(A) Other than flood lights and flood lamps, all outdoor area and parking lot lighting fixtures of more than 2,000 lumens shall be full cutoff fixtures, or comply with division (D) below. Dusk-to-dawn open bottom non-cutoff security lights must be fully shielded to provide a full cutoff light distribution.
(B) The same or similar light source color temperature (K°) must be used on any one site that is part of a master-planned development (i.e., a mixture of metal halide and high pressure sodium is not allowed in the same development). This applies to all street light fixtures and to area and parking lot light fixtures that are mounted on a pole or to the side of a building. Exceptions must be approved by the Planning Director.
(C) The mounting height of all outdoor lighting, except outdoor sports field lighting and outdoor performance area lighting shall not exceed 37 feet above finished grade, unless approved by the town’s Planning Department as having no adverse effect.
(D) For lighted parking lots, the minimum light level shall be no less than 0.2 footcandles. All light levels are measured at ground level. The minimum light level requirements vary depending on the activity classification. The specified minimum FC value above 0.2 FC, as outlined in the following table, means that the lowest light level point or location in the parking lot must not exceed the minimum stated FC value in the table (i.e., 0.9 FC for large shopping centers). An average to minimum uniformity ratio of 4:1 means that the average FC to minimum FC ratio cannot be worse (higher) than 4:1. See the following table.
Light Levels for Open Outdoor Parking Facilities*
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Use/Task | Maintained Footcandles | Uniformity Avg/Min |
Light Levels for Open Outdoor Parking Facilities*
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Use/Task | Maintained Footcandles | Uniformity Avg/Min |
(a) Parking residential, multi-family | ||
Low to medium vehicular/pedestrian activity | Range from 0.2 min. to 0.7 min. | 4:1 |
(b) Parking, industrial/commercial/institutional/municipal | ||
High activity, i.e., large shopping centers/fast food facilities, major athletic/civic cultural events | 0.9 min. | 4:1 |
Medium/low activity, i.e., community shopping, office parks, hospitals, commuter lots, cultural/civic/recreational events, residential neighborhood shopping, industrial employee parking, schools, church parking | Range from 0.2 min. to 0.7 min. | 4:1 |
Source: IESNA 8th Edition Lighting Handbook; Modifications: Medium and Low Activity Level recommendations have been combined and modified. | ||
Notes: 1. Illumination levels are horizontal on the task, e.g., pavement or area surface. 2. Uniformity ratios dictate that average illuminance values shall not exceed minimum values by more than the product of the minimum value and the specified ratio. For example, for commercial parking medium/low activity, the average footcandles shall not be in excess of 2.8 (0.7 x 4). 3. The town’s Planning Director or his or her designee shall be responsible for determining the activity level for a development. Any project that requests a light level that exceeds the footcandle values outlined above must demonstrate a need for a higher light level, be approved by the Public Planning Director, and meet lighting trespass limits described herein. | ||
(E) Criteria that can demonstrate a need for a higher light level or other changes that may be required when higher levels are used include, but are not limited to:
(1) Safety and security. The Illuminating Engineering Society of North America (IESNA) provides guidance in its 9th Edition of the Lighting Handbook in Chapter 22. Footnote number two reads:
“If personal security or vandalism is likely and/or severe problem, a significant increase of the basic level (0.2 FC horizontal) may be appropriate.”
(2) Adjacent uses. An adjacent use that is non-residential with a higher light level (light surround) level may required more light to provide the same visibility than an adjacent property with less light (dark surround);
(3) Full cutoff fixtures with shields. In cases where a higher light level is approved, full cutoff fixtures with shielding for designated fixtures may also be justified to better contain the lighting on the property to be lighted and reduce the amount of glare coming out of the fixtures; and
(4) Guideline for increased light level.
(a) The Illuminating Engineering Society of North America (IESNA) provides guidance in its Ninth Edition of the Lighting Handbook in Chapter 22. Footnote number two reads:
“Many retailers prefer even higher light levels, with a specification of 10 lux (1 FC) minimum value.”
(b) The town’s upper limit where a need for higher lighting levels is demonstrated is 4.8 maximum average maintained footcandles. Therefore, the upper limit for the minimum point of illumination is 1.2 FC with a 4:1 average to minimum ratio. (1.2 x 4 = 4.8).
(F) Exceptions to open parking facility standards include the following.
(1) Non-cutoff decorative post-mounted fixtures may be used but must be equipped with a solid top. Mounting heights of 18 feet or less above ground are allowed when the maximum initial lumens generated by each fixture does not exceed 9,500 initial lamp lumens.
(2) All metal halide, mercury vapor, fluorescent, induction, white high pressure sodium, and color improved high pressure sodium lamps 9,500 lumens and less used in non-cutoff fixtures shall be coated with an internal white frosting inside the outer lamp envelope.
(3) All metal halide solid-top decorative post fixtures equipped with a medium base socket must use an internal refractive lens, a diffuse outer lens, or a wide-body refractive globe as described in § 153.02.
(4) Temporary lighting for special events of short duration. Typically, these are low wattage or low voltage applications for public festivals, and the observance of holidays, carnivals, and celebrations.
(G) Garage parking facilities light to IES recommendations outlined below:
Recommended Maintained Illuminance for Parking Garages | |||||
Minimum Horizontal2 | Max to Min Horizontal Uniformity Ratios3 | Minimum Vertical5 | |||
Lux | Footcandle4 | Lux | Footcandle4 | ||
Recommended Maintained Illuminance for Parking Garages | |||||
Minimum Horizontal2 | Max to Min Horizontal Uniformity Ratios3 | Minimum Vertical5 | |||
Lux | Footcandle4 | Lux | Footcandle4 | ||
Basic1 | 10 | 1 | 10:1 | 5 | 0.5 |
Ramps6 | |||||
Day7 | 20 | 2.0 | 10:1 | 10 | 1.0 |
Night | 10 | 1.0 | 10:1 | 5 | 0.5 |
Entrance Areas8 | |||||
Day | 500 | 50 | 250 | 25 | |
Night | 10 | 1.0 | 10:1 | 5 | 0.5 |
Stairways | 20 | 2.0 | 10 | 1.0 | |
Source: IESNA 9th Edition Handbook | |||||
Footnotes: 1 For typical conditions: while these values are intended to address personal security issues, some retailers may increase them to further offset perceived concerns. Top levels of garages open to the sky shall not exceed 0.5 FC minimum with a maximum to minimum uniformity ratio of 15:1 horizontal and 0.25 FC minimum vertical illuminance (source: IESNA Ninth Edition Handbook). The mounting height on the top level of a garage shall not be greater than 22 feet above the parking deck top floor, including raised foundations and the light fixture classification shall be full cutoff. 2 Measured on the parking surface, without any shadowing effect from parked vehicles or columns. For preliminary design, an average value of 50 horizontal lux (five horizontal FC) for basic illuminance (and equivalent for other conditions) may be calculated. 3 The highest horizontal illuminance area, divided by the lowest horizontal illuminance area, should not be greater than the ratio shown. 4 Rounded conversion of lux to footcandles. 5 Measured at one and one-half meters (five feet) above parking surface at the point of lowest horizontal illuminance, excluding facing outward along boundaries. 6 Applies to clearway ramps (no adjacent parking) but not to sloping floor designs. 7 Daylight may be considered in the design calculation. | |||||
(2003 Code, § 28.4) Penalty, see § 153.99