HOW HAS THE MLO CHANGED FROM ITS FIRST VERSION?
The MLO has improved greatly because of the public review process. The comments were constructive and helped in developing the current MLO language. We simplified the prescriptive method, developed an optional Street Lighting Ordinance, added a user’s guide, replaced initial lamp lumens with initial luminaire lumens, minimized the number of additional allowances (performance method), reduced the lumen allowances (performance method), revised the BUG system to decouple the glare from the uplight, required a revision to TM-15, recalibrated the uplight to match the lighting zone (U0 equals LZ0, U1 equals LZ1, etc), and discouraged the use of LZ4.
The current version is far more than a compilation of parts from previous codes. It has essentially been rewritten completely through a rigorous and sometimes heated effort to embrace a range of concerns. At every step of the way, the MLO required goals evaluation. For instance, were reduced lighting allowances during curfew hours technically sound? Were lumen allowances actually reducing light pollution? Is the performance method too complicated for a small municipality?
The MLO includes sections on lighting zones, general requirements for all outdoor lighting, requirements for nonresidential outdoor lighting, requirements for residential outdoor lighting, lighting by special permit only, existing lighting, enforcement and penalties, and the usual tables and definitions. An optional street lighting ordinance is included for those smaller communities that may not have a separate street lighting ordinance, but is not properly part of the MLO.
The user guide is incorporated as parallel text into the MLO and is a substantial improvement. It should make adoption much easier. For each section, terminology is explained and examples are often shown in order to illustrate the more formal language. Initial response from reviewers has been that the guide is both technically accurate and helpful.
WHAT IS NEXT? In March, the MLO went to the IDA and IES boards of directors for conditional approval. While the MLO is going through these reviews, the performance method values will be undergoing a validation. This validation is necessary to calibrate the prescriptive with the performance method, and to evaluate the MLO values in comparison to the light level values described in the new IES 10th edition Lighting Handbook due to be released in the second half of 2011. Since many of the outdoor lighting levels are changing in the new handbook, this is a great opportunity to make sure the MLO matches. The goal is to have the MLO ready for use this summer, if all goes well.
WILL THE MLO REDUCE SKY GLOW AND LIGHT TRESPASS? My prediction is yes. California Outdoor Lighting Baseline Assessment CEC P500-03-082-A-18 shows that only 33 percent of all outdoor lighting in California is full-cutoff, and that 48 percent is non-cutoff. It seems clear that regulating luminaire uplight and glare will greatly reverse these trends. By limiting lumen allowances, overlighting will be curtailed, thus reducing sky glow.
Use of lighting zones will help communities customize the MLO. For instance, smaller communities may choose to only use one lighting zone, while larger ones may have multiple zones. This will prevent overlighting and light trespass, especially in mixed-use neighborhoods. Complex lighting designs will still need to meet requirements that minimize sky glow and light trespass.
WILL THE MLO BE SUCCESSFUL? The MLO should be successful, since the goals are ones we can all agree on. But the MLO will only be successful when it is adopted nationwide as a de facto standard. This will require community support efforts and education. Supporting communities in the process of assigning lighting zones to their municipalities and adopting the MLO is crucial. Education for lighting designers, engineers, developers, and city planning departments will allow a higher MLO success rate. Cooperation with lighting manufactures in supplying BUG ratings and initial luminaire allowances for all luminaires will make the applications simpler.
It was also crucial to have lighting professionals involved in this process of writing and evaluating the guidelines, ordinances, and code revisions. Without the lighting designers’ involvement, practitioners have to live with poorly written regulations that affect our designs. It would have been great if the MLO had taken less time to develop, but I believe that the time, effort, and resources spent have been well worth it and have resulted in a quality MLO document. It has been a long journey for the MLO, but the destination is finally in sight.
Nancy Clanton, PE, IALD, FIES, president of Clanton & Associates in Boulder, Colo., is chair of the IDA/IES Model Lighting Ordinance Joint Task Force, chair of the IES Outdoor Environmental Lighting Committee and IES Mesopic Committee, and serves on the IDA Board of Directors.
MODEL LIGHTING ORDINANCE JOINT TASK FORCE: Nancy Clanton, Clanton & Associates, representing the IDA (chair)
Jim Benya, Benya Lighting Design, representing the IDA (former chair)
Cheryl English, Acuity Brands Lighting, representing the IES
Eric Gibson, Kenall Manufacturing Company, representing the IES
Denis Lavoie, Philips Lumec, representing the IES
Leslie Lipstein, Leslie Lipstein Consulting, representing the IDA
Naomi Miller, Pacific Northwest National Laboratory, representing the IES
Michael Mutmansky, Clanton & Associates, representing the IDA
Leo Smith, International Dark-Sky Association, representing the IDA
John Walter, National Grid, representing the IES