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LEGIONNAIRES DISEASE AND COOLING TOWERS FREQUENTLY ASKED QUESTIONS

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LEGIONNAIRES DISEASE AND COOLING TOWERS FREQUENTLY ASKED QUESTIONS Powered By Docstoc
					                                                                                                                     Breese Parade
                                                                 Fact                                          FORSTER NSW 2428
                                                                Sheet                                                   PO Box 450
                                                                                                               FORSTER NSW 2428
                                                                 E-PH                                      Phone 02 6591 7222
                                                                  003                                        Fax 02 6591 7200
                                                                                            Email council@greatlakes.nsw.gov.au



              LEGIONNAIRES DISEASE AND COOLING TOWERS
                   FREQUENTLY ASKED QUESTIONS
What caused Legionnaires’ disease?

Legionelia bacteria of which there are over 20 species cause this disease. Legionelia Pneumophilla is
the most common.

Where do you find Legionelia bacteria?

Legionelia is a bacteria associated with water and is widespread in the environment. It has been found
in lakes, rivers, creeks, hot springs and other bodies of water.

It can also be found in man made systems such as cooling towers associated with air conditioning and
industrial processes, as well as in reticulated warm water systems, where the temperature of the water
is kept between 200C and 450C. These man-made systems can provide conditions, which allow the
bacteria to breed to large numbers.

Why are cooling towers a problem?

During the normal operation of a cooling tower, aerosols are formed which will be carried into the
environment through the tower exhaust. If Legionelia is present in tower water breathing the aerosols
can result in infection. Poorly maintained cooling towers have been implicated in outbreaks of
Legionnaires disease in Australia.

How do you get Legionnaires’ disease?

The infection is acquired through breathing in aerosols (very fine droplets of water) that contain the
bacteria. It is not passed from person to person nor is it acquired through drinking contaminated water.

How can Legionnaires disease be prevented?

To minimise the risk and hazards posed by the bacteria in such systems the following steps can be
undertaken:

•      Keeping water-handling systems visually clean – that is, without sludge, slime, algae, fungi, rust,
       scale, dust and dirt, or any other foreign material.
•      Choosing a system, which has been designed and constructed of materials that are easy to clean
       and do not enhance the growth of legionelia.
•      Operating the regulated system as required by AS3666.2 1995Air handling and Water Systems of
       Building, Microbial Control, Operation and Maintenance.
•      Equipping the cooling system with a process designed to control microbial growth. This process:-
-      Must be in operation at all times,
-      Must be certified by a competent person annually as being an effective process of disinfection
Mission Statement – Great Lakes – Great Service – Great Lifestyle – Committed to the provision of infrastructure and services which
conserve the natural environment and achieve a quality lifestyle for residents and visitors
G:\ONSITE\Web Page\Web page fact sheets\E-PH003-Legionnaires Disease and Cooling Towers Frequently Asked Questions.doc Created on 1/09/2009
10:51:00 AM
-      Must be sufficiently affective so that no sample taken from the system subjected to a test in
       accordance with the relevant Australian Standard has a level of Legionnella or more than a
       colony – forming units per millilitre, OR a heterotrophic plate count of more than 100,000 colony
       forming units per millilitre.

Where these levels are exceeded remedial action must be taken immediately by a competent person.
Reducing the generation and spread of aerosols to a minimum level. Cooling towers must have well
designed drift eliminators.

What are my responsibilities as a building owner, occupier or manager?

The maintenance and cleaning of cooling towers is the responsibility of the owner, occupier and/or
building manager. The proper maintenance and cleaning of systems is a legal requirement under the
Public Health Act 1991 and Public Health Regulation 2000.

Who can perform this maintenance?

It is strongly recommended that a specialist water treatment company be engaged to conduct the
cleaning, chemical treatment and analyses, and to arrange bacteriological monitoring. These
companies are aware of the requirements of the legislation.

Operating and maintenance manuals

All cooling systems are required to be equipped with an operating and maintenance manual. These
manuals are to be kept in a readily accessible position and available 24 hours a day, in the operation
area where the system is installed.

Do I have to keep records?

Yes – all records of bacteriological monitoring, water treatment, testing, cleaning and disinfection must
be maintained in an orderly manner and kept on site for a minimum of seven years. Failure to comply
may attract a maximum penalty of $1100.

Specific Obligations

The said Act and Regulation also make specific references to operating certain systems only under
certain conditions. These include but are not limited to:-

Cooling Towers (Water Cooling Systems)

•      Only operate the system if it is equipped with a process of designed to disinfection control
       microbial growth and only if that process is in operation
•      All cooling tower systems are to be inspected monthly
•      All maintenance work found to be necessary as a result of the inspection is to be carried out
       within a reasonable time prior to the next inspection
•      All systems are to be cleaned at three monthly intervals

Warm water systems

•      All drainage and liquid discharges are to be directed into a waste water system
•      Systems are to be cleaned if any inspection revels this to be necessary
•      Whenever maintenance work is carried out it is necessary to ensure that at all times while the
       system is operating, it is capable of delivering water at each hot water outlet at a temperature of
       not less than 600C and at each warm water outlet at a temperature of not more than 60OC.



Mission Statement – Great Lakes – Great Service – Great Lifestyle – Committed to the provision of infrastructure and services which
conserve the natural environment and achieve a quality lifestyle for residents and visitors
G:\ONSITE\Web Page\Web page fact sheets\E-PH003-Legionnaires Disease and Cooling Towers Frequently Asked Questions.doc Created on 1/09/2009
10:51:00 AM
Air Handling Systems

•      Inspect and maintain outside air intakes, exhaust outlets, line strainers, values, sparge pipes,
       spray nozzles, tanks trays and discharge devices on a monthly basis
•      Ensure that any air handling system or component of an air handling system that is shut down on
       a seasonal basis is inspected immediately after being shut down and any maintenance work
       found to be necessary as a result of the inspection is carried out within a reasonable time
•      Air handling systems that have terminal unit components, ductwork in the vicinity of moisture
       producing equipment and at access points in the vicinity of fire dampers, condensate drains,
       tundishes, traps, coils, trays and sumps are all required to be inspected annually and cleaned if
       the inspection discloses this to be necessary.

Council’s Obligations

Council is required to keep a register of water cooling and warm water systems installed on premises.
It is your responsibility to ensure that Council is provided with the necessary information. Maximum
penalty for failing to provide council with the required information is $1100.

Relevant References

•    Public Health Act 1991
•    Public Health (Microbial Control) Regulation 2000
•    Australian Standard AS 3666 Air handling and water systems of buildings – Microbial Control Part
     1: Design, installation and commissioning Part 2 and Part 3
•    NSW Health Department – NSW Code of Practice for the Control of Legionnaires Disease, June
     2004 – downloaded at www.health.nsw.gov.au/public-health/ehb/gener al/microbial/microbial.html




Mission Statement – Great Lakes – Great Service – Great Lifestyle – Committed to the provision of infrastructure and services which
conserve the natural environment and achieve a quality lifestyle for residents and visitors
G:\ONSITE\Web Page\Web page fact sheets\E-PH003-Legionnaires Disease and Cooling Towers Frequently Asked Questions.doc Created on 1/09/2009
10:51:00 AM

				
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