There is growing evidence that personal control over lighting is a key determinant of office-worker environmental satisfaction and productivity.1 For one, the U.S. Green Building Council's (USGBC) LEED rating system clearly recognizes that individual user control is a contributor to indoor environmental quality and sustainable design. And recently, a survey of professionals in the building products and facilities industries identified tasklighting as the most important type of lighting in the office environment, with ambient lighting identified as a close second.2 However, increasingly restrictive energy codes and growing pressure to design “beyond code” are resulting in general office lighting systems that provide no allowance for tasklights and can leave end users wanting. If tasklighting is to be provided, it must not only be counted as part of the energy solution, it must be anticipated in the design and relied on to do a significant amount of the lighting work.STRATEGIES FOR CHANGE
Designs for office lighting are trending toward two strategies. One approach positions portable tasklights at primary task areas to supplement a reduced level of overhead lighting. Another uses portable task/ambient luminaires at those locations to provide a balanced illumination with no conventional overhead lighting. Both methods satisfy two important aspects of high-performance workspaces: They save energy and provide personal lighting control.
California's Title 24 Energy Efficiency Standard is advancing the trend toward these “low-ambient” office lighting strategies by providing a limited exemption for furniture-mounted office lighting. This progressive code recognizes that much of the future energy infrastructure for accommodating sustainable growth in our cities will be gained by reducing the electrical demand of commercial buildings, especially office buildings. California understands that tasklighting and other portable task-specific lighting solutions will dramatically reduce electricity demand, thus also playing a key role in expanding the capacity of the existing power grid to serve a growing population.
However, “low-ambient” solutions present new challenges for a design industry that has traditionally focused on reflected ceiling plans and overhead lighting systems to fulfill primary office lighting needs. Under the newest lean-energy guidelines, conventional lighting solutions fall short, and those that merely anticipate supplemental tasklighting are rarely successful. Properly composed low-ambient workspaces rely on a coordinated effort in which the lighting issues and vision are understood and supported by the owner and/or client, architect, engineer, lighting professional, space planner, and furniture dealers alike.
Failure to align the design process, project documentation, and product delivery with the new reality has recently resulted in a range of missteps and misfortunes. This includes projects where:General overhead lighting consumes the entire lighting energy allowance while delivering borderline conditions with no energy allowance latitude for adding tasklights.The overhead lighting anticipates tasklighting, but no tasklights were delivered because the tasklighting design, specification, and/or procurement responsibilities were not clearly defined.A disconnect or mismatch between the ambient lighting and the tasklighting relative to quantity, quality, lamp color, controllability, or other aspects leaves the occupant unfulfilled.
To secure success, tasklighting should no longer be left to chance or left out of the project's design-to-implementation equation.LEARNING A NEW LIGHTING GENRE
Tasklights and furniture-mounted task/ambient luminaires differ from traditional ceiling-based lighting in a number of ways:They are portable.They are not part of the project electrical rough-in.They usually do not require an electrician for installation.They can be purchased from furniture dealers.They operate at 120V.They connect to the building via standard power receptacles.They do not have traditional control-wiring connections.
To successfully implement an office lighting model that relies largely on portable tasklights and integrated task/ambient luminaires, traditional design processes and practices must evolve to reflect these unique characteristics.
In fact, to maximize user satisfaction, productivity, and energy conservation, it is best to satisfy the personal lighting requirements of the office first, and then add lighting to address luminance ratios and any non-personal, collaborative work activities. Lighting professionals historically have not built their designs around individual task needs and locations, in part because these details often evolve later in the design process. Lighting retrofit projects are one exception where the workstations and visual tasks are pre-existing and quickly become the focus of the lighting scheme. Owners and clients should make early decisions about individual workstations and arrangements and work with their lighting professional to integrate task or task/ambient lighting that best serves the individual workers.
Through this collaboration, lighting professionals will become conversant in workstation design and adopt furniture plans, even early schematic furniture arrangements, rather than reflected ceiling plans as a platform for applying lighting that directly relates to office activities. Early determination of where fixed, hardwired lighting is required and where it is not needed will result in lean lighting solutions that provide and consume no more and no less energy than required. Likewise, workstation designers, space planners and end-users will become more knowledgeable in lighting and visual issues and begin to see tasklighting as an extension of a comprehensive lighting- and energy-management system with critical performance attributes, not just an element of form or fashion.