Protecting the vulnerable from scalding and bacterial risks

Stephanie Allchurch, Product Development Manager at Altecnic explores the importance of getting it right when it specifying and designing water systems in healthcare settings. 

While we hope that the worst days of the Coronavirus pandemic are behind us, during the toughest of times, healthcare estates had to perform often beyond their designed capacity. Now, more than ever, we all understand the need to create reliable, safe and flexible spaces if the NHS is to perform at its best. 

For health care specifiers, architects and facilities managers, the ‘HTM04-01 – Safe Water in Healthcare Premises’ regulation must be complied with to ensure healthcare settings are safe for vulnerable patients.  

In particular, HTM04-01 part C - Pseudomonas aeruginosa – advice for augmented care units, describes how ‘hospital water is a recognised potential source of Pseudomonas aeruginosa, which is a microorganism that can act as an opportunistic pathogen and colonise and infect vulnerable patients. Several outbreaks of P. aeruginosa have been attributed to contaminated water systems in hospitals’. 

We know that legionnaire’s disease is responsible for approximately 2-9% of pneumonia cases and that the disease is spread through the breathing in of aerosolized water contaminated with the legionella bacteria. This can be created in environments such as hot and cold water outlets, atomisers, wet air conditioning plants, and whirlpool or hydrotherapy baths. 

Harmful bacteria, such as legionella, grows in water systems where water is stored between 20 – 60°C. So, it makes sense to keep water stored and distributed at temperatures above 60°C to thermally disinfect systems, without use of chemicals.  

However, HBN 00-10 Part C – Sanitary Assemblies advises that outlets above 46°C present a significant scalding risk and should be labelled as such. It also advises that thermostatic devices, such as thermostatic mixing valves (TMVs), should be used at each outlet to remove the scalding risk. 

According to the Child Accident Prevention Trust, every year around 20 people die as a result of scalds caused by hot bath water and a further 570 suffer serious scald injuries. Young children and older people are most at risk from bath water scalds because their skin is thinner and therefore less tolerant to higher water temperatures than that of other age groups. As a result, they sustain scalds more quickly, at lower water temperatures and often with a greater depth of burn. 

Not only that, but ‘risk of scalding’ is still on the NHS ‘Never Events’ list for all organisations that provide NHS care. The list highlights serious incidents that are wholly preventable because guidance or safety recommendations are available at a national level and should have been implemented by all healthcare providers. 

TMVs are used to blend hot and cold water to maintain a set constant outlet temperature. This ensures safe and comfortable hand washing, shower and bath temperatures, and significantly reduces the risk of scalding. 

TMV regulatory standards in NHS facilities 

To store water at temperatures that will thermally disinfect the water system, a TMV must be specified that adheres to the strict testing regime of the TMV3 / NHS D08 regulatory standard.  

The TMV3 approval scheme provides assurance that a TMV is tested and deemed safe to use in a NHS setting. This scheme applies to TMVs for use in high-risk commercial healthcare applications within the UK. These valves offer a high level of protection, reacting much more quickly in shutting off the flow of water if the cold water fails, or if a safe temperature is exceeded. Testing bodies must ensure that the valve adheres to the NHS D08 regulatory standard, which ensures stable temperature output despite varying supply pressures and temperatures.  

Other important factors taken into consideration when carrying out performance testing for TMV3 accreditation include: 

• The company/manufacturer applying for accreditation of the valve must prove their compliance with ISO 9001 (or equivalent quality management system) 

• The valve must feature the correct markings making it identifiable in the field 

• The installation and maintenance documents must include information stated by the scheme. 

It is highly recommended that, once installed, TMV valves are checked and maintained annually to ensure they are still providing sufficient scald protection. The outlet temperature should be tested to check there is no significant change (≤2°C) and the failsafe shut-off activates as intended. If this is no longer the case, a full TMV service plus recommissioning, or replacement, will be required. The valve and filters, strainers and any other components forming the device should also be inspected, cleaned, descaled and disinfected. 

The importance of thermal disinfection 

This approach addresses the thermal disinfection of 95% of the water system, but there are several places in which harmful bacteria can still form. One of these includes the dead leg of pipe between the TMV and the outlet. According to the HSE’s approved code of practice and guidance on regulations on controlling legionella bacteria in water systems, operators should: “Consider the individual nature of the site and system as a whole, including deadlegs and parts of the system used intermittently. These should be included because they can create particular problems, as microbial growth can go unnoticed. When they are brought back online, they can cause heavy contamination, which could disrupt the efficacy of the water treatment regime.” 

For this reason, it is recommended that: 

• TMVs are installed as close to the water outlet as possible, mixing water at the point of use where possible 

• Multiple TMVs should be used in the case of multiple outlets; use of a single TMV increases the risk of bacteria growth. 

Full thermal flushes of water systems, right up to the outlet, are also strongly recommended to prevent the growth of harmful bacteria in the dead leg between the TMV and the outlet. However, this can be costly and take considerable time in a facility with multiple outlets and TMVs. This is because each valve will need to be bypassed in order to successfully complete the thermal disinfection. 

To give a real scenario setting of the drawbacks to this traditional complete thermal disinfection method, consider the scenario of a dormant ward needing to be recommissioned to house vulnerable patients at short notice – something that was not uncommon during the Covid pandemic. Clearly, in this case, these steps and considerations impede the facilities and operations managers ability to act swiftly to recommission the treatment space with access to clean water, distributed at safe temperatures. 

However, there is a WRAS-approved and TMV3 / D08 NHS regulatory certified TMV that allows easy thermal disinfection right to the outlet – removing the time and cost of recommissioning the valve. The Mixcal Careflo Plus TMV removes the need to take off the TMV to ‘flush’ out the whole system, making the process quicker and more efficient. Using a special tool and the manual override function, thermal disinfection can be performed through to the outlets, enabling a complete rather than a partial flush and preventing the growth of harmful bacteria. 

The Mixcal Careflo Plus TMV has been designed and made to meet the requirements of BS 7942:2000 and the NHS model engineering specification D08 for use in healthcare settings, hospitals, care homes and schools. 

TMVs already play a vital role in keeping people safe by regulating water temperatures. These latest advancements in TMV technology take that safety role even further by making it easier and faster to carry out thermal disinfection when needed. 

www.altecnic.co.uk