The Dark Side of Poor Lighting

Improve IEQ with quality illumination

By Jennie Morton
 

Originally published in Interiors & Sources

Eye strain, headaches, low mood, poor concentration, absenteeism, and job dissatisfaction – even a few minutes working under the wrong lighting can kill productivity.

Proper lighting is a cornerstone of indoor environmental quality. It encourages better learning in students, increased purchases in retail settings, faster healing in patients, and higher performance levels in workers.

You can easily keep occupants energetic in well-lit spaces without sacrificing your utility bill. Improve the quality of lighting by focusing on personalized controls and glare reduction.

A Glaring Problem

A Library Shines a Light on the Classics

 
Credit: DAVID WAKELY PHOTOGRAPHY

You don’t need to squint to flip through the stories of Huck Finn or Pippi Longstocking in this library. Natural light floods the stacks of the Valley Hi/North Laguna Library, located near Sacramento, CA.

Daylighting is an invaluable component of a library environment. It creates an inviting atmosphere, reduces eye strain in readers, encourages study habits, and provides illumination for book shelves. Guests are also more likely to linger in the library if they find it visually comfortable.

To maximize the building’s design, a daylighting analysis was conducted in order to optimize site orientation. The modeling led to three key features:

  • The roof of the northern facade is raised to provide diffused light (seen in the main reading room above).
  • A southwest-facing clerestory provides additional daylighting to interior spaces.
  • Sunshine is controlled with horizontal and vertical sunscreens on the southern facade.

By tilting the roof, the southern angle is also ideally situated for photovoltaics. Building integrated photovoltatics, which are applied directly to the standing seam roof, can supply up to 12% of needed energy. The library opened in 2009 and earned LEED Gold for New Construction.

Information courtesy of Noll & Tam Architects and Green Building Services

Consider how the workplace has changed in the past decade. Collaborative trends encourage employees to have dynamic interactions, not remain stationary and isolated in a cubicle. Occupants need comfortable lighting so they can switch between work modes and devices wherever they are at in the building.

“Lighting plays such an integral part in collaborative spaces,” observes Jennifer Woofter, president of Strategic Sustainability Consulting. “When you look at the latest trends in urban office design, they often have very different lighting configurations than your standard corporate interior. That’s done intentionally to set the tone and maximize interaction.”

Time can also render lighting choices obsolete. Your interior layout will likely change long before lamps burn out or fixtures need to be replaced. When the workplace evolves but the lighting remains static, occupants will suffer from the disparity.

“Companies will rearrange their office but never touch the lighting. Fixtures that were originally positioned over workstations are now shining on the aisles, making what was once appropriate lighting all wrong,” explains Richard Manning, principal with Green Building Services, a sustainability consulting firm.

No matter the cause, inappropriate lighting isn’t just a waste of energy. It contributes to low or high contrasts, glare, poor color rendering, and inadequate distribution, notes Mark Havira, director of national accounts with Efficient Lighting Consultants. When occupants are distracted and frustrated, their productivity and job satisfaction substantially decreases.

Poor illumination also detracts from workplace safety. If people can’t properly see what they are doing, accidents and mistakes are more likely to occur, says Havira. Could a customer see the water spill on the floor to avoid a slip? Can a warehouse worker identify an accident waiting to happen? Did a librarian grab the wrong book because she couldn’t easily read the call numbers?

For example, abundant natural light can create areas of high contrast. If workers are unable to distinguish the faces of approaching guests, it could cause a security risk as their ability to recognize threatening behavior is delayed.

Beyond the functional considerations for visibility, lighting is also psychological. “It plays a huge factor in how a person perceives the workplace,” says Woofter. Studies have shown that happier workers are more industrious, their impression of the company is higher, and they have lower absenteeism or turnover rates. The right fixtures can even foster creatvity, boost morale, and encourage communication. A little mood lighting is good for the bottom line.

Shine a Light on Complaints
The Illuminating Engineering Society, OSHA, and ASHRAE outline minimal standards for lumens per square foot, but these best practices largely focus on energy efficiency and safety. How can you tell if your lighting isn’t meeting the needs of your occupants? Simply ask.

A simple walkthrough of your facility can reveal lighting disparities. Look for tape over occupancy sensors, personal lamps brought in from home, lights that are never turned on or have their bulbs removed, and unused task lights, Havira recommends. These are all indications that employees aren’t satisfied with the lighting status quo.

If you’ve ever conducted a thermal comfort survey, try adapting it for lighting quality. A simple feedback form can help identify your worst offending problems. You may find that only one area of the building is suffering from undesirable lighting. You could save significant time and money if you can target one floor or row of offices rather than a mass relamping.

You can also use a standard light meter to review lumen levels, suggests Manning. Take multiple readings throughout the day, particularly if there’s natural light, so you capture the full spectrum of light activity in the space.

While a light meter is a valuable tool, remember that it doesn’t measure color rendering index, cautions Havira. Understanding a fixture’s footcandles is only one piece of the lighting quality puzzle. A light meter alone can’t tell you if the CRI is appropriate for the space or the tasks occurring in it. Havira worked with a company that tried increasing the footcandles in a retail setting. The resulting raise in CRI, however, cast a purple tinge in the space that was ultimately deemed unsuitable.

“Sometimes the quality of lighting has nothing to do with footcandles and everything to do with the perception about how bright a space is,” Manning stresses. “For example, lighting a ceiling can make a space feel brighter, even if you haven’t adjusted the footcandles shining on people’s desks.”

Lighting should be tailored for the types of activities that will occur in a space, says Woofter. Don’t assume the lighting needs for a cluster of workstations will transfer to a private office. Individual task lighting, for example, doesn’t make sense in a boardroom if everyone is sitting around the same table.

Lighting should also set the tone for a space. “You may want a conversational lighting atmosphere for meeting rooms, which is usually created with soft or yellow lights. You might use standup torchieres to make the setting more intimate rather than overhead fluorescents,” Woofter explains.


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