Next best thing to address is how to select a specific lighting zone for an area. Different areas fall into different lighting zones and each has their own set of instructions for lighting design requirements. This will go over these different set of definitions and help understand what area fits into what lighting zone.
Lighting Zone Selection
Selecting a lighting zone can sometimes be as simple as understanding where the project fits best. Is it a residential application? Then probably LZ1 will work best. Is this a business in a business district with lots of ambient lighting? Then probably LZ3 fits best. Speaking to the local permitting and building code office can sometimes help determine what lighting zone the project would fit into best. Pay attention to exemptions, waivers, relaxations and “grandfathering” as well as long term planning when looking into determining the correct lighting zone.
Different population densities fit into different lighting zones. Higher density areas are more likely fit into LZ3 and LZ4 where lower density areas are in LZ1 and LZ2. Understanding the density of the area where lighting is required will help determine what lighting zone fits a project best. Also understanding curfews will help determine the correct lighting zone. New York City (the city that never sleeps) will fit in LZ4 and have no dimming or off periods as there is no curfew or majorly reduced activity levels, whereas the suburbs around NYC would fit into a different lighting zone.
Some communities are looking to make additional changes when implementing new lighting. Some of these changes include reducing light pollution, supporting or maintaining safety for pedestrians and the public, improving quality of life in neighborhoods or reducing impact on local wildlife are all things that communities may want to work on with new lighting projects. Different lighting zones are meant for different applications and understanding this will help determine which lighting zone the application fits in.
Is the local community looking to reduce sky glow, limit glare, and diminish light trespass or conserving energy? Everything needs to be taken into account when determining lighting zone and lighting requirements for new project installations. LZ0 and LZ1 should be used when covering large areas to reduce the impact on sky glow where LZ2 through LZ4 can be used to reduce glare and light trespass as this is a local phenomenon and specific to the topography of the situation. There are two major exceptions to this: nearby observatories require less sky glow and prisons require brighter lighting requirements.
Is there a lighting curfew in place or one that is going to be put into place? This changes the lighting zone requirements and allows for lighting to be turned off or reduced after this time. Lighting benefits are shown when people are present, but after the people all leave, the risk to the public is reduced and the lighting can be reduced or eliminated. Exemptions include roadway lighting, some industrial areas and lighting of public monuments.
Some areas need different lighting due to the population requirements. For example, senior center areas need additional lighting to allow for better visibility, but still need reduced glare. Residential areas require lower lighting requirements so sleep patterns are undisturbed. Understanding population requirements help determine if an adjustment to the lighting zone is appropriate.
Adjacent zones need to be compatible with one another. Lighting zone 2 should be adjacent to either lighting zones 3 or 1. Too drastic of a change causes issues such as spill over as well as lowers the security and visibility, especially along the borders.
Understanding these variances and exceptions to lighting zones will help better chose what lighting zone a project may fall in to. This can greatly affect the requirements for a project and help determine what fits every project best.