| I appreciate the reminder on the danger of Legionella if we reduce water temperatures too much in our efforts to control the temperature at the faucet and also control energy. Brad Dow, C.E.O.E., Director of Properties, Mohonk Mountain House, Lake Mohonk, New Paltz, NY provided the following "tip" on the energy article in the February Newsletter:
"Ray, your comments in the energy use are correct. We should not be delivering 140-145 degree water at the tap. That said, it is important to note that water should be heated to 140 degrees to prevent Legionella growth. I would not want to have engineers lowering the temperature of their hot water tanks to an unsafe level if they don't have the ability to mix their finished potable water." Thanks, Brad.
I went to the archives and have an OSHA advisory from 12/1/2007 that further addresses this problem.
OSHA recommends the following preventive maintenance program:
Regularly maintain and clean cooling towers and evaporative condensers to prevent growth of LDB. This should include twice-yearly cleaning and periodic use of chlorine or other effective biocide.
Maintain domestic water heaters at 60 degrees C (140 degrees F) The water should be at 50 degrees C (122 degrees F) or higher at the faucet. This puts the property on a collision course with possible scald incidents. The Burn Foundation recommends 120 degrees F at the faucet. To meet this challenge, it is necessary to add another element to the preventive maintenance program. Continuing maintenance of the mixing valve to ensure the proper mix of hot and cold water when being used by an individual.
Avoid conditions that allow water to stagnate. Large water storage tanks exposed to sunlight can produce warm conditions favorable to high levels of LDB. Frequent flushing of unused water lines will help alleviate stagnation .
If it is suspected the water system is already contaminated, OSHA recommends special cleaning procedures and water treatment. In many cases, these procedures involve the use of chlorine-producing chemicals or high water temperatures. Seek professional assistance before attempting to clean a contaminated water system.
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A WATER TEMPERATURE CAUTION!