Because water is a finite resource it is imperative that we try to conserve as much as we can whilst carrying out our daily routines of washing, cooking and bathing.

In addition to that, the Water Supply (Water Fittings) Regulations 1999 state that ‘there is a general move towards the conservation of water’ and actually include requirements ‘for installers and users not to cause or permit waste, misuse, undue consumption or contamination of the supply of wholesome water’. Also, there is a growing demand from government and councils to try to use devices that can make savings on the use of water and energy when used in domestic, commercial, industrial, leisure and institutional applications.

Water efficiency and water conservation are quickly becoming key features of system design. This trend is set to continue when new regulations are introduced in Part G of the Building Regulations next year. In this article we will consider a specific type of control for commercial and public bathroom/washroom environments, i.e. where rows of basins and/or showers are used, as well as potentially high water use fixtures such as WCs and urinals as would be found in leisure centres, schools, sports club changing rooms, secure units, motorway service areas etc.

Electronic Control

Senselec® basin control - spout with infrared sensor

Reliance offers a high quality range of infrared operated taps, shower controls, WC controls, and urinal controls. The system uses active infrared sensors which have an adjustable detection beam that can be altered to between 40mm and 200mm depending on site conditions or customer requirements. The sensor itself is programmed to open a solenoid valve for a specific length of time when it detects movement in the infrared beam. After this time has elapsed, the sensor will automatically shut off the water flow. Basin sensors also incorporate a 2 second shut off delay so that if a user’s hands move away from the detection area briefly, to get soap for instance, the taps are not continually shutting on and off.

To prevent wastage and vandalism the sensor will automatically shut the solenoid valve off if it detects a presence for more than 30 seconds, for example if chewing gum or something similar was stuck on to the sensor. The tap would not operate until the blockage was removed, after which its normal function would automatically be resumed. All the infrared taps and control packages can be used with either battery packs using 6V lithium type batteries or a 230VAC/ 6VDC stabilised mains power supply unit, these are supplied with each control package or tap.

The solenoid valve is a latching type, which means that only a single pulse is required for the solenoid to either open or close. This is why the 6-volt lithium batteries can last so long (300,000 operations).

The Basin Tap

A new model from Reliance's Senselec® infra-red basin tap range - the Curve design

Basin controls are available in a wide selection of formats, including taps with integral sensors and deck mounted and wall mounted spouts that come with separate sensor modules. The sensor modules and taps come with a 1 metre length of cable as standard and are available in panel mounting or cross-wall configurations. Reliance has recently extended its range of infrared basin taps to give customers a much wider choice in terms of size and styling of the terminal fitting. In all cases, though, the functionality and flexibility of the system remains the same.

Shower Sensors
For shower applications, the sensors have to be separate from the outlet, as the users of the shower are not of uniform height. However the showerhead will have a particular shower pattern and the sensor can be set so that the shower operates when someone is standing in that optimum position.

The Urinal

Senselec® urinal control with infrared sensor

For this area, Reliance offers the Senselec IR infrared Urinal Control Pack (mains water connection). This infrared Urinal Pack is designed to work on mains water pressure and is available as battery operated or mains electric operated, through a 6-volt transformer. When the sensor detects a presence for a minimum of five seconds, the control goes into active mode. Three seconds after the presence is no longer detected, the unit will flush for five seconds. The urinal control also features a 12-hour hygiene flush, which means that if a presence is not detected for 12 hours, the controller will automatically flush once to maintain a trap seal. A type DC backflow preventer is also included to prevent any possibility of cross
contamination by backflow.

The WC
Individual control units can be used with cistern fed WCs. The infrared sensor is positioned so that when a person interrupts the beam, the sensor becomes active and the unique electronic flush valve will open and the toilet will flush.

Remote Control
Another new addition to the range is a remote control programmer. By connecting the sensor cables to the controller, the installer is able to activate or de-activate a myriad of extra functions such as solenoid valve opening time, hygiene flush, sensing distance, time delay before closing the solenoid, and security lockout time. In addition, the controller has a diagnostic mode that allows interrogation of the sensor settings for fault finding purposes and for testing battery voltage.

As can be seen from the above examples, there are a number of choices that have to be made depending on the type of application and how the building is used. As in all things, care must be taken to use the correct product for the appropriate application.

BRE-EAM
By the utilisation of this type of water saving device, points can be awarded by the British Research Establishment – Energy Assessment Method (BRE-EAM). This means that this type of system complies with the environmental control for energy efficiency, which is part of the Building Regulations Part L.

Systems which are environmentally friendly that are installed within a development that can achieve these awarded points from BRE-EAM, and this is something that developers consider to be an increasingly important issue when designing and planning a project.

General Guidance

Selected Senselec® products feature in Defra's Water Technology List

In any public facility it is essential to ensure that there is a current risk assessment in place. In particular, close attention should be paid to the control of the hot water system. This should also include assessing the type of person likely to use the facilities so that the correct types of thermostatic mixing valve can be fitted. If people judged to be at risk of scalding are expected to use the facilities, then TMV3 thermostatic valves will have to be used in that particular area or special facilities will have to be provided