PREVENTION OF LEGIONNAIRES’ DISEASE
The following text is based on exerpts from the new ASHRAE 188 standards.
HACCP : Hazard analysis and critical control points. A risk assesment program to protect people from harming people.
HACCP : Principlles of this plan in the written documentation should be developed
1) Water cooled systems using water cooled towers or similar type equipment should have both a physical and chemical cleaning at least once during its operating season. Preferably, the systems should be cleaned chemically and physically twice a year. Units that operate 12 months a year should be cleaned twice a year. It is desirable to do the first cleaning before unit is put into operation.
2) The cleaning of these water cooled units should consist of removal of dirt and organic growths (algae and slime) by physical and chemical means. The use of adequate detergents and disinfectants should be applied to the cooling tower and circulated for approximately 24 hours before being drained, flushed and refilled.
3) Bardon’s recommends the use of one of ther specialized blends of dispersants and penetrants that break down and remove slime, algae, dirt, organic matter, nutrients for bacteria, along with scale and corrosion.
4) For a remidiation process an Industrial Grade Sodium Hypochlorite will be used. This product has been shown in laboratory tests to kill known Legionnaires’ Disease bacterium at levels of 10 PPM or higher active materials.
5) After cleaning and testing by a certified laboratory the systems should be treated with a biocide program. Bacteria tests are then taken monthly to insure bacteria counts are down and the biocide program is effective.
6) Fan coil units, air handlers and other places that collect air-borne matter should be cleaned annually.
7) It should be pointed out that while the above maintenance has not yet been established as a standard for the prevention of Legionnaires’ Disease, it represents a snapshot of a program that minimizes the potential growth of Legionella.
8) Bardon’s personal, are available to establish building surveys, hazard analysis , risk assestment programs, test procedures, and supervisory service to insure the success of this program