Case Studies Lighting Control Delivers Cost and Energy Saving Benefits to Nationwide The futuristic-looking white aluminium-clad building, Nationwide’s HQ, has been a landmark in Swindon since it was built in 1992. It comprises four blocks centred round a large glass atrium. Extensive landscaping - 100,000 trees were planted - and a scenic lake with fountains add to the grandeur of the building. Home to 3,000 employees, it is almost like an enclosed town. Internal trees and shrubs, a boulevard of cafes and shops, even a Starbucks coffee shop all contribute to the street scene atmosphere created inside the building. Such is its innovative design it received a prestigious award from the British Institute of Architects. But above all it is a working environment, with open plan office areas, cellular offices, boardrooms, meeting rooms and staff recreation areas throughout the building. Energy efficiency is the responsibility of David Bailey, Nationwide group energy manager. The building has impressive credentials - fully air conditioned with variable air volume to eliminate any water borne disease risk, double glazed throughout, high insulation specification with low heat transmission value of 0.2. However, his concern was that the lighting within the building was not being effectively controlled. A review carried out by Jim Ure, managing director of leading lighting consultants ABS Consulting, revealed there was some staff dissatisfaction with the high levels of artificial light, with a number of people complaining of headache and eyestrain as a result. “This was the first reason for us looking at how we should effectively control levels of lighting in the building,” said Bailey. “The second reason was that the lighting needed to comply with the latest requirements of the Display Screen Equipment Regulations, especially as the majority of the staff in the building used computer screens. “The third reason was the company’s desire to become even more energy efficient. We run a 24 hour operation within the building, all the lights were operated manually, no-one had ownership of the off switches. Consequently lights remained on throughout the complex whether they were needed or not. Further energy wastage was caused by the air conditioning plant which had to work harder to combat the excessive heat generated by the lights being left on needlessly.” Nationwide and ABS Consulting then conducted a major survey of lighting controls manufacturers before identifying three candidates. Following this, Ex-Or Ltd, European leaders in lighting management systems, was chosen following a review of the candidates’ range of systems, capabilities, installation and commissioning abilities and a competitive price tender. Nationwide visited previous Ex-Or installations at the Land Registry in Gloucester and the Scandinavian Bank in London before finally making its choice. In the complete design and fit contract, Ex-Or installed its MLS Digital Managed Lighting System throughout 60 per cent of the occupied office space within the complex. A total of 3,000 luminaires are now under control. In the open plan areas, where flexibility and expansion capability is paramount, groups of three luminaires are individually controlled and lighting levels respond to both occupancy and levels of natural light. The communicating presence detectors then swap this information with other luminaires within the complex so automatically delivering optimum lighting conditions. MLS detectors communicate with each other to provide the correct level of lighting to occupants in work zones and hold lights on automatically in key circulation areas. As part of the installation, completely carried out outside working hours to ensure there was no disruption to occupants, Ex-Or upgraded the existing luminaires by adding Tridonic high frequency digital dimmable ballasts. Working groups within the open plan areas are flexible at Nationwide and likely to change rapidly as new financial products, such as internet banking, are offered to customers. Zoned groups of luminaires are easily reprogrammed using the hand-held remote MLS infrared programmer. In some cellular offices and meeting rooms, equipped with large plasma screens for AV presentations, Ex-Or commissioned the SceneSelect capability built into the MLS system. This enables occupants to choose previously set lighting scenes to best suit the current use of the room. Again, individual control is provided by dedicated hand-held remote control units. Said Bailey: “We are delighted with the Ex-Or installation. It was completed on time, within budget, and the lighting system does everything it is supposed to do. Feedback from staff and senior managers has been very positive. The installation was a challenge, especially considering the vast amount of high level external glazing which exacerbated the problem of excessive high lighting levels. But the end result is that the system has met our expectations entirely.” In particular, he said, the benefits delivered by the Ex-Or lighting system installations are: Greater visual comfort for staff, significantly reduced incidence of light-related headache and eyestrain, and enhanced productivity Reduced heat gain in the office areas Ability to change configuration quickly and easily to match changing working patterns Increased lamp life Reduced lighting maintenance costs Compliance with the Display Screen Equipment Regulations Preservation of the environment due to reduced carbon dioxide emissions. In terms of energy savings and cost reduction, Bailey estimates that a 70 per cent reduction in lighting costs has been achieved. Electricity savings have been brought about by reduced light demand and resulting reduced demand on air conditioning load.