQ$LU LV FXUUHQWO\ could include any of the products of interest to CTI SURFHHGLQJ ZLWK WKLV WKH ÂżUVW UHVHDUFK SURMHFW GHPaul Lindahl that move air with a fan or blower. CTI has asked veloped under the relatively new CTI Research and Editor-In-Chief for exemption of heat rejection equipment from the Development Committee.Projects are proposed via rule, and have been successful in gaining the exemption in the term the standing technical committees, and proceed through a process sheet agreed upon by the working group. The DOE is writing the administered by the R&D committee.Funding is raised and adminÂżQDO UXOH ZKLFK LV H[SHFWHG LQ VR ZH ZLOO QHHG WR FRQWLQXH WR istered via the CTI Finance Committee. Other projects are under watch this closely. CTI members who produce fans for any purpose consideration, and new ones may be proposed within the standing should be aware that they could be affected by this rulemaking, technical committees at any time. ZKLFK ZLOO VHW PLQLPXP IDQ HIÂżFLHQFLHV E\ HTXLSPHQW W\SHV )RU more information, contact Larry Burdick, Frank Morrison, or me. Licensed Sound Testing: /LFHQVHG VRXQG WHVWLQJ LV LQ LWV ÂżUVW IXOO Legionnaires Disease: Outbreaks in New York City and Flint, MI, year of operation in 2016. We look forward to growth in this testhave brought media attention to the issue, and in the case of NYC/NYS ing service by CTI. have focused on cooling towers. Since then, the CDC has become There is much happening with our very active CTI volunteer techvocal about the need for a whole building approach to Legionnaires nical organization; we again encourage you to get involved in the Disease risk, and has published a nicely done Toolkit to supplement CTI technical committees. ASHRAE STD-188 (2015) Legionella: Risk Management for Build- Respectfully, ing Water Systems. CTIâ€™s GDL-159 is expected to be a useful tool with this standard when completed, hopefully, this year. The CDC Paul Lindahl, CTI Journal Editor toolkit and the ASHRAE standard are available on their websites.

CTI Journal, Vol. 37, No. 2

Hope Creek Circulating 144-inch Water Pipeline Carbon Fiber Upgrade Jim Melchionna, Corporate Program Manager - Engineering Services, Piping, PSEG Nuclear â€“Salem & Hope Creek Generating Stations Anna Pridmore, Ph.D., Vice President-Pipeline Solutions, Structural Technologies

Abstract

from 5 to 20 lineal feet. A common failure mode of PCCP is breakage of the prestressing wires within individual PCCP sections. Once enough prestressing wires break on an individual segment of PCCP, the concrete core in the region near the broken wires is no longer in compression and can crack, exposing the steel cylinder to ground water, causing corrosion. Depending on the nature of the wire break, number of broken wires and other factors, the process of pipe failure can take from days or weeks to years to complete the process.

Hope Creek Nuclear Generating Station has a comprehensive asset management program to address their cooling tower in addition to their circulating water pipelines. Results from condition assessment of their circulating water pipelines in recent years indicated the need for repair of Because of the segmental construction of PCCP seven (7) distressed segments. The plant elected and the predictability of failure following a large to repair the segments of 144-inch pre-stressed Anna Pridmore number of wire breaks, technology was invented concrete cylinder pipe (PCCP) of the circulating to inspect it with an objective of identifying broken wires. Elecwater pipelines during an outage taking place in October 2013. tromagnetic inspection technologies assist owners by allowing &DUERQ ÂżEHU UHLQIRUFHG SRO\PHU &)53 D WUHQFKOHVV VWUXFWXUDO them to locate, with precision and accuracy, individual sections in repair system, was selected to strengthen the damaged PCCP. CFRP need of replacement or repair. An electromagnetic inspection was is a repair material used to provide targeted structural upgrades performed and led to identifying the areas of broken wires â€“ and within distressed or damaged pipeline sections. This paper will ultimately the distressed segments â€“ which Hope Creek selected discuss all aspects of design and implementation of the repair. for upgrade during the fall 2013 refueling outage.

Background On Hope Creek Generating Station

In 1974, construction began on the Hope Creek Nuclear Generating Station. In operation since 1986, Hope Creek Nuclear Generating Station is owned and operated by PSEG Nuclear LLC. It is a single unit boiling water reactor with a total generating capacity of 1,178 megawatts net. As one of four licensed nuclear power reactors in New Jersey, whose combined output supplies over one half the electrical power to the state, Hope Creek generates enough electricity to power approximately one million homes each day. Hope Creek shares a 700 acre man-made island with its sister plant, Salem Nuclear Generating Station.

2QFH WKH VHJPHQWV ZHUH LGHQWLÂżHG +RSH &UHHN WKHQ KDG WR SULoritize and discuss options for how to best proactively address the pipeline system. To immediately mitigate further distress to the above-ground portions of the circulating water pipelines, an external concrete encasement was installed. Beyond this stopgap measure the pipes either needed to be replaced or undergo a full structural repair in place. Due to their size, location and outage duration, replacement of the pipe segments was ruled out as an option. Hope Creek opted for a trenchless, fully structural repair utilizing a CFRP liner to address the distressed sections.

Several years ago external distress was observed on the 144-inch PCCP circulating water system. Due the observed distress and due to its location directly adjacent to the natural draft cooling tower, Hope Creek management implemented a condition assessment program for the large diameter pipelines. It was through this program WKDW VHYHQ VHJPHQWV ZHUH LGHQWLÂżHG IRU UHSDLU LQ DQG D proactive upgrade project was launched, budgeted and executed.

7KH EHQHÂżWV RI WKLV RSWLRQ LQFOXGHG FRPSOHWLRQ RI WKH UHSDLUV ZLWK no excavation required, the ability to perform the repair within the outage window and nearly no hydraulic loss because of the ORZ SURÂżOH ÂżQLVK RI &)53 OLQHUV 8QOLNH PRVW OLQLQJ V\VWHPV CFRP liners, which are hand laid into place, can be engineered and LQVWDOOHG RQ WKH VSHFLÂżF SLSH VHJPHQWV UHTXLULQJ VWUXFWXUDO XSJUDGH

Background On Circulating Water System And Condition Assessment Program

Given that the CFRP repair method needed to provide a fully structural repair, the design process was an important phase of the project. PSEG worked directly with the CFRP designer, Simpson Gumpertz & Heger, to make sure all design requirements were met. The CFRP lining system was designed as a standalone structural system where the CFRP system resists all internal and external structural demands without reliance on the host pipe.

The 144-inch diameter sections of the circulating water system for Hope Creek are comprised of embedded-cylinder type (ECPtype) PCCP, which is composed of an inner concrete core, a steel cylinder, an outer core, high strength wires under tension that are wound over the outer core, and a protective mortar coating (Figure 1). PCCP is generally a segmental pipe install in sections ranging

Options Analysis

Design Of The Cfrp System

CTI Journal, Vol. 37, No. 2

The CFRP design process involves collection of the design inforPDWLRQ LQFOXGLQJ DV EXLOW GUDZLQJV OD\ VFKHGXOHV SLSH VSHFLÂżFDtions, and pipe inspection reports. Typical parameters accounted for in the CFRP system design include: working pressure, transient (surge) pressure, vacuum pressure, temperature differential, soil cover, height of the water table soil material properties, and any YHKLFXODU WUDIÂżF UXQQLQJ RQ WKH JURXQG DERYH WKH SLSH CFRP systems are typically designed using a Load and Resistance Factor Design (LFRD) approach, where factors are applied to loads combinations and material properties to account for uncertainties within the design assumptions. As part of this design approach, design limit states are analyzed separately and the CFRP lining design is governed by the limit state that has the lowest demand to capacity ratio for the particular design scenario. From this process it is determined how many layers of unidirectional CFRP will be applied both longitudinally and circumferentially within the designated pipe segment. Typically longitudinal layers provide resistance to thrust, thermal changes, and Poissonâ€™s ratio, while the circumferential layers provide strength in the hoop direction for internal pressure and external loads.

were an important element of successful project completion. In all CFRP pipeline projects, the environment within the interior of the pipe repair area needs to have the temperature and humidity FRQWUROOHG WR PHHW VSHFLÂżFDWLRQV RI WKH &)53 PDQXIDFWXUHU )RU Hope Creek, and all projects requiring an expedited schedule, the pipe interior is heated to aid the curing process. Surface preparation was performed using sponge blasting as shown in Figure 2. Sponge blasting is a unique abrasive blasting media consisting of abrasive embedded within a polymer. The sponge component helps to minimize airborne particulate and is recyclable, which reduces the quantity of overall blasting media used on the project. It is much more environmentally friendly than typical sand blasting operations.

PCCP has is an inner concrete substrate and surface preparation is a critical component to the successful long term performance of the CFRP liner. Proper bond to the sound concrete substrate is DFKLHYHG E\ SUHSDULQJ WKH VXUIDFH WR ,&5, &63 ÂżQLVK UHPRYLQJ laitance from the surface of the concrete, and exposing the aggregate. This allows for a mechanical bond to the pipe surface. Joint detailing for the CFRP system requires carefully chipping down to the steel cylinder at the end joints and preparing the exposed Preplanning VWHHO WR 663& 63 QHDU ZKLWH PHWDO ÂżQLVK )ROORZLQJ VXUIDFH 7KH LQFK SLSHOLQH XSJUDGH ZDV D KLJK SURÂżOH SURMHFW DW +RSH preparation, bond tests were completed to insure proper adhesion Creek during the fall 2013 outage, with an aggressive schedule of the CFRP system. These tests are discussed in the Quality and challenging working conditions. In order to ensure successful Control section of the paper. implementation, an extensive preplanning process was put in place and soft mobilization to the site was scheduled well ahead of the Task Stage 2: Material preparation (saturation). outage. To drive the preplanning process, the contractor and Hope CFRP systems are comprised of fabrics, glass and carbon, along Creek initiated planning conference calls twice a week for the 6 ZLWK D SDUW VROLGV HSR[\ V\VWHP 7KH FDUERQ DQG JODVV ÂżEHU months leading up to the outage. DUH GU\ UROOV RI IDEULF ZKLFK DUH VDWXUDWHG LQ WKH ÂżHOG 7KH ÂżUVW VWHS These planning sessions included a wide variety of topics including coordination of roles and responsibilities and creation of extensive contingency plans for all aspects of the project. The contingency plans helped to insure all team members were aware of the processes for dealing with potential unforeseen developments or conditions.

in material preparation is mixing of the 2-part epoxy, Part A and Part B. The Part A and Part B arrive at the jobsite in premeasured 5-gallon buckets and are poured together per the manufacturer VSHFLÂżFDWLRQV DQG PL[HG WKRURXJKO\ WR DFWLYDWH WKH HSR[\

The epoxy system is used for multiple purposes throughout the installation process including saturation of the material and priming of the pipe substrate. A thickened version of the epoxy system Cfrp Installation Process is also created using fumed silica. This thickened epoxy is used The CFRP liner installation process consists of several typical WR ÂżOO LPSHUIHFWLRQV LQ WKH SLSH VXUIDFH DQG DV D FRDWLQJ EHWZHHQ VWHSV ZKLFK DUH EURNHQ GRZQ LQWR ÂżYH WDVN VWDJHV EHORZ 7KH layers of CFRP. task stages are as follows: Prior to installation, the fabric is wet out in a mechanical saturation 1. Mobilization to surface preparation machine used which has two (2) baths of epoxy and a calibrated 2. Material preparation (saturation) rolling system. The fabric is fed through the saturation machine, 3. Application of the CFRP system and top coat and through the roller system the proper amount of epoxy is com4. CFRP repair system termination details pressed into the fabric. 5. Final curing of the system. 6HH ÂżJXUH IRU H[DPSOH RI PHFKDQLFDO VDWXUDWLRQ PDFKLQH The Hope Creek project consisted of some unique challenges which are discussed in a separate section of the paper. Following The materials preparation process takes place in a tent to eliminate the chance for contamination and to reduce airborne particulate is a description of the task stages for Hope Creek: during the use of fumed silica. To insure the long term durability Task Stage 1: Mobilization to surface preparation. of the CFRP system, the materials preparation process has quality Following mobilization of all personnel, materials and equipment control procedures which are discussed later in the paper. to the Hope Creek site, an extensive amount of safety protocols Task Stage 3: Application of the CFRP system and were reviewed and put into place prior to entry into the pipe. All top coat. FRQÂżQHG VSDFH HQWU\ ZDV SHUIRUPHG LQ FRPSOLDQFH ZLWK WKH &RQtractor, Hope Creek and OSHA regulations. Given the schedule As the material and surface preparation were completed at the constraints at the Hope Creek project, environmental controls Hope Creek project site, installing the CFRP system began within WKH SLSH 7KH ÂżUVW VWHS ZLWKLQ WKH SLSH LQWHULRU IROORZLQJ VXUIDFH CTI Journal, Vol. 37, No. 2

preparation, was application of the primer coat of epoxy. Following the primer coat, a layer of thickened epoxy is placed on the concrete VXEVWUDWH ZKLFK LV PHDQW WR LQÂżOO LPSHUIHFWLRQV DQG FUHDWH D OD\HU RI HSR[\ IRU SURSHU ERQGLQJ RI WKH ÂżUVW OD\HU RI &)53

1. Removal of cooling tower muck Before access to the repair site could be established, the cooling water tower basin needed to be cleared of the muck seen in Figure 8. This situation was challenging in that the quantity of muck was 7KH VDWXUDWHG FDUERQ ÂżEHU ZDV WKHQ DSSOLHG WR WKH LQVLGH VXUIDFH an unknown at the outset of the project. The CFRP contractor of the host pipe in what is referred to as a wet lay-up process. The was required to set up a system to remove the muck as rapidly as wet-out fabric was pressed to the inside surface of the host pipe to possible to gain access to the pipe (s) to be repaired. achieve intimate contact. Any entrapped air between layers was 2. Two-tiered scaffolding system with multiple vertical UHOHDVHG RU UROOHG RXW ZLWKRXW ZULQNOLQJ RI FDUERQ ÂżEHUV slopes When the CFRP was not properly aligned, the affected layer of On typical CFRP projects, following the surface preparation and the CFRP system was removed and replaced prior to curing. If the prior to CFRP installation, portable scaffolding is erected, as CFRP layer cannot be removed without affecting the integrity of WKH VXUURXQGLQJ FDUERQ ÂżEHU DQ DGGLWLRQDO OD\HU ZDV RYHUODLG RQWR needed, spanning the pipe section to be lined. This is to give the WKH RII D[LV ÂżEHUV WR UHVWRUH WKH ODPLQDWH VWUXFWXUH WR LWV LQWHQGHG installation crew the ability to apply the CFRP liner to all areas of the pipe section without the need to walk on the pipe. Best industry axial-strength requirements. practice to ensure a successful installation is that the application )RU +RSH &UHHN XQLGLUHFWLRQDO FDUERQ ÂżEHU IDEULF ZDV PDQXDOO\ takes place continuously in a manner that avoids contact with the LQVWDOOHG LQ ERWK ORQJLWXGLQDO VHH ÂżJXUH DQG FLUFXPIHUHQWLDO CFRP after installation and until cured. The pipe sections being OD\HUV VHH ÂżJXUH WR PHHW GHVLJQ UHTXLUHPHQWV DV SUHVHQWHG LQ repaired required scaffolding for the 144-inch diameter pipe segthe project drawings. ments to be built on a vertical slope and span over an area which Following installation of the prescribed number of layers on the had a vertical bend within the scaffold span. This required a +RSH &UHHN UHSDLU VHJPHQWV D ÂżQDO WRS FRDW RI HSR[\ ZDV LQVWDOOHG specialized access system to be engineered and built in-place, as The top coat installed over CFRP repairs adds to the long term VKRZQ LQ ÂżJXUH durability of the CFRP system, by providing protection from wear. Single point of entry for repairs In cases where water constituents require chemical resistance, the 3. top coat can be engineered to meet project requirements. On typical CFRP pipeline repair projects, two (2) points of entry are established within the repair area for safety and ventilation Task Stage 4: CFRP repair system termination QHHGV $V VKRZQ LQ ÂżJXUH DW +RSH &UHHN WKH SURMHFW KDG WR details. EH FRPSOHWHG WKURXJK D VLQJOH HQWU\ SRLQW ZLWK D EXWWHUĂ€\ YDOYH One of the most important individual components of the design as an obstruction. This presented several challenges for project and implementation process for CFRP pipeline repairs, including execution; these challenges were addressed in the pre-planning the Hope Creek project, is the water tightness of the system. Water process and steps to overcome were put in place and successfully LQÂżOWUDWLRQ EHKLQG WKH &)53 UHSDLU V\VWHP LV D PRGH RI IDLOXUH implemented. and this places a special importance on the points of termination, Removal of existing epoxy system during surface most often at the joint regions on each end of the repair. The best 4. practice for design of these â€œend detailsâ€?, as they are referred to, preparation includes removal of the concrete at the joints down to the steel At the pipeline segments to be repaired at Hope Creek there was F\OLQGHU $ JODVV ÂżEHU LV WKHQ LQVWDOOHG GLUHFWO\ RQWR WKH VWHHO F\O- a build-up of epoxy on the pipe substrate, from previous repairs LQGHU DQG WLHG LQWR WKH &)53 UHSDLU V\VWHP *ODVV ÂżEHU LV XVHG DV performed by others, which had to be removed during surface a dielectric barrier between the steel and the CFRP. After the glass SUHSDUDWLRQ 7KLV LV VKRZQ LQ ÂżJXUH 7KHUH ZHUH VHYHUDO FRPÂżEHU LV LQVWDOOHG DQG WLHG LQ WKH MRLQW LV ÂżOOHG ZLWK DQ HSR[\ PRUWDU ponents to this unknown condition including the amount of pipe WR FUHDWH D QDWXUDO VORSHG WUDQVLWLRQ VHH ÂżJXUH 7KH HQG GHWDLO which had adhered epoxy, the thickness of the epoxy (up to Âźâ€?) and LV ÂżQLVKHG ZLWK OD\HUV RI &)53 SHU WKH GHVLJQ DQG WKLV SURFHVV the condition the pipe substrate would be in following removal of DV FRPSOHWHG DW +RSH &UHHN LV VKRZQ LQ ÂżJXUH the epoxy. As with other unknowns, contingency plans were put in place to address a variety of scenarios which might be present. Step 5: Final Cure $IWHU WRS FRDW ZDV LQVWDOOHG DW +RSH &UHHN WKH ÂżQDO FXUH RI &)53 V\VWHP WRRN SODFH XQGHU PRQLWRUHG FRQGLWLRQV 6HH ÂżJXUH ,Q general, CFRP systems are to have a minimum 80% cure before the pipe is returned to service. Durability of CFRP is affected by the degree of cure at the time the pipe is returned to full service. As discussed previously, the schedule at Hope Creek was expedited so the air temperature inside the pipe was elevated to over 100 degrees F to help accelerate cure. Testing has shown that the CFRP system cures faster at higher temperatures.

Unique Project Challenges From the onset of the project at Hope Creek there were several unique project challenges which were evaluated and addressed. These issues are discussed below:

5. Special details and substrate pitting 2QFH WKH VXEVWUDWH ZDV VXIÂżFLHQWO\ SUHSDUHG DW +RSH &UHHN DQG epoxy removed, extensive pitting, concrete patches, and other deWDLOV VXFK DV SHQHWUDWLRQV E\ WKH WHPSHUDWXUH SUREH VKRZQ LQ ÂżJXUH 13 were evident. The surfaces with pitting needed to be repaired and for areas of penetration, such as the temperature probe, special GHWDLOV VXFK DV VKRZQ LQ ÂżJXUH ZHUH SXW LQ SODFH

Qa/Qc Program The pipeline repair project at Hope Creek included a comprehensive Quality Assurance / Quality Control (QA/QC) program that involved multiple owner representatives, a fulltime quality assurance manager and a third party quality control inspector in a rigorous system of tracking. Up to nine (9) data points were CTI Journal, Vol. 37, No. 2

CTI Journal, Vol. 37, No. 2

captured during each phase of the project. From environmental conditions where the materials were stored through to curing of the installed system, each phase and step was documented and signed off throughout construction.

7KH H[WHQVLYH SUH SODQQLQJ SURFHVV FRQWULEXWHG VLJQLÂ¿FDQWO\ WR the projectâ€™s success and as well. The reliability of the cooling water system at Hope Creek was upgraded to meet long term requirements.

QA/QC documentation recorded each stage of repair implementation, beginning with receipt of materials. Material lot numbers ZHUH YHULÂ¿HG DQG UHFRUGHG IRU DOO SURGXFWV VKLSSHG WR WKH VLWH

Figures

QA/QC - surface preparation. For surface preparation, all prepared concrete substrate achieved a PLQLPXP VXUIDFH SURÂ¿OH RI ,&5, &63 Â¿JXUH $OO SUHSDUHG VWHHO VXUIDFHV ZKHUH YHULÂ¿HG WR KDYH D QHDU ZKLWH PHWDO EODVW RI SSPC-SP10, with a minimum roughness of 2 mils. The representaWLYH VWHHO SUHSDUDWLRQ LV VKRZQ LQ Â¿JXUH 2QFH VXUIDFH SUHSDUDWLRQ LV FRPSOHWHG WKH VXEVWUDWH ZDV YHULÂ¿HG WR EH DOO FOHDQHG DQG dry prior to CFRP installation process begins.

QA/QC â€“ mixing and saturation. For mixing and saturation, lot numbers of fabrics and epoxies are recorded as a starting point. A sample of the fabric is cut and weighed prior to saturation in the mechanical saturation machine. :HLJKW WHVW VKRZQ LQ Â¿JXUH )ROORZLQJ WKLV WKH VDPSOH LV VDWXUDWHG DQG ZHLJKHG DJDLQ 7KLV ZHLJKW WHVW YHULÂ¿HV UDWLR RI IDEULF WR HSR[\ LV ZLWKLQ WROHUDQFH IRU FDUERQ Â¿EHU IDEULF IRU JODVV Â¿EHU IDEULF Â“ ,Q DGGLWLRQ WKH JDS EHWZHHQ VDWXUDWRU rollers is measured and calibrated using weigh test.

Figure 1. Components of an ECP-type Prestressed Concrete Cylinder Pipe Section.

QA/QC â€“ CFRP liner installation. During the installation process at Hope Creek there were several check points for the pipe interior throughout the installation and curing process. The environmental conditions monitored and recorded periodically included air temperature, surface temperature, and humidity. In addition the physical installation is observed and misalignment of over 5 degrees is addressed. One additional instalODWLRQ REVHUYDWLRQ LV GHYHORSPHQW OHQJWK RI WKH LQVWDOOHG Â¿EHU )RU Hope Creek, the design called for a minimum development length RI LQFKHV LQ WKH Â¿EHU GLUHFWLRQ

QA/QC â€“ Terminations And Special Detailing. Along with other data points collected throughout the pipe (environmental), the termination points, joint details, have the epoxy PRUWDU YHULÂ¿HG WR LQVXUH D VORSH

Figure 2. Pipe segment during surface preparation.

4$ 4& Â± FXUH DQG Â¿QDO ZDON WKURXJK 'XULQJ WKH Â¿QDO FXUH SURFHVV DW +RSH &UHHN WKH HQYLURQPHQWDO conditions were monitored closely including air temperature, surface temperature and humidity. In addition, Shore D hardness values were recorded to assist in monitoring the progression of cure RI WKH &)53 V\VWHP $ Â¿QDO FKHFN RQ FXUH WLPH LV YHULÂ¿FDWLRQ RI testing in place to verify the degree of cure as determined by time and temperature. Following cure of the CFRP system at Hope &UHHN D Â¿QDO 4$ 4& ZDON WKURXJK WRRN SODFH DV VHHQ LQ Â¿JXUH

Conclusion The use of CFRP at Hope Creek Nuclear Station provided a trenchless, fully structural repair of the distressed 144-inch diameter pipeline segments. Through the use of well-tested materials, a conservative design, experienced installers and a rigorous QA/QC program, the project was safely and successfully implemented. 12

Figure 3. Mechanical saturation machine.

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Figure 4. Installation of longitudinal layers of CFRP at Hope Creek. Figure 8. Final curing preocss being monitored

Figure 5. Installation of circumferential layers of CFRP at Hope Creek.

Figure 9. Muck in the cooling tower basin that served as primary access into the pipeline. Muck removed prior to installation.

Figure 6. Joint region following surface preparation and installation of epoxymortar.

Figure 10. Two-tiered scaffolding system.

Figure 7. Joint region showing installation of CFRP layers.

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Figure 14. Detailing of CFRP repair at location of protruding temperature probe. Figure 11. Single point-of-entry for pipeline repair project at Hope Creek.

)LJXUH 9HULÀFDWLRQ RI FRQFUHWH VXUIDFH SUHSDUDWLRQ XWLOL]LQJ ,&5, &63 SURÀOH VDPSOH

Figure 12. Epoxy build-up on pipeline interior.

)LJXUH 9HULÀFDWLRQ RI VWHHO VXUIDFH SUHSDUDWLRQ W o near white metal SP-10. Figure 13. Pitting of concrete and temperature probe penetration requiring special detailing.

Figure 17. Weighing of fabric prior to saturation process.

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)LJXUH 4$ 4& Ă€QDO ZDON WKURXJK

References ASTM D3039, Standard test method for tensile properties of polymer matrix composite materials. American Standard for Testing and Materials (ASTM) ASTM D4541, Standard test method for pull-off strength of coatings using portable adhesion: American Standard for Testing and Materials (ASTM) ICRI Guideline No. 310.2, Selecting and specifying concrete surface preparation for sealers, coatings and polymer overlays. International Concrete Repair Institute (ICRI) SSPC-SP No.10 / NACE 2 Near-White Blast Cleaning. Society for Protective Coatings (SSPC) and the National Association of Corrosion Engineers International (NACE)

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Proposed Methodology For CTI ATC 6RXQG &HUWLË‰FDWLRQ 2I )DFWRU\ Assembled Towers John Dalton and Larry Burdick Spx Cooling Technologies

The Cooling Technology Institute has a very successful, long standing program for thermal capability certification of factory assembled WRZHUV EXW WKLV W\SH RI FRQÂżGHQFH RU UG SDUW\ validation for published sound levels does not exist within the industry. This paper discusses an approach taken, with its successes and challenges, to establish a sound data set for an entire packDJHG SURGXFW PRGHO OLQH WKDW DFFXUDWHO\ UHĂ€HFWV sound emission of all models within the line, and SURSRVHV EDVLF $7& FHUWLÂżFDWLRQ UHTXLUHPHQWV and guidelines. John Dalton

Methodology for model selection, testing, and data analysis is provided to facilitate the breadth of data and the considerations needed to establish information suitable for cooling WRZHU VLWH GHVLJQ DQG FHUWLÂżFDWLRQ

Â‡

Sound Data Quality

Â‡

Â‡ The outdoor location is a compromise, so efforts such as testing at night are made to minimize background sound levels and to monitor the levels during testing. ATC-128 provides limits. Â‡ 7KH WHVW SDG LV D UHĂ€HFWLYH SODQH PRVW VXLWDEOH for this type of equipment. No adjustments are made to the measured sound levels due to the UHĂ€HFWLYH SODQH Â‡ Personnel are trained in equipment use, setup, and testing. Â‡ The products being tested are part of a CTI ATC FHUWLÂżHG SURGXFW OLQH Â‡ The sound equipment meets requirements for accuracy per CTI ATC-128, e.g. Type 1 equipment. Â‡ Sound equipment calibrations are current per CTI ATC-128 requirements. An adequate sampling of models in the product line must be initially tested in order to apply the trends with small adjustments to the remaining untested variations. The manufacturer and a 3rd party CTI licensed Test Agency witness and take part in the sound measurements. The manufacturer uses the measured trends and applies small adjustments to closely estimate sound levels for the product line. The data is reviewed and must be approved by a 3rd party CTI licensed Test Agency.

,GHDOO\ VRXQG PHDVXUHPHQWV DUH PDGH IRU HDFK PRGHO LQ D TXDOLÂżHG Â‡ test chamber and meet very high standards for testing, but this type of testing is typically reserved for equipment in sound-sensitive DUHDV VXFK DV LQGRRU RIÂżFH VSDFHV (YHQ WKHQ LW LV RIWHQ LPSUDFWLÂ‡ cal to test every product line variation, so good estimates based on empirical data are applied. Table 1 describes some of the different ways sound data may be determined with progressively more er- Adjustments: ror from left to right. Ambiguous data can often be recognized by A key factor in judging how many units and variations must be vague descriptions and lack of units. tested is the determination of how far test data can be reliably exTable 1: Data Acquisition & Quality of Results trapolated. Howden [2] developed equation 1 to calculate fan sound power and presented it as part of CTI Technical Paper TP93-03 on fan noise reduction. Equation 1 states that sound power can be calculated by combining empirical data, C, with adjustments for tip speed, net power delivered to the air by the fan (not including HIÂżFLHQF\ ORVVHV IDQ GLDPHWHU DQG DGMXVWPHQWV IRU YDULDQFHV such as inlet and outlet obstructions, tip clearance, fan guards, and beams located near the fan. The equations below are used to adjust data from test conditions to published design conditions with good success. The adjustments are applied uniformly across all octave bands.

Pragmatic cooling tower and large industrial product testing best practice usually blends â€œIdealâ€? and â€œGood Estimatesâ€? categories to produce sound data. For example:

CTI Journal, Vol. 37, No. 2

PWL = the sound power level, W C = fan characteristic value, dB(A) utip = fan tip speed, m/s T IDQ DLU Ã€RZ P3/s Ptot = total pressure = static pressure + velocity pressure, Pa Dfan = fan diameter, m Â¨G% FRUUHFWLRQ WHUPV G% $

Based on sound radiating spherically from the source, sound power is directly related to sound pressure by equation 2, [2], so it follows in equation 3 that changes in tip speed and / or a change in fan power directly correlate to sound pressure level. Eq. 2: PWL = SPL + 10 LOG (S / SREF) dB

PWL = sound power level, dB (re 10-12 W) SPL = sound pressure level, dB (re 20x10-6 Pa) 6 VXUIDFH DUHD RI D VSKHUH ÊŒ U2, m2 SREF = reference area, 1m2 & WHVW GDWD VRXQG SUHVVXUH DW D VSHFLÂ¿F RSHUDWLQJ FRQGLWLRQ GLVWDQFH

Chart 1: Measurement locations at 1.5m (5â€™) and 15.2m (50â€™) from unit.

and location, dB (re 20x10-6 Pa) TSdesign = tip speed of the fan whose sound level is being determined TStest = tip speed of the test fan BkWdesign = fan motor power of the fan whose sound level is being determined BkWtest = fan motor power of the test fan

Note that the correction for environment disappears. This is because the basis data, C, is test data of the fan in the tower environment, not a set of additions and subtractions based on theory. It includes how the fan and unit actually respond acoustically at the tested operating conditions. Likewise, the fan diameter term disappears as it is absorbed in the adjustment for the ratio of fan speeds. Finally, the DGMXVWPHQW IRU SRZHU LQFOXGHV WKH IDQ DQG GULYH HIÂ¿FLHQF\ ORVVHV all of which contribute to the sound characteristics of the system.

Photo 1: Microphone stationed at 1.5m (5â€™) from a tower Louver Face (LF).

Comparison Of Overall Sound Pressure Level Adjustments To Test Data Tables and charts 2a-2d compare overall A-weighted SPL test averages to A-weighted SPL predictions using equation 3: Table 2a shows base case measurements used for equation 3 predictions; tables 2c-2d compare predictions to actual measurements. The difference between tested sound pressure levels at various conditions and predicted sound pressure levels is a simple subtraction, rounded WR G% 7KH H[DPSOH WHVW GDWD LV IURP D ODUJH GRXEOH Ã€RZ PRGXODU FURVVÃ€RZ SDFNDJH FRROLQJ WRZHU QRPLQDOO\ Â¶ORQJ [ Â¶KLJK x 22.4â€™wide and with a 3658mm (12â€™) fan. Four fan speeds and UHVSHFWLYH Ã€RZ UDWHV DVVRFLDWHG ZLWK WKH WRZHUVÂ¶ FDSDFLW\ DW Âƒ& KRW ZDWHU Â± Âƒ& FROG ZDWHU Â± Âƒ& ZHW EXOE FRQGLWLRQV Âƒ) DUH FRQVLGHUHG 6RXQG SUHVVXUH OHYHOV ZHUH PHDVXUHG DW locations 5â€™ and 50â€™ from the louver face (LF), the cased face (CF), and above the fan (AF), as depicted in Chart 1.

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Tables 2a-2d show examples of equation 3 predicting overall sound levels to within 0.9 dB when the fan rpm is within +/- 20% of the tested fan rpm, but when fan speed is different from the test condition beyond 25%, error increases rapidly to as much as 1.8 dB. The increasing error occurs because equation 3 models changes in magnitude and does not capture changes in frequency.

Table 2e, below, is another example illustrating the closeness RI SUHGLFWLYH UHVXOWV 7KH WRZHU LV D PRGXODU GRXEOHÀRZ ZLWK a 3658mm (12’) 8-blade fan tested in 1998 at various speeds. Predictions yield accuracy within 2 dB of actual at fan speeds as high as 120% of the base 214 rpm conditionTable 2e: Example of predicting sound at faster than tested fan speeds.

between linear and A-weighted SPL at low frequencies shown in Table 6 minimize the impact of error at these frequencies on overall SPL. However, octave bands are important in predictive sound modeling, and low frequencies such as 63Hz are also the PRVW GLI¿FXOW WR DWWHQXDWH 2QH RI WKH UHDVRQV XOWUD TXLHW IDQV KDYH low overall sound pressure levels is A-weighting; another is that blade pass frequencies are often shifted to the 31.5 Hz band which we currently do not report. Chart Group 4: Comparison of sound test data at 242 rpm

Predicted Individualoctave Band Sound Pressure Levels Versus Actual Test Data Mechanical equipment operating frequencies create sympathetic vibrations in the tower structure and accessories. Consequently, resonances show up as octave bands variations that occur at different fan speeds. Tables 3 - 5 compare the predictive model using equation 3 to the octave bands that make up the overall sound pressure levels shown in Appendix B. When limited to +/-20% of tested fan speed, it is evident from tables 3-5 that equation 3 often predicts the middle frequencies reasonably well, but does not account for frequency variations at different conditions. The lower frequencies are also close most of the time, yet the most pronounced error is at the low end in the 63Hz band due to fan speed. Since water noise dominates the upper frequencies, separating water and fan noise contributions, applying equation 3 to the fan portion to make predictions and recombining with water noise may yield the least error. In fact the data shows that the sound pressure level remains essentially constant at 8000 Hz across all four fan speeds at the 1.5m (5’) louver face location. Therefore the predicted sound level becomes more accurate if no adjustment is made to the base data at 8000 Hz for the 1.5m (5’) louver face location; the absolute error is reduced from 4.5 dB to 0.9 dB at 1.5m (5’) louver face in table 4.

$ ZHLJKWLQJ G%$ UHÀHFWV KXPDQ VHQVLWLYLW\ WR VRXQG DW GLIIHUent octave band frequencies, so the overall sound pressure level is usually listed in dBA. Octave bands are typically communicated as “linear,” or unweighted (dB) sound levels. The large adjustments

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3UHGLFWLRQV :KHQ 7KH )DQ 3UR¿OH ,V &RQVWDQW And The Fan Size Changes Table 7 contains overall tested SPL’s for a small and a medium VL]HG FURVVÀRZ SDFNDJH WRZHU KDYLQJ GLIIHUHQW IDQ GLDPHWHUV 7KH smaller tower is nominally 8.5’ long x 18’wide x 11’high. The larger tower is nominally 12’long x 22.4’wide x 11’high.

Using the data in table 7 and equation 3, adjustments are made to the small box (S) test data to predict medium sized box (M) sound levels.

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Chart 6 and table 9 show that: extrapolations of fan size by 40% yielded 4 dB errors. (Values rounded to 0.1) A second case of predicting sound levels of one tower size using WHVW GDWD IURP D WRZHU RI DQRWKHU VL]H FRQVLGHUV ¿YH IDQ VSHHGV 7KH mid-size box (M) was nominally 12’long x 11’high x 22.4’wide and utilized a 3353mm (11’) diameter fan. The larger box (L) was nominally 14’long x 11’high x 22.4’wide and utilized a 3658mm ¶ GLDPHWHU IDQ 7KH GDWD LQFOXGHV ¿YH IDQ VSHHG DQG FRUresponding fan power increments. The comparison of 50’ above fan is not included as these two boxes were tested at 24’ and 33’ above fan, respectively and adjustments could introduce error into this comparison.

Predictions Across Both Cabinet Size And Fan Size Charts 7a-e and table 11 depict how much even incremental variations in box and fan size can affect predictions.

Application For Quiet Fans At Low Fan Power And Rpm 8VH RI WKH FRHI¿FLHQWV LQ HTXDWLRQ ZLOO XQGHU SUHGLFW WKH XQLW sound level when applied to very quiet fans, especially at low power and rpm. As fan induced sound fades off with lower and lower power, falling water noise stays relatively constant and mechanical noise from the motor and gear reducer or belt drive becomes audible. Changes in fan induced noise become so quiet that they are inconsequential, so continuing to predict quieter operation using equation 3 (generic black curve in chart 8) results in

CTI Journal, Vol. 37, No. 2

XQUHDOLVWLF VRXQG OHYHOV :DWHU QRLVH LV D JRRG VRXQG OHYHO Ă€RRU for an operating cooling tower.

Chart 8: Tower sound levels become asymptotic as air noise lessons. Limits are relatively constant mechanical noise and water QRLVH /DUJH FURVVĂ€RZ SDFNDJH WRZHU PP Âś GLDPHWHU YHU\ ORZ QRLVH IDQ

Choosing Units To Sound Test

Setup And Testing 6HW XS LQ D IUHH ÂżHOG DUHD ZLWK D UHĂ€HFWLYH SODQH SHU &7, $7& Measure fan rpm with a calibrated strobe light or other means to match actual fan speeds with VFD settings. Measure fan power with a calibrated power meter for each condition, then calculate motor RXWSXW SRZHU EDVHG RQ WKH PRWRU QDPHSODWH HIÂżFLHQF\ 0HDVXUH ZDWHU Ă€RZ LQLWLDOO\ XVLQJ D SLWRW WXEH WR YDOLGDWH Ă€RZ PHWHU UHDGLQJV WKHQ VHW WKH Ă€RZ WR PDWFK WRZHU FDSDFLW\ DW Âƒ) IRU each model being tested. Measure sound pressure level at 1.5m (5â€™) and 15.2m (50â€™) distances from the louver face, cased face, and above the fan. Above fan measurements can be facilitated with a pneumatic mast at the 1.5m elevation, or by mounting the microphone to an extension mounted to a man-lift basket. Ensure that background levels are adequately low and record two measurements of each point to eliminate occasional anomalies. Test with a UG 3DUW\ &7, OLFHQVHG 7HVW $JHQF\ ZLWQHVV &RPSDUH DQG DIÂżUP collected data with the Test Agency witness.

Extrapolating test data far from the test points can quickly lead to differences between the predicted and actual sound levels, thereIRUH WHVWLQJ PXOWLSOH FRQÂżJXUDWLRQV LQ PDQ\ ER[ VL]HV LV QHFHVVDU\ to provide high quality data. Minimizing both the number of boxes that need to be tested initially while at the same time minimizing how far data is extrapolated quickly reduces the number of test candidates a manufacturer may consider. Additionally, test data may already exist for a unit and this can further narrow the selection process. Exceptions arise for large, low blade count fans operated at fan EODGH WLS VSHHGV QHDU P V ISP XQGHU GLIÂżFXOW FRQGLtions. In this case, pulsing and unit vibration occur yielding sound levels that do not trend with higher blade count variations. Additionally, if beams or obstructions are near the fan, a pulse frequency is more likely to be generated with a small blade count or a blade count coincidental with the number of obstructions. Â‡ Once towers are selected, test as many models as possible within that unit size. Recommend testing additional points that aid trending and closely align with points of adjacent box sizes that may not be tested at this time. A variable frequency drive (VFD) allows many fan speed changes in a short time. Model selection within the box size can be determined by mapping in a spreadsheet the motor speed, motor power, fan speed, drive ratio, and blade count. . Â‡ %DVHG RQ XWLOL]LQJ D 9)' XVH DIÂżQLW\ ODZV WR SUHGLFW power draw as a function of fan rpm for each drive ratio, motor rpm divided by fan rpm, at a given fan pitch. Â‡ For each rpm associated with a different model, check that the motor power is close to the design power, per CTI-ATC-128. Â‡ The goal is to be able to mimic several models without major mechanical changes. Â‡ Change the fan pitch between test points as needed during the test period to extend the number of test models. &RXQWHUĂ€RZ WRZHUV SUHVHQW D IHZ RWKHU FKDOOHQJHV LQFOXGLQJ determination of adjustments for falling water height variations, DLU LQOHW KHLJKW YDULDWLRQV DQG ÂżOO KHLJKW YDULDWLRQV

Photo 2: Sound test setup.

Analysis $SSO\ HTXDWLRQ RU RWKHU DGMXVWPHQWV WKDW ÂżW WHVW GDWD WUHQGV DQG test data nearest the design conditions for published literature. Trend data for very low sound models as mechanical equipment and water noise become predominant. Gain approval through the 3rd Party CTI licensed Test Agency.

Conclusion It is clear that making adjustments to test data with the goal of SUHGLFWLQJ VRXQG OHYHOV RI GLIIHUHQW XQWHVWHG FRQÂżJXUDWLRQV LV imperfect, and therefore a variety of models in many cabinet sizes need to be tested to arrive at published overall sound levels with an accuracy of +/- 3 dB at all locations. Testing of an initial group of towers coupled with use of existing sound test data yields some sound predictions that are quite accurate while others are â€œballSDUNÂ´ HVWLPDWHV $7& WKHUPDO FHUWLÂżFDWLRQ SURYLGHV FXVWRPHU FRQÂżGHQFH WKDW WKH WRZHUV WKH\ SXUFKDVH SHUIRUP DW WKH SXEOLVKHG OHYHOV FODLPHG E\ PDQXIDFWXUHV 7KLV SDSHU SURYLGHV MXVWLÂżFDWLRQ IRU WKH FRQFHSW RI D SDUDOOHO $7& VRXQG FHUWLÂżFDWLRQ SURJUDP summarized in table 11, and targeted at achieving the same goal. The process begins with testing an initial group of towers and transforms â€œballparkâ€? sound data into â€œgood estimatesâ€? gradually, E\ XVLQJ DGMXVWPHQWV EDVHG RQ DQQXDO UHFHUWLÂżFDWLRQ WHVWLQJ

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Appendix B: Octave band data, Test, Predictions, Errors.

Appendix A: References [1] Table adopted from TRANE training video, Evaluating Sound Data, video @ t =14:25/51:00 minutes. http://www.trane.com/commercial/north-america/us/en/products-systems/education-training/ educational-resources-by-type/continuing-education/EvaluatingSound-Data-HVAC-Acoustics.html [2] Reduction of Noise Generation by Cooling Fans, CTI 1993 Annual Meeting, TP93-03, Ir. Henk F. van der Spek, Ventilatoren Sirocco Howden B.V., Hengelo, The Netherlands [3] CTI ATC-128 (14), February 2014, Equation 4.

CTI Journal, Vol. 37, No. 2

6DIHW\ ,Q &RROLQJ 7RZHU 0DLQWHQDQFH Magose Abraham Eju Energy Business Total Solutions, Ltd

Abstract Maintenance of Cooling Towers usually poses quite a number of occupational / personal safety challenges. For example, the process of removing and replacing packing (fill) in a cooling tower involves working at height in most cases. If not well managed, this exercise can result to accident of falling; leading to Magose Abraham Eju injury and/or fatality. In order to avert such safety incidences during Cooling Tower Maintenance, a robust safety management system needs to be developed for every maintenance work.

Figure 1.1: Picture of the 9-Cell Cooling Tower

This paper uses a case study to show the various safety hazards that can be associated with maintenance of Cooling Towers, as well as, suggest ways that these hazards / risks could be mitigated.

Introduction A major maintenance activity was carried out at one of the 9-cell FRROLQJ WRZHU RI WKH 1LJHULD /LTXHÂżHG 1DWXUDO *DV &RPSDQ\ 7KH work scope include the production of new cooling water packing ÂżOO UHPRYDO DQG UHSODFHPHQW RI WKH ROG ÂżOO WKH UHYDPS RI WKH cooling water tower demister, cooling fan refurbishment, water EDVLQ GUDLQLQJ FOHDQLQJ UHÂżOOLQJ DQG WKH FOHDQLQJ RI DVVRFLDWHG heat exchanger tubes. Gas liquefaction in this plant is performed with the aid of three cooling circuits: the cooling-water circuit, the propane refrigerant circuit and the mixed refrigerant circuit. The mixed refrigerant (which is a mixture of Nitrogen, Methane, Ethane and Propane JDVHV OLTXHÂżHV WKH QDWXUDO JDV E\ UHIULJHUDWLQJ LW GRZQ WR D WHPperature of -160oC. The propane refrigerant circuit pre-cools the natural gas and partially condenses the mixed refrigerant. The cooling water circuit condenses and sub-cools the propane. The entire liquefaction circuit is a complete refrigeration cycle consisting of condensers, compressors, expanders and Joule-Thompson valves, in addition to a cryogenic heat exchanger, which acts as the evaporator where the actual liquefaction of the natural gas occurs. The cooling tower provides cooling water to both process and equipment heat exchangers using water for cooling or condensing ZLWKLQ WKH /LTXHÂżHG 1DWXUDO *DV /1* 3ODQW $ SLFWXUH RI WKH 9-cell cooling tower is shown in Figure 1.1 while, Figure 1.2 is a line diagram of the cooling tower system at NLNG plant. Each of three LNG Plant Production Train is equipped with an independent open re-circulation water-cooling system.

Figure 1.2: Line Diagram of NLNG Cooling Tower System (Courtesy of NLNG Operating Manual)

Cooling is achieved by pumping treated fresh water to process exchangers and other equipment (â€œusersâ€? in Figure 1.2) and then EDFN WR WKH LQGXFHG GUDXJKW ÂżOP W\SH FRXQWHU Ă€RZ FRROLQJ WRZHUV The water to be cooled is fed into the top of the cells and the air and water streams come into intimate contact as the water falls by gravity into the three cooling water basins that feed the cooling water pump basin. Within the cells, the water is distributed to the spray nozzles which spray the water evenly unto the PVC packing (see Figure 1.3 below for cooling tower cell schematic). This packing ensures that there is proper heat exchange between the air DQG ZDWHU E\ EUHDNLQJ XS WKH ZDWHU LQWR ÂżQH SDUWLFOHV In March 2012, a comprehensive revamp maintenance of the cooling tower system was done. The scope of work included: Â‡ Changing defective/damaged nozzles. Â‡ 5HSODFLQJ ÂżOO SDFNV 39& SDFNLQJ 7KLV ZDV WKH PDMRU part of the job requiring a large number of personnel working at height. All safety precautions were taken as directed in the Job Hazard Analysis. 3,000 cubic meters RI ÂżOO SDFNV ZHUH UHPRYHG DQG UHSODFHG ZLWK QHZ RQHV LQ D VSHFLÂżHG DUUDQJHPHQW Â‡ Flushing of the drift eliminators: The drift eliminators were removed and washed with high pressure water to clear the algae on it. CTI Journal, Vol. 37, No. 2

Cleaning the cooling water cells and pump basin (water MHWV ZHUH XVHG WR ÀXVK WKH FRROLQJ ZDWHU FHOO ZDOOV DQG fan blades. Shovels and water jets were then used to clean the basin into which all the dirt from the top had fallen). Cleaning the trash screens at the pump inlet. %DFN ÀXVKLQJ RI SLSLQJ Maintenance work such as this usually poses a number of occupational / personal safety challenges and hence requires a robust safety program in order to avert the hazards resulting in accidents / incidence. This discourse shall highlight some of these safety issues that were highlighted / considered during this particular cooling tower maintenance by reviewing the activity of removing the old IRXOHG GDPDJHG SDFNLQJ ¿OO RI WKH 1/1* FRROLQJ WRZHU DQG replacing them with new ones.

Figure 2.1: Work Hazard Analysis Sheet for Removal of Old Fill

Production Of Pvc Packing / Fill

Figure 1.3: Cooling Tower Cell Schematic (Courtesy of NLNG Operating Manual)

Removal Of Old Packing / Fill From The Cooling Tower 7KH UHPRYDO RI WKH ROG ¿OO ZDV D ODERXU LQWHQVLYH MRE EHFDXVH RI the volume of material involved. The workers / personnel were arranged in chain across the cell and out of it so that the old packs could be moved in an organized way. Two 40-tonne cranes with man-baskets were used to move the removed packs to the ground ÀRRU IURP WKH WRS RI WKH WRZHU IHHW PHWHUV KHLJKW

Each cooling water cell contains 2,058 (1800 X 300 X 300mm) packs and 126 (600 X 300 X 300mm). Since there are 9 cells, the target production of the packs was as follows: 20,000 packs (1800 X 600 X 600mm) 2,000 packs (600 X 300 X 300mm) The raw materials come in sheets and 15 sheets make up a pack. The sheets are held together by an adhesive produced from a mixture of chemicals. 7KH ¿OO SDFNV ZHUH SURGXFHG RQ VLWH ZLWK SURGXFWLRQ OLQHV HDFK with 4 men working 30 minute shifts. The work steps were as follows: 1.

A valid permit to work is obtained from Operations Department

The Job Hazard Analysis (see Figure 3.1 below) is discussed with the men at the beginning of every 12 hour shift.

Mixing of the chemicals was done in a mixer in the following proportion: Cyclohexanone 100% weight Tetrahydrofuran 1-3% weight PVC powder 4-5% weight Stir the mixture for about 5 minutes

Charge the rolling machines with the solution

Run the PVC sheets through the machine ensuring that the joining points adequately make contact with the solution.

Stack 15 sheets together to make one pack.

Safety And Job Hazard Analysis The job hazard analysis was conducted with the lead men on the job, safety professionals and the occupational hygienist. The prepared document is shown below and was discussed with the workers at the beginning of each 12 hour shift on the job. The analysis was done with the Materials Safety Data Sheet (MSDS) and all hazards were examined with recommended mitigation measures proposed.

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Safety And Job Hazard Analysis The job hazard analysis was conducted with the lead men on the job, safety professionals and the occupational hygienist. The prepared document is shown below and was discussed with the workers at the beginning of each 12 hour shift on the job. The analysis was done with the Materials Safety Data sheet (MSDS) and all hazards were examined with recommended mitigating measures proposed.

The pictures below show some of the work activities, the hazards and the safety precautions that were applied:

Picture 1: Damaged Fill of the Cooling Tower

Picture 2: Fouled Fill of the Cooling Tower

Figure 3.1: Work Hazard Analysis Sheet for On-Site Production of New Fill

Picture 3: Cooling Tower after Removal of Old Fill

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Picture 4: Cooling Tower Removal of Old Fill Picture 7: Height of the Cooling Tower – 33 feet

Picture 5: Old Fill Removed from Cooling Tower

Picture 8: Workers Installing Fan Blade

Picture 6: Lighting inside the Cooling Tower

Picture 9: Flushing of Pump Suction Pipe – 72-inch

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Picture 10: New Fill Installed in Cooling Tower

Conclusion Cooling Tower maintenance work usually involves personnel IURP GLIIHUHQW ÂżHOGV RI HQJLQHHULQJ DQG VRPHWLPHV IURP GLIIHUHQW companies / organizations. In order to avoid downtime / loss time injuries due to accidents, it is essential that a Job Hazard Analysis is carried out prior to commencement of work to identify all the possible hazards and recommend / develop mitigating measures that will have to be put in place. Also, proper safety orientation of the various personnel on the work site has to be ensured. For example, it is necessary to have a safety brief / tool box session between supervisors and workers before the start of work. At this safety brief, all the work for that day, the possible hazards and the necessary precautions will be discussed in details. Finally, it is recommended that CTI develop a â€œCooling Tower Maintenance Safety Guideâ€? that will outline minimum safety requirements, based on best practices, for different types of maintenance work on Cooling Towers.

References

Atuchukwu, C. (2013), Cooling Tower Revamp. In: Nigeria Society of Engineers Projects Report, Nigeria. %ULWLVK 6WDQGDUGV ,QVWLWXWH 6SHFLÂżFDWLRQ IRU :DWHU Cooling Towers, BS 4485, Part 2 and Part 3. 1LJHULD /LTXHÂżHG 1DWXUDO *DV 3ODQW 2SHUDWLQJ 0DQXDO

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Advancements in Cleaning and 3DVVLYDWLRQ RI &RROLQJ :DWHU 6\VWHPV Raymond M. Post, P.E., Prasad Kalakodimi, Ph.D. Jeffrey Oâ€™Brien, and Richard H. Tribble, Chemtreat

Abstract

all the areas of the system where the deposits are located. Chemical cleaning is more versatile in being able to reach all areas of the system and more effective in terms of removing all traces of rust and deposition.

Newly installed piping and heat exchangers should be pre-cleaned to remove surface rust and passivated to protect against initial corrosion prior Traditional methods employed for chemically to entering service. Traditionally, high levels of removing corrosion products relied upon strong polyphosphate [1], organic phosphate [2], ortho acids and required special precautionary measures phosphate, and combinations have been used to for handling and application. Additionally, the both preclean and passivate in one step. Both polyextreme pH risked excessive loss of the base metal, phosphate and organic phosphate have good iron separticularly in systems with mixed metallurgy. questering and rust removal properties. Chromate More recently, considerably safer neutral pH cleanDQG ]LQF DUH HIIHFWLYH DW IRUPLQJ D SURWHFWLYH ÂżOP ing programs for rust removal were introduced. Raymond M. Post but have fallen out of favor due to environmental These formulations essentially consist of (1) a restrictions. Nitrite is an effective passivator in strong reducing agent to reduce ferric (Fe3+) iron oxide deposits closed cooling loops, but promotes microbiological activity in open 2+ cooling tower systems and does not become incorporated into a into a soluble ferrous (Fe ) form, and (2) an organic phosphate GXUDEOH SURWHFWLYH ÂżOP +LJK OHYHOV RI PRO\EGDWH DUH DOVR XVHG chelant to complex the dissolved iron. The system is thoroughly for pretreatment, but molybdate is expensive for large systems and Ă€XVKHG DIWHU WKLV SURFHVV WR UHPRYH WKH GLVVROYHG LURQ 7KRXJK safer to handle, neutral pH cleaners still can still be very aggressive increasingly subject to environmental restrictions. WR FDUERQ VWHHO EDVH PHWDO 3URYLGHG WKDW WKH ÂżQDO S+ RI WKH VROXPeriodically it may also be necessary to clean equipment to remove tion is greater than approximately 6.0, these neutral pH cleaners accumulated corrosion products and deposits in order to restore can provide some degree of passivation. thermal performance. Traditional cleaning methods include mechanical brushes and scrapers, acid cleaning, or neutral pH Regardless of whether the cleaning is performed mechanically or cleaning using high levels of sequestrants or chelants. Regardless chemically, freshly cleaned steel surfaces are extremely vulnerof whether a mechanical or chemical cleaning method is used, DEOH WR Ă€DVK UXVW $ VHSDUDWH SDVVLYDWLRQ VWHS LV UHTXLUHG DIWHU WKH the freshly cleaned steel surfaces should also be passivated im- FOHDQLQJ SURFHVV WR SURWHFW WKH EDUH PHWDO IURP Ă€DVK UXVW DQG WR PHGLDWHO\ IROORZLQJ FOHDQLQJ WR SURWHFW DJDLQVW Ă€DVK UXVW XQWLO WKH protect against the high initial corrosion rate that occurs when the normal treatment program is established. Proper initial passivation equipment is initially placed into service. has been reported to approximately double the life expectancy of To achieve a one-step cleaning and passivation, there exists a need mild steel heat exchangers [3]. for a strong corrosion inhibitor chemistry that protects the steel This paper describes the development and application of a new surfaces from the aggressive cleaning chemistry and provides a non-phosphate pre-treatment chemistry that forms a truly passive VWURQJ SDVVLYH ÂżOP WR SURWHFW WKH VXUIDFHV DV WKH\ DUH SODFHG LQWR ÂżOP RQ VWHHO VXUIDFHV 7KLV SDVVLYDWLRQ WUHDWPHQW FDQ EH XVHG LQ service. The starting point for corrosion inhibitor development combination with either mildly acidic or neutral pH solutions to was an inhibitor chemistry originally developed to comply with provide a one-step cleaning and passivation. The use of electro- emerging restrictions on phosphorus discharge. The development chemical techniques in the development and evaluation of the and application of this corrosion inhibitor for use in cooling towers chemistry, including cyclic polarization and electrochemical im- under normal operation has been described in earlier publications pedance spectroscopy, are discussed. A case history is provided [4] [5]. This corrosion inhibitor chemistry was selected because to illustrate the effectiveness of this technology for cleaning and it interacts directly with metal surfaces to form a reactive polyhypassivation as part of a comprehensive program for protecting droxy complex (RPC) that is independent of calcium, pH, or other water chemistry consitutents. It also possesses many of the other industrial cooling systems from corrosion. GHVLUHG DWWULEXWHV LQFOXGLQJ DQ H[FHOOHQW DTXDWLF HIIHFWV SURÂżOH 7KH ability of the RPC chemistry to protect and passivate the base metal Introduction Industrial cooling systems rapidly form iron oxide deposits which GXULQJ SUHRSHUDWLRQDO FOHDQLQJ LV WKH IRFXV RI WKLV VWXG\ (IÂżFDF\ UHGXFH WKHLU KHDW WUDQVIHU HIÂżFLHQF\ ,W LV FRPPRQ WR PHFKDQLFDOO\ of the RPC chemistry was compared to traditional polyphosphate clean these systems when the iron oxide deposits become excessive. and organic phosphate cleaning and passivation chemistries. Mechanical means such as scraping, brushing, sand blasting, and Laboratory Studies high pressure water washing are few of the well-known mechanical cleaning methods. Mechanical cleaning, while effective in many Most metallic corrosion occurs via electrochemical reactions at the cases, is time-consuming, laborious and expensive. Also, it is interface between the metal and an electrolyte solution. Since cornot always possible for the physical removal methods to access rosion phenomena are electrochemical in nature, they are governed by the measurement of equilibrium corrosion potential (Ecorr) of

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the metal surface. During the late â€˜70s and early â€˜80s, corrosion specialists began to discover that electrochemical instruments and techniques could be valuable tools for mechanistic understanding and problem solving. Electrochemical methods can be very helpful in rapidly evaluating the persistence of a passive layer formed on a metallic specimen in the presence of inhibitor when that specimen is transferred into a second solution not containing a corrosion inhibitor.

Open Circuit Potential (OCP) Evaluation â€“ Open circuit potential measurements were made in blank water with bare mild steel (MS) coupons and also on the coupons passivated as described above using the organic phosphate, polyphosphate, and RPC chemistries. OCP measurements were taken at 5 minute intervals IRU DQ H[WHQGHG SHULRG RI KRXUV &RPSDULQJ WKH 2&3 SURÂżOHV obtained for these electrodes indicate that after the electrode surface was passivated using RPC, the OCP is >200 mV more positive than that the MS coupons passivated with polyphosphate and organic Electrochemical Experimental phosphate chemistries. These results indicate that the RPC pasThe passivation chemistries selected for laboratory evaluation were VLYH ÂżOP LV WKHUPRG\QDPLFDOO\ PRUH VWDEOH WKDQ SKRVSKDWH DQG LV two well-established phosphate chemistries and the RPC chemistry, YHU\ HIIHFWLYH LQ UHGXFLQJ FRUURVLRQ 0RUHRYHU WKH SDVVLYH ÂżOP which were compared to untreated blank water samples for their retained its effectiveness in the untreated blank water, with the OCP DELOLW\ WR IRUP D SHUVLVWHQW SURWHFWLYH ÂżOP 7KH RUJDQLF SKRVSKDWH decreasing <100 mV during the 36-hour exposure. In the cases of (HEDPA) was evaluated at a concentration of 1,250 mg/L as PO4=, the polyphosphate and organic phosphate passivations, the OCP the polyphosphate (TKPP) was evaluated at a concentration of 320 values quickly become more negative, indicating rapid dissolution mg/L as PO4=, and the RPC was evaluated at a concentration of RI WKH SDVVLYH ÂżOP E\ GLIIXVLRQ RI DJJUHVVLYH LRQV DQG VXEVHTXHQW 12 mg/L. The blank water contained 150 mg/L Ca as CaCO3, 100 increase in corrosion rates. mg/L Mg as CaCO3, 100 mg/L M-Alkalinity as CaCO3, 50 mg/L chloride as Cl-, 10 mg/L silica as SiO2, at pH 8.0. Working electrodes were made from cylindrical shaped carbon steel electrochemical coupons. Corrosion resistance performance of different passivation chemistries was evaluated using electrochemical techniques including open circuit potential (OCP), cyclic polarization (CP), and electrochemical impedance spectroscopy (EIS) measurements. Carbon steel coupons were passivated for 8 hours in baths containing the passivation chemistries. After passivation, the electrochemical coupons were rinsed with RO water and placed in the blank water. The pH of the blank solution was maintained at 8.0-8.2 using caustic soda. Electrochemical measurements were performed in a three electrode cell consisting of a graphite counter electrode, an Ag/AgCl reference electrode, and the carbon steel coupon. Electrochemical impedance spectroscopy (EIS) measurements were performed using the excitation signal of 10 mV sinusoidal potential through a frequency domain from 100 kHz down to 10 mHz. The impedance diagrams were recorded at the equilibrium OCP, while polarization scans were traced at a rate of 0.5 mV s-1. Unless otherwise stated, each experiment was conducted in at least triplicate using freshly prepared solution in each case and with the average of the reliable data reported. Figure 1 shows the electrochemical testing apparatus used for the experimental work.

Figure 2. Open circuit potential after passivated coupon is placed in untreated water

Figure 3. Cyclic polarization after passivated coupon is placed in untreated blank water

From the cyclic polarization curves, some electrochemical corrosion kinetic parameters can be obtained, such as the corrosion potential (Ecorr), Tafel slopes, corrosion current density (Icorr), and corrosion rates in Table 1.

Figure 1. Potentiostat arrangement used for electrochemical studies

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Table 1. Cyclic polarization data of various passivation treatments

An immediate observation from comparing the Ecorr (Figure 3 & Table 1) and OCP (Figure 2) is that both the electrochemical techniques are in good agreement. Small differences could be attributed to the effect of polarization. It is clearly seen from Fig. 3 that the coupon passivated with RPC chemistry has lower passivation current and lower currents at all applied potential values. The corrosion resistance of different passivation treatments was calculated using Stern-Geary Equation: ,FRUU EDEF ED EF 5S

From the graph and the table, it is clear that the corrosion current for different passivation treatments increases in the order: ,FRUU 53& ,FRUU 2UJDQLF SKRVSKDWH ,FRUU 3RO\SKRVSKDWH

,QKLELWLRQ HIÂ¿FLHQF\ ,QK RI YDULRXV SDVVLYDWLRQ WUHDWPHQW programs has been calculated using the formula: ,QK ,FRUU EODQN Â± ,FRUU WUHDWPHQW ,FRUU EODQN

,W LV FOHDU IURP 7DEOH WKDW KLJKHU LQKLELWLRQ HIÂ¿FLHQF\ ZDV REtained by the RPC passivation treatment than the polyphosphate and organic phosphate chemistries, indicating the stability and SHUVLVWHQW QDWXUH RI WKH 53& QRQ SKRVSKDWH SDVVLYH Â¿OP Electrochemical Impedance Spectroscopy Measurements â€“ The long-term corrosion behavior of the three passivation treatments on the surface of carbon steel electrodes was probed by electrochemical impedance spectroscopy (EIS). Electrical resistance is a well-known parameter for characterization of the ability of a circuit HOHPHQW WR UHVLVW WKH Ã€RZ RI HOHFWULFDO FXUUHQW 6LPLODU WR UHVLVWDQFH impedance is also a measure of the ability of a circuit to resist the Ã€RZ RI HOHFWULFDO FXUUHQW +RZHYHU XQOLNH UHVLVWDQFH LPSHGDQFH is not limited by the simplifying properties of a single resistor. Electrochemical impedance is usually measured by applying an AC potential to an electrochemical cell and then measuring the AC current response through the cell. EIS is one of the most useful techniques to discern the corrosion mechanism, evaluate protective Â¿OPV RQ PHWDOV LQ DJJUHVVLYH VROXWLRQV DQG DQDO\]H Â¿OP IRUPDWLRQ at the metal-electrolyte interface. When a metal surface is covered (passivated) with a protective layer, the corrosion is controlled by WKH WUDQVSRUW RI WKH VSHFLHV LQ WKH SURWHFWLYH Â¿OP WKURXJK GLIIXVLRQ FKDQQHOV UHVXOWLQJ IURP SDVVLYH Â¿OP EUHDNGRZQ RU PLFUR FUDFNV The response can be represented as the relationship between the imaginary and real components of impedance, referred to as a Nyquist plot. Figure 4 presents the Nyquist impedance diagram recorded at OCP for various passivation treatments.

Figure 4. Nyquist plots for different passivated coupons in untreated water

It is clear that the semicircle diameter increases in the order: 3RO\SKRVSKDWH Â” 8QSDVVLYDWHG 2UJDQLF SKRVSKDWH 53& Since the diameter of the capacitive semicircle represents the resistance of the coating, an increase in diameter represents increased resistance. Figure 4 illustrates that the corrosion resistance of RPC SDVVLYH Â¿OP LV PXFK JUHDWHU WKDQ RWKHU WUDGLWLRQDO RUJDQLF SKRVphate and polyphosphate passivation treatments, consistent with OCP and CP measurements in Figures 2 and 3. The EIS results DOVR FRQÂ¿UPHG WKDW 53& SDVVLYDWLRQ IRUPV D KLJKO\ SURWHFWLYH Â¿OP RQ PLOG VWHHO LQ WKH WHVW ZDWHU VLJQLÂ¿FDQWO\ RXWSHUIRUPLQJ the polyphosphate and organic phosphate passivation chemistries.

Comparison with Nitrite and Molybdate Passivation Carbon steel coupons were passivated for 6 hours in baths containing the treatment solutions of interest in blank water (described above). Baths 1 and 2 contained the RPC corrosion inhibitor at 12 mg/L and 6 mg/L respectively, bath 3 contained 100 mg/L of molybdate (as MoO4=), and bath 4 contained 1,200 mg/L of nitrite (as NO2-). Following the 6-hour passivation period, the coupons were rinsed in DI water and placed into untreated blank water for D SHULRG RI GD\V WR HYDOXDWH WKH SHUVLVWHQFH RI WKH SDVVLYH Â¿OP After exposure, the coupons were removed and photographed. Average corrosion rate was determined by weight loss. The coupon appearance and corrosion rate are shown in Table 2.

Table 2. Corrosion rate and coupon appearance after 6-hour passivation and 3-day exposure to untreated blank water.

Preoperational Cleaning Passivation OCP Evaluation One of the major needs for passivation chemistry is during preoperational cleaning when the freshly cleaned surfaces are most YXOQHUDEOH WR Ã€DVK UXVW MXVW SULRU WR WKH HTXLSPHQW HQWHULQJ VHUYLFH To simulate the condition of new steel heat exchangers subject to environmental rusting during the construction period, a new steel KHDW H[FKDQJHU WXEH ZDV Â¿UVW DOORZHG WR UXVW RXWGRRUV IRU VHYHUDO days, then cut into sections approximately 3 in (7.5 cm) long. One rusted tube section was placed into a beaker containing a neutral pH, precleaning and passivation solution containing organic phosphate, reducing agent, and surfactant. A second section from the same tube was placed into another beaker containing the same chemistry with the addition of the RPC passivating chemistry. The solutions were stirred for 6 hours until the both specimens were substantially free of rust. The pH of the cleaning solutions remained in the 6.5-6.7 range during the 6-hour exposure. Figure 5 and 6 show the specimens in the beakers before and after cleaning. CTI Journal, Vol. 37, No. 2

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metal. Following the cleaning, both specimens were placed in baths of untreated blank water for 24 hours to evaluate their ability to resist corrosion using open circuit potential as illustrated in Figure 7. In this test, the precleaning solution containing the RPC chemistry exhibited an open circuit potential more than 200 mV higher than the solution without RPC (Figure 8).

Figure 5. Precleaning and passivation study at start of 6-hour exposure. Specimen on right contains the RPC passivation chemistry. Figure 8. OCP of cleaned specimens over 24 hours in untreated water, with and without RPC passivation chemistry

Figures 9 and 10 show the two specimens after the 24-hour exposure to the untreated blank water. The steel tube section that was exposed to the cleaning solution containing the RPC passivation chemistry clearly resisted rusting, while the specimen not exposed to RPC readily rusted after cleaning.

Figure 9. Tube section cleaned and passivated with RPC, organic phosphate, and reducing agent after 24-hour exposure to untreated blank water. Figure 6. Precleaning and passivation study at completion of 6-hour exposure. Specimen on right contains the RPC passivation chemistry.

Figure 10. Tube section cleaned with organic phosphate and reducing agent after 24-hour exposure to untreated blank water.

&RSSHU 6XOIDWH 9HUL多FDWLRQ 7HVW

Figure 7. OCP measurement of cleaned tube specimens

As shown in Figure 6, after 6 hours, the cleaning solution without the RPC passivation chemistry is noticeably darker than the solution with RPC chemistry due to additional corrosion of the base

A simple, visual test for passivation is to expose steel or stainless steel specimens to a copper sulfate solution. Immersion in a FRSSHU VXOIDWH VROXWLRQ LV RQH RI WKH YHUL多FDWLRQ WHVWV GHVFULEHG LQ WKH $670 $ VWDQGDUG VSHFL多FDWLRQ IRU FKHPLFDO SDVVLYDWLRQ treatments [6]. Copper ions in solution act as electron acceptors at the cathode of the corrosion cell and readily electroplate onto unpassivated or weakly passivated surfaces, producing a very pronounced copper discoloration to the steel surface (Figure 7KH WHVW FDQ EH SHUIRUPHG LQ WKH 多HOG DV DQ DFFHSWDQFH WHVW

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criteria for equipment passivation procedures. A well passivated steel coupon will exhibit considerable resistance to copper plating even when exposed to a solution containing a high concentration of copper ions. Figure 13. Passivated steel coupon after 2 day exposure to pH 3 cleaning solution containing RPC

)LJXUH &RXSRQ VXUIDFH PDJQLÂżHG [ Figure 11. Mechanism of copper electroplating onto steel surfaces

Exposure to a copper sulfate solution was used to evaluate the effectiveness of RPC passivation chemistry compared to established organic phosphate and polyphosphate passivation chemistries. Mild steel coupons were treated for 6 hours in passivation solutions and then exposed to a 15% copper sulfate solution for 20 seconds. Following exposure, the coupons were rinsed with deionized water, dried, and visually inspected for copper plating as an indication of passivation effectiveness. A relatively high concentration of copper sulfate was used in order to produce severe test conditions that would discriminate among the passivation chemistries. As shown in Figure 12, the RPC passivation chemistry clearly demonstrated effectiveness superior to organic phosphate and polyphosphate in the copper sulfate exposure test, DQG DW VLJQLÂżFDQWO\ ORZHU WUHDWPHQW concentrations.

Carbon steel coupons exposed during the cleaning process were further evaluated to determine the corrosion resistance of the SDVVLYH 53& ÂżOP 7KH FRSSHU VXOIDWH YHULÂżFDWLRQ WHVW GHVFULEHG earlier was performed on the exposed coupon shown in Figure 13 and compared to a new, carbon steel coupon. The lower half of each coupon was exposed to a 15% copper sulfate solution for 20 seconds. As shown in Figure 15, the new coupon is copper plated on its lower half, while the coupon passivated during the acidic chemical cleaning effectively resisted copper plating.

Organic phosphate passivation 640 mg/L as PO4=, for 6 hours Surface is copper plated. 3DVVLYH ÂżOP IDLOHG Polyphosphate passivation 320 mg/L as PO4=, 6 hours Surface is copper plated. 3DVVLYH ÂżOP IDLOHG

Figure 15. New coupon (top) and coupon passivated with RPC during the acidic chemical cleaning (bottom) after half-exposure to a 15% copper sulfate solution for 20 seconds. Note the copper plating on the new coupon as compared to the absence of copper plating on the RPC-passivated coupon.

RPC passivation 3.8 mg/L as RPC, 6 hours 6WHHO UHVLVWHG FRSSHU SODWLQJ LQGLFDWLQJ D VWURQJ SDVVLYH ÂżOP

A second carbon steel coupon that was exposed during the chemical cleaning process was evaluated for passivation by placing it in untreated blank water and comparing its OCP to a new coupon over time as described in the Experimental section. The RPC passivated coupon maintains its potential for several days in untreated water (Figure 16).

Figure 12. Passivated coupons after 20 sec. exposure to 15% CuSO4 solution

Preoperational Cleaning Application A Midwest manufacturing plant resumed operation after being idle for 18 months. Prior to resuming operation, the cooling system was cleaned using an acidic cleaning solution with surfactant and dispersants recirculated at a target pH of 3.0. The cleaning solution was inhibited using a triazole together with the RPC passivation chemistry. Mild steel coupons were installed to evaluate base metal loss and passivation effectiveness. The steel coupons were removed for after 2 days showed a dull grey passivated surface (Figures 13 and 14). The presence of RPC on the coupon was FRQÂżUPHG E\ VXUIDFH DQDO\WLFDO PHWKRGV

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Figure 18 shows the coupon appearance before and after cleaning in the neutral pH formulations with and without RPC.

Figure 16. OCP measurement over time on carbon steel coupon passivated with RPC during chemical cleaning compared to a new carbon steel coupon.

As further visual evidence of passivation, the untreated OCP test baths were photographed after 3 days. Figure 17 shows the rustcolored solution containing the new coupon on the left and the clear solution containing the RPC-passivated coupon on the right.

Figure 18. Before and after cleaning photos of the corroded coupons in standard neutral pH cleaners with and without RPC. Cleaning duration was 6 hours for all.

Formulations #1, #2, and #3 with RPC cleaned more effectively DQG OHIW WKH FRXSRQV ZLWK D GXOO JUH\ ¿QLVK FRQVLVWHQW ZLWK SDVsivation. A fresh corrosion coupon was inserted into each of the cleaning bath to study the effect of the cleaner product on the base metal. Corrosion rates were measured by weight loss. The cleaning solutions containing RPC also exhibited a ~60-70% reduction in corrosion rate as compared to the standard neutral pH cleaner.

Conclusions

Figure 17. OCP test baths after 3 days showing the rust-colored solution containing the new coupon on the left and the clear solution containing the RPC-passivated solution on the right.

Neutral pH Cleaning Formulations With RPC Neutral pH formulations containing various levels of RPC were studied for their effectiveness in cleaning rusted coupons and were also evaluated for corrosion rate on fresh coupons. Cleaning solutions were prepared according to Table 3 and applied at a dosage of 10%.

Effective cleaning and passivation of heat exchangers and piping is required during initial start-up and periodically during the operational life of the system. Using advanced electrochemical techniques, a powerful new passivation chemistry has been developed that protects the base metal during the cleaning process and SURYLGHV D SHUVLVWHQW SDVVLYH ¿OP WKDW UHVLVWV FRUURVLRQ IRU VHYHUDO days as the system is placed back in service. The new Reactive Polyhydroxy Complex (RPC) based chemistry was found to be superior to traditional polyphosphate and organic phosphate based WUHDWPHQWV LQ WHUPV RI IRUPLQJ D VWDEOH DQG SHUVLVWHQW SDVVLYH ¿OP The RPC chemistry can be used in conjunction with either acidic or neutral pH cleaners to achieve simultaneous cleaning and passivation, eliminating the need for a separate passivation step.

Acknowledgements The authors gratefully acknowledge DeAnn Wills-Guy of ChemTreat for conducting the electrochemical studies.

Nomenclature ba

Anodic Tafel slope, Eq. (1)

Cathodic Tafel slope, Eq. (1)

Beta

Anodic Tafel slope, mV/decade, Table 2

cfu

Colony forming units

Cyclic polarization

Ecorr

Corrosion potential at equilibrium, mV or V

EIS

Electrochemical impedance spectroscopy

HEDPA 1-Hydroxyethylidene-1,1-diphosphonic acid Table 3. Table showing neutral pH cleaning solution chemistries used to clean coupons in Figure 18.

Icorr

Corrosion current at equilibrium, mA or A

CTI Journal, Vol. 37, No. 2

mHz

Megahertz

mpy

Mils per year, 0.001 inch/yr., equivalent to 0.0254 mm/yr.

OCP

Open circuit potential mV or V

Polarization resistance, Eq. (1)

RPC

Reactive polyhydroxy complex

TKPP

Tetrapotassium pyrophosphate

Impedance (of surface), Ohm-cm2

Zimag

Imaginary component of surface impedance, Ohm-cm2

Zreal

Real component of surface Impedance, Ohm-cm2

References 1. Initial Conditioning of Cooling Water Equipment, NACE RP0182-95. 2. Rust Removal and Composition Thereof, Waller, J.E., Gray, J.A., and Aston, D.A., US Patent 4,810,405, 1989. 3. Proper Initial Passivation of Cooling Water Heat Exchangers - Is This a Lost Art? P.R. Puckorius, 63rd International Water Conference, IWC-02-62. Engineers' Society of Western Pennsylvania, Pittsburgh, 2002. 4. Development of Next Generation Phosphorus-Free Cooling Water Technology. R.M. Post, R.H. Tribble, & J.R. Richardson, International Water Conference, IWC-10-23. Engineers Society of Western Pennsylvania, San Antonio, 2010. 5. Development and Application of Phosphorus Free Cooling Water Treatment. R.M. Post, R.P. Kalakodimi, & R.H. Tribble, CTI Journal Vol. 35, No. 2, pp. 52-67, 2014. 6. 6WDQGDUG 6SHFLÂ¿FDWLRQ IRU &KHPLFDO 3DVVLYDWLRQ 7UHDWPHQWV for Stainless Steel Parts, ASTM A967/A967M-13, 2013.

CTI Journal, Vol. 37, No. 2

0HFKDQLFDO %HKDYLRU RI 3RO\PHU )LOOV Nina Woicke, PH.D, Daniel Dierenfeld, ENEXIO Water Technologies GmbH, 2H Components and Solutions

Abstract The paper outlines the mechanical properties of SRO\PHU ÂżOOV DQG GLVFXVVHV WKH LQĂ€XHQFH RI GLIferent parameters (e.g. PP vs. PVC, foil thickness, design) with particular regard to cooling tower aspects.

Introduction

PP normally performs well under Gardner conditions, because it is more ductile then PVC. To visualize this effect, in Figure 2 the results of instrumented indention test are shown. The diameter of the test â€œdartâ€? in this case was 1.65 mm (0.065â€™â€™). Two foils with the same weight, one PP and one PVC, have been tested. The results can be seen in Figure 2. The PVC breaks, when the maximum force is reached. PP on the other hand will stretch locally more than 100% extra distortion EHIRUH WKH ÂżQDO IDLOXUH

This paper will give an overview on the mechaniTherefore normally impact tests with notched FDO EHKDYLRU RI FRROLQJ WRZHU ÂżOOV 7KH PDLQ IRFXV Nina Woicke test bars like the notched Izod test are used for is thereby the short term behavior. Temperature the characterization of PP (blue specimen in Figure 3). The notch dependent and time dependent properties play their role in the increases the local stress, so that as well PP will break at the hit of FRROLQJ WRZHU ÂżOO OLIH DV ZHOO EXW KHUH WKHVH VXEMHFWV ZLOO RQO\ the hammer and a distinctive value can be given. Unfortunately WRXFKHG EULHĂ€\ the values of Gardner tests and notched Izod tests are not directly The paper is structured in three sections: comparable, since the overall test set-up is quite different. 1. Material properties +HDW GHĂ€HFWLRQ WHPSHUDWXUH 2. 0HFKDQLFDO WKHRU\ RQ FRROLQJ WRZHU ÂżOOV 7KH KHDW GHĂ€HFWLRQ WHPSHUDWXUH $670 ' LV D WHFKQRORJLFDO 3. 5HVXOWV RI VSHFLÂżF WHVWV LQ FRPSDULVRQ test. A small specimen is put in an oil bath and preloaded with a Material properties certain load (either 66 or 264 PSI) under bending. The bath then 7KH WZR PDLQ PDWHULDOV XVHG IRU FRROLQJ WRZHU ÂżOOV DUH SRO\YLQ\O- LV VORZO\ KHDWHG 7KH KHDW GHĂ€HFWLRQ WHPSHUDWXUH LV UHDFKHG ZKHQ chloride (PVC) and polypropylene (PP). In the following Table 1 WKH VSHFLPHQ KDV D FHUWDLQ GHĂ€HFWLRQ (YHQ WKRXJK WKLV WKH PHFKDQLFDO PDWHULDO SURSHUWLHV PLQLPXP YDOXHV GHÂżQHG E\ test is used in the STD 136 as a reference, neither the load case CTI STD 136 are summarized. These properties are for the non- QRU WKH GHĂ€HFWLRQ OLPLW LV LQ OLQNHG WR WKH RQHV RI GULIW HOLPLQDWRUV engineered material only and are mainly used for general quality RU ÂżOOV 7KHUHIRUH WKLV WHPSHUDWXUH FDQQRW GLUHFWO\ EH UHODWHG WR temperatures in use in a cooling tower. control.

Strength The strength is the maximum load a tensile bar can take under tensile load (ASTM D638 or EN ISO 527-1/-2) or a bending bar $670 ' RU (1 ,62 XQGHU Ă€H[XUDO ORDG ,Q ERWK FDVHV the usual standard test bars are much thicker (about 10 times) than WKH ÂżQDO IRLOV 7KDW PHDQV LI \RX ZDQW WR WHVW DFFRUGLQJ WR the standard it is not possible to measure this property directly from the foils. Modulus 7KH PRGXOXV GHÂżQHV WKH VWLIIQHVV RI WKH PDWHULDO 7KDW PHDQV WKH stiffer the material the less deformation at certain loads. Therefore it is not recommended to use the strain as an absolute failure criteria over both materials discussed. Both PP and PVC modulus can be measured under tensile or Ă€H[XUDO FRQGLWLRQV VLQFH WKH\ DUH QRW GLUHFWLRQDO UHLQIRUFHG OLNH e.g. FRP). Impact resistance There are several different standards available to measure the impact resistance. One standard is the Gardner impact strength, which is also called â€œfalling dartâ€? test, which already describes the method of impact (test set-up in Figure 1).

The mechanical behavior of PP and PVC is different as the temperature increases. PVC is very rigid and stiff at temperatures between URRP WHPSHUDWXUH DQG DERXW Âƒ& Âƒ) 7KH FKDQJH LQ PRGXOXV LV YHU\ ORZ IRU WKLV UHJLPH $ERYH Âƒ& WKH PDWHULDO UHDFKHV LWV glass transition and changes its behavior drastically, so there is not D ORW VWUXFWXUDO LQWHJULW\ OHIW DERYH Âƒ& Âƒ) 7R UHGXFH WKLV effect, PVC can be partly mixed with other polymers like ABS or SAN. This composition is is normally referred as â€œHPVCâ€?. Another possibility is to use chlorinated polyvinyl chloride (CPVC), which as well has higher glass transition temperature. 33 RQ WKH RWKHU KDQG KDV LWV PDLQ PHOWLQJ RQVHW DW DERXW Âƒ& Âƒ) 7KHUHIRUH XSWR Âƒ& Âƒ) WKH PHFKDQLFV LI VL]HG properly can be still strong enough and applicable to be used [5]. Nevertheless the softening slope of the material is there as well and at the same time the thermal degradation through oxidation has to be carefully addressed through engineering and product design characteristics. Therefore at higher temperatures the use of specially heat stabilized and probably thicker material is advisable.

Density Additionally to the properties mentioned in the CTI STD 136 material density has to be recognized for the full understanding RI WKH PHFKDQLFDO EHKDYLRU RI FRROLQJ WRZHU ÂżOO CTI Journal, Vol. 37, No. 2

The densities of the two materials differ quite a lot due to the fact that the chloride in the PVC is a rather â€œheavyâ€? atom. Additionally ERWK PDWHULDOV FDQ EH DGGHG ZLWK LQRUJDQLF ÂżOOHUV 7KH GHQVLW\ ranges about 0.92-1 kg/l (0.033-0.036 lb/inÂł) for PP and 1.351.55 kg/l (0.049-0.056 lb/inÂł) for PVC. Therefore, if you compare two products (PP and PVC) with the same material gauge, the PP product will be lighter than the PVC.

0HFKDQLFDO EHKDYLRU RI FRROLQJ WRZHU ÂżOO 7KH RYHUDOO PHFKDQLFDO ÂżOO SURSHUWLHV DUH D FRPELQDWLRQ RI WKH PDWHULDO SURSHUWLHV WKH ÂżOO GHVLJQ WKH WKLFNQHVV UHVSHFWLYHO\ WKH overall weight of the product and the quality of the bonding. The second aspect is not the main focus of this paper, but of course has WR EH WDNHQ LQWR DFFRXQW DV ZHOO $ ÂżOO WKDW KDV EHHQ EDGO\ ERQGHG can have totally different strength than one that is bonded properly. In this case the number of bonding points and the bonding quality of a single point is important.

Foil thickness ,Q IRUPHU WLPHV QHDUO\ DOO ÂżOP ÂżOOV ZHUH SURGXFHG E\ WKHUPRIRUPLQJ $W WKDW WLPH LW ZDV HVWDEOLVKHG WKDW D ÂżOO ZDV GHÂżQHG E\ LWV IRLO VKHHW ÂżOP WKLFNQHVV QRUPDOO\ PHDVXUHG LQ PLO HVSHFLDOO\ EHIRUH IRUPLQJ ,Q WKDW FDVH \RX KDYH D Ă€DW IRLO ZKHUH LW LV SUHWW\ easy to measure the thickness at any point. After the corrugation process, the measurements already become a lot more complicated depending on the complexity of the corrugation or forming. After bonding only the outer edges are available for any check on site. Even with a single foil you will have a differential of the thickness throughout the sheet and it is WKHQ GLIÂżFXOW WR PHDVXUH WR D IDLU OHYHO RI DFFXUDF\ WKH DFWXDO IRLO thickness for the entire sheet.

$VS 6SHFLÂżF VXUIDFH RI WKH ÂżOO IWĂ° IWĂą 7KLV LV D ÂżOO W\SH VSHFLÂżF QXPEHU DQG LV QRUPDOO\ SURYLGHG E\ WKH ÂżOO VXSSOLHU 1HYHUWKHOHVV LQ 7DEOH WKHUH DUH LQGLFDWLRQ QXPEHUV IRU VRPH XVXDO ÂżOO W\SHV The area has to be divided by two because of the two sided of a foil. :HLJKLQJ D ÂżOO LV D VLPSOH PHWKRG WR FURVV FKHFN LI WKH IRLO WKLFNness is about what the supplier stated.

Buckling under compression ,I WKH IRLO ERQGLQJ LV GRQH SURSHUO\ FRROLQJ WRZHU ÂżOOV XQGHU SUHVsure normally fail by buckling of the foil. In Figure 5 you can see D FRPSOHWHO\ YHUWLFDO Ă€XWHG ÂżOO ZKLFK LV EXFNOLQJ EHWZHHQ WKH connection points. The theory of buckling is rather complicated; nevertheless it is QHFHVVDU\ WR XQGHUVWDQG WKH PDLQ LGHD WR XQGHUVWDQG WKH ÂżOO EHhavior. To keep it as simple as possible we model it as a column between two supports, which are represented by the bonding points (see Figure 6). Euler established a formula for the maximum force a slender FROXPQ FDQ FDUU\ (XOHU FDVH > @ 2I FRXUVH FRROLQJ WRZHU ÂżOOV are far from a perfect slender column, but still the equation can be used for the general understanding: 2 F: The maximum Force ( 7KH PRGXOXV LQĂ€XHQFHG E\ WKH PDWHULDO DV GLVFXVVHG LQ

/6 7KH XQVXSSRUWHG OHQJWK 7KLV LV LQĂ€XHQFHG E\ WKH GHVLJQ DV ZHOO DV WKH TXDOLW\ RI ERQGLQJ )RU H[DPSOH D IW KLJK ÂżOO ZKLFK is only bonded at the edges, is four times more likely to Eulerian 1RZDGD\V WKHUH DUH VHYHUDO PRUH PHWKRGV WR SURGXFH D ÂżOO H J EXFNOLQJ WKDQ D ÂżOO ZKLFK KDV DQ DGGLWLRQDO ERQGLQJ LQ WKH PLGGOH LQMHFWLRQ PROGLQJ IRU WKH VR FDOOHG ÂłK\EULGÂ´ ÂżOOV RU WKH GLUHFW RI WKH ÂżOO H[WUXVLRQ SURFHVVHV ZLWKRXW DQ\ GHÂżQHG VHPL ÂżQLVKHG SURGXFW LQ IF: is the so called momentum of inertia of the foil, which is inbetween. These methods even allow having an optimized, uneven Ă€XHQFHG E\ WKH GHVLJQ RYHUDOO GHVLJQ DV ZHOO DV WKH FRUUXJDWLRQ foil thickness to enhance higher loaded parts. Especially the edges design). This is hard to calculate for a so complex geometry like RI WKH ÂżOO DUH PRUH OLNHO\ WR EH EDWWHUHG E\ WKH ZDWHU LPSDFW RU LQVSHFWLRQ WUDIÂżF (URVLRQ LV WKHUHIRUH D W\SLFDO FRROLQJ WRZHU ÂżOO a corrugated cooling tower foil. Nowadays the only meaningful PHWKRG WR FDOFXODWH WKH EXFNOLQJ LV ÂżQLWH HOHPHQWV DQDO\VLV )($ problem. (see Figure 7 as an example). Only with this method you can get In this respect an uneven thickness distribution to strengthen the the height and distribution of the load. HGJHV )LJXUH RI WKH ÂżOO FDQ KHOS WR PLQLPL]H WKLV SUREOHP ZLWK If you have a look at one single, rectangular element, the momen33 DV ZHOO DV ZLWK 39& ÂżOOV tum of inertia is then easy to calculate: 7KHUHIRUH LW LV UHFRPPHQGDEOH WR XVH WKH ÂżOO ZHLJKW DV DQ H[WUD measure. It is, of course an overall property and doesnâ€™t give you 3 DQ\ LQGLFDWLRQ RQ WKH VSHFLÂżF GLVWULEXWLRQ EXW D ÂżOO IURP WKH VDPH material and same design, bonded the same way, but has e.g. 30% higher weight will behave stronger under mechanical load. IE: Momentum of inertia of element To get an idea how the weight and the mean foil thickness are WE: Width of the element related, use the following equation: TE: Thickness of the element, which normally is directly related to the thickness of the foil. That means the thickness of the foils is 1 LQĂ€XHQFLQJ WKH ORFDO PRPHQWXP RI LQHUWLD E\ WKH SRZHU RI WKUHH DQG LV WKHUHIRUH DQ LPSRUWDQW ÂżJXUH TF: Thickness of the foil (mil) Bending 0 0DVV RI WKH ÂżOO OE

/ /HQJWK RI WKH ÂżOO IW

7KH ÂżOO LQ WKH FRROLQJ WRZHU LV QRW RQO\ ORDGHG XQGHU GLUHFW SUHV: :LGWK RI WKH ÂżOO IW

sure, but the bottom layer is normally on a support structure, which + +HLJKW RI WKH ÂżOO IW

implies local compression point loading as well as bending into ČĄ 'HQVLW\ RI WKH ÂżOO PDWHULDO OE LQĂą

WKH ÂżOO ,Q PRVW RI WKH FDVHV WKDW PDNHV WKH ERWWRP OD\HU WR WKH CTI Journal, Vol. 37, No. 2

PRVW FULWLFDO OD\HU 7KLV LV QRW RQO\ LQĂ€XHQFHG E\ WKH ÂżOO EXW DOVR by the distance between the supports, the width of the support and WKH DUUDQJHPHQW RI WKH ÂżOOV $V DQ H[DPSOH DFFRUGLQJ WR HODVWLF bending theory [4] two 3 ft long blocks will bend more than double to one 6 ft long block on the same support structure.

2QH DSSURDFK RI FRPSDULVRQ LV WR XVH WKH VDPH VSHFLÂżF ÂżOO ZHLJKW Due to the differences in densities this results in differences in the foil thickness. Under these circumstances, the pure compression VWUHQJWK RI 39& ÂżOOV LV ORZHU

)RU WKH VDPH ERUGHU FRQGLWLRQV WKH GHĂ€HFWLRQ XQGHU ORDG ORRNV GLIIHUHQW %RWK WKH EHQGLQJ DQG WKH ORFDO GHIRUPDWLRQ IRU WKH 33 ÂżOO are slightly higher due to the lower modulus of the material. For a direct visual comparison it is useful not to take the direct strain but its inverse (which is called bending resistance and compression Bending as well depends on the stiffness and the momentum of resistance in this paper).This is done, so higher values represent LQHUWLD EXW WKLV WLPH QRW RQO\ RI WKH ORFDO IRLO EXW RI WKH ZKROH ÂżOO â€œbetterâ€? and not the opposite. structure. This is again not really computable by easy equations, The overall comparison summarized in Figure 11. VR WKH EHVW SRVVLELOLW\ WR JHW DQ LPSUHVVLRQ RI WKH Ă€H[XUDO EHKDYLRU Fill weight/foil thickness LV D GLUHFW WHVW RI WKH ÂżOO 7KH IRLO WKLFNQHVV ÂżOO ZHLJKW KDV REYLRXVO\ D PDMRU LQĂ€XHQFH RQ WKH ÂżOO PHFKDQLFV IRU RQH PDWHULDO WKH WKLFNHU WKH EHWWHU ,I \RX 5HVXOWV RI VSHFLÂżF FRROLQJ WRZHU ÂżOOV To illustrate the theoretical background of the previous chapters, ORRN DW WKH VDPH ÂżOO ZHLJKW VHH DOVR WKH FRPSUHVVLRQ VWUHQJWK LQ WKLV FKDSWHU VSHFLÂżF GDWD LV JLYHQ PDLQO\ LQ D TXDOLWDWLYH PDQRU of the PP is higher. In contrast to that, if you look on the same to emphasis the main differences. They all refer to data measured PHDQ IRLO WKLFNQHVV RI WKH IRUPHG IRLO WKH 39& ÂżOO KDV WKH KLJKHU with 2HÂŽ ÂżOO 7KH PHDVXUHG ÂżOO ZHUH WKH .)3 .9& IRU compression strength. This variation is visualized in Figure 12. WKH PP FURVVĂ€XWHG ÂżOO WKH .33 IRU WKH PP FURVVĂ€XWHG &RQFHUQLQJ WKH EHQGLQJ WKH LQĂ€XHQFH RI WKH VSHFLÂżF WKLFNQHVV LV ÂżOO WKH .93 IRU WKH YHUWLFDO Ă€XWHG ÂżOO DQG .*3 .%3 even harder to determine. The general behavior is of course that IRU WKH RIIVHW ÂżOO W\SHV $OO UHVXOWV DUH SORWWHG TXDOLWDWLYHO\ WR VKRZ WKH GHĂ€HFWLRQ LV ORZHU WKH KLJKHU WKH ÂżOO ZHLJKW UHVSHFWLYHO\ WKH WKH JHQHUDO LQĂ€XHQFH RI WKH SDUDPHWHUV foil thickness is. As an example 22 kg/mÂł (1.37 lb/ftÂł) and 27 kg/ PĂą OE IWĂą 33 PP FURVVĂ€XWHG ÂżOO LV FRPSDUHG LQ WKH ORFDO Compression test set-up compression as well as in bending in Figure 13. You can see that The pure compression tests have been conducted with a 305 mm WKH ORZHU ZHLJKW KDV VLJQLÂżFDQWO\ KLJKHU GHIRUPDWLRQV (1 ft) x 305 mm (1 ft) x 610 mm (2 ft) set-up at room temperature and a test speed of about 2 ft/min (see Figure 9). The respective If you choose a too low weight (too thin foil) for a certain distribstrain rate in this test is in the magnitude than the strain rate to XWHG ORDG WKH ÂżOO ZLOO IDLO DW WKH VXSSRUW E\ D ORFDO EXFNOLQJ VHH determine the tensile strength (ASTM D638). So these results can )LJXUH 7KHUHIRUH RQH PXVW FDUHIXOO\ FKRRVH WKH ULJKW ÂżOO IRU be used for direct correlations between the material strength and the design load. WKH ÂżOO VWUHQJWK 2I FRXUVH WKLV RQO\ WHVWV WKH VKRUW WLPH EHKDYLRU RI ,QĂ€XHQFH RI ÂżOO GHVLJQ WKH ÂżOO 1RUPDOO\ WKH VDPH WHVW LV GRQH ZLWK GLIIHUHQW VSHFLPHQV %HVLGH DOO DVSHFWV GLVFXVVHG EHIRUH WKH ÂżOO GHVLJQ KDV D WUHPHQGRXV ,Q )LJXUH RQH FDQ VHH WKH QRUPDO RXWSXW RI WKH IRUFH GHĂ€HFWLRQ LQĂ€XHQFH RQ WKH RYHUDOO VWDELOLW\ DQG SHUIRUPDQFH $QG DJDLQ WKH curve. For the evaluation of the tests the mean value of the maxi- aspect of buckling (due to compression) has to be looked at as mum force is taken. well as the bending. 6LPLODU LW LV WUXH WKDW WKH VDPH ÂżOO RQH RU WZR IHHW KLJK ZLOO EHQG differently. Even though there may be a small drawback in performance, normally it is recommendable to use a 2 ft high block as a bottom layer to improve the overall stability.

Bending test set-up for the bottom layer The tests to simulate the bending situation of the bottom layer were done with 610 mm (2 ft) high and 2440 mm (8 ft) long test specimens. The support structure was spaced 900 mm (2.95 ft) and a cantilever of 320 mm (1.05 ft) on each side (see Figure 10). The width of the support was 60 mm (2.4 â€™â€™). There were seven measurLQJ SRLQWV DORQJ WKH VLGH RI WKH ÂżOO 7KH GLIIHUHQW SRLQWV ZHUH FKRVHQ to separate the local deformation at the supports from the bending EHWZHHQ WKH VXSSRUWV ZKLFK DGGV XS WR WKH RYHUDOO GHĂ€HFWLRQ 6WDWLF ORDGV ZHUH DSSOLHG RQ WRS RI WKH ÂżOO VHH )LJXUH 7KH GLVWDQFH RI ÂżOO SRLQWV WR WKH Ă€RRULQJ ZDV GHWHFWHG EHIRUH ORDGLQJ and after 24 h after applying the load.

)LOOV ZLWK FURVV Ă€XWHV KDYH QRUPDOO\ D JRRG FRPELQDWLRQ EHWZHHQ the necessary properties. They even have an extra value in their GHVLJQ 7KH\ GLVWULEXWH ORFDO ORDG DORQJ WKH Ă€XWH LQFOLQDWLRQ LQWR WKH ÂżOO 'XH WR WKH ERQGLQJ RI WKH IRLOV WKH FURVV Ă€XWHG ÂżOOV EHKDYH similar to carpenters work in house. Fills with offset are normally D ORW PRUH VHQVLEOH WR SXUH FRPSUHVVLRQ WKDQ WKH ÂżOOV PHQWLRQHG before, while for the bending issue the offset again helps to staELOL]H WKH ÂżOO In Figure 15 you can see the comparison of different compression VWDELOLW\ RI GLIIHUHQW ÂżOO W\SHV LQ 33 7KH EOXH FROXPQV DUH IRU D FRPSDULVRQ DW WKH VDPH IRLO WKLFNQHVV RI WKH ÂżQDO SURGXFW DQG WKH UHG FROXPQV DW WKH VDPH VSHFLÂżF ZHLJKW ZKLFK HTXDOV D FDOFXODWHG PHDQ WKLFNQHVV RI WKH PLO RI PP FURVVĂ€XWHG ÂżOO 7KH compression strength has been normalized to the value of the 19 PP ÂżOO VR WKLV GLDJUDP FDQ EH XVHG LQ SULQFLSOH IRU RWKHU ZHLJKWV thicknesses and PVC similarly.

Material Since all of the mechanical data is very different, it is not so easy WR GLUHFWO\ FRPSDUH 33 ZLWK 39& ÂżOO $QG DV ZHOO LW YHU\ PXFK GHSHQGV RQ WKH VSHFLÂżF GHVLJQ KRZ KLJK D FHUWDLQ HIIHFW LV 7KHUHIRUH in the following only relative measures are given to illustrate the What you can see is that you have to be careful when you compare general tendencies. As a reference 27 kg/mÂł (1.68 lb/ftÂł) 19 mm GLIIHUHQW ÂżOOV EHFDXVH GXH WR WKH GLIIHUHQFHV LQ FRUUXJDWLRQ KHLJKW FURVV Ă€XWHG ÂżOO WKHUPDOO\ ERQGHG KDV EHHQ WDNHQ DV D UHIHUHQFH the general tendencies can vary (see also 5.3). of being 100%.

CTI Journal, Vol. 37, No. 2

$W WKH VDPH WLPH WKHUH LV WKH EHQGLQJ EHKDYLRU RI WKH GLIIHUHQW ÂżOOV )URP WKH SXUH FRPSUHVVLRQ SRLQW RI YLHZ WKH IXOO\ YHUWLFDO Ă€XWH is the best, because the column-like structure supports strongly in the vertical direction.

Figures

These columns on the other side have only a low stability into the other two directions. Therefore bending stability of this design LV QRW DV JRRG 7KHUHIRUH WKH ERWWRP OD\HU RI VXFK ÂżOO VKRXOG EH VWLIIHQHG ZLWK Ă€DW VKHHWV DV VKRZQ LQ )LJXUH 7KLV SUREOHP LV due to the design and has to be addressed for PP and PVC alike. The results of the deformations of these variations are summarized LQ )LJXUH $JDLQ KHUH ÂżOO ZLWK NJ PĂą OE IWĂą WKHUPDOO\ ERQGHG LV FRPSDUHG 7KDW UHĂ€HFWV DERXW PLO IRU WKH PP FURVVĂ€XWHG DQG

Summary 7KLV SDSHU LOOXVWUDWHV GLIIHUHQW DVSHFWV RI WKH FRROLQJ WRZHU ÂżOO mechanics: PP and PVC differ in all properties and therefore canâ€™t be directly compared by comparing pure material values Â‡ The material thickness is an important measure, but hard WR FKHFN 7KHUHIRUH WKH VSHFLÂżF ZHLJKW RI WKH ÂżOO LV WKH better measure for a comparison for all product types Â‡ 7KH GHVLJQ KDV HTXDO LI QRW PRUH LQĂ€XHQFH DV WKH PDWHULDO RQ WKH RYHUDOO PHFKDQLFDO VWUHQJWK RI D ÂżOO Â‡ 7R MXGJH WKH RYHUDOO PHFKDQLFDO EHKDYLRU RI D ÂżOO LW LV necessary to evaluate the bending properties as well as WKH FRPSUHVVLRQ VWUHQJWK RI WKH ÂżQDO SURGXFW (YHQ WKRXJK LW KDV QRW EHHQ YHULÂżHG E\ WKLV VWXG\ WKH PHFKDQLFDO VWUHQJWK RI WKH ÂżOO DOVR GHSHQG RQ WKH W\SH DQG IUHTXHQF\ RI WKH bonding points. )RU WKH ÂżQDO GHFLVLRQ IRU D FHUWDLQ FRROLQJ WRZHU ÂżOO LW LV WKHUHIRUH necessary to evaluate carefully all aspects of engineering and product design.

Figure 1: Gardner â€œfalling dartâ€? test set-up

Figure 2: Instrumented indention test of PP and PVC foils of the same weight

Tables

Table 1: Overview of material properties of PP and PVC [1]

Figure 3: Notched Izod test set-up

7DEOH 2YHUYLHZ RI VSHFLÂżF VXUIDFH DUHD RI GLIIHUHQW ÂżOO W\SHV

Figure 4: Sketch of a 2 ft wide foil/sheet with optimized thickness distribution

CTI Journal, Vol. 37, No. 2

Figure 5: Foil buckling (thermally bonded)

)LJXUH )($ YLVXDOL]LQJ WKH VWUHVV GLVWULEXWLRQ RI WZR ERQGHG Â¿OO VKHHWV

Figure 6: Principle of buckling [2] )LJXUH )RUFH GHÃ€HFWLRQ FXUYH RI D FRPSUHVVLRQ WHVW

Figure 9: Picture of the test set-up

CTI Journal, Vol. 37, No. 2

)LJXUH 5HODWLYH FRPSUHVVLRQ VWUHQJWK RI PP FURVV Ã€XWHG Â¿OO WKHUPDOO\ bonded in dependence of different parameters (A: Spec. weight, B: Foil thickness) (test method as described in 5.1)

Figure 10: bending test set-up

)LJXUH 5HODWLYH GHIRUPDWLRQ IRU WZR GLIIHUHQW Â¿OO ZHLJKWV WKHUPDOO\ ERQGHG

)LJXUH &RPSDULVRQ RI 33 DQG 39& IRU WKH VDPH Â¿OO ZHLJKW NJ PÃ± PP FURVV Ã€XWHG Â¿OO WKHUPDOO\ ERQGHG

Figure 14: Fill under local buckling (set-up like in Figure 10)

CTI Journal, Vol. 37, No. 2

)LJXUH &RPSDULVRQ RI GHIRUPDWLRQ EHKDYLRU RI GLIIHUHQW ¿OO types in PP (27 kg/m³, thermally bonded) Figure 15: Compression strength comparison for different ¿OO W\SHV WKHUPDOO\ ERQGHG

)LJXUH )ODW IRLO ZLOO LPSURYH WKH EHQGLQJ SURSHUWLHV RI IXOO\ YHUWLFDO ÀXWHV

CTI Journal, Vol. 37, No. 2

Literature [1] CTI STD 136-2010 [2] Wikimedia Commons [3] DUBBEL - Handbook of Mechanical Engineering, Wolfgang Beitz, Karl-Heinz Küttner, Springer, 1994, page B45 [4] DUBBEL - Handbook of Mechanical Engineering, Wolfgang Beitz, Karl-Heinz Küttner, Springer, 1994, page B19-B22 [5] DUBBEL - Handbook of Mechanical Engineering, Wolfgang Beitz, Karl-Heinz Küttner, Springer, 1994, page D57

ASHRAE Legionella Standard 188: Evidence-Based Interpretation And Application Janet E. Stout, Ph.D. Special Pathogens Laboratory & University Of Pittsburgh

Abstract

in the building water systems. The standard tells WKH WHDP ZKDW WR GR EXW SURYLGHV OLWWOH VSHFLÂżF information on how to successfully control Legionella in building water systems. Reliance on evidence-based decisions validated from peerUHYLHZHG VFLHQWLÂżF LQYHVWLJDWLRQV ZLOO VWUHQJWKHQ the effectiveness of the Team and defensibility of the Program and close the â€œgaps.â€?

The first U.S. standard for the prevention of Legionnaires' disease was published by the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) on June 26, 2015. The normative sections of the standard The â€œGapsâ€? include development of a Water Management Plan Following are a few instances of potential gaps for building water systems and devices including Janet E. Stout within the standard: open and closed circuit cooling towers and evapo1. Critical knowledge for effective disease prevention rative condensers. ASHRAE Standard 188 is a process standard and critical decisions are left to the discretion of the Water Management Â‡ The â€œWater Management Program Team" must have Team. Information will be shared to help inform these decisions "knowledge of the building water system design and so that they are evidence-based and defensible. water management as it relates to Legionellosis." Â‡ This critical knowledge of Legionella will not typiIntroduction cally be available in-house as most building owners ANSI/ASHRAE Standard 188-2015 Legionellosis: Risk Managedonâ€™t possess the necessary specialized knowledge ment for Building Water Systems is a good step in preventing of Legionella in the built environment. Legionnairesâ€™ disease in building water systems. However, the Â‡ For example, the presence and growth of Legionella standard provides only minimum requirements and compliance can be impacted by how water systems are operated would not insure Legionella control. Building owners are presented and maintained. The Water Management Team with a framework for a risk management approach to the prevenshould understand the differential effectiveness of tion of Legionellosis, but are left to rely on their own judgment FRQWURO VWUDWHJLHV LQFOXGLQJ GHÂżQLQJ FRQWURO OLPLWV and knowledge in deciding the most appropriate course of action. and monitoring of the water treatment/biocide This gap between the understanding of the how, what and why of program for cooling towers and secondary water compliance, and the creation of an effective Water Management treatment of the building water system if applicable. Program could leave building owners vulnerable to liability claims Â‡ )RU WKH ÂżUVW WLPH PDQ\ EXLOGLQJ RZQHUV PD\ EH if cases occur. At the end of the day, building owners could develop confronted with decisions such as whether or not a plan without Legionella control. to install a disinfection system. Selecting the most appropriate and cost-effective technology requires Implementing The Standard knowledge of Legionella and engineering, as well &RPSOLDQFH LV EDVHG RQ GHÂżQLQJ ZDWHU V\VWHPV LQ EXLOGLQJV GHas water treatment expertise. termining if they are covered by the standard, and going through 2. The microbiology of prevention risk management steps in the standard, but not necessarily demonstrating the effectiveness of the plan in controlling Legionella. Â‡ In the case of outbreaks involving cooling towers, This represents a critical "gap" that could be closed with in-depth the causative agent has almost exclusively been knowledge and decision-making. ASHRAE has placed the standard Legionella pneumophila, serogroup 1. The majority on "continuous maintenanceâ€? providing a mechanism for changes of drinking water-associated outbreaks are caused throughout this process that could address these â€œgapsâ€? in future by Legionella pneumophila. Overall, most reported iterations of the standard. cases of Legionnairesâ€™ disease are caused by L. pneumophila, serogroup 1, with other serogroups 7KH SODQ PXVW LQFOXGH FRQÂżUPDWLRQ WKDW WKH 3URJUDP HIIHFWLYHO\ (mostly 3, 4 and 6) and Legionella micdadei, and controls the hazardous conditions throughout the building water Legionella longbeachae accounting for a small systems. Practically speaking, the â€œhazardâ€? is growth and exposure percentage of cases. to Legionella bacteria in the building water systems and subsequent risk of illness. A Water Management Team is formed to develop and Â‡ Interpreting the relative risk of these disease-causing implement the Water Management Program for Legionella control strains is important for determining and deploying resources for risk management. The Water

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Management Team is tasked with decisions for testing (if, where, how many locations) and results interpretation. 3. Sources of exposure to Legionella For sporadic community-acquired cases, the public health threat from improperly managed cooling towers is relatively unknown—with the exception RI ZHOO GH¿QHG RXWEUHDNV OLNH WKH RXWEUHDN LQ the Bronx in New York City that reportedly caused 138 cases and 16 deaths. In contrast, warm water distribution systems inside buildings are a wellGH¿QHG VRXUFH RI H[SRVXUH The risk of illness from building water systems was established with our 1982 publication in The New England Journal of Medicine. We showed that hospitalized patients acquired Legionnaires’ disease from the water in their hospital rooms, not from cooling towers. Since then, the link between illness and exposure to Legionella from building warm water distribution systems in hospitals, hotels, senior high rise apartments, prisons, nursing homes, and private homes has been well established. In 2006, a National Research Council report cited Legionella as “the single most common etiologic [disease-causing] agent associated with outbreaks involving drinking water.” Recently, the Centers for Disease Control and Prevention (CDC) reported that for the period between 2011 and 2012, Legionella accounted for 66% of the

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drinking water–associated outbreaks that resulted in 431 cases of illness, 102 hospitalizations, and 14 deaths. All 14 outbreak-associated deaths reported were caused by Legionella, including 12 (86%) cases associated with health care facilities. Legionella in building plumbing systems was among the WZR PRVW FRPPRQO\ LGHQWL¿HG GH¿FLHQFLHV >IDFWRUV@ leading to drinking water–associated outbreaks. 4. ASHRAE 188 does not require Legionella testing to validate that your risk management program is working. Studies show that the only reliable way to validate HI¿FDF\ RI \RXU ULVN PDQDJHPHQW SURJUDP DQG residual disinfectant (if you are using one) and the threat from Legionella is to test for Legionella. Culture of viable Legionella is the standard method for detection. The International Organization for Standardization: ISO 11731 -1998, “Water Quality - Detection and Enumeration of Legionella” is D PHWKRG WKDW LV ˪DFFHSWHG LQWHUQDWLRQDOO\ DV EHVW practice for Legionella culture. 5. ASHRAE 188 requires hazardous conditions be redressed to ³DFFHSWDEOH´ OHYHOV EXW GRHVQ¶W GH¿QH ³DFFHSWDEOH ´ 7KDW¶V left up to the Water Management Team. The approval of ASHRAE standard 188 has the potential to introduce a new era Legionnaires’ disease prevention. The success of this effort will depend upon well-informed Water Management Team and evidence-based Water Management Programs. Such efforts could prevent illness and death from a preventable waterborne disease.

New York Legionella Regulations: Are They Missing The Boat? by Sarah Ferrari

Legionella concentrationsâ€™ discussed within this paper pertain only to the virulent, or infectious, form of the bacteria. A large outbreak of Legionnairesâ€™ disease in the The vast majority of LD occurs as apparently Bronx in 2015 prompted NYC to enact law and isolated cases. Of cases reported to the CDC, 96% NYS to propose emergency regulations on the DUH FODVVLÂżHG DV VSRUDGLF DQG DUH QRW W\SLFDOO\ registration and maintenance of cooling towers. investigated4 $ FOXVWHU RI FDVHV LV FODVVLÂżHG DV DQ This paper describes the fundamental characteroutbreak when two or more people are exposed to istics of point sourced vs. potable water sourced Legionella and get sick in the same place at about outbreaks and discusses the Bronx outbreak the same time. Recognized outbreaks of LD are from those perspectives. Ultimately a case is rare; but when they occur, they provide opportunimade that these new regulations will not have ties to understand the epidemiology of the illness a measurable impact on reducing the incidence and improve prevention strategies. This opportuof Legionellosis. Rather, more detailed and nity is wasted if the extensive data that is generated open-minded investigations of future outbreaks, during an outbreak is not evaluated impartially. including investigation of potential potable waSarah Ferrari ter sources, are called for to inform appropriate The recent outbreak in the South Bronx has reregulations and disease prevention activities. sulted in New York City enacting a local law5 on the registration and maintenance of cooling towers in the city. Also, the State of Introduction New York has proposed emergency regulations for the registration Legionnairesâ€™ disease (LD) is a severe form of pneumonia which and maintenance of cooling towers state-wide6. As more facts have is contracted by inhaling or aspirating water droplets containing emerged, it appears that the hastily prepared emergency regulations Legionella deeply into the lungs. For many years it was believed KDYH IDOOHQ YLFWLP WR WKH ÂłGHWHFWLRQ ELDVÂ´ UHIHUUHG WR LQ WKH ÂżUVW the disease could be transmitted only by large equipment which paragraph above and that authorities have not only squandered emits aerosols or by equipment designed to aerosolize. Thus spas, an opportunity to expand our understanding of the disease but GHFRUDWLYH IRXQWDLQV JURFHU\ PLVWHUV VSUD\ KXPLGLÂżHUV FRROLQJ imposed regulations and cost on cooling tower owners that have towers and other aerosol sources were the only water systems little chance of reducing the incidence of disease. investigated when an outbreak occurred. In the early 1980s investigations of potable water systems in hospital outbreaks indicated This paper will describe the outbreak in the Bronx that instigated that the potable water is also a vector in disease transmission, either WKHVH UHJXODWLRQV :KLOH D VSHFLÂżF FRROLQJ WRZHU ZDV LGHQWLÂżHG via aspiration of Legionella from the mouth into the lungs 1 or via as the source of the original outbreak, two subsequent outbreaks inhalation of droplets emitted by sinks and showers. It now appears occurred. Potable water in the building where people lived was that many LD outbreaks were initially blamed on cooling towers SRVLWLYHO\ LGHQWLÂżHG DV WKH VRXUFH IRU VHFRQG RXWEUHDN 7ZR PRQWKV due to a â€œdetection biasâ€? that has not been widely recognized, and DIWHU WKH WKLUG RXWEUHDN HQGHG D FRROLQJ WRZHU ZDV LGHQWLÂżHG DV WKH that these outbreaks were actually caused by potable water issues. source, even though all of the cooling towers in the area had been In more recent years it has been found that the primary source of recently cleaned in accordance with the newly enacted NYC laws. The Bronx outbreak and regulatory response has many similarities hospital-acquired Legionnairesâ€™ disease is potable water 2. In the United States there have been requirements to address Le- to a French outbreak in the winter of 2003-2004. In Pas-de-Calais a gionella in hospital potable water systems from the Joint Commis- large outbreak was attributed to a cooling tower and resulted in the sion on the Accreditation of Healthcare Organizations (JCAHO), promulgation of regulations for the registration and maintenance Allegheny County (Pittsburgh), Maryland, New York, and others; of cooling towers. The inconsequential result of those regulations however, until recently there have been no similar mandates in the on the reduction of the incidence of disease will also be described United States for cooling towers. Although not mandated, many in this paper.

Abstract

industrial groups such as CTI, ASHRAE, and AWT have published best practice guides that describe methods for maintaining equipment to minimize the risk of Legionellosis. 0RUH WKDQ ÂżIW\ Legionella VSHFLHV KDYH EHHQ LGHQWLÂżHG EXW QRW DOO have been linked to disease. Legionella pneumophila serogroup 1 is the most virulent strain causing the majority of infections3. Virulence varies not only between strains and their subtypes but can also vary within a particular cell. There are two major phases to the life cycle; a non-pathogenic vegetative phase and a virulent transmissive phase. The concepts of â€˜infectious doseâ€™ or of â€˜relative

Outbreak Characteristics Aerosol Point-Source There have been many Legionnairesâ€™ disease outbreaks traced to an aerosolized point source of the bacteria. Point sources of aerosols include decorative fountains, spas, grocery misters, and cooling towers. Investigation of these outbreaks typically reveals a close relationship between time spent near the source and incidence of infection. A dose-response relationship between exposure and illness has been demonstrated in numerous carefully investigated

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studies. This is particularly true for indoor sources where proximLW\ WR WKH DHURVRO VRXUFH KDV EHHQ LGHQWLÂżHG DV DQ HVVHQWLDO IDFWRU for infection. For cooling tower sources the same relationship exists, i.e., a close correlation between proximity to the source and incidence of disease. However, for some outbreaks where the purported source is a cooling tower there is little spatial correlation between the incidence of disease and the alleged source. The unstated assumption is that there is a hidden variable that causes disease seemingly randomly a great distance from the source. This lack of spatial correlation was evident in the South Bronx outbreak where there was no clustering of cases near the purported tower at the Opera House Hotel. What that hidden variable could be is not clear. The following paragraphs describe several well studied outbreaks where, as one would expect, proximity to the source strongly affected the incidence of disease. ,Q D VSD DW D Ă€RUDO WUDGH VKRZ LQ WKH 1HWKHUODQGV ZDV LGHQWLÂżHG DV WKH VRXUFH RI D ODUJH RXWEUHDN RI /HJLRQQDLUHVÂś GLVHDVH Among exhibitors a close correlation was found between elevated antibodies to Legionella and proximity of their booth to the source. The most important visitor-related risk factor was pausing at the whirlpool spa display7. Clive Brown et al. investigated a 29-case community outbreak of Legionnairesâ€™ disease in 1994 linked to a hospital cooling tower8. This investigation showed that the risk of infection decreased by 20% for each 0.1 miles from the hospital and increased by 80% for each visit to the hospital. The paper described an Aerosol ([SRVXUH 8QLW GHÂżQHG DV WKH UDWLR RI WLPH VSHQW QHDU WKH VRXUFH and the distance from the source and found a strong correlation between exposure and incidence of disease. The image in Figure 1 taken from this study illustrates the expected distribution of cases of disease from a single aerosol source. The cases are clustered near the source and taper off rapidly at increasing distance. Proximity was well demonstrated in a 1993 outbreak at a Michigan prison which was traced to a hospital cooling tower. Fourteen (0.6%) of 2253 prisoners who used exercise yards each day within 100 yards of the prison hospital were infected, compared with only two (0.1%) of the 2270 inmates who used yards at least 400 yards from the prison hospital.9 This equates to roughly a 50% reduction in infection risk in 0.1 miles. 7KH LQĂ€XHQFH RI SUHYDLOLQJ ZLQG RQ DHURVRO GLVSHUVLRQ ZDV DGdressed by P. Wilmot et al. using geographic information system (GIS) data10. They developed plume dispersion models to help locate a potential cooling tower source during outbreak investigations. A plume refers to the moist exhaust air from a cooling tower. The plume will mix with ambient air as it travels away from the tower becoming more and more dilute. If a case occurs outside of the plume dispersion model â€œthe chance that it originated from that cooling tower remains highly unlikelyâ€?. Figure 2 displays a case where the cooling tower would not be considered a likely source. The plume is diluted with increasing distance from the tower reducing the concentration of Legionella in the air. Legionella can live only a relatively short time in the air and contamination at a large distance from the tower is unlikely. A person would need to VSHQG VXIÂżFLHQW WLPH QHDU WR WKH WRZHU LQ RUGHU WR LQKDOH DQ LQIHFtious dose of bacteria. Dr. Richard Miller at the University of Louisville has stated: â€œLegionnaires' Disease, like all infectious diseases, requires a minimum infectious dose in order to cause disease. While the exact number required for humans varies depending on the susceptibility (i.e. immune status) of the individual, it is likely that the number for most individuals is relatively large. It should be apparent from

the ubiquitous nature of this bacterium in the environment, that in order to cause disease, the number of Legionella in the water would need to be much higher than that found in most normal aquatic habitats11.â€? The virulence of a particular genetic type of Legionella is not a constant and may change during its lifecycle and also may change by exposure to chemicals, heat, or interaction with amoebae. Nevertheless, the ubiquity of Legionella in nature implies that everyone has been exposed to at least a low concentration of the bacteria. In addition to dilution of the aerosol over distance, cooling towers have made dramatic improvements in drift eliminator technology. Drift eliminators are the component of cooling towers that separates UHFLUFXODWLQJ ZDWHU IURP H[LWLQJ DLU 2YHU D SHULRG RI DERXW ÂżYH years ending around 2000 all major manufacturers of factory-built cooling towers developed low-drift eliminators. These modern drift eliminators reduce aerosol emissions by an order of magnitude from the previous generation of towers. If the water in a cooling tower was contaminated with 1,000 CFU/ml of Legionella, a person standing on top of the tower and breathing in only tower exhaust for 1 hour would breathe in droplets containing a total of 10 bacteria12. As a comparison of transmission pathways between inhalation and aspiration, a person drinking 4 ounces of water from a potable water source contaminated with only 10 CFU/ml would consume over 1,000 bacteria in the few seconds it took to drink the water. These bacteria would be in the mouth and not in the lungs, but the numbers of bacteria that can enter the body are VLJQLÂżFDQWO\ KLJKHU ZLWK DQ DVSLUDWLRQ URXWH IURP SRWDEOH ZDWHU than inhalation from a modern cooling tower. $V WKH & %URZQ KRVSLWDO VWXG\ WKH 1HWKHUODQGV Ă€RZHU VKRZ study, and the Michigan prison study imply, there should be a doseresponse with exposure and incidence of disease. The higher the dose that a particularly susceptible individual receives, the higher will be the likelihood of infection. Also, because of Legionellaâ€™s ubiquitous presence in nature, there should be a threshold dosage below which there is no disease. The key characteristics of an aerosolized point source exposure to Legionella are: 1. The original source of the bacteria is colonization of the potable water supply. 2. While many water-based devices could be contaminated due to an upset in the potable water system, only in one will the EDFWHULD ÂżQG KRVSLWDEOH JURZLQJ FRQGLWLRQV IRU DPSOLÂżFDWLRQ and susceptible individuals to infect. 3. The bacteria reproduce in an individual aerosol producing device. This usually requires the water in the equipment to UHDFK WHPSHUDWXUHV WKDW SHUPLW DPSOLÂżFDWLRQ 4. The bacteria are emitted from a single point. There is a strong correlation between incidence of infection and proximity of the individual to the aerosol source in both time and space. While a correlation between proximity to the aerosol source and disease incidence seems fundamental, there are many outbreaks where investigations concluded that this was not the case. This is particularly true of outbreaks attributed to cooling towers. There have been numerous cases, including the July 2015 outbreak in the Bronx, where a cooling tower in the general area was blamed for causing disease without any apparent association of patients with the aerosol source. This lack of spatial correlation between disease incidence and the purported source is an extremely strong LQGLFDWLRQ WKDW WKH VSHFLÂżF FRROLQJ WRZHU LV QRW WKH VRXUFH RI WKH outbreak. CTI Journal, Vol. 37, No. 2

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may infect only a few patients per year and appear somewhat Municipal potable water systems in the United States and Eu- sporadically. ropean countries have been very effective at reducing, but not The key factors of a potable water outbreak of Legionnairesâ€™ eliminating, waterborne diseases. Potable water is sanitary but disease are: not sterile. Disinfection is designed to eliminate many pathogens 1. The original source of the bacteria is colonization of the transmitted by the oral-fecal route, such as cholera and typhoid, potable water supply. however many other bacteria that are natural inhabitants of aquatic 2. While many buildings could be contaminated due to an upset environments may survive. Most water pipes contain a layer of in the potable water system, only in some buildings will the ELRÂżOP 7KLV ELRÂżOP PD\ KDUERU PDQ\ QRQ SDWKRJHQLF EDFWHULD EDFWHULD ÂżQG KRVSLWDEOH JURZLQJ FRQGLWLRQV IRU DPSOLÂżFDWLRQ but can also harbor bacteria such as Legionella. When a known and susceptible individuals to infect. upset occurs, such as a power outage or water main break which 3. The bacteria reproduce within several building potable wacauses loss of system pressure, warnings to boil water before using ter piping systems to reach infectious levels. This usually are sent to the system users. There are an estimated 240,000 water 13 requires the water in the system to reach temperatures that main breaks per year in the United States . Minor upsets such as SHUPLW DPSOLÂżFDWLRQ SUHVVXUH VXUJHV WKDW FRXOG GLVWXUE ELRÂżOPV LQ WKH SLSHV PD\ VHHP 4. The bacteria are emitted at multiple points in multiple buildunremarkable or go unnoticed yet could release bacteria into the ings throughout the affected portion of the municipal water water stream. A study conducted in Wales and northwest England distribution system. from 2001 to 2002 found a very strong association between selfreported diarrhea and reported low water pressure at the home tap14. 5. Since the bacteria are emitted from widespread sources there The investigators hypothesized that most of the reported episodes is a seemingly random distribution of cases of disease all of pressure loss were due to main breaks in which contamination within the same municipal water distribution system. entered the distribution system. As the infrastructure ages, the 3RWDEOH ZDWHU KDV DOVR EHHQ LGHQWLÂżHG DV WKH VRXUFH IRU /HJLRQfrequency of upsets that can potentially cause contamination in nairesâ€™ disease in non-hospital settings, but again usually with very the system has increased. low infection rates. High risk buildings tend to be tall with complex 7KH ÂżUVW LQFLGHQFH LQ ZKLFK D PXQLFLSDO ZDWHU V\VWHP ZDV IRXQG WR piping and many residents. If Legionella from the municipal water be the vector for disease transmission occurred during the cholera VXSSO\ FRORQL]H VHGLPHQW DQG ELRÂżOP LQ D EXLOGLQJ ZDWHU V\VWHP epidemics in mid-19th century London. Sir John Snow, an English there may be occasional incidents of disease. When multiple cases physician, prepared a map of where cholera deaths had occurred. occur in a single building, the health department will evaluate that This map15 clearly showed that most of the deaths were in build- building for contamination but rarely investigate other buildings ings that received their water from a particular contaminated well receiving water from the same municipal system. An incident in that was the source of the disease. However, it took 20 years after the municipal potable water supply system that contaminated many Snow generated his map and 8 years after Snow passed away buildings over a short period of time could result in an outbreak of before the correlation between contaminated water and cholera disease occurring in the area downstream from the incident over a was accepted16. The â€œdetection biasâ€? that cholera was caused by relatively short period of time. DLUERUQH ÂłPLDVPDÂ´ ZDV WRR ÂżUPO\ HQWUHQFKHG LQ WKH QLQHWHHQWK century zeitgeist to be easily dislodged. Figure 3 reproduces Sir Epidemiology â€“ Not an Exact Science John Snowâ€™s map. Cholera fatalities are indicated by small red Determining the source of a particular outbreak requires gathercircles; public drinking water wells are indicated by larger blue ing and sifting through large amounts of information. Patients circles. The cases are spread uniformly over the area where the are interviewed, commonality between sites visited by patients is evaluated, possible sources are examined, and an attempt is made contaminated water was used. A more recent potable waterborne infection occurred in Denmark to match the DNA of infectious bacteria grown from patient isolates in 200717. There an outbreak of gastroenteritis affected a high to that found in the environment. It is only when all of these fall percentage of residents in one section of the city. Investigation LQ OLQH WKDW D VRXUFH RI WKH GLVHDVH FDQ EH GHÂżQLWLYHO\ LPSXWHG showed massive contamination of a part of the water distribution As of this writing, there are approximately 2,000 different Legiosystem, while other parts of the distribution system appeared to nella pneumophila genotypes known worldwide, but only 10% EH XQDIIHFWHG 7KH VRXUFH ZDV HYHQWXDOO\ LGHQWLÂżHG DV EDFNĂ€RZ of those are known to be associated with disease in the US19 20. A of sewage into that portion of the drinking water system. Figure DNA match between environmental and patient isolates is not as 4 shows the case map for this outbreak with contamination in one determinative of the infection source as one might expect. In a VSHFLÂżF JHRJUDSKLFDO UHJLRQ WKHUH DUH XVXDOO\ IHZHU WKDQ VHYHUDO subsection of the water supply. 21 Legionellosis is a waterborne disease. Since the early 1980â€™s, dozen genotypes endemic to the water systems . Since potable water is the ultimate source of the bacteria, many water features in potable water has been known to be a vector for Legionnairesâ€™ an area can be contaminated with the same genotype of bacteria. disease. The best studied cases with a potable water source are In fact particular genetic types of Legionella can become endemic hospital acquired infections. A hospitalâ€™s internal piping system to a given water system with the same genetic match appearing can become contaminated with Legionella from the municipal potable water supply. In warm areas of piping, particularly if there in seemingly unrelated environmental sources. Thus the lack of LV D ELRÂżOP RQ VXUIDFHV RU VHGLPHQW LQ WKH V\VWHP WKH Legionella a DNA match can disprove that a particular feature is the source, can multiply and occasionally release large numbers of bacteria but a DNA match on its own cannot prove that it is the source. into the water18. The bacteria may be transmitted to many hospital 7KH GLIÂżFXOW\ RI GHWHUPLQLQJ D VRXUFH ZDV FOHDUO\ VHHQ LQ DQ RXWpatients via aspiration of contaminated drinking water or ice chips break in South Dakota in 200722. There had been a dramatic inor, more commonly, via aerosols generated by sinks and showers. crease in the incidence of Legionnairesâ€™ disease over a short period Since Legionella are not as virulent as cholera this contamination of time. There was little in common with the patients except that

Potable Water Supply Source

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WKH\ VSHQW WLPH LQ 5DSLG &LW\ 7R WKH LQYHVWLJDWRUV WKLV DW ÂżUVW DSpeared to be a likely cooling tower issue, though there was no clear relationship with time spent near a tower and incidence of disease.

features in the area and had caused previous outbreaks in NYC24. A particular strain is likely to be present throughout the potable water system, so commonality in activity among patients relative Cooling towers throughout the city were located and sampled. to a particular potential source must be established in order to Many had detectable levels of Legionella and were required to be GHGXFH WKH VSHFLÂżF VRXUFH V RI LQIHFWLRQV disinfected. However, none of the towers Legionella were a genetic The particular cooling tower located at the Opera House Hotel match to the patientsâ€™ isolates. The investigators continued to look circulated water at 800 gpm; at full fan power it moves 49,700 for other aerosol sources without success as infections were still CFM; and it is equipped with drift eliminators that reduce the drift occurring. Then the investigators noticed that many of the patients to less than 0.001%. The drift rate then is: 0.00001 x 800 gpm x had eaten at the same restaurant during their likely infection period. 3785 ml/gal = 30 ml/min. At full fan power this drift results in a When investigators revisited the restaurant they sampled a small concentration of: 30/49700CFM x 1CF/7.48 gal x 1 gal/3.785 liters fountain and found both a high level of Legionella in the fountain = 0.00002 ml of drift /liter of exhaust air. If each ml contained and an exact genetic match to the Legionella found in the patients. 1000 CFU of Legionella, then on average there would be 0.02 The fountain was removed and no additional infections occurred. Legionella per liter of undiluted tower exhaust air or in every 50 It was fortunate that none of the cooling towers testing positive liters of air there would be a single bacteria. If a typical person for Legionella were a genetic match to the particular bacteria that has a 500 ml tidal volume and takes 15 breaths per minute, and infected patients. Had there been a match, even with little data if they were breathing only undiluted tower exhaust for an hour, showing that infected persons spent more time near the towers they would inhale 0.5 x 15 x 60 = 450 liters of air or only about than the general population, that tower may likely have been de- 10 bacteria. As one moves away from the tower the exhaust air clared the source and the fountain would have continued to infect containing the drift becomes more dilute and a person would require much longer time in the diluted exhaust air to inhale a similar restaurant patrons. number of bacteria.12 2015 Bronx Outbreaks Recall that proximity has been well established in aerosol pointsourced outbreaks, with reduced infection rates at increasing Initial Outbreak in South Bronx distance from a source. The circle around the Opera House Hotel During the summer of 2015 a large outbreak of Legionnairesâ€™ in Figure 6 indicates a 0.1 mile radius. This is the area where one disease occurred in the South Bronx. The onset dates, 2 to 10 would expect the highest cluster of cases, but there is no cluster of days after the infection dates, were between July 8th and August cases at or immediately adjacent to the hotel. There is no gradient UG 7KH RXWEUHDN ZDV RIÂżFLDOO\ GHFODUHG RYHU RQ $XJXVW WK with radial or, presuming wind, with directional distance. Rather, During this outbreak 133 individuals were diagnosed with the the cases appear randomly across a broad area, producing a case disease with 16 deaths. The graph in Figure 5 is from the NYC map with more similarity to the waterborne cholera outbreak. CoolDepartment of Health23. This epidemic curve is characteristic of ing towers and fountains were sampled as part of the investigation, a common source outbreak where the individuals were exposed to EXW SRWDEOH ZDWHU ZDV QRW &LW\ RIÂżFLDOV UHSHDWHGO\ FODLPHG WKDW a source of the bacteria over a short period of time. Based on the â€œthe drinking water is unaffectedâ€?. This claim was not substantishape of the curve, this common origin could be an aerosolized ated with data by NYC because no testing of potable water was source with an upset condition or a municipal water system with performed. In fact it was dramatically disproven in only a few an upset condition. weeks when the cases associated with the Melrose Houses were 7KH VRXUFH RI WKLV RXWEUHDN ZDV LGHQWLÂżHG E\ WKH 1<& '2+ DV D more fully evaluated. cooling tower on the Opera House Hotel. Note that the particular FRROLQJ WRZHU DW WKH 2SHUD +RXVH +RWHO WKDW ZDV LGHQWLÂżHG DV WKH Outbreak at Melrose Houses source of the outbreak had a small 7.5 HP fan and was equipped There was a second outbreak of four cases of Legionnaires disease with modern low-drift eliminators that reduce by an order of at tKH 0HOURVH +RXVHV LQ WKH 6RXWK %URQ[ LGHQWLÂżHG DIWHU WKH LQLWLDO magnitude the quantity of drift that the tower emits. The cooling outbreak. An arrow in Figure 6 indicates the location of the Melrose tower was disinfected on August 1st with the last reported case +RXVHV OHVV WKDQ PLOHV IURP WKH 2SHUD +RXVH +RWHO 7KH ÂżUVW onset on August 3rd. The infection date for all of these cases could case in the Melrose Houses outbreak occurred in March 2015 and have been prior to the cleaning of the cooling tower, though the was not investigated at that time. Two more cases occurred during declining case rate in late July indicates that the outbreak had likely the July outbreak and were originally included in that outbreak, stopped before the tower was disinfected. It is likely that none of and the latest occurred in late August after the July outbreak was the testing and cleaning of cooling towers demanded by the NYC declared over. No potable water sources were investigated by the DOH had any effect on ending the initial outbreak. 1<& '2+ XQWLO IRXU FDVHV ZHUH LGHQWLÂżHG DW D VLQJOH ORFDWLRQ DW The cases were distributed fairly uniformly over a large area of the Melrose Houses. When the potable water at Melrose Houses with South Bronx. The NYC DOH has provided the map in Figure 6 over two thousand residents was investigated, Legionella were showing approximately 85 of 133 case locations and the locations found in the potable water and the potable water was positively of cooling towers.23 Circles represent cases and triangles cooling LGHQWLÂżHG DV WKH VRXUFH RI LQIHFWLRQ 3RLQW RI XVH ZDWHU ÂżOWHUV ZHUH towers with the large red triangle at the location of the cooling installed on all faucets and showerheads and a copper-silver ionizatower at the Opera House Hotel. Red circles are cases where ge- tion system was installed in the buildingsâ€™ potable water piping. netic testing of the Legionella was performed. The patient samples In spite of 3 cases occurring in the same facility over a period of and the bacteria found at the Opera House Hotel were of the same only a few months, potable water was not sampled. It was only genetic type, but as discussed above, genetic typing alone can rule after the original outbreak was declared over yet an additional case RXW D SRWHQWLDO VRXUFH EXW FDQQRW RQ LWV RZQ GHÂżQLWLYHO\ HVWDEOLVK RFFXUUHG WKDW WKH SRWDEOH ZDWHU ZDV VDPSOHG DQG LGHQWLÂżHG DV WKH a source. In fact the particular strain found in the patients and source of the infections. in the Opera House Hotel cooling tower was also found in other

CTI Journal, Vol. 37, No. 2

Outbreak at Morris Park A third outbreak of Legionnairesâ€™ disease occurred in the Morris Park neighborhood of the Bronx. Morris Park is about 4 miles from the Opera House Hotel in the East Bronx. There were 13 cases in this outbreak and 1 death. Figure 7 shows the epidemic curve for this outbreak. The onset dates for all but one of the cases included in the outbreak were between September 14th and September 21st with infection occurring 2 to 10 days prior. On August 6 a city wide order had been issued which mandated that: â€œRegardless of the outcome of the evaluation required by item (2) above, direct the environmental consultant to carry out a disinfection/treatment VXIÂżFLHQW WR UHPRYH RUJDQLF PDWHULDO ELRÂżOP DOJDH DQG RWKHU FRQWDPLQDQWV DQG GLVLQIHFW LQ D PDQQHU VXIÂżFLHQW WR FRQWURO IRU WKH SUHVHQFH RI Legionella organisms within 14 days of receipt of this letterâ€?25 Due to this city-wide order, all cooling towers in the area had been disinfected by August 20th a few weeks prior to the earliest possible date of infection. If indeed a cooling tower was responsible for the outbreak, then the remediation requirements in the NYC newly enacted laws were ineffective at preventing an outbreak. If potable water or another feature was the source or sources then the newly enacted laws which focus only on cooling towers actually hindered a proper investigation of the outbreak. ,Q ODWH 6HSWHPEHU WKLUW\ ÂżYH FRROLQJ WRZHUV LQ WKH DUHD ZHUH WHVWHG IRU Legionella and 15 had detectable levels of the bacteria. These 15 towers ZHUH GLVLQIHFWHG IRU D VHFRQG WLPH EHJLQQLQJ 6HSWHPEHU WK VLJQLÂżFDQWO\ after the outbreak had ended. A press release issued by the NYC DOH on 1RYHPEHU IXOO\ WZR PRQWKV DIWHU WKH RXWEUHDN KDG HQGHG LGHQWLÂżHG a cooling tower as the source26. With this outbreak it is unequivocally clear that none of the testing and cleaning of cooling towers demanded by the NYC DOH had any effect on ending the outbreak. In the large South Bronx outbreak and also in the Morris Park outbreak, infection occurred over a relatively large area in a short time-span. Although the pattern could be due to an upset in the municipal water system simultaneously infecting a large number of buildings, the only sources that were investigated were aerosol point sources such as cooling towers, spas and fountains.

Impact of regulations on public health Incidence of Disease in the United States and Europe Legionnairesâ€™ disease is a reportable illness in the United States and many European Countries. Records are made available by the CDC27 in the US and the ECDC28 in Europe. For 5 European countries these records go back at least to 2003. Figure 8 shows the reported incidence of LD for these countries and the US in illness per 100,000 of population. There are many factors which can affect the shape of the curves besides actual incidence of disease. Legionnairesâ€™ disease is believed to be underreported. The US reported incidence rate has steadily increased over the period shown. The CDC believes that this may be partially due to: â€œAn increasing population of older persons contributed to the increase in reported legionellosis cases. Other factors that might have contributed include an increasing population of persons at high risk for infection; improved diagnosis and reporting, possibly stimulated by the 2005 CSTE endorsement of more timely and sensitive legionellosis surveillance; and increased use of urine Legionella antigen testing29â€?. The graph in Figure 8 shows that there is little difference in the incidence rate of Legionnairesâ€™ disease between Western Europe and the United States. This lack of difference exists in spite of burdensome regulation of cooling towers which has been in place in Europe for many years.

Legionella Regulations in France France provides an interesting study of the effects of cooling tower regulations on the incidence of disease. Guidelines to improve underreporting of the disease were written in 1997 along with introduction of the urinary antigen detection test30. In the winter of 2003 to 2004 a large outbreak ZLWK FRQÂżUPHG FDVHV DQG IDWDOLWLHV RFFXUUHG LQ 3DV GH &DODLV France31. An industrial cooling tower was implicated as the source for the

contamination. As a result of this outbreak regulations were promulgated for the control of cooling towers. Cooling tower regulations for hospitals had been enacted in 2003 but with the Pas-de-Calais outbreak they were extended to all cooling towers32. The 2004 regulations require frequent testing of cooling towers for Legionella. The regulations mandate monthly testing for Legionella unless 12 consecutive monthly tests are less than 1 CFU/ml then the testing can be reduced to quarterly. If the reading exceeds 100 CFU/ml the tower must be immediately shut down and cleaned. More frequent testing is then required until the system again meets the strict low limits. The graph in Figure 9 indicates that the incidence rate for LD infection has been hovering around 2 per 100,000 of population for over a decade. After the regulations were issued at the end of 2004, there was an increase in the reported incidence of LD. This could well be due to a heightened awareness of the disease from both the issuing of the regulations and the widely publicized outbreak at Pas-de-Calais. There has been a gradual decline in the reported incidence since 2005, but a dramatic reduction has not been observed since the regulations were implemented. The author believes that these results indicate that the cooling tower regulations had little to no effect on the incidence of sporadic cases of Legionnairesâ€™ disease.

Conclusion There are outbreaks of Legionnairesâ€™ disease which have been clearly linked to a sole aerosolized source of bacteria. In these outbreaks, acute proximity and duration were shown to govern exposure and incidence of Legionnairesâ€™ disease. However, there are many outbreaks attributed to a cooling tower source which do not adhere to these rules. These outbreaks KDYH FDVH SURÂżOHV ZKLFK DUH PRUH UDQGRP DQG FRYHU ODUJHU DUHDV 7KHVH RXWEUHDNV PLPLF WKH GRFXPHQWHG SURÂżOH RI FHUWDLQ SRWDEOH ZDWHU RXWEUHDNV where a single â€˜upstreamâ€™ source contaminates multiple exposure sites. The source(s) of future Legionnairesâ€™ disease outbreaks must be investigated more thoroughly, exploring the possibility of multiple exposure sites including potable water, in order to advance our understanding of LD transmission. The traditional epidemiological models that assume causality with a genetic match but with only a tenuous exposure mechanism have resulted in the promulgation of regulations that have not resulted in D VLJQLÂżFDQW UHGXFWLRQ LQ WKH LQFLGHQFH RI GLVHDVH ,QFUHDVHG DZDUHQHVV and the issuing of explicit orders for the care of cooling towers did not prevent the outbreaks from occurring at Melrose Houses or in Morris Park. Strict cooling tower regulations imposed in France after the Pas de &DODLV RXWEUHDN KDYH QRW UHVXOWHG LQ DQ\ VLJQLÂżFDQW UHGXFWLRQ RI GLVHDVH Is it time we say, perhaps, that it is not always the cooling tower? And what of the other 96% of reported LD cases, those considered sporadic? A 2006 report issued by the National Academy of Sciences states â€œCommunities should squarely address the problem of Legionella, both via changes to the plumbing code and new technologies.â€?14 The report goes on to call for UHVHDUFK SURMHFWV ZKLFK VSHFLÂżFDOO\ DGGUHVV SRWHQWLDO SUREOHPV DULVLQJ IURP premise plumbing. Regarding outbreaks the report states, â€œEnvironmental assessments of outbreaks should begin to incorporate new insights and allow possible cause-and-effect relationships to be established.â€? This would include a much greater emphasis on dose reconciliation in outbreaks in order to develop basic practical data on dose-response relationships. &OHDUO\ WKH VFLHQWLÂżF FRPPXQLW\ UHFRJQL]HV WKH KHDOWK ULVNV DVVRFLDWHG with premise plumbing, or building potable water systems. These potential risks were also well-recognized by the team of experts who contributed to ASHRAE Standard 188 Legionellosis: Risk Management for Building Water Systems. The Standard provides minimum Legionellosis risk management requirements for buildings and their associated potable and non-potable water systems. Subsequent to the recent outbreaks, NYC adopted a small subset of the Standard, the portion addressing cooling towers. Adoption of the full Standard, as intended by the expert authors, LV QHFHVVDU\ LQ RUGHU WR KDYH D VLJQLÂżFDQW SRVLWLYH HIIHFW RQ SXEOLF KHDOWK

CTI Journal, Vol. 37, No. 2

Figure 1 – Case Map from Aerosolized Point-Source

Figure 4 – Gastroenteritis Epidemiology Denmark 2007

Figure 2 – Case Outside Dispersion Model

Figure 5 – Epidemic Curve of Initial Outbreak in South Bronx 2015

Figure 3 – Cholera Epidemiology London 1854

Figure 6 – Map of Cases and Cooling Towers in South Bronx July 2015 Outbreak

CTI Journal, Vol. 37, No. 2

Figure 7 â€“ Epidemic Curve for the Third Outbreak in East Bronx 2015

Figure 8 â€“ Incidence of Legionnairesâ€™ Disease in the US and Western European Countries

Figure 9 â€“ Incidence of Legionnairesâ€™ Disease in France

References: 1. Stout, J. et al. (1982) Ubiquitousness of Legionella Pneumophila in the Water Supply of a Hospital with Endemic Legionnairesâ€™ Disease, New England Journal of Medicine (Feb. 25). 2. Sabria, M; Yu, V. (2002) Hospital-acquired Legionellosis: solutions for preventable infection, THE LANCET (Jun). 3. Yu et al. (2002) Distribution of Legionella species and serogroups isolated by culture in patients with sporadic community-acquired legionellosis: an international collaborative survey. J Infect Dis, 186:127â€“128 4. CDC Morbidity and Mortality Weekly Report (2015) August 14. 5. Local Laws of the City of New York No. 77, Article 317 Cooling Towers 6. NYS Department of Health Emergency Rule Making, Protection Against Legionella, HLT-35-15-00005-E, NYS Register/December 2, 2015.

7. Den Boer, J. (2002) A Large Outbreak of Legionnairesâ€™ disease at a Flower Show, the Netherlands, 1999, Emerging Infectious Diseases (Jan). 8. Brown, C. et al. (1999) A Community outbreak of Legionnairesâ€™ disease linked to hospital cooling towers: an epidemiological method to calculate dose of exposure, International Epidemiological Association Vol 26:353-359. 9. CDC Morbidity and Mortality Weekly Report (1994) July 15. 10. Wilmot, P. et al., (2004) Modelling Cooling Towers Risk for Legionnairesâ€™ Disease using Bayesian Networks and Geographical Information System, University of Adelaide. 11. Miller, R., Reducing the risk of Legionnairesâ€™ Disease, Environmental Safety Technologies 12. Bugler, T. et al. (2008) Cooling Towers, Drift, and Legionellosis, IWC-08-21, International Water Conference. 13. 2013 Report Card for Americaâ€™s Infrastructure. American Society of Civil Engineers. Web. 2 Nov. 2015. 14. Committee on Public Water Supply Distribution Systems: Assessing and Reducing Risks, Water Science and Technology Board, Division on Earth and Life Studies, National Research Council, National Academies Press, Dec 22, 2006. 15. http://www.udel.edu/johnmack/frec480/cholera/cholera2.html 16. Competing Theories of Cholera. UCLA Department of Epidemiology, School of Public Health. Web. 2 Nov. 2015. 17. Vestergaard, LS. et al. (2007) Outbreak of Severe Gastroenteritis With Multiple Aetiologies Caused by Contaminated Drinking Water in Denmark, January 2007, Eurosurveillance, Vol 12 Issue 13. 18. Stout, J. et al. (1984) Ecology of Legionella pneumophila within Water Distribution Systems, Applied and Environmental Microbiology (Oct). 19. Kozak-Muiznieks N. et al. (2013) Prevalence of Sequence Types among Clinical and Environmental Isolates of Legionella pneumophila Serogroup 1 in the United States from 1982 to 2012, Journal of Clinical Microbiology. 20. EWGLI Sequence-Based Typing (SBT) Database for Legionella pneumophila. The European Working Group for Legionella Infections. Web. 21 Dec 2015. 21. Drenning S. et al. (2001)Unexpected Similarity of Pulsed-Field Gel Electrophoresis Patterns of Unrelated Clinical Isolates of Legionella pneumophila, Serogroup 1, Journal of Infectious Disease. 22. Oâ€™Loughlin, R. E. (2007) Restaurant outbreak of Legionnairesâ€™ disease associated with a decorative fountain: an environmental and case-control study, BMC Infectious Diseases (Aug). 23. http://www.nyc.gov/html/doh/html/diseases/cdlegi.shtml 24. Private Communications with CDC. 25. NYC DOH Order of the Commisioner, August 6, 2015. 26. â€œBronx Psychiatric Center Cooling Tower Blamed For Morris Park Legionnairesâ€™ Outbreakâ€?, CBS New York, 20 November 2015, Web, 12 Dec. 2015. 27. Morbidity and Mortality Weekly Report (2015) October 23. 28. ECDC Annual Surveillance Report Legionnairesâ€™ disease in Europe. 29. CDC Morbidity and Mortality Weekly Report (2011) August 19. 30. Campese, C. et al. (2011) Progress in the surveillance and control of Legionella infection in France 1998-2008, International Journal of Infectious Diseases. 31. Eurosurveillance (2004) Vol.9 Issue 1-3. 32. ArrĂŞtĂŠ du 13 dĂŠcembre 2004 relatif aux installations de refroidissePHQW SDU GLVSHUVLRQ GÂśHDXGDQV XQ Ă€X[ GÂśDLU VRXPLVHV j DXWRULVDWLRQ DX WLWUH GH OD UXEULTXH QR -RXUQDO 2IÂżFLHO GH OD 5pSXEOLTXH FranĂ§ais. Acknowledgements The author gratefully acknowledges Dr. Claressa Lucas of the Centers for Disease Control and Prevention National Center for Infectious Respiratory Diseases, Division of Bacterial Diseases for her careful review of the technical portions of this paper.

CTI Journal, Vol. 37, No. 2

Cooling Technology Institute /LFHQVHG 7HVWLQJ $JHQFLHV For nearly thirty years, the Cooling Technology Institute has provided a truly independent, third party, thermal performance testing service to the cooling tower industry. In 1995, the CTI also began providing an independent, third party, drift performance testing service as well. Both these services are administered through the CTI Multi-Agency Tower Performance Test Program and provide comparisons of the DFWXDO RSHUDWLQJ SHUIRUPDQFH RI D VSHFLÂ¿F WRZHU LQVWDOODWLRQ WR WKH GHVLJQ SHUIRUPDQFH %\ SURYLGLQJ VXFK LQIRUPDWLRQ RQ D VSHFLÂ¿F tower installation, the CTI Multi-Agency Testing Program stands in FRQWUDVW WR WKH &7, &RROLQJ 7RZHU &HUWLÂ¿FDWLRQ 3URJUDP ZKLFK FHUWLÂ¿HV DOO PRGHOV RI D VSHFLÂ¿F PDQXIDFWXUHU V OLQH RI FRROLQJ WRZHUV SHUIRUP in accordance with their published thermal ratings.

Licensed CTI Thermal 7HVWLQJ $JHQFLHV License Type A, B* Clean Air Engineering 7936 Conner Rd, Powell, TN 37849 800.208.6162 or 865.938.7555 Fax 865.938.7569 www.cleanair.com / khennon@cleanair.com Contact: Kenneth (Ken) Hennon Cooling Tower Technologies Pty Ltd PO Box N157, Bexley North, NSW 2207 AUSTRALIA +61.2.9789.5900 / (F) +61.2.9789.5922 coolingtwrtech@bigpond.com Contact: Ronald Rayner

To be licensed as a CTI Cooling Tower Performance Test Agency, the agency must pass a rigorous screening process and demonstrate a high level of technical expertise. Additionally, it must have a sufÂ¿FLHQW QXPEHU RI WHVW LQVWUXPHQWV DOO PHHWLQJ ULJLG UHTXLUHPHQWV IRU accuracy and calibration. Once licensed, the Test Agencies for both thermal and drift testing must operate in full compliance with the provisions of the CTI License Agreements and Testing Manuals which were developed by a panel RI WHVWLQJ H[SHUWV VSHFLÂ¿FDOO\ IRU WKLV SURJUDP ,QFOXGHG LQ WKHVH UHTXLUHPHQWV DUH VWULFW JXLGHOLQHV UHJDUGLQJ FRQÃ€LFW RI LQWHUHVW WR insure CTI Tests are conducted in a fair, unbiased manner. Cooling tower owners and manufacturers are strongly encouraged to utilize the services of the licensed CTI Cooling Tower Performance Test Agencies. The currently licensed agencies are listed below.

Licensed CTI Drift 7HVWLQJ $JHQFLHV Clean Air Engineering 7936 Conner Rd, Powell, TN 37849 800.208.6162 or 865.938.7555 Fax 865.938.7569 www.cleanair.com / khennon@cleanair.com Contact: Kenneth (Ken) Hennon McHale & Associates, Inc. 4700 Coster Rd, Knoxville, TN 37912 856.588.2654 / (F) 865.934.4779 www.mchale.org / ctitesting@mchale.org Contact: Jared Medlen

Cooling Tower Test Associates, Inc. 15325 Melrose Dr., Stanley, KS 66221 913.681.0027 / (F) 913.681.0039 www.cttai.com / cttakc@aol.com Contact: Thomas E. (Tom) Weast McHale & Associates, Inc. 4700 Coster Rd, Knoxville, TN 37912 856.588.2654 / (F) 865.934.4779 www.mchale.org / ctitesting@mchale.org Contact: Jared Medlen * 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.

CTI Journal, Vol. 37, No. 2

Cooling Technology Institute Sound Testing Cooling towers are used extensively wherever water is used as a cooling medium or proFHVV Ã€XLG UDQJLQJ IURP +9$& WR D QDWXUDO GUDIW FRROLQJ WRZHU RQ D SRZHU SODQW 6RXQG emanating from a cooling tower is a factor in the surrounding environment and limits on WKRVH VRXQG OHYHOV DQG TXDOLW\ DUH IUHTXHQWO\ VSHFLÂ¿HG DQG GLFWDWHG LQ SURMHFW VSHFLÂ¿FDWLRQV 7KH SURMHFW VSHFLÂ¿FDWLRQV DUH H[SHFWHG WR FRQIRUP WR ORFDO EXLOGLQJ FRGHV RU VDIHW\ standards. Consequently, it may be in the interest of the cooling tower purchaser to contract IRU Â¿HOG VRXQG WHVWLQJ SHU &7, $7& LQ RUGHU WR LQVXUH FRPSOLDQFH ZLWK VSHFLÂ¿FDWLRQ requirements associated with cooling tower sound.

Licensed CTI SoundTesting Agencies Clean Air Engineering 7936 Conner Rd Powell, TN 37849 800.208.6162 or 865.938.7555 Fax 865.938.7569 www.cleanair.com khennon@cleanair.com Contact: Kenneth (Ken) Hennon

McHale Performance 4700 Coster Rd Knoxville, TN 37912 865.588.2654 Fax 865.934.4779 www.mchale.org ctitesting@mchale.org Contact: Jared Medlen

&RROLQJ 7HFKQRORJ\ ,QVWLWXWH &HUWLÂ¿FDWLRQ 3URJUDP STD-201 for Thermal Performance As stated in its opening paragraph, CTI Standard 201... "sets forth a program whereby the Cooling Technology Institute will certify that all models of a line of water cooling towers offered for VDOH E\ D VSHFLÂ¿F 0DQXIDFWXUHU ZLOO SHUIRUP WKHUPDOO\ LQ DFFRUGDQFH ZLWK WKH 0DQXIDFWXUHU V SXEOLVKHG UDWLQJV %\ WKH SXUFKDVH RI D FHUWLÂ¿HG PRGHO WKH 8VHU KDV DVVXUDQFH WKDW WKH WRZHU ZLOO SHUIRUP DV VSHFLÂ¿HG SURYLGHG WKDW LWV FLUFXODWLQJ ZDWHU LV QR PRUH WKDQ DFFHSWDEO\ contaminated-and that its air supply is ample and unobstructed. Either that model, or one of its close design family members, will have been thoroughly tested by the single CTI-licensed testing DJHQF\ IRU &HUWLÂ¿FDWLRQ DQG IRXQG WR SHUIRUP DV FODLQHG E\ WKH 0DQXIDFWXUHU &7, &HUWLÂ¿FDWLRQ XQGHU 67' LV OLPLWHG WR WKHUPDO RSHUDWLQJ FRQGLWLRQV ZLWK HQWHULQJ ZHW bulb temperatures between 12.8oC and 32.2oC (55oF to 90o) D PD[LPXP SURFHVV Ã€XLG WHPSHUDWXUH RI oC (125oF), a cooling range of 2.2oC (4oF) or greater, and a cooling approach of 2.8oC (5oF) or greater. The manufacturer may set more restrictive limits if desired RU SXEOLVK OHVV UHVWULFWLYH OLPLWV LI WKH &7, OLPLWV DUH FOHDUO\ GHÂ¿QHG DQG QRWHG LQW KH SXEOLFDWLRQ Those Manufacturers who have not yet chosen to certify their product lines are invited to do so at the earliest opportunity. You can contact Virginia A. Manser, Cooling Technology Institute at 281.583.4087, or vmanser.cti.org or PO Box 681807, Houston, TX 77268 for further information

Licensed &7, 7KHUPDO &HUWLÂ¿FDWLRQ $JHQFLHV Agency Name Address

Contact Person Website / Email

Telephone/ Fax

Clean Air Engineering 7936 Conner Rd Powell, TN 37849

Kenneth (Ken) Hennon www.cleanair.com khennon@cleanair.com

800.208.6162 or 865.938.7555 (F) 865.938.7569

Cooling Tower Test Associates, Inc. 15325 Melrose Dr. Stanley, KS 66221

Thomas E. (Tom) Weast www.cttai.com cttakc@aol.com

913.681.0027 (F) 913.681.0039

McHale Performance 4700 Coster Rd Knoxville, TN 37912

Jared Medlen www.mchale.org ctitesting@mchale.org

865.588.2654 (F) 865.934.4779

CTI Journal, Vol. 37, No. 2

,QGH[ RI $GYHUWLVHUV

Aggreko Cooling Tower Services ....... 42-43 AHR Expo ................................................... 69 Amarillo Gear Company ........................ IBC AMSA, Inc. .................................................. 15 Bailsco Blades & Castings, Inc .................... 4 Bedford Reinforced Plastics ...................... 25 Brentwood Industries .................................. 3 ChemTreat, Inc............................................ 39 CTI Certified Towers ........................... 74-79 CTI License Testing Agencies ................... 80 CTI Sound Testing/Thermal Performance .. 81 CTI ToolKit ........................................... 82-83 Cooling Tower Resources .......................... 55 Denso ........................................................... 21 Dynamic Fabricators .................................. 45 EvapTech, Inc .............................................. 17 Gaiennie Lumber Company........................ 6 Hewitech ...................................................... 47 Hudson Products Corporation ................. 13 IMI Sensors ................................................. 41 Industrial Cooling Towers...................IFC, 2 Kipcon .......................................................... 53 KIMCO Cooling Towers ........................... 73 Midwest Cooling Towers ........................... 29 North Street Cooling Towers .................... 23 Paharpur ...................................................... 51 Paltech Cooling Towers & Equipments ... 61 PowerGen .................................................... 63 Research Cottrell Cooling ......................... 59 Rexnord Industries ..................................... 27 C.E. Shepherd Company, LP ....................... 7 Simpson Strong-Tie.................................... 67 Solid State Technologies LLC.................... 57 Spraying Services, Inc. ............................... 33 SPX Cooling Technologies ....................OBC Strongwell .................................................... 11 Tower Performance, Inc....................... 35, 84 Turbo Machinery ........................................ 71 Walchem (Iwaki America) ........................ 65

CTI Journal, Vol. 37, No. 2