Lighting that meets the energy-efficiency challenge
An installed lighting load 40% below the norm for this type of building has been achieved in the new headquarters of John Wiley & Sons using a scheme based on RIDI AIDA fittings.
Harmonising natural and artificial lighting in the new headquarters of John Wiley & Sons has reduced the installed lighting load by 40%. John Attard gives the details.Sustainable building design has received significant attention in recent years. A growing movement for sustainability has seen designers seeking to create buildings which are environmentally friendly and also cheaper to run. One goal of sustainable design is to reduce energy consumption, particularly of non-renewable sources. Concern over sick building syndrome and the energy costs attached to air conditioning and other services has prompted building owner/occupiers to seek solutions that can offer better management of energy costs. Innovative architects and building engineers are designing office buildings incorporating natural ventilation instead of air conditioning. There is also significant interest, where possible, in maximising the use of daylight and reducing artificial lighting. The use of natural light can reduce internal heat load and increase the effectiveness of natural ventilation. A demonstration of these principles can be seen at the new UK headquarters of technical publisher John Wiley & Sons of Chichester. The building has 4650 m2 of work space over three storeys with a mainly open floorplan and some cellular offices at the perimeter. Built by Mowlem, the centre of the building has a large atrium, which has allowed HBS Consulting Engineers of Reigate, to exploit natural ventilation and daylight. Research has demonstrated that up to 40% of the energy needed to light a building can usually be saved when good use is made of daylighting. Daylight is an essential component of any visually attractive atrium building, but the correct specification of artificial lighting is also vital. The lighting brief for HBS was to create a scheme that could balance natural and artificial light, whilst enhancing the wellbeing and productivity of occupants. The client wanted a low-energy solution, and there were to be no false ceilings, so luminaires would have to be mounted direct to slab. Conscious of the changes within CIBSE LG3 addendum, a conventional category 2 solution was deemed unsuitable. This would not complement the building design or create the desired ambience. Critically the LG3 standards now emphasise good ceiling and wall illumination. However, the client’s energy concerns also had to be accommodated, and an aggressive target of 8 W/m2 was set, combined with a general illuminance of 400 lux. The lighting design required detailed planning, and, a suspended, predominantly uplift solution was favoured. The scheme creates visual comfort, with interior surfaces and brightness levels to complement the brightness of computer monitors. Uplighters on structural columns enliven the space and provide visual contrast and atmosphere. This uplift solution enabled a spacing layout to fit the structural grid. RIDI supplied around 600 AIDA 2x35 W T5 wire-suspended uplighters to illuminate the main office areas. The column-mounted wall lights are from the AIDA-W range, which fill in the perimeter areas and are match the profile of the main AIDA fittings. Other areas were supplied with matching products. A key factor in winning over the client to the proposed system was the use of 3D perspectives at design stage to visualise the final illuminated interior environment. This approach is the result of two years of design and development. culminating in ‘LUXvision’, a state-of-the-art design package that features comprehensive furniture displays and 3D luminaire modelling to simulate a tour of the proposed installation and incorporate any shape of room or building configuration. The installation offers the right blend of performance and low energy consumption. Although as Ken Beall of HBS points out, ‘In the event we never quite achieved the 8 W/m2. However we did get it down to 9 W/m2 — still a great achievement when you consider that 15 W/m2 is the norm.’ Significant energy savings have been made possible. It is becoming apparent that effective lighting has to go hand-in hand with the new climate of cost saving that now permeates the corporate world. Even a small investment in better lighting can affect the bottom line. John Attard is managing director of RIDI Lighting Ltd, 14 Spire Green Centre, Flex Meadow, Harlow, Essex CM19 5T