Sunday, 26 June 2016: 1:30 PM-3:00 PM
Indoor Environment: Health, Comfort, Productivity
Chair:
Tim Keane, Legionella Risk Management Inc.
Technical Committee: 06.06 Service Water Heating Systems
CoSponsor: 03.06 Water Treatment
ASHRAE 188-2015 provides legionella risk management requirements for the design and operation of plumbing systems. ASHRAE Guideline 12, being updated, provides direction on how to accomplish them. Legionnaires' disease, a disease of plumbing systems, is frequently caused by issues related to plumbing system design. Misperceptions are all too common and many think it is an accident that can't be avoided. This seminar focuses on the design, construction and commissioning of building potable water systems. A discussion from three different perspectives, the key factors impacting Legionella growth in piping systems: velocity, turnover, temperature, materials and complexity of components is held.
1 Are Energy Efficiency and Legionella Risk Mitigation at Odds?
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Gary Klein, Gary Klein and Associates, Inc. |
The rules for plumbing design were codified shortly after World War II. Since then, flow rates and fill volumes of plumbing fixtures and appliances, have been reduced. However, the math for sizing pipe has not yet been revised to account for these reductions. This effect is very noticeable in hot water distribution systems, where lowering flow rates increases the time for hot water to arrive, resulting in much less energy savings than would have been expected. This presentation will discuss this and other unintended consequences of water use efficiency measures and provide practical means of mitigating the negative impacts.
2 The Role Materials Can Play in Legionella Risk Mitigation
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Jeff Ramey, United Technologies, Carrier Corporation |
Risk minimization strategies for biofilm and bacteria prevention need to include consideration of piping system materials. Research and real-world experience shows that piping material affects biofilm growth rates and chlorine consumption in water, while common disinfectants used to prevent bacterial growth have significant impacts on piping system integrity. Best-in-class materials should possess resistance to bacteria and biofilm growth, and to all forms of chlorine disinfection. Attendees will see evidence of why chlorinated polyvinyl chloride (CPVC) possesses both of these forms of resistance, and should be strongly considered by designers as part of their risk minimization strategy.
3 Lessons Learned from Failure Analysis
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Tim Keane, Legionella Risk Management Inc. |
Henry Ford said “The only real mistake is the one from which we learn nothing.” Legionnaires' disease outbreaks are worst-case failures typically resulting in multiple illnesses and deaths. The subsequent costs associated with investigation, remediation, control and frequently litigation can be from the hundreds of thousands to hundreds of millions of dollars. This presentation will provide lessons learned from engineering analysis of Legionnaires' disease outbreaks investigations in varying building types across the US.