Flex Connectors’ flex7 lighting connection and control System was recently installed over 6 floors at 4 Carlton Gardens, London. The system was designed by Stinton Jones Consulting Engineers LLP and installed by Contractor Langley Electrical of Harlow. Flex Connectors were selected for the project due to their user-friendly design, quick installation time and the fact that they do not require any commissioning.
The building lies within a conservation area, and has much historical significance. It served as headquarters for General Charles de Gaulle during World War 2, who set up the Free French Forces Headquarters there in 1940. It was awarded a blue plaque in 1984 to commemorate their use of the building. Another plaque outside the building details the historic radio broadcast he gave upon first arriving in Britain.
The lighting control specification called for absence control in the open plan offices on each of the 6 floors.
Absence sensors are always the first choice for office lighting control and differ from the more commonly known occupancy type in that they require a pulse from a switch to turn on the lights rather than simply turning on when ever they detect movement. But like occupancy sensors they time out once movement is no longer detected.
In this case however, a solution was required for the open plan office where several absence sensors operating locally needed to be initiated on by just a single switch located at the main doorway. This was simple to achieve using a number of absence sensors from the flex7 Control plus range of networkable sensors. Each sensor is networked back to the single switch, so that operating the switch say, first thing in the morning, initiates all the lights on ready for others to arrive. Importantly because each sensor works locally for absence, the lights under a particular work station will eventually time out if they are left unoccupied – thus saving energy where it was not needed.
Absence detection, with presence enabled
This sounds ideal but there is a problem which is particular to large open plan offices – let us suppose that a person leaves their desk to talk to a colleague at the next desk. It is possible that during their absence their own lights switch off, but now, because they are absence sensors and they can only be turned back on via the switch it will be necessary for the person to walk all the way back to the switch at the doorway to turn their lights back on. Not only could that be a long walk in an open plan office but it could also result in turning on lights at other work stations that have been left unoccupied all day. This is where the flex7 control plus sensors come into their own – during set up it is possible to set flex7 absence sensors with presence detection enabled. Now revisiting the same scenario, when the individual walks back to his desk his lights will automatically switch back on.
This type of hybrid sensor, we believe unique to flex7, is in many ways the perfect choice for control and is probably the most optimal in energy saving. Furthermore because a 3 position centre off switch was chosen it is also possible to initiate the lights off as well as on, thus making it perfect as a last man out switch.
Daylight Dimming Lighting Control
It was also a requirement that the lights should daylight link, so dimming type sensors were chosen. This means that not only will the light output of the luminaires above any particular work station adjust automatically to compensate for any changes in ambient light thus saving energy, but because they are dimmable type, the single switch at the doorway is now not only capable of initiating the lights on and off but also of master dimming up and down the entire open plan office if required. Note that switching previously master dimmed lights off and on again reinstates the daylight linking to all work stations.