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DUALING IT OUT Researchers at Duke University

and North Carolina State University compared the impact on study participants of dual source lighting versus just overhead lighting. Participants strongly agreed that task lighting was better, made their work physically easier, helped them perform tasks more efficiently and reduced their visual fatigue at the end of the day. Another study by the Renassalear Polytechnic Institute’s Lighting Research Center found that subjects who had controllable lighting felt more comfortable in the room, rated tasks as being less difficult, and rated the lighting quality higher than subjects who did not have control.

adjusting to varying light levels in the environment, and are less tolerant to glare. It’s estimated that for the same amount of light entering the front of the eye, a 20 year-old’s retina will receive three times more light than a 60 year-old’s. This means that, as we get older, our eyes need more light and higher contrast to see the same thing.

So what’s the solution to individuals needing different levels of light? Introducing adjustable task lights at every work station, says Cohen. And at the same time reducing the ambient lighting level to around 300 lux. “At this ambient lighting level, people can talk and walk with their

colleagues but there will be no glare on the computer screens. And with the task light, light is directed to where they need it.”

But not just any old task light will do the trick of helping people to work comfortably and happily, warns Cohen. “There are a lot of factors to consider. The light has to be effortlessly adjustable with one hand; it has to reach a wide area, in other words have a large lighting footprint, to accommodate people working with multiple documents; be cool to the touch, produce a single shadow; have a long life and actually provide enough light (500 to 1,000+ lux) for doing the task.”

“Monitor-document conflict is real and causes issues.”

David Clements, Managing Director of FUTURE Designs, which designs and manufactures commercial luminaires for the workspace, explains why we need to look at the big picture when lighting our workspaces: “There are a number of requirements that need to be taken into account, some regulatory, some advisory, including those regarding uniformity of light. “Sudden contrasts in light levels from high output task light to a low level ambient light should be avoided because it takes the eye several seconds to adjust to new lighting conditions.”

Clements suggests that the best solution will be unique to the workspace and its staff. “In many

cases, office space can be lit correctly and effectively using the traditional overhead lighting system,” he says. “Or a mixture of overhead lighting and task lighting might be best. It’s up to lighting professionals, designers and architects and FMs to collaborate in order to arrive at the best solution, which will vary depending on the workplace and the requirements of its users. The most important point is to remember why we illuminate the space – for the benefit of the end user. Aesthetics and fashion must always take a back seat.”

All lighting options, including task lighting

should be taken into account at the very beginning of a project whether it is a new build or a refurbishment, so that task lighting is part of the overall lighting solution as opposed to an ‘add on’. With the quality of the final lighting solution in mind, Cohen reinforces this point. "Proper task lighting must be designed with the overall lighting needs of the facility in mind, in the early stages of a project, so that all aspects of a lighting design can be achieved. If one goes into a project with the understanding that people need to work effectively and comfortably with light, the overall lighting design can be beautiful and very functional."


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