This morning I looked into Hot Water temperatures for Mike, and I decided that as I’d done most of the work, it would make a nice little blog item. Some of the information is related to social care, and the rest related to water calorifiers.
Related to Social Care
Hot water should be maintained above 50 oC, or 60 oC to control legionella bacteria. 50 oC seems to be the benchmark, with 60 oC being preferable, however, water at the source (taps, bathtubs etc) shouldn’t be delivered at >44 oC to prevent a risk of scalding.
Below is guidance to the maximum hot water temperatures for a range of applications.
|
Application |
Maximum temperature |
|
Bidet |
38 oC |
|
Shower |
41 oC |
|
Washbasin |
41 oC |
|
Bath |
44 oC |
Where vulnerable people are at risk from full body immersion the HSE recommends that water temperatures do not exceed 44 oC
The Social Care Sector is of the opinion that inspectors need not take enforcement action requiring different water temperatures, for different applications. Enforcement action should only be considered where there is a risk to vulnerable people of whole body immersion in water exceeding 44oC.
Related to water calorifiers
Hot water calorifier temperatures must be maintained at 60°C or above throughout the entire vessel. Sometimes legionella bacteria proliferate in the lower section of a calorifier (i.e. below the heating elements) where the water can be less than 30°C even if water at the top of the unit is > 60°C. In this case the installation of a shunt pump is recommended. The Secondary flow temperature from the calorifier must exceed 60°C and the secondary return must exceed 50°C (if applicable) while all associated hot water outlet temperatures must be at least 50°C. However, there are some cases where this outlet temperature is not allowed such as hospitals and elderly care homes due to scalding. As a result, these premises must install thermostatic mixer valves and these should be adjusted to achieve an outlet temperature of 43°C. Cold water outlet temperatures must never exceed 20°C.
As a point of interest, legionella can not survive for long periods above 50°C and most will die within 2 minutes at 60°C.