22 August 2006
LIGHTING DESIGN CONSIDERATIONS
INTRODUCTION. The Lighting Handbook defines visibility as, "the ability to
extract information from the field of view."1 Visibility is affected by glare, uniformity,
illuminance, surface brightness, and lighting components. The consideration of these
factors improves task performance, mood and atmosphere, visual comfort, aesthetic
judgment, health, safety and well-being, and social communication. Additionally,
sustainability concerns, lighting control, and maintenance issues all affect the amount of
energy required to achieve, operate, and maintain this level of visibility. The Lighting
Handbook, Chapter 10 "Quality of the Visual Environment" discusses each of these
aspects in detail. A lighting design guide matrix lists the critical design issues that must
The criteria outlined in this UFC describe the most relevant issues for DoD
facility applications and it refers extensively to the Lighting Handbook. However, the
Lighting Handbook criteria may at times be superseded by other UFC requirements.
This chapter describes the most important lighting design considerations.
Each issue is discussed with the specific requirements that must be met as well as the
items that should be considered during the design process. To use this document,
review these requirements and considerations and refer to chapters 3 5 to get more
detailed information on sustainability issues, daylighting, and lighting equipment.
Chapters 6 and 7 give specific examples of various lighting applications. If a designer
has very little time, these examples provide immediate and specific equipment
recommendations that can be used to meet the outlined criteria.
Task visibility describes how size, brightness, and contrast of a particular
activity affect the lighting required to view that activity. The ability to actually perform a
task well includes other non-visual human factors such as skills and experience,
independent of the task visibility.
2-2.1.1 Large tasks generally require less illuminance, brightness, and contrast to be
performed. Small detailed tasks may require task lighting to increase the light level
significantly. Knowing a description of the task is essential to designing the lighting for
that task. The luminance or brightness of a task increases the task visibility. Brighter
tasks are easier to see, so long as it is not so much brighter than its surroundings that it
becomes uncomfortable or a source of direct glare. As task contrast decreases, the
light level required to see it will increase. If the contrast is too low, it will be difficult to
distinguish various components of the task, reducing visibility.
"Quality of the Visual Environment", Lighting Handbook Reference and Application, Chapter 10, Ninth
Edition (New York: The Illuminating Engineering Society of North America, 2000), p. 10-1.