The importance of customizing lighting for individuals, tasks, and spaces has been conveyed in preceding installments of this series.  That theme continues here, where the unique characteristics of office spaces and their impact on lighting design decisions are explored.
            In most offices, the range of activities, or tasks, is relatively narrow, aiding specification of appropriate lighting parameters.  However, other factors, such as the type of displays in use, the proportion of time spent on each task type, visual capabilities of users, and psychological influences of lighting complicate system design.
            Competing task requirements and varying needs of occupants creates tradeoffs that must be considered.  Where balance cannot be achieved, priorities must be established.  Understanding the characteristics of office spaces and tasks is paramount if one hopes to design a lighting system that suitably balances its objectives.

            A local lighting strategy relies on area lighting (see Part 12) to provide minimum levels of illumination required to maintain safety and task lighting to provide the higher illuminances required for satisfactory performance of demanding visual tasks.  This strategy provides great flexibility in lighting small areas, allowing customization of the visual environment to suit the task and individual performing it.
            Customization of a task-specific area presents its own challenges, in part due to the proximity of luminaires to individuals performing the task.  Maintaining visual performance requires ensuring that sufficient light is provided where it is needed without sacrificing visual comfort.  Balancing these competing objectives requires another level of analysis and planning, which is the subject of this installment of the “Workplace Illumination” series.