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WATER HEATING Making light work of water By Iain Stringer, Commercial Director of Bristan W


hen specifying taps and showers for commercial premises, there are many


decisions to make. Some buildings might require thermostatic mixing valves to protect against scalding and legionella, whereas others could benefit from the installation of capacitance taps that offer hands-free operation and reduce the spread of germs and bacteria. For other buildings, considerations revolve around the environment,


access, design,


functionality or maintenance. While requirements can vary quite


dramatically – the needs of a modern boutique hotel, for example, will be worlds apart from the demands of a highly functional, robust hospital – a crucial element to consider in any commercial project is hot water safety. Each year scalding hot bath water causes 20 deaths and almost 600 serious burns – but by fitting a thermostatic mixing valve (TMV) anywhere that hot water is delivered, the risk of scalding can be significantly reduced. TMVs allow water to be stored and distributed at a high enough temperature to kill harmful legionella bacteria (60°C or above), but reduce it to a safe temperature at the point of use by mixing it with the cold supply.


Best practice


The recommended safe temperatures for baths, showers, washbasins and bidets range between 37°C and 46°C, but can differ depending on the application and who is using the facilities (37-37.5°C, for example, is recommended for bathing children). A TMV will maintain the preset temperature even if the water pressure fluctuates when other appliances are used, and will completely shut down the outlet flow if the hot or cold water supply fails. It is now considered best practice to install


a TMV in all cases, unless a risk assessment has established that it is absolutely safe not to do so, and current legislation in healthcare and education makes the use of TMV3 approved valves a must.


The type of TMV (1, 2 or 3) depends on the application, with guidance being available for required, recommended or suggested best practice. TMV3 valves are tested in line with NHS Model Engineering Specification D08 – making them suitable for use with society's most vulnerable such as the elderly and less able.


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The Water Supply (Water Fittings) Regulations 1999 recommend the use of TMVs for safety in schools, public buildings and other public facilities, and they are required (by law or authoritative guidance) in housing association dwellings for the elderly, care homes for young people, schools (including nurseries) and NHS hospitals.


Meeting guidelines


Current guidance on the prevention and control of legionella advises that each outlet should be fitted with its own TMV, with pipework from the valve being no longer than two metres to minimise deadleg. Any spur to a TMV from a hot water recirculation system should not exceed five metres. Meanwhile, taps and showers that aid


bacterial control will be a principal requirement in certain applications, healthcare being the most obvious. As well as having to be mindful of the risk of legionella from hot water systems, hospitals also have to control potential outbreaks of other bacteria, germs, viruses and infections, including MRSA and C.difficile, which can be passed from tap to tap. Elbow- operated taps can help to minimise the risks, as can non-touch control technology. Infrared technology, which uses a sensor, has been around for several years, but the new generation of non-touch taps and showers are based on capacitance technology. This harnesses the electrical impulses naturally generated by the human body, automatically turning taps and showers on and off when they do or don’t sense movement.


Environmental performance


On some projects, the taps and showers installed must have strong eco credentials too, especially if a building needs to achieve good environmental performance in accordance with BREEAM (BRE Environmental Assessment Method). Water is a precious resource, and so specifiers are often tasked with finding products that use water and energy responsibly yet don’t compromise on performance, design, ease- of-use, safety or health. Fortunately, there are many water-saving options on the market;


for example flow regulators can enable a flow of as little as


four litres per minute and showerheads with additional spray inserts provide water economy.


Meanwhile flow and spray


regulators and aerators can reduce a tap’s flow to around one litre per minute. Timed flow showers and taps provide a set amount of water, and switch off after a specific time, or, if it’s non-touch technology, when there’s no movement. They can be particularly useful for applications with heavy usage – for example schools (the average pupil is estimated to use around 4,000 litres of water every year), swimming pools, sports clubs and gyms – and have the added benefit of minimising the risk of flooding caused by taps and showers being left running, either accidently or deliberately.


Reasonable access


Accessibility is sometimes another key concern. Part M of the Building Regulations (Access to and Use of Buildings) legislates that all non-domestic buildings should offer


key factor. This might be the case in modern hotels, restaurants and bars, for example, when cutting-edge bathroom and washroom design can have a big impact on the guest experience. Fortunately for specifiers, the taps and


showers market is far from staid, and there’s no shortage of contemporary, stylish products. It’s important to remember that as well as being aesthetically pleasing, these products should be functional, easy-to-use and safe. At Bristan we call this ‘liveable style’.


In other applications, functionality will be more important. In a school for example, taps and showers must be durable, and easy for small hands to use. And when specifying products for high-risk areas where vandalism can be an issue we’d recommend concealed working parts and pipework, tamper-resistant fittings, fixed shower heads and robust, hardwearing products like shower panels. Some products on the market are even resistant to spray paint and graffiti. Some buildings will need fit-and-forget products that are easy to maintain, and it’s here that corrosion-resistant, easy-to- clean materials are a must. However, commercial products are often in constant use, so a regular, planned maintenance regime is often essential for hygiene purposes, trouble-free operation and longer product life.


Minimise downtime


It can pay dividends to choose products that are easy to


‘reasonable access’ so that people with disabilities can use the facilities – and this includes washing and showering.


Solutions to consider include lever-


operated taps and showers with sequential control for temperature and flow, non-touch taps and showers that sense the user’s proximity, thermostatically controlled taps and showers to quickly achieve and maintain a constant temperature (with a maximum limit), products with safe-touch surface temperatures to prevent accidental burns and accessories such as grab rails. Products should always be positioned for optimal comfort, with adequate space. On some projects design is seen as the


service, as they can save time and effort and minimise downtime. For example, isolation elbows enable easy servicing without


having to shut off the water supply. Some quite recent innovations that can save many man hours are showers with removable front panels to provide easy access to serviceable parts and taps and mixers that can be serviced from above the bath or basin.


With ever-changing legislation, regulations, standards and end user requirements to consider, tap and shower manufacturers are investing heavily in new product development to ensure they can meet the evolving needs of the commercial market – and specifiers should find there are wealth of products and new innovations to choose from.


OCTOBER 2011 BUILDING SERVICES & ENVIRONMENTAL ENGINEER 31


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