What is a thermostatic mixing valve?
A thermostatic mixing valve (TMV) is an anti-scald device which blends hot and cold water to deliver that water at a preset, constant and safe temperature to the user. The TMV may be a separate mixing valve which sits between the supply pipes and a mixer tap or hot water tap, or it may even be part of a mixer tap itself. The TMV can be a life saver since in the UK alone there are as many as 20 deaths per year and almost 600 serious injuries from bath-time scalding. TMVs are therefore a very welcome and sometimes essential piece of bathroom equipment. The Scottish Position On 1st May 2006 the Scottish Building Regulations were published and they are very specific. They state that, in order to prevent scalding, the temperature of hot water discharged into any bath or bidet (in a new domestic property) should not exceed 48C. Only baths or bidets are covered in the regulations and there is no requirement to control maximum discharge temperature to a domestic washbasin or shower or kitchen
The definition is a relatively simple one: it is a valve with a hot and cold inlet and a mixed water outlet. Hot and cold water supplies enter the valve, mix in the mixing chamber, and then the blended water leaves via the outlet to a terminal fitting. The valve incorporates a temperature sensitive element that responds to changes in the inlet conditions to make sure that the outlet temperature is always stable. The valve must also be fail-safe: that is if the cold supply fails the valve must shut down and not allow full temperature hot water to be discharged. How to Comply Along with the regulation, guidance will be published on how to comply with the regulation. Within this guidance one simple method of compliance will be to use a thermostatic mixing valve which meets BSEN 1111 or BSEN 1287 to limit the temperature at the bath taps to 48°C. BSEN 1111 is the European standard for thermostatic mixing valves for high pressure applications (1-6 bar) and BSEN 1287 is for low pressures (0.
Thermostatic Mixing Valves are used to mix hot and cold supply water in required proportions to maintain the warm water outlet at a constant temperature. In addition to the temperature control function the valves incorporate a safety function that shuts off all water flow in the event of cold water being shut off. This valve was developed to prevent scalding from hot tap water that can result in serious injuries especially when in the bath or shower. People most at risk include people with disabilities, the aged, and children. Bluewater Plumbing Solutions is a Sydney Water accredited supplier, installer and certifier of Thermostatic Mixing Valve.
