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.

Last autumn the Health and Safety Executive issued new guidelines to care homes instructing them to install temper proof thermostatic mixing valves (TMV). This new set of guidelines came in the wake of another tragic fatal injury from scalding water.

Scottish Building Standards already include a requirement to install thermostatic mixing valves on all new property developments and major retrofit projects. The rest of the UK is not currently requiring this, but the Building Regulations body is reviewing this issue at the moment.

Regulations in the UK require storing hot water (such as inside your hot water cylinder) at between 60c and 65c to reduce the risk of Legionella. It is believed that the virus that causes the disease does not survive at these temperatures. However, water coming out at that temperature may cause scalding and must be mixed before coming in contact with the user.

Public buildings and communal hot water systems are predominantly in need of a TMV. This is due to the requirement of keeping the hot water at extremely high temperature all the way to the point of delivery to reduce the risk of Legionella.

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 broadly two types of thermostatic mixing valves that are suitable for installation and certified:

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).

According to manufacturers of thermostatic mixing valves, qualified plumbers are the only ones that should be allowed to install their kits. A professional plumber can easily install the kit between the cold and hot pipes to create the mixing action of the valve. The kits are normally fully assembled to provide all necessary components including tailpieces with isolation, a strainer and test points. When the installation is within a location with limited space, there are kits with a flexible connector and isolating filter valve.