CTI Bibliography of Technical Papers - Legionella

Revised 2017

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Order NumberTitleAuthorDate
Design Cooling Tower System to Reduce the Risks of Transmitting Legionnaires’ Disease Mario Bellavance, Blue Heron Cooling Tower Inc. 2017
Abstract: ASHRAE Standard 188-2015 established minimum legionellosis requirements for building water systems. When a building survey determines that it has an open and closed circuit cooling tower or evaporative condenser then hazardous conditions such as no-flow and low-flow portions of the piping, equipment siting that inhibits access to the equipment for the required maintenance, vapor and water droplets discharging into occupied spaces and so on should be addressed, Considering that system design is often ignored while implementing a management program to reduce the risks of transmitting Legionella, the speaker will present case stories for discussion.
Current Microbiological Control Techniques in Cooling Tower Water Systems May Not be Controlling Legionella Bacteria Paul R. Puckorius, Puckorius & Associates, Inc. 2017
Abstract: Due to the recent out breaks of Legionnaires Disease such as in New York City it was decided to investigate how and why this could have occurred by cooling tower water systems that were chemically treated. Cooling tower water systems are normally treated by the traditional method of applying microbiocides and often monitored with traditional total bacteria monitoring methods. This has prompted a detailed review of the traditional microbiological treatment applications in numerous cooling tower water systems in all types of industry systems to see if there are any reasons that Legionella Bacteria could still be present. The review showed that traditional microbiological control techniques might be incorrect and misleading in controlling Legionella Bacteria due to the way the microbiocides are being applied. Examples are provided that identify what was found in numerous cooling tower water systems. They show some very interesting and revealing information in that the biocides are applied based on the use of microbiological monitoring such as with “dip” slides or ATP tests which may not control Legionella Bacteria. It also shows that the traditional monitoring of total bacteria that has indicated good microbiological control as reported by culture or “dip” slides maybe incorrect and that the guide lines by CTI and others that ten to the 4th or less is good microbiological control is actually incorrect. This study and the results suggest new application and monitoring methods should be adopted.
ASHRAE Legionella Standard 188: Evidence-Based Interpretation And Application Janet E. Stout, Ph. D, Special Pathogens Laboratory and University of Pittsburgh 2016
Abstract: 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 include development of a Water Management Plan for building water systems and devices including open and closed circuit cooling towers and evaporative condensers. ASHRAE Standard 188 will be shared to help inform these decisions so that they are evidence-based and defensible.
Upgrading Existing Cooling Tower's Maintenance Programs to Prevent Legionella Transmission Mario Bellavance, Blue Heron Cooling Tower Inc. 2015
Abstract: In the summer of 2012, the city of Quebec experienced a large outbreak of legionnaire’s disease. Nearly 200 people were infected; 14 of them died. A public inquiry reported after: “The measures introduced were not effective enough...” As a consequence, Quebec Government adopted a Regulation for cooling towers maintenance. The speaker will present major points from his two (2) years of experience in the upgrading of Cooling Towers Maintenance Program to prevent Legionella transmission.
Can Total Bacteria Measurement Be Used To Predict Legionella Presence? Janet E. Stout and Scott Duda, Special Pathogens Laboratory 2015
Abstract: Microbiological growth in cooling water systems presents several challenges for water treatment providers. Culture methods such as heterotrophic plate count (HPC) and "dipslides" provide valuable information related to general microbiological water quality but require several days to produce results. Alternative methods using adenosine triphosphate (ATP) measurement provide faster results and have been applied when rapid water quality assessment is necessary. Our evaluation reviewed potential applications for ATP analysis in cooling water systems. We also assessed whether total bacteria measurement using culture methods or ATP analysis can predict the Legionella presence/absence using both experimental data and data collected from field observations.
An Update on ASHRAE Standard 188P: Prevention of Legionellosis Associated with Building Systems William F McCoy, Phigenics and Paul Lindahl, Jr., SPX Cooling Technologies 2012
Abstract: The American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) has developed a proposed Standard Practice that specifies what is required to prevent legionellosis associated with building water systems. The proposed Standard Practice was approved in July 2010 for public review publication. The first public, review was completed in November 2010; there were many supportive comments posted and also many excellent suggestions to improve the Standard. A revision was produced in response to comments received during the public review. The second public review opened June 10, 2011 and closed July 25. This paper gives perspectives in relation to CTI Standard 159, Legionellosis Related Practices for Evaporative Cooling Water Systems, which is in process and could be public by the time of the presentation of this paper.
Biocide Treatments for Controlling Amoeba Amplified Legionella in Cooling Towers Jana Rajan and Paul Schook, Dow Microbial Control 2012
Abstract: There is an expanding body of evidence that highly prevalent free-living amoebae increase both the numbers and virulence of water based, human-pathogenic, amoeba-resisting microorganisms such as Legionella. We have focused on controlling amoeba-amplified forms of Legionella by various biocide regimes commonly used in water treatment and provide proof for a hypothesis that explains the inability of conventional treatments in controlling these hardy and relevant forms. Our studies demonstrate a need to revisit current biocide dosing practices in order to meet the new guidelines for Legionella control in industrial water systems. This paper will discuss, with supporting data, some feasible alternatives that provide adequate control of amoeba-fed Legionella in cooling towers by employing a combination of US EPA approved organic biocides.
Efficacy of Non-chemical Devices In Controlling Legionella: Results From A Model Cooling System Janet E. Stout, Ph.D., Scott M. Duda, M.S. and Radisav D. Vidic, Ph.D., University of Pittsburgh 2011
Abstract: The objective of this investigation was to assess the ability of several classes of non-chemical water treatment devices (NCD’s) to control the growth of Legionella in a model cooling system. In addition, water samples from cooling towers treated with NCD’s were also tested. NCD devices did not prevent Legionella growth in the model cooling towers or in field tests. Building owners and engineers should test water samples for Legionella from cooling systems, especially if they are only treated with non-chemical devices.
A Systematic Review of Biocides Used in Cooling Towers for the Prevention and Control of Legionella ssp. Contamination Kelly Rangel, University of Texas Health and Science Center 2009
Abstract: The use of biocides is very important for controlling Legionella contamination in evaporative cooling systems. This study is a systematic review of research studies that evaluated the effectiveness of biocides in evaporative cooling systems for Legionella control.

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