Thermostatic Mixing Valve service & Failsafe Testing

There is a risk of scalding where water comes out of taps at temperatures above 44°C. In certain facilities eg care homes, this is especially so for whole-body immersion in baths and showers of vulnerable patients, the very young, elderly people, and people with disabilities or those with sensory loss who may not be able to recognise high temperatures and respond quickly.

You have a legal duty to assess the risk of scalding and to adopt appropriate measures to control it. Your approach will depend on the needs and capabilities of patients or residents. 

For most people, the scalding risk is minimal where water is delivered up to 50°C at hand-wash basins and a hot water warning notice may be sufficient.  However, where vulnerable people can get access to baths or showers and the scalding risk is considered significant, the fitting of thermostatic mixing valve (TMV) Type 3 is required to prevent water being discharged at more than 44°C (HSG274 Part 2).

All thermostatic mixing valves should be tested to ensure the failsafe function is operating within the HTM 04-01 D 08 guidelines. The frequency of this testing should be at least annually or more frequently if required. Should any valve fail then they should be replaced / repaired and the valve retested. (HTM 04-01, 2017)