The challenges in our changing climate, and rising energy costs, have seen people thinking much more about how to reduce their costs and water consumption. Many consumers underestimate their water use, and don’t understand how much water each appliance or various water fittings use. Saving water, of course, also saves money, as all non-households are metered, and can reduce energy consumption – whether it is for heating hot water, or pumping costs. Leaks can also be a costly addition to water bills. Thames Water’s smart metering insights showed that over 25% of water supplied to non-household customers was continuous flow, and may be leaking.1 In this article we’ll focus on options for reducing usage in a healthcare setting, the potential impacts, and, more importantly, how healthcare engineers can mitigate or avoid these risks
Making changes
Taps: Let us consider the humble handbasin tap, since good hand hygiene is essential in healthcare. Traditionally these taps would have come only with a simple flow straightener in the spout outlet, or nothing at all, offering little to no water savings. On a system with a modest 2 to 3 bar pressure it would not be uncommon to see flow rates at around 15 litres per minute, and more when pressures are higher. This means the user would need to make the conscious decision to turn the taps down, or run the tap for less time, to make savings. Although a flow of 4 litres per minute should be sufficient for handwashing, on this ‘traditional-style’ tap, this will look visually inadequate.
Thankfully there are technologies that can help – by enhancing the appearance of the flow volume while keeping the actual water usage low, but also still providing sufficient water for effective handwashing. This can make a flow of 4 litres per minute appear distinctly usable, and it easier for users to save water. It is easy to see how this could be an attractive proposition given the potential water saving of around 70%. Savings don’t stop there; if the water is being pumped or heated, then there could be energy savings too. Don’t forget to fix any dripping taps promptly, as leaving them in this condition wastes water, and may add to your energy bills
WCs and urinals: However, it is not just with taps where savings can be made. Why not choose dual-flush WCs, which reduce flush volumes below the regulatory maximum of 6 litres? Some of these can consume as little as 3.5/2 litres when flushing, (full/reduced flush), which can result in significant water savings – of around 40% for a full flush, and 60% when using the reduced flush. However, if you do opt for a dual-flush, make sure that it is clear to users how to operate the small flush, as research has shown that consumers are confused by many dual-flush button designs.2 Don’t forget either to check for leaky toilets, and get these fixed as quickly as possible. Waterwise reports that ‘between 5-8% of toilets leak, losing around 400 million litres a day across the UK. A single leaking toilet typically wastes 200-400 litres of water per day, which could be costing the customer around £200 a year’.1
Urinals also provide another great opportunity to save water. According to Thames Water, an uncontrolled urinal could be losing approximately 1,800 litres a day.1 So, ensure that all urinals have a controlled flush, and are not programmed to automatically flush when not in use. It is easy to see that in a small restroom housing five WCs and washhand basins, these savings soon build up, while across larger buildings or a healthcare estate they can be very substantial.
Better regulations for new build
Alongside the economic factors, building regulators are prioritising reducing environmental impacts. Some parts of the UK have already seen changes to Building Regulations and Approved Documents. There is a move to promote an individual water fittings approach, where there are maximum flow rates or volumes for each fitting, rather than setting limitations on a ‘basket’ of fittings using the water calculator approach. Wales has already published updates to its requirements, and in England Defra (the Department for Environment, Food & Rural Affairs) and the Department for Levelling Up, Housing & Communities (DLUHC) are considering a similar approach.
In Wales, in an attempt to improve water efficiency in new buildings, handbasins in such buildings can be limited to 5 litres per minute, with dual-flush WC options of 4/2.6 litre or 4.5/3 litres (full/reduced flushes).
Choosing water-efficient products and appliances
Manufacturers are continuously improving their designs to reduce water consumption without compromising performance. Defra is planning to introduce a mandatory water label, which will give consumers better information on exactly how much water every product is designed to use. In the meantime, buyers should look out for the Unified Water Label (see page 23) to obtain information about water use – see www.uwla.eu.
Demand reduction devices
What do we mean when we talk about water saving and demand reduction devices? In fact these come in many forms. Pressure reduction or limiting devices typically use a spring to reduce the pressure, and will come either fixed at a particular pressure, or be adjustable to suit the conditions. Flow may also be lower because of reducing the pressure – but is not the devices’ primary function. These devices are plumbed in line, and usually fitted to mains-fed systems, or on equipment for safe operation, such as pressurised hot water cylinders.
Flow restrictors simply reduce the effective bore of a pipe, thereby slowing the flow. These devices can either be a simple hole in a disc, or a short fitting which has narrower section through it. The degree of flow reduction can vary depending on pressure, as flow restrictors do not actively adjust for it, and so will be less precise about the flow rate delivery
Flow regulators are similar to flow restrictors, in that they too utilise small holes to reduce the flow. However, they have an additional active element which takes account of the upstream pressure varying the hole size. This gives greater control, and offers consistent flow delivery over a wider range of pressures.
Tap aerators are fitted to the outlet spout of the tap. They typically contain a flow regulator within the cartridge, but then have an additional element which draws in and mixes air in with the water flow. The air gives a visible increase to the volume of the flow. This also ‘softens’ the flow, which reduces splashing when the water makes contact with the sink or basin. As these are fitted to the ends of the tap, it is easier to select the right flow for each tap and to maintain it.
Impacts on systems
When designing new buildings it is much easier to incorporate these technologies. However, retrofitting them into an existing system may have unintended impacts, so requires careful consideration. This applies not only to the water supply system, but also to other connected services such as the drainage, which we are not able to go into in this article. So, what do all these savings mean for the system itself? Firstly, reducing point of use flow rates or usage has the knock-on effect of slowing the speed that water flows through the pipes supplying them. This can also increase the time that water stays in the pipe. In the aforementioned example the residence time can be two to three times longer
Longer residence times can have a number of significant impacts. Firstly the residual disinfectant, in public water supplies to limit microorganism growth, dissipates over time. Long residence times mean that its protective effect will be lost. Secondly, water has much more time to absorb heat from the pipe’s environment, increasing its temperature. This can be problematic if the temperature gets too high. Temperatures between 20 °C and 45 °C give microorganisms the ideal thermal conditions for them to thrive and multiply. This is the reason why there are controls, set out in guidance such as HTM 04-01, and the Health and Safety Executive’s ACoP (Approved Code of Practice and guidance) L8, Legionnaires’ disease. The control of legionella bacteria in water systems, which rightly require cold water to be kept below 20 °C. However, these are not the only problems.
The speed at which water travels through pipes can help limit biofilm growth within pipes and fittings. It does not need to be a continuous flow, but does need to be sufficiently high on a frequent basis so that it turns over the whole volume of the pipe. Good system design – including the selection of pipe sizes – can prevent stagnation, and maintain water safety within plumbing systems.
Common mistakes and concerns
There are a few common mistakes made in striving to save water – for example, using isolation valves to reduce flow by partially closing them. This is a less than optimal method, particularly for the quarter-turn style valves. It creates high speed flows across the face and seating of the valve, which can result in high wear, and may not fully shut off when you need it to. Without reducing pipe sizes, residence times can increase, allowing stagnation and potential biofilm growth. Reducing flow rates can also affect the balance within return loops, which can affect the way they operate.
When planning to introduce watersaving technologies it is imperative that the whole water system is fully considered. Combining water saving measures across multiple outlets can mean a substantial change to flow patterns, which will be compounded when applied across a larger building’s system. This may mean reconfiguring pipe routes, pipe size reduction, or rebalancing to optimise flows, not only on cold supplies, but the hot water system as well. Sufficient throughput needs to be maintained throughout all legs to ensure that stagnation and heat gain are limited. Designers also need to take care if they remove storage cisterns, which have backflow protection integrated. A better alternative may be to reduce the size of the cistern, thus achieving sufficient turnover.
Risks with aerators
In areas where there is a high level of infection control, aerators on the end of taps may not be an appropriate watersaving method, as they can retain water within them. Additionally, these types of outlets need to be easily disinfected, which may require the outlet fittings to be readily removed. In these circumstances inline flow control may provide the better option. However, anything which places a restriction, or has the potential to trap debris, needs to be readily accessible. Choose designs that enable easy removal for maintenance, and the flexibility to alter the flow rate using replacement cartridges.
Installer competence and compliant fittings
As well as protecting the quality of drinking water, the Water Fittings Regulations are designed to prevent the ‘waste and undue consumption of water’. These regulations also govern the design, installation, operation, and maintenance, of plumbing systems, water fittings, and appliances which use water
Plumbing products and appliances supplied by wholesome water from public supply must be of an appropriate quality and standard. It is only when fittings are properly tested that manufacturers and suppliers can be certain that they comply. As you might expect, conformity standards include tests to check that products won’t leak and waste water
Surprisingly, not all products sold have been appropriately tested, so it is worth checking that products have been tested to conform with the Water Fittings Regulations. The regulations give two routes to demonstrate that a water fitting is of an appropriate quality or standard:
1 It conforms to an appropriate British Standard, or some other national specification which provides an equivalent level of protection and performance, or
2 It conforms to a specification approved by the regulator
Approval by a UK certification body
A simple way to be sure of compliance is to check if the water fitting has been approved by a certification body. There are a number of approval schemes operating in the UK. It is not just the plumbing fittings which must comply, but also the design and installation. The regulations stipulate this as needing to be ‘suitable for the circumstances used’. It is vitally important that all involved – whether the designer, installer, or building manager, are competent.
Only installers with the appropriate qualifications, regulatory knowledge, and competence, should be used to install and maintain water installations. WaterSafe is the national register of approved contractors in the UK, supported by all the UK water companies and the drinking water quality regulators. Approved contractors on its register are all trained in the Water Fittings Regulations. However, only approved plumbers are approved for all types of plumbing work.
Legal duty to notify the water company
For most types of plumbing work, installers have a legal duty to notify the local water company before they start work, which can lead to delays, as water companies have 10 days to give consent. Approved contractors can carry out some work without advanced notification. A certificate of compliance issued by an approved contractor also provides a defence from prosecution if the work is later found not to comply, provided the work was within their scope of approval.
In summary, water is a precious resource, and there is a duty on us all to reduce water usage to save money and reduce our environmental impact, without compromising compliance and water safety. Healthcare building owners and operators can take a leading role in this by:
Selecting suitable, compliant fittings that are also water-efficient.
Using a suitably qualified, competent installer to install fittings correctly.
Making sure that the whole water system is compliant, and that any water efficiency changes do not have unintended consequences.
Fixing leaks promptly.
Helping users reduce their water use – for example making toilet dual buttons clear, and controlling urinal flushing
Paul Millard
Paul Millard, the organisation’s Technical manager, joined Water Regs UK (formerly WRAS) in August 2012, where he provides technical liaison and support both to the water industry and other external organisations. Before this he worked for Anglian Water, where he was Water Regulations manager responsible for the company’s enforcement of the Water Fittings Regulations. With over 30 years’ water industry experience, his early career at Cambridge Water saw him involved in a range of activities, including network management, leakage, and customer complaints. For the last 20 years he has focused on the Water Fittings Regulations, providing technical expertise and guidance on their enforcement and interpretation, with involvement in national standards, where he provides water industry representation.
References
1 Waterwise UK Water Efficiency Strategy to 2030. www.waterwise.org.uk/ strategy2030/
2 Dual Flush –WRAS share findings of survey. WRAS press release. www. wrasapprovals.co.uk/news/articles/dualflush/