Legislation and ordinances are being proposed and adopted in many locations these days. Some are elegant, some are effective, some are difficult, some are self-contradictory and impossible to apply properly or even legally. The lack of technical understanding of the issues involved in outdoor lighting can be addressed by people who want to learn, and hopefully that will happen before the legislation and ordinances are proposed and adopted.
The goals of lighting legislation, ordinances and energy codes are typically:
- to improve the quality of outdoor lighting
- to reduce energy use
- to reduce or eliminate light trespass
- to reduce light pollution
and these are worthy goals that most people will eagerly support.
However lighting legislation, ordinances and energy codes rely on technical aspects to work properly, and the complexity and intracacies can be daunting, even overwhelming. This website tries to provide basic information that should help interested people learn.
Among the issues which can be most confusing to people with little technical experience in lighting is the difference between initial and maintained conditions. That topic is discussed here, and more information is available on the related topics of rated lumens, rated life, efficacy, Lamp Lumen Depreciation (LLD) and Light Loss Factor (LLF). These issuess should be clearly understood in order to develop technically successful legislation and ordinances. Any ordinance that hopes to allow lighting that meets recommended practice - and at the same time impose successful limits on maximum illumination - will need to recognize the differences between initial and maintained conditions of lighting systems.
Comparing proposed ordinances with adopted ones can be informative - although some existing ordinances will be less suitable as models than others. The Town of Parker has in their ordinance a requirement for cutoff for all area lighting luminaires at 80 degrees above nadir - and typical flat glass luminaires in the Town Hall parking lot.
The objective of ordinances are to limit the impact by neighbors on neighbors, and should be developed to achieve that by using objective metrics of the performance of lighting systems. This means focussing on the impact at property lines and using measurements of the impact produced by the lighting system, such as illuminance and luminance, to evaluate the impacts. This still allows for stringent control of light trespass, in terms of both spill light and glare. Limits on energy use and uplight can also be included. Such ordinances would also control the results of any changes that occur between plan submittal and the end of construction. However such ordinances would avoid any restrictions on the equipment, installation and operation of lighting system, as long as the resulting impact is appropriate. A PowerPoint presentation (59kb) about the elements in such a Model Lighting Ordinance based on lighting system performance is available here.back to the top
Outdoor lighting can be subjected to many different restrictions, and some may even achieve what is intended - but unintended consequences will certainly appear. This is an important fact to remember when deciding which elements to include. As more elements are included, the likelihood for and significance of future unintended consequences and even conflicts increase.
Some ordinances have a minimum number of elements and correspondingly simple information on compliance. For example, the ordinance for Boulder County, Colorado is summarized here. Of course some ordinances include quite a bit more, including restrictions on lamps' type, lamps' wattage, luminaire shape, luminaire light distribution, pole height, pole locations, luminaires or watts or lumens per pole, maximum illuminance levels, minimum illuminance levels, illuminance at the property line, uniformity over the site or part of the site, lighting controls, time of use and even more.
Elements typical to lighting ordinances are discussed in the presentation Legislation, Ordinances and Energy Codes: the Future for Outdoor Lighting - the outline is available here and the Powerpoint presentation (255 kB) is available here.back to the top
Another significant issue concerning legislation and ordinances is recognition of the interaction of the different restrictions that apply - from the same ordinance or overlapping ones - such as a state energy code and local restrictions on lamps, poles, distributions and even perhaps hours of operation. When a lighting system is required to provide post-curfew lighting at no more than 10% of the pre-curfew levels, the simple approach of adding 10% to the allowed connected power (LPD or UPD)is dangerously attractive. However a competent understanding of the details of lighting systems recognizes that the power at lowered light levels is more than a proportion of the power for the system at full output - if for no other reason than the unavoidable drop in the efficacy of lamps and ballasts when using either smaller lamps or low-output ballasts. Any additional limits on the lighting system - say on the number of luminaires allowed on each pole - can further complicate any post-curfew lighting.
One of the most basic errors in ordinances is the recurring misunderstanding of the interaction of site uniformity requirements and boundary illuminance limits. This is discussed in detail here. Improper combinations of these restrictions will prohibit lighting systems from producing the illumination levels recommended for providing safety and security. Such is the case with ordinances under consideration in 2003 by jurisdictions in Colorado's Front Range. The April 2003 draft of Boulder's ordinance had a definition of uniformity which referred to specific areas (none of which are not defined at all) while including uniformity ratios for the "remainder of site" in the tables on restrictions. Without clear definitions of the areas over which unifromity ratios apply, compliance with an ordinance is entirely at the discretion of the plan reviewer.
Location and height restrictions on poles are another area potential problems. The requirements for pole setback from a property line along with restrictions on the mounting height of luminaires can make it extremely difficult, expensive and energy wasting to light properly - in some cases even make it impossible.
From such a simple review, it should be clear to anyone with an understanding of basic arithmatic and the way multiple restrictions in ordinances work with lighting systems that a proposed ordinance may include restrictions that are confused, incorrect or contradictory - and maybe even all of those.back to the top
Enforcement is an aspect of legislation and ordinances that gets little discussion. Most often, enforcement is based on plan review by paid staff from the jurisdiction involved, and compliance is required before occupancy cetificates are provided. This means that all projects are forced to expand the submittals - sometimes more than doubled in cost to produce - and the entire community subsidizes the expanded plan review process through taxes. This is a very thorough approach in some ways, but requires that everyone pay and sufffer because some people install inappropriate lighting.
An alternative approach is through complaints, and such an approach has its own problems and opportunities. Staff only work on projects that have demonstrated problems sufficient to engender complaints, and nuisance complaints can be relatively easily identified and made to pay for the nuisance. In fact the entire process can be made revenue-neutral by requiring the "loser" - either the complaintant or the transgressor - to pay the costs of the complaint depending on the finding of the staff.
Whatever approach is adopted, it is important to realize that enforcement is a significant and on-going cost to the community from imposing legislation and ordinances - as well as to the businesses or individuals involved. This cost should be included in any evaluation of the impact of legislation and ordinances - too often it is ignored until after adoption.back to the top
The specifics of legislations and ordinances can be extremely technical and complex and can sometimes actually work against some of the stated goals. In the fall of 2002, a project in Boulder to expand an existing parking lot (lighted to meet IESNA standards) proposed 17 poles to cover the expansion. After the city planner reviewers told the designers in 2003 to comply with the proposed Boulder lighting ordinance (unfortunately adopted in 2004), the design was resubmitted with 54 poles - each shorter than the original design's. Now the project has three times the maintenance costs and a 60% increase in connected load compared to the earlier design. This hardly seems to meet the objective of reducing energy use, and will certainly increase light pollution (which is closely related to installed lumens which also increased by 60%) while imposing substantial additional mandatory initial and ongoing costs on the owner of the facility in order to improve the quality of outdoor lighting (the light levels at the perimeter remained in compliance.)
One element of some lighting ordinances is restrictions on lamp types, often under the name of "white light". This sort of restriction tends to apply mostly to High Pressure Sodium (HPS) lamps and to encourage the use of Metal Halide (MH) lamps. When providing the same light levels, MH sources use 50% or more energy, cost more to install and even more to maintain, and contribute significantly more to light pollution and skyglow (two to three times as much!) and to mercury pollution (three to one hundred times as much!!) compared to HPS. The details are discussed here. Such source restrictions hardly support the goals presented above. Since light trespass is the same problem for either source, the difference in the quality of the lighted environment is bought at very high costs in terms of money, energy and light pollution. Giving each of the goals equal merit, it seems just as reasonable to ban MH sources due to their associated energy use and contribution to light pollution.back to the top
There is more and more information about lighting being published and presented these days, and some of it is very good (that includes ALI, of course) and some is not. Some is published or presented in professional context, some in discussions about legislation or ordinances. Readers with limited experience in the technical aspects of lighting may have difficulty in evaluating the quality of information, particularly the technical elements. However some cases are perfectly obvious - is this outdoor retail or a parking lot? Some examples of confusing, misleading, incorrect or wrong information are discussed in the links below.Errors in the Eley Outdoor Lighting Research Report shows some of the problems found during a partial review of the document that is the sole technical basis for the outdoor lighting portion of the CEC's proposed legislation.
If you have suggestions, comments or recommended sites, please contact ALI
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