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Hazardous Substances - COSHH Regulations - Legionnaires Disease

Control of Substances Hazardous to Health (COSHH) Regulations 2002
Notification of Cooling Towers and Evaporative Condensers Regulations 1992

Legionnaires’ disease is a potentially fatal pneumonia caused by legionella bacteria.

Infection is caused by breathing in small droplets of water contaminated by the bacteria. The disease cannot be passed from one person to another. 

Everyone is potentially susceptible to infection but some people are at higher risk, eg those over 45 years of age, smokers and heavy drinkers, those suffering from chronic respiratory or kidney disease, and people whose immune system is impaired.

What conditions cause Legionnaires?

The legionella bacteria thrives in water systems at temperatures between 20°C and 45°C when nutrients such as rust, sludge, scale, algae and other bacteria are present.  It is spread via water droplets, generally through showers, spa baths or evaporating condensers. 

The bacteria is killed by high temperatures and water treatments.  Keeping the water system clean and free of foreign bodies also reduces the risk.

You need to find out if your water systems (including the equipment associated with the system such as pumps, heat exchangers, showers etc) are likely to create a risk.
Ask yourself the following: 

Are conditions right for the bacteria to multiply, for example is the water temperature between 20oC and 45oC?   If it rises above 60 oC anywhere in the system before being dispensed, the risk is reduced but water at above 48 oC will scald.

Are there areas where stagnant water occurs (deadlegs), eg pipes to a washing machine that is no longer used?

Are there infrequently used outlets, for example showers and taps?

Is there debris in the system, such as rust, sludge or scale (often a problem in old metal cisterns) that could provide food for growing legionella?

Are there thermostatic mixing valves that set a favourable outlet temperature for legionella growth?

Are any of your employees, residents or visitors vulnerable to infection, eg older people or those already ill?

Answering “yes” to any of these questions indicate that there is a risk.

As the design, maintenance and operation of the system are crucial in controlling the growth of legionella, any action you take is likely to include the following:

ensuring water cannot stagnate anywhere in the system, for example remove redundant pipework, run taps and showers in unoccupied rooms at least once a week;

keeping water cisterns covered, insulated, clean and free of debris;

insulating pipework.

 You may take these steps in any event to reduce the ongoing risk.

If you decide that the risks are insignificant, your assessment is complete. You need take no further action other than to review the assessment periodically in case anything changes in your system. If you decide that there may be a risk you should conduct a full legionnaires risk assessment and review your control measures.

What should you do if you identify significant risks?

If you identify a significant risk you will need to conduct a formal legionnaires risk assessment and i
ntroduce proper controls, which could include disinfecting the system with the help of a professional.

Reporting the Disease

If you have a case of legionellosis in an employee who has worked on cooling towers or hot water systems that are likely to be contaminated with legionella, you have to report this under the Reporting of Injuries, Diseases and Dangerous Occurrences Regulations.

Cooling Towers and Evaporative Condensers

If you have a cooling tower or evaporative condenser on site you must, under the Notification of Cooling Towers and Evaporative Condensers Regulations 1992 , notify the local authority in writing with details of where it is located. You must also tell them when/if such devices are no longer in use.

Notification forms are available from your local environmental health department.

Contact us to help you conduct a full risk assessment of your premises

Additional Reading:

Hazardous Substances
Hazard Symbols
Cooling Towers & Evaporising Condensers
Private Water Supplies

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