Trends in Office Lighting
Lighting represents a vast untapped area of opportunity for building owners, facility managers and occupants due to its role in increasing productivity, comfort, sense of well-being and safety and in reducing errors, rejects and accidents. Today, people spend a lot more time looking at the computer screen, communicating on phone or talking with others face to face and in meetings. So the direction of view has become rather 'vertical' instead of horizontal as when writing on paper or ledger posting. The immediate consequence is to reduce glare and at the same time make the surroundings bright in order to avoid a gloomy looking interior. Some conflict already starts here!
The office world is also rapidly changing due to other influences. The Internet in particular has had an enormous impact on the way we do our work and on organisational structure and business. Part-time jobs, tele-working, flexible work, all have their influence on interior design and occupancy of workplaces. Each specific office concept is largely dependent on the type of organisation, autonomy of the employee (alone or as part of a team), autonomy of the department and impact of internal and external communications.
Philips Lighting has developed an office model that classifies office areas according to their function. This model enables lighting design and hardware to satisfy the requirements of both the organisation and its people. The five office functions defined in the model are Hive, Cell, Club, Meet and Lobby.
Hive (Open Plan Multiple Workstations)
Uniform lighting is desirable in a Hive system so as to provide full flexibility in the placement and orientation of workstations. Low-brightness, Omni directional Luminance Control (OLC optic) luminaires are useful to reduce glare and avoid reflections on computer screens, with sun screening and indirect lighting in combination with daylight-linked control systems. For the so-called Call-Centers, where people have to work in different shifts to suit overseas' requirements, the brightness of walls and ceilings should be somewhat high to cheer up people.
Cell (Private Office)
A standard Cell (or private) office requires general lighting, while a more luxurious Manager's office may need a split lighting system (viz. general lighting as well as task and ambience lighting). Aspects such as flexibility, aesthetics and personal preference/control are also important considerations.
Meet
Diffuse lighting is used for group meetings, where the expression on faces should be pleasantly visible. Light is focused on the desk for meetings where concentration is the main issue and notes may be taken. Light control is needed for audio-visual projection and presentations.
ClubIt is possible to light a Club area with uniform general lighting. However, to really underline the Club concept with its dedicated work stations, the lighting systems can be separated. Local and general lighting are used according to user's preference (e.g. in Advertising agency, Architects' office, TV News team etc). A brighter, higher and bigger space can be created with architectural lighting in the form of coves, with accents providing the correct visual ambience.
Lobby
The Lobby is a place, which is used to wait, relax or move to other areas of the interior. The lighting here can help to create a place where people feel comfortable. Using lighting control systems, different atmospheres, accent lighting on posters etc, can be creative. Even showcases of a company's products are increasingly found in lobbies.
What does this mean for Lighting Technology?
Key words that drive future technology are
- Flexibility
- Modularity
- Aesthetics with wider range of application possibilities
- Environmental Friendliness
Lamp technology has undergone a revolution in the last decade. Energy Efficiency and miniaturisation of lamps has been the call of the day. Added to that, great emphasis is placed on the colour quality aspects both in terms of colour rendering index (Ra) and colour temperature (Tc). This focus on technology is due to the fact the lighting quality is more governed by human emotions than just performance.
New Generation Fluorescent lamps with extra low Mercury Content are replacing standard fluorescent lamps. The new TL5 lamp with a diameter of 16mm enables slim and attractive luminaires with precise optics, which occupy less space in the ceiling and use less material.
Create your own Lighting environment
The real challenge is in offering personalized lighting solutions to users. State-of-the-art Lighting Control systems which are compatible with Building management systems, can now offer to users the freedom of choosing their own lighting level or even create their own personalized lighting environment. This is possible with large scale integration of electronics in Lighting, starting from simple hardware like High Frequency Electronic Ballasts, modular local lighting control to integrated lighting control systems!
Light and Health
There is first the well-known research into the effects of lighting on Productivity, Errors and Fatigue.
In all the cases, it is interesting to note that 2000 lux seems to be optimum for visual performance and to minimize fatigue and mistakes. However, due to high-energy consumption and possible glare, it is not yet practical to have 2000 lux in most interiors. However, 500 lux seems more practical. Below 500 lux, all 3 parameters seem to deteriorate sharply. Yet many feel that 500 lux is high! All we need to know is that the Sun (on normal days) produces anywhere up to 100,000 Lux about noon time and we are used to it for millions of years!
Over the past few decades, medical science and research have discovered that almost all human 'physiological' and 'psychological' processes exhibit some rhythms that are linked to our daily (Circa-dian), monthly (Circa-lunar) and seasonal (Circa-annual) effects of light and dark. The Earth's 24-hour rotation, the phases of the moon and the earth going round the sun, have blueprinted these rhythms as a feature of all life on earth. Among others, they affect the biological clock inside us, which regulates our times of sleep, wakefulness, feeling well and activities. Of these, the daily or Circadian rhythm is important as it controls our:
· Moods
· Body temperature
· Production of Sleep hormone by Pineal Gland
· Production of Growth hormone by Pituitary gland
· Production of Stress hormone by Adrenaline gland
· Urination
· Sleep / Wake pattern etc
Cortisol
Melatonin
Alertness
Bodytemp
Consider a daytime office worker. Any light deficiency might increase the melatonin secretion, which can de-synchrone the worker's biological clock. That can make the body and mind prefer to rest but in reality, they need to be active. That feels like 'jet-lag' and lowers performance, alertness, sleep quality (later) and in the longer term affect health. Conversely, sufficient light received during the natural light period (daytime) can synchronize the bio-clock and provide the direct stimuli needed to function well and feel healthy. Research projects show that high illuminance during the day has a positive effect on alertness, performance, vitality, energy level and mood. This is more evident in cases researched in the 'dark' seasons, where there is less light and shorter days.
Because the brain gets its stimulus from light, it is also possible to adjust the onset of Melatonin secretion so that the sleep-wake pattern can be adjusted from day-shift to night-shift. This adjustment usually comes from exposure to daylight or artificial lighting of about 3000 - 5000 Lux for a specific duration at predetermined times, depending on whether it is from day shift to night shift or vice versa.
In night-active (nocturnal) animals, Melatonin can be suppressed by low lighting levels of a few lux. But in humans, light stimuli of about 1000 lux still seems necessary to prevent sleepfulness! However it is not practical to achieve 1000 Lux in the working place due to cost and energy reasons. So the exposure to several thousand lux for a shorter duration in a specific dedicated area of the workplace can support a quick adjustment of the circadian rhythm.
However, investigations in this field are relatively new and a lot more research needs to be done before stipulating some standards of lighting to suit human moods.
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