New linear lighting brightens work space

New linear lighting brightens work space

By DENISE SIMPSON
Lumena Lighting Design

Have you ever wondered why newer buildings feel more techno-friendly than workspaces constructed 20 years ago? A major part of the answer lies in lighting, which has evolved dramatically over the past several decades – both in response to needs of information workers and to take advantage of innovative lighting technology.

The goal of any lighting design has always been to maximize available light and minimize glare, in a way that is aesthetically pleasing. Early incandescent lights, like living room lamps, achieved this by shielding the bulb beneath a shade. The shade diffused and reflected the light, providing a cozy, homey environment with little direct glare.

Buzz and blink of early fluorescents

Incandescent lights went out the window for commercial applications, however, with the advent of fluorescent technology. Early fluorescents were recessed prismatic fixtures, sized about two by four feet, which fit flat into the grid system of the ceiling.

Two-by-two parabolic lighting

Two-by-two indirect lighting (left) vs. Two-by-two parabolic lighting (right).
Photos courtesy Lithonia Lighting

They were wonderfully energy efficient, and gave off a brilliant, bright light compared with incandescents. By the 1970s, prismatic fluorescents were used almost universally in offices, schools and hospitals.

With widespread adoption, however, came complaints, because early prismatics produced an irritating hum. They flickered and strobed. They also made glare on computer screens, which were beginning to make their way into the office environment.

Some of the problems were mitigated by improvements in lamps and ballasts. But as computer use increased in the general office environment, the constant glare of the prismatic fixture became a major problem, and prompted the lighting industry to find a new solution.

The parabolic 'dark ceiling' look

Enter parabolic lighting, the industry standard of 80’s and 90’s commercial office space. If you're reading this article in your office, look up.

Chances are you'll see a louvered panel emitting light somewhere over your head – an example of a recessed parabolic fixture.

Parabolic lights are comprised of open cells, silver in color, constructed into configurations up to two-by-four inches in size and recessed into the ceiling. They offer a sharp cut-off level, meaning that light can be focused directly downward more effectively than with older prismatic fixtures. This definitive focus contributes to a uniform, dark appearance when you scan the ceiling and the room itself.

Computerization of the workforce has driven big changes in commercial lighting design. The latest trend is direct-indirect lighting, with recessed fixtures that use reflected light, to simulate the look (and many of the benefits) of skylights.

The primary benefit of parabolic technology is that it is inexpensive (being fluorescent), and it also cuts down on monitor screen glare. This was essential beginning in the 80’s, given the proliferation of computers in offices.

Another benefit of parabolic lighting is that it fits well into a standard two-foot-by-four-foot ceiling grid and the crowded space above the ceiling plane. The interstertial passage between a hard slab floor and the suspended ceiling plane is rarely more than 24 inches these days. Cram into this area the sophisticated systems of a modern office building: heat, ventilation, air conditioning, communication cable trays, sprinkler piping, fire alarm wiring, and so on. You have little room left for bulky recessed lighting.

Parabolic fixtures fit the bill, being shallow in depth requirements yet powerful in lumen output.

The parabolic fixture was first designed for small individual offices, where its sharp cut-off created a nice clean look. But then offices went to the open layout we see everywhere today, with partition walls dividing space into individual work stations. Unfortunately, parabolic lighting causes a lot of shadows in cubicles. Workers have to compensate by using desk lamps for hand tasks, especially if they are assigned to cubicles without windows or other natural light sources.

Time for a change

You can sometimes have too much of a good thing. Despite the overall usefulness of parabolic fixtures, people gradually became bored with dark ceilings, dark walls, and focused direct light sources. Now we're seeing a decided shift toward a very different concept: pendant linear indirect lighting – an option that has been around for more than a decade, but is only now beginning to catch on in the general commercial office market.

Instead of imbedding fluorescent tubes in the ceiling, pendant linear indirect lighting relies on long runs of fixtures on cable mounts hung below the ceiling plane. They must be suspended 12 to 18 inches beneath the ceiling surface, in order to prevent hot spots directly above the fixture runs. They therefore require a greater room height than traditional eight-foot ceiling office areas.

Why would anyone opt for the obvious expense of two extra feet of height in each floor throughout a building? Because linear indirect light sources “feel” more comfortable.

By reflecting light up off the ceiling and back down to work areas, linear technology results in a softer, more diffuse light. Reflected light improves shadowing problems, and is therefore a good lighting solution for open-office concepts. Furthermore, because the ceiling plane is one color and intensity, it becomes less noticeable on a monitor screen. This helps to resolve the glare problem. Equally important is the fact that indirect lighting systems don't hog precious above-ceiling space.

The most recent recessed lighting product to be introduced into the marketplace is the recessed direct/indirect fixture, which creates a skylight effect. These fixtures require no increase in slab-to-slab dimensions, and they do a better job of illuminating ceilings and walls.

They also have a shielded lamp, which mitigates glare on computer screens.

So recessed direct/indirect fixtures are becoming an attractive solution to building owners, designers and engineers alike.

Schools lead the way

Many educational facilities are now choosing linear direct/indirect lighting. The reasons for this are many. Schools are designed to last longer than commercial office space. They use lots of computers. Each space is used for a variety of tasks, and classrooms must be flexible enough to accommodate unknown future uses. Also, schools have to consider lighting needs for hand tasks – better served by direct systems than totally indirect options.

Central Washington University recently installed linear direct-indirect lighting in its new 300,000-square-foot science building. Classrooms are frequently used as labs, traditional lecture classrooms, and distance-learning transmission points – all within the same day. Students and faculty members use computers every day.

The best way to meet these diverse needs was with high-quality illumination from rows of cable-mounted direct/indirect linear fixtures.

Coming to an office near you

Other local companies are turning to the new direct/indirect lighting technology as well. Boeing Commercial Airplane Group’s new headquarters building at the Longacres site features linear indirect lighting to enhance the all-inclusive atmosphere of its open office layout.

The World Trade Center in Seattle has adopted recessed direct-indirect lighting as the standard in the two buildings of 240,000 square feet. Lakeridge Corporate Square, a four-building campus about to open in Redmond, is doing a pilot to compare linear indirect and recessed direct/indirect systems. Microsoft is considering installing recessed direct-indirect lighting in its conference and multi-purpose areas, too.

You're going to see more companies following Boeing, Microsoft and the World Trade Center to linear lighting and recessed direct/indirect systems for a very simple reason. People like it. It creates less strain, both on the eyes and the mood, and so workers say they feel happier. And with people spending the long hours we do in our offices, any technology that makes us feel better is definitely worth the investment!

Denise Simpson is senior lighting design consultant of Lumena Lighting Design in Seattle. She has specialized in lighting engineering and design for 22 years.

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