Thermostatic mixing valve
Encyclopedia
A thermostatic mixing valve (TMV) is a valve
that blends hot water with cold water to ensure constant, safe shower and bath outlet temperatures, preventing scalding.
The storage of water at high temperature removes one possible breeding ground for Legionella
; the use of a thermostat
, rather than a static mixing valve, provides increased safety against scalding, and increased user comfort, because the hot-water temperature remains constant.
Many TMVs use a wax thermostat for regulation. They also shut off rapidly in the event of a hot or cold supply failure to prevent scalding or thermal shock.
It is increasingly common practice around the world to regulate the storage water temperature to above 60 °C (140 °F), and to circulate or distribute water at a temperature less than 50 °C (122 °F). Water above these temperatures can cause scald injuries. Many countries, states, or municipalities now require that the temperature of all bath water in new build and extensively refurbished domestic properties be controlled to a maximum of 48 °C (118 °F). Installing thermostatic mixing valves can ensure that water is delivered at the required temperature, thereby reducing the risk of scalding accidents; it also reduces hot water consumption from a supply that is maintained at a higher temperature.
There are three main categories for water temperature controlling devices: Heat Source, Group Control, and Point-of-Use.
Heat Source
These are used with central heating
systems that use water as a medium.
Group Control
These provide a uniform distribution temperature for all hot water outlets in a household.
Point-of-Use
These are single Outlet Thermostatic Mixing Valves, often called "thermostatic faucets", "thermostat taps
" or "thermostat valves".
Although other temperature regulating valves exist, thermostatic mixing valves are the preferred type in health care facilities, as they limit maximum outlet temperature, regardless of pressure or flow.
Valve
A valve is a device that regulates, directs or controls the flow of a fluid by opening, closing, or partially obstructing various passageways. Valves are technically pipe fittings, but are usually discussed as a separate category...
that blends hot water with cold water to ensure constant, safe shower and bath outlet temperatures, preventing scalding.
The storage of water at high temperature removes one possible breeding ground for Legionella
Legionella
Legionella is a pathogenic Gram negative bacterium, including species that cause legionellosis or Legionnaires' disease, most notably L. pneumophila. It may be readily visualized with a silver stain....
; the use of a thermostat
Thermostat
A thermostat is the component of a control system which regulates the temperature of a system so that the system's temperature is maintained near a desired setpoint temperature. The thermostat does this by switching heating or cooling devices on or off, or regulating the flow of a heat transfer...
, rather than a static mixing valve, provides increased safety against scalding, and increased user comfort, because the hot-water temperature remains constant.
Many TMVs use a wax thermostat for regulation. They also shut off rapidly in the event of a hot or cold supply failure to prevent scalding or thermal shock.
It is increasingly common practice around the world to regulate the storage water temperature to above 60 °C (140 °F), and to circulate or distribute water at a temperature less than 50 °C (122 °F). Water above these temperatures can cause scald injuries. Many countries, states, or municipalities now require that the temperature of all bath water in new build and extensively refurbished domestic properties be controlled to a maximum of 48 °C (118 °F). Installing thermostatic mixing valves can ensure that water is delivered at the required temperature, thereby reducing the risk of scalding accidents; it also reduces hot water consumption from a supply that is maintained at a higher temperature.
There are three main categories for water temperature controlling devices: Heat Source, Group Control, and Point-of-Use.
Heat Source
These are used with central heating
Central heating
A central heating system provides warmth to the whole interior of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC system.Central heating differs from local heating in that the heat generation...
systems that use water as a medium.
- Tempering valves for use on hot water heat distribution systems
- High flow rates suitable for use in under floor (radiant) heating applications
- Allows water to be stored at a higher temperature
Group Control
These provide a uniform distribution temperature for all hot water outlets in a household.
- Designed for multi-point applications
- High flow rates (from 14 gpm to 51 gpm at 45 psi)
- Temperature stability
Point-of-Use
These are single Outlet Thermostatic Mixing Valves, often called "thermostatic faucets", "thermostat taps
Tap (valve)
A tap is a valve controlling release of liquids or gas. In the British Isles and most of the Commonwealth, the word is used for any everyday type of valve, particularly the fittings that control water supply to bathtubs and sinks. In the U.S., the term "tap" is more often used for beer taps,...
" or "thermostat valves".
- Designed for single point applications, such as individual showering, hand wash basin mixers, bath or tub fillers
- High level protection against scalding and thermal shock
Although other temperature regulating valves exist, thermostatic mixing valves are the preferred type in health care facilities, as they limit maximum outlet temperature, regardless of pressure or flow.