Legionnaires' Disease is spread by legionella bacteria and can be fatal. The legionella bacteria can contaminate and grow in air-conditioning units and people working in or living near buildings can contract legionnaires disease (see more information, below)
There have been a number of outbreaks in Victoria over the past few years, and the government has introduced legislation (see below) to reduce the risk of contamination. Health and safety reps have a role to play to ensure that the requirements are being complied with.
Action Plan for the Health and Safety Representative
As with all workplace hazards, the hazard should be dealt with in this way:
- Identification of the hazard
- Assessment of the risk
- Elimination or reduction of the risk
- Review and evaluation of any control strategies.
STEP ONE – Identification of the hazard
- Talk to your members about Legionnaires Disease and its symptoms. Ask them whether they are experiencing problems with the air-conditioning. Consider doing a questionnaire (a sample one can be downloaded from this site).
- Check that your employer has a list of all the cooling towers on the site, and proof that they have been registered. Check also that there is an RMP and check the records (for inspection, biocide dosing and maintenance)
Inspect the air-conditioning maintenance records to discover when the system was last inspected and cleaned.
- Ask that the employer measures workplace temperature and humidity.
STEP TWO – Assessment of the risk
In assessing the severity of the problem, consider the following:
- Temperature: The acceptable zone of thermal comfort for most kinds of work lies between 16° - 26°C. (18° - 24°C for offices, shops, showrooms, canteens, dining rooms - depending on the outside temperature; as low as 13°C for heavy work in factories). Humidity 40-50%.
- Air Movement: 0.15-0.25 metres per second.
- Minimum Fresh Air Rate: Offices require 10 litres of fresh air per person per second (computer rooms 25 litres, cafeterias 15 litres).
- Oxygen Content: 18-21%.
- Carbon Dioxide: Limit of 1,000 parts per million.
- Microrganism Level: Less than 1,000 colony-forming units per cubic metre. (ie less than 10%)
- Inspection of Air Intakes and Exhaust Outlets: At least annually.
- Cleaning and Replacement of Air Filters: In accordance with manufacturer's specifications.
- Inspection of Humidifiers and Evaporative Coolers: At least monthly.
- Inspection of Ductwork: Annually.
- Inspection & testing of Cooling Tower/s: At least monthly.
- Cleaning of Cooling Tower: Every three to six months or according to the Risk Management Plan .
Warning: If any of your members have flu-like symptoms and you discover the air-conditioning system has not been cleaned for some time, call your Union and the Department of Health and Human Services on 1300 253 942 (free call in Victoria except with mobile phones) immediately. Contact details for regional offices on this page.
STEP THREE – Elimination/reduction of the risk
Reducing the risks associated with the air-conditioning system should involve:
- Providing all information you have gathered under Steps One and Two to the employer representative and your co-workers.
- In consultation with the union delegate, arranging a meeting with management to discuss the problems you have identified and agree on a control plan.
- If you cannot agree, then reporting back to the members. The next step may be to serve a PIN or raise the issue at the Health and Safety Committee. You may also contact a WorkSafe inspector for advice.
- If you have reached agreement, setting a time frame for each action item to occur.
STEP FOUR - Review
The fourth step is to review the success of the actions taken to fix the air-conditioning problems. This may involve discussions with management and members and a follow up questionnaire survey might be helpful. Consider negotiating an Air-conditioning Policy with your employer. Contact your union to see if they have a model policy.
The employer has a duty under the Victorian Occupational Health and Safety Act (2004) to provide and maintain for employees, as far as practicable, a working environment that is safe and without risks to health. This includes providing safe plane, a safe system of work, information, training, supervision, and where appropriate personal protective equipment. The employer also has the duty to monitor conditions at the workplace, and to monitor the health and safety of employees.
There are a range of Victorian regulations that specifically seeks to limit the occurrence of Legionnaire's Disease. This follows the occurrence of a large number of cases of legionnaires disease due to contaminated air-conditioning units. On 1 January 2010 the Public Health and Wellbeing Regulations 2009 (under the Public Health and Wellbeing Act - PHWA) came into effect. Included in these regulations are important changes concerning the regulation of cooling towers and warm water systems for the control of Legionella. In addition to the PHWA, there are the Plumbing Regulations 2008 [pdf]. Download this factsheet [pdf] on the Public Health and Wellbeing Regulations. It also includes some information on requirements under the Plumbing regulations.
All land owners to register all cooling tower systems with the Building Control Commission, and renew these registrations annually. Landowners must also take all reasonable steps to ensure that a risk management plan (RMP) is prepared and implemented for each cooling tower system on their land. This may be satisfied through commercial lease agreements with tenants/business owner/operators. RMPs must specify how five critical risk factors, including stagnant water and nutrient growth, will be managed. The RMP must be audited annually by a person accredited by the Department of Human Services.
People who own, manage or control cooling tower systems ('business owners') have maintenance and cleaning and record-keeping requirements. They must also carry out monthly water tests for hetertrophic colony counts (HCC) - levels of 100,000 or more are unacceptable.
What is Legionnaires Disease?
Legionnaires is a type of pneumonia (an acute infection of the lungs). The early signs are like having the flu: headaches, fever, chills, muscle aches and a dry cough. This is usually followed by shortness of breath. Sometimes sufferers may have diarrhoea, mental confusion and kidney failure. It can be fatal.
How is Legionnaires Disease caught?
Legionella bacteria are widespread in the environment and commonly found in natural water courses and soils and so can contaminate and grow in other water systems such as: air conditioning cooling towers, evaporative condensers, and hot and cold water services. Other potential sources include: potting mix, humidifiers, spa and whirlpool baths, showers and ornamental fountains.
People can catch the disease by breathing in very fine droplets (aerosols) of contaminated water that contain the bacteria. Workers in the building with the contaminated airconditioning system are at risk, as well as the people who live in the area. The disease cannot be passed from one person to another, nor caught by drinking Legionella contaminated water.
Who is at risk and how much of a risk is it?
Large numbers of workers are at risk:
- workers in air-conditioned buildings, including office staff, cleaning staff and security staff
- staff in air-conditioned venues such as hotels, museums, aquariums, gaming venues
- building maintenance workers (such as mechanics, electricians, etc)
- air-conditioning company workers
Codes of Practice and other information:
Victorian Government Department of Health and Human Services Environmental Health has information on Legionella, including this page.
AS 1668 series: on air-conditioning and ventilation; and AS3666 series: on Air-handling and water systems of buildings - Microbial control. Covers the Design, installation, commissioning, operation and maintenance of these systems.
- Code of Practice from Western Australia - Prevention and Control of Legionnaires Disease (2014)
- NSW Health Code of Practice for the Control of Legionnaire's Disease, dealing with hazard minimisation, safe work practices and advice.
- Officewise – A guide to health and safety in the office, and also available free of charge from WorkSafe Victoria.
- From the UK's occupational health and safety regulator, the HSE has lots nof resources on the topic:
- a webpage on Legionella and Legionnaire's Disease,
- resources such as: Management of the risks from legionella in cooling towers and evaporative condensers
- Technical guidance
- The HSE also has an Approved Code of Practice L8: Legionnaires' Disease - The control of legionella bacteria in water systems, which sets out an effective approach to control.
The information is revised and updated regularly.
- FAQ: Temperature and Humidity in Offices
Last amended March 2016