According to an article posted in Plant Engineering, the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has worked with industry, scientific, and medical communities to develop a more comprehensive approach to reducing the risks associated with Legionella infection.
The new standard, ASHRAE Standard 188P: Prevention of Legionellosis Associated with Building Water Systems is currently under public review and still in “preliminary” format. The collaboration of experts from various industries and scientific communities has allowed for more information about growth, infection methods, and remedial steps. This in turn gives the HVAC industry a better understanding on how to adjust their processes.
ASHRAE 188P does not point to exact HVAC processes need to be changed; instead, it lists typical areas that have the potential for contamination as well as appropriate remediation steps. Locations of potential contamination include:
- Cooling towers
- Evaporative condensers
- Domestic hot water systems
- Humidifier systems
- Decorative water fountains
- Spas and whirlpools
- Dental water lines
- Stagnant water systems
Although Legionella can affect both hot and cold water systems, the proposed standard focuses more on hot water as it is affected more frequently (80%) compared to cold water’s 20%. This standard recommends that water be stored and distributed at 140°F, and that it is no cooler than 122°F at the point of use. “Super Heat and Flush” is also a key element in remediation, but cause damage to the system due to the high temperatures (160-170°F); it can also cause scalding.
The ASHRAE standard also outlines plans for remediation efforts including water system treatment management, hazard analysis, and critical control points. It also points out a few other disinfection methods that could be used. All have their pros and cons, but it is hoped that when used in conjunction with other precautionary measures, Legionella infection will be prevented
For more information on this story, please visit http://www.plantengineering.com/single-article/ashrae-188p-and-the-effects-on-steam-process/e2eb936b8bf11d5b507b21a8b064266e.html