Alliance for Lighting Information

Review of Denver's Proposed Lighting Ordinance

by David M. Keith, Fellow of the IESNA

The City and County of Denver was invited by the local section of the IESNA to present the proposed ordinance to local lighting professionals and in May 2003 Leslie Lipstein made a presentation. Denver City Council is scheduled to vote on the actual ordinance - in effect a "blank check" for the Planning department - by the end of June. According to Ms Lipstein, the Planning Department spent at least a year developing the document that is now available for public review and comment, for a period of no more than six weeks - even less since any comments must be supplied before the City Council meeting in order to be considered. If the document were less draconian and more technically sound, this might be enough time. As the document is extreme and complex - and riddled with technical errors, misstatements and contradictions - the period for public review and comment between public presentation and the vote of the City Council is inadequate. The Denver City Council should not approve this proposed ordinance at this time.

The ordinance itself is only about a page long and not subject to change. It has a section that states in part:

"To control glare, 
fixtures for surface parking lots, point of service canopies and awnings (with the exception of shielded indirect
lighting under canopies and awings), sales and display, and security and loading must be downcast, meeting
the requirements for full-cutoff fixtures as defined by Illuminating Engineer Society of North America."

The definition of "downcast" is not included (nor is there any reference), the organization's name is actually the Illuminating Engineering Society of North America (IESNA) and any "requirements for full-cutoff" from IESNA do not apply to fixtures but to photometric distributions - a small but technically critical point. On that quick review the ordinance deserves to fail - a critical term is not clear, the principal reference is wrong and the one effort at technical terminology is incorrect. In some games, after three strikes you are out.

This does seem sufficient to bring the entire proposed ordinance into question and even recommend its defeat. The current version of the Rules and Regulations confirms this judgement. And the problems with the entire ordinance are compounded by the lack of time to consider the problems in the particular documents and make any effort to correct them, due to the scheduling by the City staff.

The schedule's brevity is exacerbated by the lack of response from the city to the recommendations made by the liasion from the local IESNA section. The version provided at the beginning of the May 13 meeting was described at that time as being out of date because the responses to earlier comments had not been made - but after another week there is no newer version for review and the city's contact person is out of the office. Therefore the version of the Rules and Regulations provided at the May 13 meeting must be considered as the appropriate one for public review at this time.

This is unfortunate, because this document could clearly benefit from some competent professional advice. For example, there is a requirement that photometric plans be submitted, and include the effects of luminaires (public lighting) not included on the plan (section C, 2nd heading, requirement 2) - and the requirement is:

"In addition to the above requirements, a photometric plan will be required if a lighting layout is 
different from the approved vignettes.  Photometric plan must include:
...
2.	Light contribution from streetlights within 20' of the parking field
	Assume 0.6 footcandles for local streets, 0.8 footcandles for collector streets, 
	1.1 footcandles for commercial arterials and 1.0 footcandle for all other arterial streets."

First - there are no examples of "the approved vignettes" yet for review - who knows who has to submit a photometric plan? Well probably the Planning Department - they will be making up the vignettes and deciding what it takes to be "different". Presumably the rest of us will be told when it matters. Second, the problem with this is more than the requirement that the photometric plans be "doctored" - the requirement makes no mention of *how much area* is supposed to be "doctored" - do the light levels over entire site have "the light contribution" added to it? Or is it just some portion - and if so how much? Never mind that providing such modified photometric plans is a violation of ethics and professional behaviour - it is also impractical as implemented. The entire recommendation indicates a lack of understanding of the profession of lighting design and brings into question the technical competence of the entire document.

Further investigation reinforces the perception of technical incompetence. For example, some of the light levels to be used in "doctoring" the photometric plans (1.1 fc) are in excess of the allowance at the corresponding property line (no more than 1.0 fc, Requirements section B.1.a-d) or public right-of-way (section B.3.a-d) - so the "photometric plan as submitted" would apparently be in violation of the limitations on light trespass.

In addition, the current version of the Rules and Regulations:

fails to cite the recommended IESNA standards that specifically apply to each section (the single general reference to "Recommend Practices" at the end of the glossary is entirely inadequate and not at all encouraging)
requires post-curfew lighting that does not comply with the nationally recognized recommended practices
claims to limit glare, but never mentions the metric associated with glare - luminance - except to define it incorrectly (and several other ways) in the glossary and refer to an antiquated unit - while the proper unit for luminance - candela per meter squared - is correctly defined in the glossary, but also does not appear anywhere in the Rules and Regulations
mandates that all lighting meet standards for which there are no examples in the entire city - the city's representative could not cite one example of lighting that meets the requirements for zone 2 or zone 3 - which will be most of Denver
claims to exempt residential lighting - but expressly requires (in section V.A.4) that residential landscape lighting be shut off at midnight
makes no provision for replacement of individual luminares in existing lighting systems, but instead adds restrictions likely to make "repaired" systems provide sub-standard lighting
restricts the choice and flexibility of lighting design through restrictions on equipment - on page 24 in the glossary, the entire definition of fixture distributions is "Reflectors or shielding, as well as fixture design, determine the fixture classification. Distribution patters other than Type IV commonly referred to a forward throw will not be allowed." - at the very least, this restriction that all lighting use "a forward throw" should be in the main body of the document.
increases the costs of and pollution from lighting systems with no consideration made of the burden to taxpayers, businesses and the environment (further information is available at http://resodance.com/ali)

The document does not include the "vignettes" that are referred to above, redefines technical terms used internationally so the terms become specific to Denver and technically meaningless, and contradicts itself on significant items. The glossary repeatedly refers to the "lamp luminance" of "fixtures as defined by IESNA" and includes accompanying diagrams. If the unknown reference here is actually RP-8-00, the ANSI/IESNA American National Standard Practice for Roadway Lighting, developed by the IESNA Roadway Lighting Committee, then both terms are technically incorrect and the accompanying diagrams have incorrect values and the wrong units (I am a member of that committee and helped write those technical definitions a few years back.) It is impossible to tell what "IESNA" definition applies, because the glossary has no references at all.

Since the proposed ordinance provides the Planning Director with the authority to make any desired changes to the Rules and Regulations, the details of the current version of the document are really beside the point. What matters is the Planning Department's ability to do a good job. The Planning Department so far has not demonstrated that it is competent to make rules and regulations on outdoor lighting. Furthermore it is always unsuitable for any individual to have the authority to arbitrarily change the rules and regulations on any issue that effects public safety. Therefore the Denver City Council should exercise its oversight responsibility by defeating the proposed Zoning Ordinance Language Amendment Summary at this time.

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