Integrated Lighting

May 10, 2006
Installation of DALI-based controls, including individual user controls, improves flexibility, worker satisfaction

By Craig DiLouie

Productivity has traditionally been measured as work output per man- hour. In today’s nonindustrial organizations, productivity is now regarded as a broad range of outcomes, with job satisfaction in the lead. A 1999 Ducker Research market research study, based on interviews with CEOs, facility executives, and real estate managers, discovered that worker satisfaction ranked higher than worker output and absenteeism as factors in making decisions about the quality of the built environment.

Research studies conducted by organizations such as BOSTI, BOMA, and Steelcase further indicate that workplace design is a major contributing factor to worker satisfaction and motivation, and individual and group performance. For example, a BOSTI study, based on surveys of about 13,000 people in 40 business units between 1994 and 2000, suggests that workplace design makes an 8 to 32 percent (smallest to largest) contribution to job satisfaction (average 24 percent), 3 to 10 percent contribution to individual performance (average 5 percent), and 6 to 15 percent contribution to team performance (average 11 percent). David Wyon of the National Institute of Occupational Health in Copenhagen, Denmark, demonstrated in studies that workers who are satisfied with their environment are up to 15 percent more productive than workers who are not.

Despite this apparent connection between workplace design and worker satisfaction, large numbers of workers are not satisfied with their workplace design, including lighting, HVAC, and acoustics, according to studies conducted by BOSTI, ASID, and others. People demonstrate highly variable preferences for lighting and thermal comfort, but the building systems that provide these utilities are installed as fixed output systems predicted to be comfortable to 70 to 80 percent of the occupants. In the case of lighting, installed general lighting systems are predicted to be uncomfortable by up to 30 percent of occupants.

Because people costs outweigh building costs by a ratio of 13:1, according to BOSTI, organizations can benefit by investing in better workplace design that can address variable, individual needs and thereby increase worker satisfaction. Allowing people to select their own light levels, for example, demonstrated greater worker satisfaction in a Light Right Consortium study.

At the Institute of Electrical and Electronics Engineers (IEEE) Command Center, a 24/7 facility in Piscataway, NJ, this concept was put to the test.

John P. Hunt, director of facilities and distribution services at IEEE, conducted a survey of the help desk and data center operators working at the organization’s Command Center, located within the IEEE Data Center. The help desk operators help more than 370,000 IEEE members and staff worldwide. The data center operators monitor IEEE critical business systems that are housed in the server room. The IEEE is the world’s largest technical professional society and a leading authority on areas ranging from aerospace, computers, and telecommunications to biomedicine, electric power, and consumer electronics.

Hunt found that due to the nature of their tasks, lighting preferences varied among the differing groups of employees. The survey also noted that light levels and glare were a problem for both groups. Staff members who needed to refer to written reports and manuals required more direct desktop lighting. Operators referring to various computer screens for their tasks wanted lower light levels.

“The surveys showed a variety of different preferences and problems related to the lighting,” says Hunt.

The question became how to gain greater flexibility from the Command Center’s lighting system, which consisted of general 2x2 light fixtures with fixed output ballasts, so as to satisfy the lighting preferences of employees performing different tasks, both within a specific working shift and as shifts change (21 shift changes per week).

Hunt consulted with Howard Wolfman, PE, senior manager of Regulatory Affairs for Osram Sylvania Inc., a lamp and ballast manufacturer, and Mike Williams, product marketing manager for Osram Sylvania, about how to solve these lighting problems through best practice in lighting design.

“We needed to give the team at IEEE an extremely flexible lighting installation so that the space could adjust to the individual preferences of all the workers in the facility,” says Williams.

The Osram Sylvania team collaborated with Starfield Controls, a manufacturer of commercial-grade lighting controls, to provide a dimming system installed in a phased upgrade. The upgrade included replacement of the existing lamps and fixed-output ballasts with 32W T8 lamps and 28 DALI-based dimmable T8 ballasts with a 100-1 percent dimming range, controllable by workers using Starfield controls including a control system, individual controls, router, and software. At first, wall-box dimmers were installed, which progressed to individual desktop controls, giving each employee control of overhead lighting directly from his or her PC. The user software interface is a simple slide control icon that allows direct control of light levels using a mouse.

“There is no way to predict what level of light an individual may be comfortable with, so it was very important to give people control over their own environment,” says Wayne Morrow, president of Starfield Controls. “Human factor research over the past 3 decades has shown that individuals who feel like they are in control of their environment are more tolerant of that environment.”

The Light Right Consortium (, for example, recently conducted a study of an open office plan mock-up in Albany, NY. Workers performed standard tasks under five lighting conditions, and output measures that were collected ranged from the subjective (participant’s opinion) to objective (quantitative performance). Scenarios included a regular array of three-lamp parabolic fixtures, a regular array of recessed lensed troffer fixtures, a linear system of direct/indirect fixtures, the linear system plus a movable desk lamp with three light levels controllable by switching, and the linear system with the direct light output dimmable using an interface on the worker’s computer. The results suggest a correlation between lighting choices and worker satisfaction.

“People with dimming control reported higher ratings of lighting quality, overall environmental satisfaction, and self-rated productivity ... people with dimming control showed more sustained motivation, and improved performance on a measure of attention ... In addition, on average, people with dimming control chose lower illuminances [light levels] than current recommended practice. This implies that individual overhead dimming control has potential for energy savings,” the Light Right Consortium concluded.

“Think about the variety of different lighting options that people use in their homes, yet when they come to work, they’ve got to work under whatever lighting is provided,” says Hunt. “Giving employees lighting control in their workspace makes them more comfortable, and thus more productive, at work, and that’s what our business is all about.”

The IEEE project is also significant in that it was one of the first to utilize DALI-based lighting controls in a retrofit application. Digital dimming provides a high degree of granularity and flexibility of control capability, including zoning control at the individual ballast level. Using software, the facility operator can zone and then rezone ballasts and groups of fixtures without rewiring. In addition, some digital ballasts provide two-way communication, enabling ballasts to both receive commands and respond with maintenance and energy information such as notification that a lamp or ballast has failed. And because most digital systems conform to the Digital Addressable Lighting Interface (DALI) protocol, a European and NEMA standard, true interchangeability between DALI-based products from different vendors is possible, dimming performance is consistent across all dimming ballasts regardless of type or manufacturer, and different ballast types can mingle in the same control area on a common communication wire.

“The DALI package enables facilities managers to control lighting with solutions that range from the simple to the complex, from basic desktop dimming to multitiered scene setting,” says Wolfman.

Digital ballasted networks require on-site field commissioning, which should be factored into the design specification. In the IEEE project, IEEE staff worked with Starfield and Osram Sylvania personnel by e-mail and telephone to commission the project. Hunt says they encountered some minor problems while adapting the new ballasts and controls to the existing fixtures, as this was a test site for retrofit installations of a DALI-based system, but that the manufacturers helped his staff to address any issues.

“The DALI-based system will provide us long-term flexibility in this dynamic space,” says Hunt. “Lighting changes for future space reconfigurations can be made via software without any wiring changes. DALI provided an exciting option for the Information Technology staff who would be using the dimming system. The project was initiated to improve the user environment; however, since implementation, we’ve seen energy savings because the lighting is set at a generally lower level. Additional features can be added at a later date, based on the changes we decide to make in the Data Center.”

After installation, Hunt again surveyed the workers about their lighting, and observed their adjustment to the new lighting. The survey revealed that the staff is highly satisfied with the lighting in the Command Center. Hunt adds that general satisfaction of the work environment increased, and that he has received fewer complaints than before the upgrade regarding other environmental issues such as thermal comfort, acoustics, and office equipment.

“Based on the success of this project, we plan to implement additional controllable lighting in our facility,” concludes Hunt.

Craig DiLouie is principal of ZING Communications Inc. ( and communications director for the Lighting Controls Association (

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