The automatic way to save water
Washrooms are inevitably major users of water, but their water consumption can be reduced considerably, and with financial benefit, using a range of automatic controls. Geoffrey Gestetner explains how.It has never been more important to consider the impact of water usage when designing and installing washrooms, both from an environmental and an economic standpoint. Even in the United Kingdom, which has traditionally been regarded as having more than enough rainfall in most areas, climate change is serving to bring about droughts and hosepipe bans in the drier regions ever more often. Rising water and sewerage charges, due in part to the water companies’ leak repair and water conservation programmes, are making it essential for both private companies and public sector bodies to give serious consideration to the rising cost of water. In washrooms, the greatest savings can be made by controlling the use of water in the automatic flushing systems serving most men’s urinals. Indeed, in the UK it has become mandatory to install flush control valves on new installations. Moreover, as they provide the opportunity to reduce water consumption by 80%, it makes excellent economic sense to retrofit these valves, even if they are not a legal requirement. As an additional incentive, several urinal flush controls are recognised by DEFRA as qualifying for Enhanced Capital Allowances, meaning that the cost of purchase and installation is fully tax deductible in the year of purchase. This reduces even further the very short payback period for these valves, which can be as little as six months. There are a number of options in automatic flush control. The simplest is a hydraulic valve, which does not require any form of electrical power and allows the urinal cistern to fill only when some other item of washroom equipment is used. This causes a reduction in water pressure, which is sensed by the valve, causing it to open and the cistern to fill. For washrooms where the toilet facilities are likely to be unused for a number of hours, 24 hour hygiene flush versions are available. In an ideal world, hand washing directly after using the urinal would cause the cistern to fill and the urinal to flush. However, in circumstances where this level of personal hygiene cannot always be relied on an electronic valve is preferable. Infrared valves operate when movement is detected in the area in front of or above the urinals. They are more reliable from a hygiene point of view as they do not rely on use of the wash hand basins for operation. In addition, they are ideal for use in washrooms that may be subject to vandalism, as the sensor can be installed in a ‘concealed’ mode using a standard wall-mounted pattress box or recessed into a suspended ceiling. An alternative to the automatic flushing cistern uses mains water supply directly to the urinal. A sensor is discreetly positioned above the urinal to detect the presence of users and triggers automatic flushing once the user departs. If a user is detected whilst flushing, the flush is automatically arrested to prevent splashing. As each urinal bowl is flushed individually, such systems provide an excellent level of hygiene maintenance. Mains water is directed only at the bowl which has been used rather than cleansing all bowls simultaneously. Where urinals have not been used for a specified amount of time, an automatic ‘hygiene flush’ can be programmed. The more sophisticated versions of these products benefit from programmable flush durations and range sensitivity. To provide further water savings in washrooms, it is now possible to install no-touch flushing systems for WCs, which can be mounted in either exposed or concealed cisterns. For increased water efficiency, they are available with dual-flush capability and operated by a simple hand movement within the sensing range. The cisterns have no handles, which can be easily broken, and the ‘hands-free’ operation provides much better protection against contagious diseases. The installer can configure flush duration to control water used per flush. This means that even if installed in an ‘old’ 9 litre cistern, the water used for a ‘full’ flush could be restricted to, say, 5 litres, with 3 litres for a part flush. However, the ultimate in both water and energy savings is provided by a complete washroom control system that is totally automated to control not only urinal flushing but also, throughout adjacent men’s and women’s washrooms, electricity used for lighting, extractor fans and water heating. In addition it also avoids potential flooding due to taps left running by careless users, malfunction or vandalism.
The key to using less water — in a fully automated washroom, users only have access to touch buttons, shower heads, basin spouts, basins and WC bowls. All pipework, wiring, solenoid valves, cisterns, controllers and power supplies are positioned remotely in service voids.
