This article is reprinted with permission from The Ergonomics Report™ Archives, where it originally appeared on March 8, 2005.
Workers in a bad mood? Maybe it’s the light.
It’s tough to be glum when the sun is beating down on you on a late winter day. But workers who spend their days indoors don’t always have the option to step outside. Instead, their moods, productivity and work performance can be affected by the lighting around them, inside the workplace. When the lighting is good, so is work. When the lighting isn’t, that’s another story altogether.
Studies have shown how much lighting can mean to mood, actions and performance. A 1999 study by Heshong Mahone Group found that retail sales increased by an average of 40 percent when stores adopted skylights. In 2003, the Light Right Consortium, a former ergonomic lighting research group funded by the Pacific Northwest National Laboratory, determined that the ability to change workspace lighting resulted in workers who were more motivated to perform their jobs. Other studies, by Heshong Mahone and by Alberta’s Education Department, have linked more daylight, or at least a better approximation of daylight via improved artificial lights, in the classroom to higher test scores in children. And earlier this month, researchers at the Oregon Health and Science University found that the right light can lead to a better mood, improved behavior and quality of sleep in Alzheimer’s patients.
For the workplace, these studies and other similar ones can be eye-opening: better lighting, particularly lighting that’s appropriate for the task, or more “ergonomic,” can result in improved job performance. In new construction, it equates to a renaissance for natural light, but in the existing workplace, getting more ergonomic lighting into the workspace can prove to be quite a challenge.
Bring In the Sun, But Not Directly
It’s not time to universally turn up the lights and open the blinds. Says Shaun Darragh, a lighting consultant for the Lighting Design Lab in Seattle, the key to effective workplace lighting involves understanding the task, how it’s performed and why a specific type of lighting is appropriate.
“Bringing daylight into the space will affect productivity in the positive,” says Darragh. “The best light for people to see under is the sun, that’s what we’ve evolved to see.” But there’s a big different between sunlight and daylight: sunlight is direct light beaming down from the sun – an unwelcome guest in the workplace. Daylight is simply the light of day.
For workers and workplaces in areas like Seattle, where direct sunlight is a rare commodity, says Darragh, daylighting options couldn’t be better. “Seattle is actually better for daylighting than the desert. You’re trying to avoid letting [direct] sunlight into the building,” he says. “It’s too bright, too extreme for eyes to really handle. But a cloudy climate like Seattle gets great daylight. Here you can effectively daylight almost any space.”
Jon Linn, commercial initiatives manager for the Northeast Energy Efficiency Partners, which has set up the Design Light Consortium to educate and encourage workplaces, builders and homeowners on improved lighting options, agrees. Sunlight, he says, causes glare, the “biggest criminal” in workplace lighting. Added to that is heat and the inability to control the sun, and the too-high contrast that sunlight brings to the work environment. Indirect daylight is much more manageable.
What You Want In Lighting
Remember how long it took to bring up the lights in the old school gymnasium or how the yellow street lights took forever to achieve their full brightness? Remember placing sheets of paper between the fluorescent bulbs and their covering to cut down on the intensity of light in the office or reduce glare? These, say both Darragh and Linn, are just a few of the workplace lighting problems that today’s artificial lighting is trying to fix.
Controllability
Workers, as the Light Right Consortium found out, want to be able to control their lighting. Different tasks performed in the workplace have different lighting requirements. Old metal halide lights that took 20 minutes to reach their full brightness aren’t practical in a location where lights are turned off and on regularly, for example. Relying solely on overhead fluorescent lights to brighten the office space means workers can’t turn the lights up to work on a pen-and-paper task, or turn them down to work on a back-lit computer.
To address controllability, workplaces have adopted task lighting like lamps or under-counter lights. “In the past, recommendations for office lighting led to over-bright offices,” says Darragh. “We typically light offices to a lower light level these days, and add task lighting when we need additional lighting.”
In manufacturing, the same holds true. Too much light, says Linn, can make it difficult to see the fine details of a shiny manufacturing part or even read some of the equipment meters. Too little light just makes it difficult for the worker to see what he or she is doing.
“[Lighting and productivity] gets to the core of lighting design,” says Linn. “In terms of sitting in an office, or the people out in the warehouse or in the factory, they all need to see what they’re doing to get their job done.” But just installing bright lights overhead doesn’t suffice. Just like individuals have their own work styles, they also have their own lighting requirements, and the ability to adjust the light on an individual basis helps workspace lighting fit each unique person.
Color
“If you have robots you don’t need lights,” jokes Linn. “If you’re working with human beings, color definition, brightness and contrast [are all important]. In some cases, too much light doesn’t work. With machine tools, you might need shadows to read those registration marks. Depending on the type of work you’re doing, having the right light source can be very important.”
One of the concerns with lighting today is how color is affected. In an office, a worker who is choosing colors for a publication layout needs to know that the color she sees is the same as the color the reader in the office down the street will see. In a warehouse environment, parts or tools might be color coded, and without quality lighting, orange and reds, or black and blue might be difficult to discern. Lights are therefore categorized based on their Color Rendering Index which offers a measurable quality distinction between light sources that emit light of the same color.
Natural light has the highest Color Rendering Index (CRI) — 100. That’s what helps make it the ideal source of light for a workspace. “The old style fluorescent had a color rendering index of about 60, as do metal halides. High pressure sodium color rendering index is 21,” says Darragh.
While natural light isn’t practical for every workspace, finding an artificial light that comes close to natural light is. Darragh recommends a CRI of 80 or above for all interior spaces; that, fortunately, also includes some of today’s more advanced fluorescent lighting options.
Vertical Light
Experts agree that today’s workspace has to focus on lighting the precise work area in which the task is performed as well as the surrounding environment. Ergonomics, as well as technology and a other factors, has helped move tasks in the workplace to a more vertical position. Computers, for example, run perpendicular to the floor, and most tasks are ideally performed in positions that don’t require the worker to hunch over and look down.
That fact, says Darragh, makes for a greater call for vertical lighting in the workplace – lighting that goes onto ceilings and walls. People are in the habit of looking up. Dark walls can add to worker dissatisfaction and a negative mood, particularly as the darkness affects peripheral vision. Lighted walls can improve overall worker satisfaction.
Advances In Lighting and Justifying a Switch
Lighting, says Linn, has come a long way over the years, but more innovations are on the horizon. Old flickering T12 fluorescent bulbs are being replaced by thinner, better models including T8s and T5s (12, 8 and 5 refer to the diameter of the bulb in 1/8 inch increments – the smaller the number, the thinner the bulb).
Other advances include LED lights that have the potential to light up a room using a fraction of the energy and emitting a fraction of the heat, although they’re currently very expensive.
But one advance in lighting that more workplaces are warming up to is the incorporation of daylight into the workspace. Says Darragh, somewhere around 80 percent of building stock is directly under a roof: perfect for skylights which, when diffused, can allow natural light to fill a space rather that relying solely on artificial light. The benefits, he says, go beyond their ergonomic considerations: they’re energy efficient as well.
That’s something Linn would like to see more businesses nationwide focus on: improving lighting for both the sake of the workplace and the worker as well as for energy efficiency. In his mind, businesses all too often rely on local utilities and government programs to dictate their lighting changes. But not all municipalities nor energy providers implement programs that focus on a switch to more economical and ergonomic lighting.
“My gut feeling is that you’ll find a geographic distribution,” says Linn, noting that the Northeast, Northwest, California and a few other spots around the country have been working hard to successfully encourage businesses to switch to newer lighting options. Other parts of the county haven’t been so diligent.
The holdup? Cash. Regardless of the return-on-investment in saved energy costs and improved worker productivity, switching workplace lights, even from old fluorescent T12s to newer T8s can be expensive – it’s not just replacing a bulb. “Somebody has to be willing to spend the money now to save it later,” says Linn. And too many businesses aren’t.
In building the case for better workplace lighting, designer Darragh is a little more direct: “Energy consumption is secondary,” he says. “The number one cost is the employee. Improving the lighting and productivity a couple of percentage points pays for each employee’s workspace capital costs each year. . . . Progressive companies, those that value their employees, are [adopting new lighting technology]. But there are still companies that are more concerned about today’s bottom line. Companies have to be interested in making an investment,” Darragh says. That’s how they’ll reap the rewards of improving productivity with lighting.