21.17.080 Nonresidential lighting.
For all nonresidential properties, and for multifamily residential properties of 12 or more dwellings and having common outdoor areas, all outdoor lighting shall comply either with subsection (A) or (B) of this section.
A. Prescriptive Method. An outdoor lighting installation complies with this section if it meets the requirements of subsections (A)(1) and (2) of this section, except that parking lot lighting shall also meet the requirements of subsection (A)(3) of this section:
1. Total Site Lumen Limit. The total installed initial luminaire lumens of all outdoor lighting shall not exceed the total site lumen limit. The total site lumen limit shall be determined using either the parking space method (Table 21.17.03) or the hardscape area method (Table 21.17.04). Only one method shall be used per permit application. For sites with existing lighting, existing lighting shall be included in the calculation of total installed lumens.
2. Limits to Off-Site Impacts. All luminaires shall be rated and installed according to Tables 21.17.05 through 21.17.07.
3. Light Shielding for Parking Lot Illumination. All parking lot lighting shall have no light emitted above 90 degrees.
a. Exception. Ornamental parking lot lighting shall be permitted by special permit only pursuant to LMC 21.17.090(C), and shall meet the requirements of Table 21.17.05 for backlight, Table 21.17.06 for uplight, and Table 21.17.07 for glare, without the need for external field-added modifications.
B. Performance Method.
1. Total Site Lumen Limit. The total installed initial luminaire lumens of all lighting systems on the site shall not exceed the allowed total initial site lumens. The allowed total initial site lumens shall be determined using Tables 21.17.08 and 21.17.09. For sites with existing lighting, existing lighting shall be included in the calculation of total installed lumens. The total installed initial luminaire lumens of all lighting systems on the site is calculated as the sum of the initial luminaire lumens for all luminaires.
2. Limits to Off-Site Impacts. All luminaires shall be rated and installed using either Option A or Option B below. Only one option may be used per permit application.
Option A: All luminaires shall be rated and installed according to Tables 21.17.05 through 21.17.07.
Option B: The entire outdoor lighting design shall be analyzed using industry standard lighting software including interreflections in the following manner:
a. Input data shall describe the lighting system including luminaire locations, mounting heights, aiming directions, and employing photometric data tested in accordance with IES guidelines. Buildings or other physical objects on the site within three object heights of the property line must be included in the calculations.
b. Analysis shall utilize an enclosure comprised of calculation planes with zero reflectance values around the perimeter of the site. The top of the enclosure shall be no less than 33 feet above the tallest luminaire. Calculations shall include total lumens upon the inside surfaces of the box top and vertical sides and maximum vertical illuminance (footcandles and/or lux) on the sides of the enclosure.
c. The design complies if:
i. The total lumens on the inside surfaces of the virtual enclosure are less than 15 percent of the total site lumen limit; and
ii. The maximum vertical illuminance on any vertical surface is less than the allowed maximum illuminance per Table 21.17.10. (Ord. 3178 § 2, 2016)