Ensuring the health and safety of residents and staff in a care home is a major responsibility. Not only are there scalding risks from hot water and surfaces, but also a very real threat of bacterial infection from legionella.

Thermostatic mixing valves (TMVs) are an essential part of care home water management that helps mitigate the risks from hot water. However, they come with their own set of problems with regard to legionella control that all facilities managers need to know about.

Why are TMVs so essential?

Care homes are typically responsible for looking after the elderly, children or the disabled, who often need practical help to live comfortable lives. This makes them more susceptible to health and safety risks, such as scalding.

Hot bath water is said to be responsible for most fatalities and injuries in the home, and around three-quarters of deaths occur in the over-65 age group, while more than three-quarters of serious scalds are suffered by children under five. These figures are likely higher in these age groups because young children and older people have thinner skin, so are especially vulnerable to scalding more quickly and suffering deeper burns from hot water.

By blending hot and cold water intake to produce a constant, safe water temperature (even if incoming water pressure or rates change), TMVs are now widely considered the primary method of reducing the risk of scalding from hot water in baths and showers. They are, therefore, essential in a care home environment to prevent any risk of harm to residents or staff.

Legionella control and Legionnaires’ disease risk

Unfortunately, the very nature of a TMV maintaining a safe, warm water temperature can lead to a greater risk of legionella bacteria growth in the water system.

Although Legionella bacteria can be found in most water sources, the higher temperatures of a man-made water system (which often reach the legionella-friendly range of 20° C to 45° C) can encourage growth of the bacteria. This can, in turn, lead to an increased risk for the users of that water system of contracting a potentially fatal form of pneumonia known as Legionnaires’ disease – a risk which is said to heighten with age.

Control of legionella bacteria is therefore an important concern when using TMVs to reduce water temperature, as the system needs to keep water in the tanks and pipework either below 20° C or above 50° C to ensure any bacteria stays dormant.

Making sure your TMV is safe

It is essential that TMVs must be fitted and regularly maintained by experts to ensure they both improve safety for hot water concerns and mitigate the risk of legionella bacterial growth.

Guidance from the HSE has made it mandatory for TMVs in care homes to be inspected – and serviced where necessary – at least once a year (depending on the system, as some systems might need a twice-annual check). Not only should this process include cleaning, descaling and disinfecting to tackle any build-up of dirt that could lead to additional bacterial growth, but thorough water temperature testing should also be carried out.

A TMV service should include:

• Checking the TMV to see if the valves operate as they should and can be set between 39° and 43° C – the recommended temperature range for hot water outlets where a TMV is installed.
• A quote for a replacement if the TMV does not pass this test.
• Isolating and stripping the TMV down to clean, descale and disinfect the strainers, once the TMV servicing safety check has been completed.

It is important to note that TMVs also need to be located as close as possible to the outlets to make sure water in the pipework is above 50° C. If it has been installed too close to a water heater (to save money by blending the whole water supply rather than feeding just a couple of outlets), it will mean the mixing of hot and cold water occurs earlier and thus the water temperature in the pipework will encourage rather than control legionella bacteria – putting residents, staff and visitors at risk.

If you’re concerned about water hygiene and temperature safety in your care home, and want to know more about how to prevent risks to your residents and staff, download our comprehensive Guide to Water Safety in Care Homes today.