Tmvs - Simple Way To Protect Your Family From Hot Water Scalding

It has happened to all of us, you turn on the hot water tap just to get a scalding flow of very hot water from the tap. The pain and sensitive skin that follows is the lowest level of injuries that are caused every year in the UK from overheated water, which in extreme cases leads to fatal injuries.

The Health and Safety Executive has issued new guidelines last autumn following a case of fatal burns due to scalding water. The new guidelines require all care homes to install temper proof thermostatic mixing valves to prevent such tragic injuries in the future.

The Scottish Building Standard already requires all new property developments and major refurbishments to install thermostatic mixing valves. Although not compulsory in the rest of the UK at the moment the Building Regulations in the UK are working towards adding it in a future update.

To reduce the risk of Legionella, it is required to keep hot water (for example within a hot water tank) at temperatures of between 60 and 65 degrees Celsius. At these temperatures it is believed that the Legionella virus does not survive. Nevertheless, water coming out of the tap at that temperature is too hot and should be mixed with colder water first.

The mixing valves are particularly important in communal water heating systems and public building. The requirement to keep water at a high temperature to reduce the risk of Legionella all the way to the point of distribution can create a risk of scalding if a TMV is not present.

Young children and old people are the most at risk from scalding water injuries. Hundreds of young children are admitted every year to hospitals in the UK with severe burns from hot baths. Their extra sensitive skin gets burned easily and they may be left with permanent scars. Similarly, older people may not feel the heat of the water fast enough or react fast enough to turn off the hot water tap, leading to severe burns. The same is true for mentally or physically impaired people that have slow response time and slow reactions to pain.

There are primarily two types of thermostatic mixing valves that are certified and approved for installation:

TMV2 are thermostatic mixing valves that are designed for domestic premises but are suitable for most other circumstances. A risk assessment must be undertaken to confirm whether the premises are used by disabled or vulnerable people.

TMV3 valves are designed for higher performance to offer the maximum safety levels. TMV3 valves are required for all healthcare premises, or premises with disabled or vulnerable people (such as mentally or physically handicapped people).

Manufacturers of thermostatic mixing valves recommend that they are installed only by qualified plumbers. The valves are positioned between the hot and the cold pipes to prevent the water coming out of the tap at an extremely high temperature. Most common TMVs are installed under the bath or under the hand basin for a simple installation. Most kits are sold with tailpieces which include isolation, a strainer and test points. Some kits have flexible connectors and isolating filter vales to deal with space limitations.

Author- Tal Potishman is the editor of Heating Central. He writes about high efficiency boilers, Luton plumbers, central heating controls, underfloor heating and solar thermal systems. He specializes in helping save money by advising on efficient heating.