Dual source lighting schemes illuminate the way ahead for office design

Element790_Siemens2_MToo bright, too dull, too much glare – lighting (alongside air conditioning) is often one of the most contentious factors in a workplace. Office workers need illumination to read, write, type and interact. Yet many workplaces get it wrong and fail to consider the downsides of poor lighting, and as such staff will suffer from eye strain, headaches and postural problems, leading to sick days, not to mention lost productivity and mistakes. Eighty per cent of office workers experience at least one negative effect from poor quality lighting, according to researchers Bruskin Goldring, and 68 per cent of employees complain about the light in their offices, according to a study by the American Society of Interior Designers.

On the other hand, clever and thoughtfully designed lighting can improve mood, contribute to staff enjoyment of their job, and impact on the look and feel of a workplace for the better. Office lighting can often be overlooked, you can have beautiful and powerful overhead ambient lighting that meets ‘specs’ and it can light up a space, but lighting is designed to work with people in spaces, not just spaces.

Many lighting schemes do not work with the actual employee, they can be inefficient and are not conducive to a healthy and productive work environment. In the 60’s and 70’s our offices were paper environments and the standard of “more lights is better” ruled. However, computers changed everything in the 80’s and people started getting sick due to headaches and eye strain, which were a result of light and glare reflecting off screens. Yet, the way we lit the office did not immediately change.

Lighting for people who sit at desks for a majority of their working day will have certain requirements that are not necessarily applicable for the rest of the office. Technology at work has changed dramatically and we need to think about how this affects our vision when we design office spaces, to ensure people are comfortable and safe in their environment. We need to think about how much light hits specifically the space on the work surface where paper is and where the computer is situated, as the two tasks require vastly different levels of light. Computer screens generate their own light and require little ambient light to use, however working with paper-based documents require five times the amount of light to view properly. If lighting a space with one level of light for everything then we run the risk of getting it wrong for all tasks.

Working in front of a computer screen is not a natural interface for our eyes, and thus we move our bodies to adapt to this artificial situation, and this affects our working posture. When a user has too much light on a screen, the glare will cause him/her to squint, then the body will follow the sight line and the user moves forward into the screen; without realising it their back is off the chair’s lumbar support and places the shoulder, neck and wrists in a crunched position, resulting in a damaging working position.

Task ambient lighting (aka dual source lighting) is the solution. It’s not just adding an adjustable task light, it also reduced the overhead lighting to lower levels, about 300 lux on the working surface. These levels are comfortable to talk and walk with your colleagues and take a tremendous amount of glare off your computer screens. The task lights focus light where it is needed it and in the full control of the user so they can adjust light for their unique needs. Workers who have dual lighting feel their work is easier, helps them perform task more efficiently, and reduces visual fatigue. Additionally research shows that employees in a space with dual source lighting have less lower back and less neck pain than those who only use standard overhead lighting.

The ‘right’ lighting is also economical, companies can save between 35 and 40% off lighting electrical costs by having dual source lighting rather then over bright overhead lighting. 40% to 50% of any building cost is lighting and if you reduce this you can see a great return on investment

The right lighting makes people work more efficiently and contributes to a safe and comfortable working environment. It is up to designers and architects to make sure that the space they design achieves this.


ShaneShane Cohen is Global Director of Lighting at Humanscale. A qualified mechanical engineer, Shane has more than 15 years of experience in product development and now specialises in providing solutions designed to enhance the human experience and travels the world talking about the benefits of intelligent lighting design. www.humanscale.com