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Thermostatic Mixing Valves (TMV)

Thermostatic Mixing Valves (TMV)

 

  Thermostatic Mixing Valves (Please click for options)

  Thermostatic Mixing Valve Accessories (Coming Soon)

 

 

Thermostatic Mixing Valves (TMV) are a way to ensure the constant delivery of hot water at a safe temperature, which can be set by the user to their own comfort. Thermostatic Mixing Valves are common in many different applications including Domestic Dwellings, Offices, Care Homes, Hospitals and Schools.

Thermostatic Mixing Valves blend hot and cold water to ensure water is supplied at the right temperature to each outlet. With TMV's in place you can safely store water at over 60 DegC which will kill almost all traces of Legionella and still ensure that the water is safe for use. Most Thermostatic Mixing Valves operate using a wax capsule which also acts as a safety feature if cold water supply should be lost, if a total loss of cold water should occur the valve will shut all supply to the hot taps.

For England and Wales, from 1 April 2010, revisions to Part G of the Building Regulations (Hot water supply and systems) include the requirement that baths, subject to building regulations, are fitted with a protective device (i.e. a thermostatic mixing valve) to limit the temperature of hot water. Similar regulations have been in force in Scotland since 2006.

NHS institutions have a duty of care that requires hot water temperature to be controlled. Maximum temperatures are 41°C for handwashing and showers, 44°C for baths and up to 46°C only for supervised baths. Injury from scalding is on the Department of Health’s ‘never events’ list, which means it must never happen and can be prevented in public hospitals. The requirements of D08, an NHS Model Engineering Specification for TMVs, are covered by the TMV3 scheme. These signify strong approval for the effectiveness of TMVs.

Care homes may also have a duty of care requirement that can encourage them to use TMVs, both to limit the risk of scalding and to ensure that water is at a comfortable temperature that does not discourage hand washing. Where there are vulnerable residents bathing, TMVA recommends the use of TMV3 valves.

In schools, there is no legally prescribed setting for TMVs but there is a legal ‘duty of care’ obligation on the school to ensure that the facilities can be used safely. The temperature of the hot water at point of use should be based on a risk assessment that the school is required to undertake to identify potential risks and actions to ensure users will be safe.

Local authorities may also refer to ‘Building Bulletin 87, 2nd Edition Guideline for Environmental Design in Schools’, which recommends a maximum hot water temperature for school wash basins of 43°C (this would mean TMVs being set to 41°C to account for a possible ± 2°C range of accuracy – the TMVA and BRE also recommend 41°C as the maximum). However, 41°C or 43°C may be too hot for children to comfortably wash their hands. Therefore, the risks of children not washing their hands should also be taken into account in a risk assessment, meaning a school may choose to set TMVs at a lower temperature than the maximum recommended by Building Bulletin 87 and other guidance.

A full list of requirements and recommendations can be found in BRE IP 14/03.

Dependent on the application and the users you will need to use a different type of Thermostatic Mixing Valve. Mixing Valves Will conform to a TMV Rating, usually in the United Kingdom they will conform to either TMV2 or TMV3 with DO8 being recognised as the standards set by Hospitals.

TMV3 Logo TMV3

The TMV3 Scheme is the third party valve accreditation programme which is administered by Buildcert. It has been set up to test independently whether valves submitted are suitable for use in high risk commercial healthcare applications within the UK. The performance testing required in order to comply is based on the NHS model engineering specification D08 for thermostatic mixing valves. Other important factors are also considered: for instance, an applying company must also prove that they comply with ISO 9001 or a suitable equivalent quality control system, the valves are checked for correct marking so they can be identified in the field, packaging and instructions are checked to make sure they conform to guidelines issued by Buildcert.

If Buildcert is satisfied that all the requirements of the scheme have been met, it will issue a certificate granting a five year period of approval for the TMV. The valve will also be entered onto the list of approved products which is kept on the Buildcert website and is updated regularly.

After five years, the manufacturer must resubmit the valve for another full TMV3 test procedure: if successful, a new certificate will be issued and the entire cycle starts over again.

This level of third party compliance testing is unheard of in the rest of the world and helps to keep the UK at the forefront of hot water safety and thermostatic mixing valve technology and product development.

TMV2 Logo TMV2

The TMV2 Scheme is very similar to the TMV3 version but with one big difference: where the TMV3 scheme is intended to be used to certify valves for use in the high risk healthcare sector, TMV2 valves are specifically designed, built and tested for the domestic market.

From April 2010, England and Wales joined Scotland in requiring, as part of the building regulations, the control of hot water temperature to a safe maximum at the bath outlet in domestic bathrooms, which can be achieved by the fitting of a thermostatic mixing valve.

In Scotland, regulations came into force in 2006, requiring control of outlet hot water temperature for baths and bidets: this applies to all new build domestic properties where the building warrant was applied for after 1st May 2006 and is also a requirement in properties undergoing bathroom renovation works which involve the movement or replacement of the bath or bidet.

There are many organizations and charities which support the work of Thermostatic Mixing Valves and recognise the necessity of them. Campaigns such as Hot Water Burns Like Fire help to promote the awareness through organisations such as the Child Burns Trust (CBT) and Royal Society For The Prevention of Accidents (RoSPA). And with new building regulations coming into force we will all be required to install at least a TMV2 rated Thermostatic Mixing Valve to all outlets in new bathrooms that require planning permission.

Below is a chart to assist with the selection of your TMV if you require it.

EnvironmentApplianceIs a TMV:Is a TMV:Is a TMV:Valve type?
    Required by legislation or authoritative guidance? Recommended by legislation or authoritative guidance? Suggested best practice?  
Private dwelling Bath
Basin
Shower
Bidet
Yes


Yes
 
Yes
Yes
TMV2
TMV2
TMV2
Housing Association dwelling Bath
Basin
Shower
Bidet
Yes


Yes
 
Yes
Yes
TMV2
TMV2
TMV2
Housing Association dwelling for the elderly Bath
Basin
Shower
Bidet
Yes
Yes
Yes
Yes
    TMV2
TMV2
TMV2
Hotel Bath
Basin
Shower
    Yes
Yes
Yes
TMV2
TMV2
TMV2
NHS nursing home Bath
Basin
Shower
  Yes
Yes
Yes
  TMV3
TMV3
TMV3
Private nursing home Bath
Basin
Shower
  Yes
Yes
Yes
  TMV3
TMV3
TMV3
Young persons' care home Bath
Basin
Shower
Yes
Yes
Yes
    TMV3
TMV3
TMV3
Schools, including nursery Bath
Basin
Shower
Yes, but 43°C max

Yes

Yes
  TMV2
TMV2
TMV2
Schools for the severely disabled, including nursery Bath
Basin
Shower
Yes, but 43°C max

Yes

Yes
  TMV3
TMV3
TMV3
NHS hospital Bath
Basin
Shower
Yes
Yes
Yes
    TMV3
TMV3
TMV3
Private hospital Bath
Basin
Shower
  Yes
Yes
Yes
  TMV3
TMV3
TMV3