The Standards and guidance links noted in this blog all highlight the need to ensure that a risk assessment should be undertaken to identify the scald risk. As noted, the purpose of the device is to protect the most vulnerable:

When it comes to inspections, it is important for you to know that a licensed fire protection sprinkler technician can legally inspect your backflow preventers, but a backflow technician cannot, by code, inspect your sprinkler system. Therefore, you can save time and money by hiring AIE’s sprinkler inspector to also inspect your backflow preventers while performing your annual certification.

Once fitted the valve must be managed and maintained following the legislative needs for workplace equipment as the TMV is being utilised as a Protective Device (PPE). The standards managing these needs note the following:

When you run a busy restaurant, there are a few general backflow problem indicators to watch for, including cloudy, muddy, or strange looking/smelling/tasting water. Also, less water pressure and/or an illness outbreak can be an indication there is a backflow preventer problem.

In this blog we will discuss; what are TMVs, why they are required, when they should be indicated for use and the risks associated with their use or non-use.

Hot water temperatures greater than 44˚C are considered high risk with full body immersion, although showering (not full body immersion) should also be considered. These temperatures have been associated with serious scalds and have led to fatalities, although it is stressed that a child or the elderly need far less exposure to hot temperatures.

TMV valveregulations

In summary, TMVs should be utilised following the results of a suitable and sufficient scalding risk assessment. The assessment should identify the valve to be installed its type and its design. This will not only confirm the valve’s need but prevent valves from being fitted in tandem resulting in possible valve failure, the introduction of crossflow contamination, microbiological contamination, or the risk of outlet users being exposed to valve failure or poor temperature records.

Now that you know how vital your restaurant backflow preventer and cross-connection devices are to the safety of your customers, staff, and business, you can see why AIE recommends that inspections occur more often than once a year. When you work with a company that provides all fire and water services, it is convenient to test them along with your other regularly scheduled NFPA fire protection and safety inspections.

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The building owners/landlord should discuss with designers and managers of water systems where to install any TMVs. The decision process should be supported by the completion of a scald risk assessment. Those managing health services have been offered additional support within Health Service Information Sheet (HSIS)No 6, published by the Health and Safety Executive (HSE), which clearly explains the risks within health and social care premises associated with hot water (bathing and showering) and hot surfaces (radiators/pipes).

The maintenance programme should be designed to ensure the valves are adequately cleaned and free from particulate matter that could inhibit the correct function of the valve and/or provide a medium for bacteria to propagate, including biofilm.

Thermostatic MixingValveBath

When water enters your restaurant from the main water supply, it should only ever flow IN. However, sometimes a pressure change in the line can occur from a water main break, power outage, or an open fire hydrant, leaving the potential for water to flow backward and seep into the main water supply line. When your backflow device is working, it stops this from happening. If it stops working and there is a pressure change, the backflow of water could lead to:

The DoH issued publication HTM 04-01 Supplement – Performance specification D 08 thermostatic mixing valves (healthcare premises) indicates that blended water temperatures should be between 38˚C and 46˚C at the point of discharge; the actual temperature depends on whether the outlet is a bidet, a shower, a wash hand basin or a bath.

The Department of Health (DoH) approached the manufacturers and industry for assistance in preventing or mitigating scald risk, especially in areas with vulnerable patients.

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Backflow preventer issues can be subtle yet dangerous, so be sure to make this critically important inspection protocol part of your overall plan. If you’re not sure who to call to locate, inspect, and/or repair your restaurant’s backflow prevention devices, AIE is at your service. We offer all fire safety services to nationwide multi-location restaurants and 24/7/365 in-house emergency assistance. Contact us today, 800-892-9863.

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The Water Hygiene Centre was established in 2009 to address the lack of independent water hygiene consultancy within the industry. From our humble beginnings, we have established ourselves as a market leader, helping clients identify and minimise the risk of waterborne contamination and disease, whilst improving compliance performance.

The Thermostatic Mixing Valve Manufacturers Association (TMVA) offered a Recommended code of practice for safe water temperatures. The D08 needs have been further supported by the testing industry developing certification to denote the valve had automatic shutoff to meet with healthcare design temperatures. This scheme is known as the TMV3 scheme currently run by NSF. The EM needs highlighted, were raised by The Royal Society for Public Health (RSPH). Best practice needs for domestic use saw similar support with the introduction of the TMV2 Scheme.

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The risk assessment is a key requirement. It should not only identify the risks, but also identify the best type of valve, process, or warning (sign) to be used. As noted, there are six TMV types, these can be fitted with automated or manual shutoff valves and certificated to TMV2 or TMV3 by NSF dependent on the area of use.

Sometimes the signs of a broken backflow preventer are not obvious but can still cause prolonged bouts of chronic illness, which is why regular inspections by a certified backflow preventer technician are critical to the health of your customers, staff, and restaurant.

From a health and safety perspective, it is underpinned by; the Health and Safety at Work etc Act (HSWA) 1974 (section 3 and part 3), Management of Health and Safety at Work Regulations (MHSWR – regulation 3) and Provision and Use of Work Equipment Regulations (PUWER) 1998). Exposure either from the surface or if the aesthetics of cold water has been changed (heat it up) is covered by the Control of Substances Hazardous to Health (COSHH) regulations 2002.

Thermostatic mixingvalvehow it works

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When considering these listed areas of legislation, you should consider utilising the HSE Codes of Practice. These Approved codes are often utilised to record changes i.e., COSHH regulations 2002, ACoP L5 rev 2013. They also explain the regulation needs.

The programme should also ensure failure devices are tested, and seepage results noted. In the case of healthcare valves, those managing the system should ensure future lifecycle planning is also considered and that regular, no greater than 2 yearly, contact with the manufacturers is made to allow the certification needs and planning to consider if a valve is to be discontinued which could impact future spares.Further reading> TMV Maintenance - Lessons Learnt!

These standards state:“When these devices are used to provide anti-scald protection for children, elderly, and disabled persons the mixed water temperature needs to be set at a suitable bathing temperature (body temperature approximately 38 °C) as children are at risk to scalding at lower temperatures than adults”.

Although the risk of scalding may be mitigated within this temperature range, there is a microbiological risk associated with the use of TMVs because waterborne bacteria such as Pseudomonas aeruginosa and Legionella propagate at temperatures between 20-45˚C. In non-healthcare utilising a TMV in a food preparation area can accelerate biological growth during hand washing when working with poultry, fish and raw meats. It’s therefore important that we consider ALL risks, including those which can be introduced by their use and service management.

According to the Certified Commercial Property Inspectors Association (CCPIA), the EPA holds each municipality accountable for its own water purity, therefore commercial backflow preventer testing requirements may differ slightly by region, however, typical inspection requirements include the following:

Type 3 TMV - Single sequential control: valves with a single control operating through a predetermined sequence of flow and temperature. These shall have a shut-off device; (actuator movement in one plane);

The British Standards Institute (BSI) is the UK's National Standards Body (NSB). They offer support to the UK government, businesses and industry via approved guidance known as British Standards (BS). Following the issue of the explanatory memorandum (EM) to Building regulations in 2009 over scald protection in areas of full body immersion (Baths), they issued a revised Standard. BS EN 1111:2017 Sanitary tapware. Thermostatic mixing valves (PN 10). General technical specification.

Note: Google Images: are for illustration purpose only - the WHC is not endorsing these as TMV types as preferred models