A thermostatic mixing valve (TMV) is a

valve A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fitting ...

that blends hot water with cold water to ensure constant, safe shower and bath outlet temperatures, preventing

scalding Scalding is a form of thermal burn resulting from heated fluids such as boiling water or steam. Most scalds are considered first- or second-degree burns, but third-degree burns can result, especially with prolonged contact. The term is from the ...

. The storage of water at high temperature removes one possible breeding ground for Legionella; the use of a

thermostat A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint. Thermostats are used in any device or system th ...

, 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 , and to circulate or distribute water at a temperature less than . Water above these temperatures can cause scald injuries. Many countries, states, or municipalities now require that the temperature of all bath water in newly built and extensively refurbished domestic properties be controlled to a maximum of . 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 A central heating system provides warmth to a number of spaces within a building from one main source of heat. It is a component of heating, ventilation, and air conditioning (short: HVAC) systems, which can both cool and warm interior spaces. ...

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 at ) * Temperature stability ;Point-of-Use These are single Outlet Thermostatic Mixing Valves, often called "thermostatic faucets", "thermostat 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.

References

Thermostatic mixing valve patent
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External links

Thermostatic Mixing Valve Manufacturers Association
Plumbing Temperature control

See also

References

External links