Legionnaires’ disease is caused by Legionella bacteria and it is a potentially deadly form of pneumonia. It is usually contracted by inhaling very small, airborne droplets containing viable Legionella bacteria. Even if every one of us is susceptible to infection, with residents and patients likely to be exceptionally vulnerable, water systems in care homes require special consideration.
Even if Legionella bacteria are very common in natural water bodies, Legionella outbreaks usually happen from exposure to the bacteria growing in purpose-built water systems where water is kept at temperatures that encourage growth. This is usually between twenty and forty-five degrees Celsius. It is also a requirement the presence of nutrients that support bacterial growth like biofilms, sludge, scale, rust and organic matter. The bacteria are actually dormant below twenty degrees Celsius and don’t survive above sixty degrees.
It is very important to keep the cold water as close to your incoming cold mains supply temperature as possible. Also, the hot water needs to be stored at least at sixty degrees Celsius and distributed in a way that it reaches a temperature of fifty degrees Celsius within sixty seconds at the outlets.
Duty holders need to take all the necessary precautions to control the risk of exposure to Legionella by implementing:
- a Legionella risk assessment
- a written scheme of control
- records of all the tests, checks as well as inspections
- a schematic diagram of the cold and hot water system
Cases of hospital-acquired Legionnaires’ disease worldwide have been on the rise in general, with recent research telling us that the deadly bug is present in about twelve to eighty-five per cent of all water systems in hospitals and healthcare premises. Studies show that almost twenty per cent of the cases are associated with long-term care home facilities and about fifteen per cent with hospital premises.
Legionnaires’ disease can be life-threatening if it’s not treated immediately. This is particularly important in care home facilities and healthcare institutions where mortality rates can be at times as high as forty per cent due to the vulnerability of patients and residents. These facilities need to be aware of the risks and where these come from, and must aim to reduce risk factors to virtually zero. In order to achieve this, care homes and other healthcare facilities can benefit from running a professional legionnaires disease risk assessment to identify potential hazards.
What shall I do about Legionella?
Under the Health and Safety at Work Act, it is your duty to contemplate the risks from Legionella that can affect individuals in your care. The Control of Substances Hazardous to Health Regulations states that you need to assess the risks to all patients and workers from bacteria like Legionella and ultimately take all the necessary precautions.
How to control the risk
Design: the system needs to be designed in such a way that it will avoid the conditions that can favour Legionella growth:
- guaranteeing that pipework is as short as possible
- guaranteeing proper insulation of tanks and pipes
- utilising materials that won’t encourage Legionella growth
- fitting storage tanks with lids etc, in order to protect against contamination
Operation and maintenance: make sure your system is operated to eliminate potential growths of Legionella. One way of doing so is storing hot water above sixty degrees Celsius and distribute it at more than fifty degrees. Water systems must be regularly inspected by a qualified expert and the risk assessment needs to be reviewed periodically.
If you do not require hot water for other reasons, for instance for the laundry, you can consider utilising alternative control methods. This will avoid the need for high water temperatures, since this carries a risk of scalding.
Alternatives to this include chlorine dioxide, ionisation, ozone treatment, regular thermal disinfection of the system or UV light. These will need adequate installation, maintenance as well as monitoring. It is highly advisable to seek professional guidance when considering such alternative treatment systems.