Mar 13, 2012 8:12 PM
TUCSON - Pima County Supervisors have passed an amendment to the lighting code at tonight's meeting.
The county's been regulating outdoor lighting, keeping the skies dark for more than three decades. This is mainly to benefit the observatories in Southern Arizona.
Updates to the current code address changes in technology and developments.
Below is the full text of the amended ordinance, from the Pima County Supervisors website:
Staff recommends approval of the attached draft 2012 City of Tucson/Pima County Outdoor Lighting Code, repealing previously adopted editions of the Pima County Outdoor Lighting Code and amending Chapter 15.12 of the Pima County Code to conform.
The item was heard by the Planning and Zoning Commission on February 29, 2012 where it was approved 8-0 (Commissioners Steinbrenner and Membrila were absent).
Pima County has been regulating outdoor lighting to preserve dark skies as a cultural and economic resource for more than three decades through adoption of standards for filtration and shielding. From an economic perspective, a 2007 study conducted by the Economic and Business Research Center of the Eller College of Management reported that astronomy, planetary and space sciences in Arizona contribute to 3,328 jobs and have an annual economic impact of $253M with capital infrastructure exceeding $1B, most of which is located in southern Arizona. This potential industry continues to grow thanks to the region's continued protection of dark skies and as evidenced by the Very-High-Energy gamma ray astronomy pioneered at the Whipple Observatory which is currently proposed to be expanded through an additional $130M capital investment and rotating visiting researchers from over 25 countries to Arizona. In addition, these numbers do not include economic impacts from related optics industries and eco-tourism associated with dark skies.
From a cultural and ecological perspective, protection of dark skies is critical to maintaining our local desert biological diversity and circadian cycle thereof, as well as securing lighting energy efficiency through maximizing its intended use of illuminating objects on or near the ground in lieu of wasting energy in the night sky.
The proposed 2012 code updates the currently adopted 2006 Pima County Outdoor Lighting Code mostly through addressing elements relating to clarifications, changes in technologies and expansion of development. This code was adopted by the City of Tucson on February 7, 2012 (Ordinance 10963).
Clarification of Wording
Code wording and location of requirements within chapters have been modified to facilitate understanding and compliance for both commercial and residential stakeholders. Honorable Chairman & Members, Pima County Board of Supervisors 2012 City of Tucson/Pima County Outdoor Lighting Code February 29, 2012 Page 2 of 2
This proposed edition introduces the concept of "developed area" for purposes of lumen cap calculations so as not to penalize lighting of future development and to provide uniformity in illumination levels. Currently, if a parcel of 10 acres has a developed area of 5 acres, it may use the full 10 acres for purposes of determining the maximum lumens for the site. If the parcel places its full allowance of lighting on the developed area and the 5 acres of undeveloped area is split from the original parcel, the undeveloped split parcel is either not allowed any further lumens or a violation would be created in the original parcel which would have exceeded its lumen cap by a factor of two. In addition, the lit developed area of this example property prior to a split would be twice as bright as typically seen in the area. The concept of "developed area" limits the lumen cap to areas developed on the site so as to both provide for uniformity in lighting levels across the area as well as preserve an allocation for future development which may occur on the property.
This proposed code edition introduces color temperature limitation for both general lighting (max 3500K) and signs (max 4400K for internal lamp sources). Prior code editions encouraged the use of low pressure sodium lighting since this lamp type emits light in a narrow wavelength band averaging 589.3 nm (1700K) which benefits optical astronomical observation for two principal reasons: the first is the very narrow emission band (0.6nm) limits light pollution across the spectrum, and two, that lower temperature light scatters less in the atmosphere resulting in limited sky glow. While this proposed edition still encourages low pressure sodium, it acknowledges that more energy efficient LED lighting has made significant entries into the market and that the technology should be encouraged for energy conservation purposes through limiting color temperature to a useful range not as detrimental to the observatories. The reason internally illuminated signs are permitted a higher temperature than other lighting was based on concerns from the sign industry that currently available lighting may not consistently be available within the 3500K limitation.
Public Right-of-Way Lighting
Illumination within public right-of-ways have been included in this proposed edition reflecting best practices for roadway lighting by the Illuminating Engineering Society of North America (IESNA), the standard currently referenced by the Pima County Department of Transportation.
Simplification of Lighting Area Boundaries No Longer Based on Land Use
This proposed edition has eliminated the confusion created around land usage in the Oracle corridor as well as has further adjusted areas to reflect the growth which has occurred within and around the Tucson city limits.
The proposed 2012 edition was thoroughly vetted within dozens of public meetings organized by the County/City Outdoor Lighting Code Committee starting in 2007 and ranging from general public invitations to meetings targeting specific stakeholder groups potentially most impacted by the proposed changes to include the Arizona Sign Association and Pima County/City of Tucson Departments of Transportation. All stakeholder groups have demonstrated support for this edition and while the observatory interests have had to compromise during the public process, this proposed edition should still provide the requisite protection of future dark skies to ensure continued astronomy industry viability in southern Arizona.
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