Almost every element of a campus lighting system eventually wears out or becomes obsolete. Replacing these elements piece by piece is not likely to result in a unified, well-designed lighting system. Master planning can help set a precedent and establish guidelines so that incremental changes do not lead to visual chaos and fragmentation.
Lighting master planning should not be done on a whim or personal preference. The designs must be based on research, history and the principles of human perception if they are to provide a clear blueprint for future growth. A lighting master plan is likely to deal with the entire visual environment, because that is the sole purpose for providing light. A plan cannot focus only on the technical aspects of illuminating paths and streets. It also must create appealing environments for people: exciting and attractive places where people can feel safe and secure. It should have a common-sense, humanistic approach with technical backup.
Street lighting beginnings
In today's society it would be unthinkable not to light a campus or city; yet that wasn't the case in 1417, when the mayor of London made the first known attempt at comprehensive street lighting in the western world. He ordered that lanterns be placed in front of every home on winter evenings. The citizens felt their taxes were high enough so they put out the lanterns but did not light them. Along with the expense, not everyone considered municipal lighting desirable. Some common complaints about municipal lighting in the 1400s:
Strong religious and social resistance; it is interfering with the divine plan.
Those who were out at night were most likely evil.
If it was necessary to be out at night, God would provide a moon.
Illuminating the streets would induce people to stay outside at night, leading to colds and other ailments.
Drunkenness and depravity would increase.
The light would aid thieves while all the good people slept.
The next attempt at lighting streets was not made until 1736, when London installed 5,000 oil lamps. The response was so favorable that by 1738 London had 15,000 oil lamps in the streets.
Many advances in street lighting occurred over the next 270 years. Cities and campuses were illuminated with oil lamps, gas lamps, incandescent and various electric-discharge lamps. The technical aspects of this revolution may be interesting to some, but the social implications are significant for everyone. Churches began holding services after dark; restaurants served dinner into the evening; theater and lectures became a nighttime event. Over the past 200 years lighting has changed the entire social structure and schedule; exterior lighting has become a necessity rather than a luxury.
A successful plan
Understanding the sociological effect of lighting our night environment helps us to define the objectives of a successful lighting plan. These objectives can be grouped into four categories: safety, security, convenience and aesthetics.
Satisfying human needs in these four areas is why lighting systems exist and the ultimate standard by which they should be judged. Meeting these objectives requires that the lighting design go beyond simply satisfying quantitative criteria for illumination on horizontal or vertical planes. The qualitative aspects of a design, although difficult to quantify and prescribe, typically are the most important.
Safety can be defined as the ability of students, faculty or visitors to reach their destinations and perform necessary tasks without causing inadvertent physical harm to themselves or others. The lighting system, in combination with the other elements of the campus, must provide enough visual information so that people don't stumble, lose their orientation, collide with vehicles, pedestrians, or inanimate objects, or cause some other accidental physical harm.
This is a hot topic on college campuses. Unlike physical safety, security is subjective and involves much more than providing adequate amounts of light. Campuses need to provide a sense of security. Lighting is only one factor contributing to this sense of security, but it is one easily manipulated, and schools usually rely on it heavily. Coordinating the lighting design to produce an environment that appears well-used, cared for and without shadowy hiding places not only fosters a sense of security in users, but also creates a deterrent to potential assailants.
How easy is it to perform desired vehicular and pedestrian tasks? Vehicular tasks include understanding the driving lanes and organization of the streets, finding street names, buildings and places to park. For pedestrians, tasks include locating streets and buildings, recognizing faces, distinguishing changes in elevation or tripping hazards, and finding the right car when leaving. The ease of accomplishing these visual tasks is not so much dependent on the amount of light, but rather the type and quality of light as well as visual cues and information provided or enhanced by the configuration of a lighting system. Convenience also relates to maintenance of the lighting system. The easier a lighting system is to maintain, the more likely it will remain functioning as intended.
Probably the most difficult objective to quantify is the creation of beauty — visual pleasure or appeal. It is also the easiest to compromise or denigrate during “value engineering” exercises. Yet it may make the most significant contribution to the overall success of the campus. Visual appeal implies the creation of a strong and positive image of the campus, day and night. Every campus should have an image that is distinctive, recognizable and memorable.
The general objectives outlined can be translated into a series of practical design principles, which serve as guidelines for developing a lighting master plan and carrying out future lighting designs. In formulating these principles, school officials should remember that a lighting system is a means to provide or transfer visual information. This information is the desired visual “signal,” and any factors that interfere with or distract one's attention from this signal can be considered to be visual “noise.” In general, the design principles should result in enhanced visual signals and reduced visual noise.
Based on the use and characteristics of various streets and roadways, a lighting system must provide adequate illumination, in the technical sense of footcandles measured at some reference surface. This reference plane should be considered carefully. In the United States, a horizontal reference plane (sidewalk, road surface) usually is chosen, but for many applications a vertical reference plane is really more relevant.
For example, to drive safely, a motorist needs illumination more on vertical surfaces such as obstructions and pedestrians than on horizontal pavement. Automobile headlights typically meet this need. To gain a sense of security, people need enough light to see other pedestrians, especially their faces.
Clear visual signals are not necessarily based on the absolute quantity of light, but rather uniformity and contrast. It is only in the change or anomaly in a regular pattern that attracts attention. It is therefore helpful to have higher illumination levels at points such as intersections to alert users of a potential conflict with vehicles or pedestrians.
It should be noted that the actual quantity of illumination required for adequate vision may be low, and raising the illumination beyond modest basic levels may not result in much noticeable improvement. However, illumination is the easiest criterion to quantify, and it can be relied on disproportionately to its importance in establishing lighting standards. Designers should take care not to over-illuminate an area as this may create a negative connotation that the area has a high crime rate.
A common source of visual noise is glare caused by lights with improper beam control. Glare can range from a mild annoyance (discomfort glare) to disabling problem (disability glare). Glare makes seeing more difficult and produces a subtle sense of discomfort or annoyance. One example: While driving at night your car headlights produce sufficient light to allow you to see the road, but if a car with its high beams on is traveling in the other direction you will not be able to see the road anymore, even though the overall light level has more than doubled. A lighting system should minimize glare.
Well-designed patterns of streets and paths add to the aesthetics and enjoyment of a campus. Classical main walkways often have been adorned in trees and elaborate street furnishings to celebrate their grandeur. Aside from aesthetics, this also serves a practical purpose: defining a campus' organization.
Drivers and pedestrians need quick and effective orientation to develop a visual sense of their location, destination and pathways. Beyond providing adequate illumination, a lighting system should be coordinated to express and clarify the overall structure and organization of the campus layout. Highlighting important features such as nodes, monuments, landmarks, paths or edges can enhance nighttime orientation.
In addition to drawing attention to other features, the lighting equipment itself can be a valuable source of visual cues, day and night. Patterns of luminaries and alignments of poles should be designed to provide drivers and pedestrians a sense of “optical guidance,” an expression of the hierarchy and organization of the campus layout. Most accidents occur not because of an inability to see, but rather a negligence to look in the proper direction. Patterns or alignments that are inconsistent, confusing or unrelated to the overall logic of the campus layout give the wrong visual cues and can be distracting. A user who clearly visualizes the organization of the roadways and paths will be able to devote more undivided attention to the immediate scene. Providing good orientation through optical guidance therefore contributes to the safety and security of the user.
Safety and security are two major objectives of a lighting master plan, but for a master plan to be a success all four objectives should be met in some manner. Every project will have its own unique set of objectives and design principles. Using the suggestions above can be a good starting point for evaluating current master plans or beginning conversations about a new lighting master plan.
Good, PE, LC, is lighting department manager for Brinjac Engineering, Harrisburg, Pa.