This website uses cookies primarily for visitor analytics. Certain pages will ask you to fill in contact details to receive additional information. On these pages you have the option of having the site log your details for future visits. Indicating you want the site to remember your details will place a cookie on your device. To view our full cookie policy, please click here. You can also view it at any time by going to our Contact Us page.

Switch Off In Whitehall

18 September 2008

The installation of lighting controls at The Cabinet Office has reduced the department’s energy wastage and carbon emissions and takes into account different occupancy and lighting levels.

LIGHTING TYPICALLY ACCOUNTS FOR 40% OF THE TOTAL energy usage within office buildings. Consequently, leaving lighting on when it was not needed was proving to be a common cause of energy inefficiencies at 22 Whitehall - the Cabinet Office. To address this issue, FM company Ecovert FM, commissioned its preferred supplier, Setsquare Limited, to survey, design, manufacture and install a flexible presence based lighting control system which would be able to accommodate the specific requirements of this building.

A spokesperson for Ecovert FM said “The cost verses the efficiency return at 22 Whitehall was good and Setsquare’s technology provided an innovative solution to the ongoing problems relating to luminaires being continuously left on. Following the installation of their lighting controls we have experienced a 60 per cent saving in energy usage within this building, giving us an annual cost saving of £6,268, as well as a 44,9221kg reduction in carbon dioxide emissions.”

This project follows the success of Setsquare’s InfraPOD presence based lighting control installations at other Cabinet Office buildings. It required both English Heritage and local authority approval and the Cabinet Office’s architects were tasked with ensuring that it caused minimal disruption to the building’s fabric. The unobtrusive design of this innovative lighting control system and the way its installation was executed proved to be ideal for this type of application.

22 Whitehall had 488 high frequency luminaries which had been specified for their energy efficiency. 416 of these are located within the office areas, and 72 illuminated the lift lobbies. The luminaries within the offices were being left on for 19 hours per day, whilst the lift lobby luminaires were operating for a full 24 hours a day.

The InfraPOD modular range of passive infrared occupancy detection sensors provided a versatile and flexible presence-based lighting control solution in the large open plan offices and the lift lobbies. A control unit incorporates switching time delay and photocell adjustment, enabling up to 10 low profile detector heads to be linked to one controller by using low voltage 2-core screened wire. As each sensor contains a passive infrared detector, this system reacts to movement, thereby ensuring that the lighting is only on when the zone is occupied.

An adjustable timer, within the unit, maintains lighting during defined periods of inactivity. As soon as movement ceases and after a specified period of time, the luminaries will be extinguished and will not be re energised until the system is activated by someone moving into the zone. By ensuring that lighting is only energised when body movement is sensed, or when there is insufficient natural lighting, this system has achieved substantial energy cost savings whilst also reducing the building’s carbon footprint.

The sensor heads are mounted in between the diffuser fins on the suspended mounted luminaries. As the detection sensors are positioned at a lower level than the existing ceiling height, the detection pattern within the centre of the controlled zone is more concentrated, making it sensitive enough to detect the movement of hands on a computer keyboard or mouse.

To achieve a higher level of sensitivity in the outer perimeters of the detection zone, Setsquare installed additional InfraPOD detectors. These provided the required detection capability so that where no movement was detected within a short time delay period the lighting would be automatically extinguished.

In the lift lobby areas facing a central atrium, the InfraPOD Controller takes account of the effect of natural daylight in order to further reduce energy wastage. By linking the InfraPOD control unit to a photocell detector, the system is able to utilise the dual relay to independently switch off the separate rows of lighting, as soon as the required lux level is reached. These controllers have also been used around the windows on the front elevation of the building to effectively control two rows of luminaries, automatically turning off each row as and when there is sufficient background or ambient lux levels.

This capability enables the system to switch at two independent lux levels, whilst still responding to the same movement. In doing so, it is able to use the available natural light to create a 50 per cent reduction in energy usage by simply switching off the row of lighting that is not required. The system only needs one photocell to operate up to 10 sensor heads, reducing the overall cost of installation and avoiding having to install combined sensor heads with built-in photocells and then having to undertake the cost of disabling these photocells when they are not required.

In areas where there is little or no natural daylight available to make the use of a photocell worthwhile, the system has established occupancy lighting control zones so that when a presence is detected, lighting would automatically turn on within that zone and turn off when vacated.

To suit the operational requirements of the cellular glass fronted meeting rooms, Setsquare featured its optional ‘demand button’ to enable users to override the system during visual media presentations. This switch takes the system from a presence mode, where the lighting is controlled by movement sensors, to absence mode where the lighting will need to be manually energised prior to being controlled. In absence mode it allows people to momentarily move in and out of the space without having to turn on the lighting, subject, of course, to there being sufficient ambient light.

The Ecovert FM spokesperson concluded: “Due to the flexibility of Setsquare’s lighting control technology we have been able to effectively manage the lighting requirements in the different areas of the building at 22 Whitehall.”

Contact Details and Archive...

Print this page | E-mail this page