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18CITY OF SOUTH MIAMI OFFICE OF THE CITY MANAGER INTER-OFFICE MEMORANDUM South Miami bOd ~ir 2001 To: The Honorable Mayor and Members of the City Commission Via: From: Hector Mirabile, Ph.D., City~ Mnage Christopher Brimo, AICP er;; Planning Director Date: October 2, 2012 ITEM No.---"=----=i==---_ SUBJECT: An Ordinance amending Section 20-3.6(U), Outdoor lighting spillage; creating additional minimum standards for outdoor lighting in residential districts. SUMMARY OF REQUEST At a recent City Commission meeting it was requested that staff consider proposed revisions to the City's current outdoor lighting requirements, as it relates to spillage of light onto adjacent properties. On August 14,2012 the Planning Board reviewed amendments to the City's outdoor lighting requirements and recommended the City Commission adopt additional regulations that pertains to outdoor lighting. The current land development regulation governing this issue is very basic and reads as follows: Section 20-3.6 (U) Outdoor Lighting Spillage. (A) It is the purpose of this section to establish a minimum standard for the provision and use of outdoor lighting in residential areas in order assure night-time safety and security for private property while at the same time protecting adjacent properties from intrusive light conditions. (B) In residentially zoned districts, (RS, RT, RM, PUD-R) outdoor lighting shall be designed so that any overspill of lighting onto adjacent properties shall not exceed one-half (liz) foot-candle (vertical) and one-half (liz) foot candle (horizontal) illumination on adjacent properties. Outdoor Lighting Proposed Ordinance October 2,2012 page 2 0/4 The proposed amendment is adapted from the 2011 model lighting ordinance, published by the International Dark Sky Association and incorporates additional language. 20-3.6(U) Outdoor Lighting Spillage. (A) Purpose and intent It is the purpose of this section to establish a minimum standard for the provision and use of outdoor lighting on public and private property and in residential areas in order to assure night-time safety and security for private property while at the same time protecting adjacent properties from intrusive light conditions. All outdoor lighting fixtures installed on private and public property after the effective date of this ordinance shall comply with this ordinance. This ordinance does not apply to interior lighting. However, overly bright inside light emitted outdoors from any structure will be subject to control by this ordinance if it is determined by the code administrator that it creates a nuisance glare or a disabling glare as defined by this ordinance. (B) General Requirements ill All outdoor lighting affecting ffi residential zoned districts, (RS, RT, RM, PUD-R) outdoor lighting shall be designed so that any overspill of'Iighting onto adjacent other properties shall not exceed one-half (Yz) foot-candle (vertical) and one-half (Yz) foot candle (horizontal) illumination on adjacent other properties. However, any special requirements concerning lighting for the categories listed below shall take precedence . .@l Lighting specified or identified in a specific use permit. ® Lighting required by federal, state, or county law. ill For residential properties, including multiple residential properties not having common areas, all outdoor lighting must be shielded and shall not exceed 1,260 lumens. (3) Light trespassing onto residential property is prohibited except for lights associated with street, roadway or public safety lighting. (4) External illumination of displays, buildings and architectural features shall be performed with a luminaire or luminaries with a total rating, of all luminaries combined, of not more than 2000 initial lumens. Lighting shall be specifically targeted at particular architectural features and shall not project beyond such features. Z:\Commission ltems\2012\1 0-2-12\Section 20-3.6(U) Lighting\Lighting_ CM report.docx Outdoor Lighting Proposed Ordinance October 2,2012 page 3 of4 (C) Definitions as used in this section .L Accent lighting means any directional lighting which emphasizes a particular object or draws attention to a particular area. 2. Foot candle means a measure of luminance or light intensity received on an area of a surface that is a sphere with a one foot radius, or how bright the light is one foot away from the source. The foot-candle is equal to one lumen per square foot. 3. Disabling glare means lighting that impairs visibility and creates a potentially hazardous situation for any person, including pedestrians and motorists. 4. Lamp or Bulb means the light-producing source installed in the socket portion of a luminaire or fixture. ~ Light pollution means general sky glow caused by the scattering of artificial light in the atmosphere and resulting in decreased ability to see the natural night sky. 2.,. Light trespass means light emitted by a fixture that shines beyond the property on which the fixture is installed. L Lumen means a measurement of the total amount of visible light emitted by a source ~ Luminaire or Fixture means a complete lighting unit including the lamps or bulbs, together with the parts required to distribute the light, to position and protect the lamps, and to connect the lamps to the power supply. 9. Nuisance glare means light that creates an annoyance or aggravation but does not create a potentially hazardous situation. ill Shielding means that no light rays are emitted by a fixture above the horizontal plane running through the lowest point of the fixture where light is emitted. lL Spotlight or Floodlight means any lamp that incorporates a reflector or a refractor to concentrate the light output into a directed beam in a particular direction. Section 2. Requirements for Residential Landscape Lighting 1. Shall comply with the above requirements. 2. Shall not be aimed onto adjoining properties. Section 3. Exceptions to this ordinance The following types of lighting shall be exempt from, and are not regulated by, this ordinance but shall be placed and directed to minimize the detrimental effects of glare on motorists, pedestrians and abutting lots: . (a) Lighting within the public right-of-way or easement for the principle purpose of illuminating streets or roads. No exception shall apply to any lighting within the public right-of-way or easement when the purpose of the luminaire is to illuminate areas outside the public right-of-way or easement, unless regulated with a street lighting ordinance. (b) Lighting for public monuments or statuary. (c) Lighting solely for signs as regulated under Section 20-4.3 -Sign Regulations. Z:\Commission ltems\2012\1 0-2-12\Section 20-3.6(U) Lighting\Lighting_ CM report.docx Outdoor Lighting Proposed Ordinance October 2, 20 J 2 page 4014 @ Temporary lighting used on construction sites, where the hours during which construction is permitted is permissible under the zoning ordinance or through special provision approved by the City. liD. One partially shielded or unshielded luminaire at the main entry, which may not exceed 420 lumens. CD Any other partly shielded or unshielded luminaires not exceeding 420 lumens. (g) Low voltage landscape lighting aimed away from adjacent properties and not exceeding 1,050 lumens. (h) Shielded directional flood lighting aimed so that direct glare is not visible from adjacent properties and not exceeding 1,260 lumens. (i) Open flame gas lamps. (j) Lighting installed with a vacancy sensor, where the sensor extinguishes the lights within 15 minutes after the area is vacated. (k) Repairs to existing luminaires provided the number of luminaries repaired does not exceed 25% of total installed luminaires. (l) Temporary lighting for theatrical, television, performance areas, or construction sites. (m) Underwater lighting in swimming pools and other water features. (n) Temporary lighting and seasonal lighting provided that individual lamps are less than 10 watts and 70 lumens. (0) Lighting that is used only under emergency conditions. (P) Low voltage landscape lighting controlled by an automatic device that is set to turn the lights off at one hour after the site is closed to the public or at a time established by the City. Z:\Commission items\20 12\1 0-2-12\Section 20-3.6(U) Lighting\Lighting_ CM report.docx 1 ORDINANCE NO. _____ _ 2 3 An Ordinance amending Section 20-3.6(U), Outdoor lighting spillage; 4 creating additional minimum standards for outdoor lighting in residential 5 districts. 6 7 WHEREAS, the City Commission directed the Administration to have staff 8 review additional requirements to regulate outdoor lighting on public and private 9 property; and 10 11 WHEREAS, the purpose of outdoor lighting requirements are intended to reduce 12 and prevent light pollution; and 13 14 WHEREAS, residents should have the right to decide how much light or 15 darkness they have, on their own properties at night, and filtering in their houses, as they 16 choose; and 17 18 WHEREAS, lighting at night can disrupt sleep patterns and has been associated 19 with increased incidence of disease and shortened lifespan; and 20 21 WHEREAS, on August 14,2012, following a public hearing, the Planning Board 22 recommended approval of the proposed draft amendments Section 20-3.6(U) ofthe City's 23 Land Development Code as set forth below. 24 25 NOW, THEREFORE, BE IT ORDAINED BY THE MAYOR AND CITY 26 COMMISSION OF THE CITY OF SOUTH MIAMI, FLORIDA: 27 28 Section 1. Section 20-3.6(U) of the City of South Miami's Land Development 29 Code is hereby amended to read as follows: 30 31 20-3.6(U) Outdoor Lighting Spillage. 32 33 (A) Purpose and intent 34 35 It is the purpose of this section to establish a minimum standard for the 36 provision and use of outdoor lighting on public and private property and in 37 residential areas in order to assure night-time safety and security for 38 private property while at the same time protecting adjacent properties from 39 intrusive light conditions. 40 41 42 43 44 All outdoor lighting fixtures installed on private and public property after the effective date of this ordinance shall comply with this ordinance. This ordinance does not apply to interior lighting. However, overly bright inside light emitted outdoors from any structure will be subject to control Page 1 of 4 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 by this ordinance if it is determined by the code administrator that it creates a nuisance glare or a disabling glare as defined by this ordinance. (B) General Requirements 1. All outdoor lighting affecting ffi residential zoned districts, (RS, RT, RM, PUD-R) outdoor lighting shall be designed so that any overspill of lighting onto adjacent other properties shall not exceed one-half (Yz) foot-candle (vertical) and one-half (Yz) foot candle (horizontal) illumination on adjacent other properties. This ordinance shall apply to all zoning districts and all lighting located therein shall comply with the provisions in this ordinance, however any special requirements concerning lighting for the categories listed below shall take precedence. (ill Lighting specified or identified in a specific use permit. .ilil Lighting required by federal, state, or county law. ill For residential properties, including multiple residential properties not having common areas, all outdoor lighting must be shielded and shall not exceed 1,260 lumens. (3) Light trespassing onto residential property is prohibited except for lights associated with street, roadway or public safety lighting. (4) External illumination of displays, buildings and architectural features shall be performed with a luminaire or luminaries with a total rating, of all luminaries combined, of not more than 2000 initial lumens. Lighting shall be specifically targeted at particular architectural features and shall not project beyond such features. (C) Definitions as used in this section Accent lighting means any directional lighting which emphasizes a particular object or draws attention to a particular area. Foot candle means a measure of luminance or light intensity received on an area of a surface that is a sphere with a one foot radius, or how bright the light is one foot away from the source. The foot-candle is equal to one lumen per square foot. Disabling glare means lighting that impairs visibility and creates a potentially hazardous situation for any person, including pedestrians and motorists. Lamp or Bulb means the light-producing source installed in the socket portion of a luminaire or fixture. Page 2 of 4 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 7. Light pollution means general sky glow caused by the scattering of artificial light in the atmosphere and resulting in decreased ability to see the natural night sky. Light trespass means light emitted by a fixture that shines beyond the property on which the fixture is installed. Lumen means a measurement of the total amount of visible light emitted by a source Luminaire or Fixture means a complete lighting unit including the lamps or bulbs, together with the parts required to distribute the light, to position and protect the lamps, and to connect the lamps to the power supply. Nuisance glare means light that creates an annoyance or aggravation but does not create a potentially hazardous situation. Shielding means that no light rays are emitted by a fixture above the horizontal plane running through the lowest point of the fixture where light is emitted. Spotlight or Floodlight means any lamp that incorporates a reflector or a refractor to concentrate the light output into a directed beam in a particular direction. 106 Section 2. Requirements for Residential Landscape Lighting 107 108 1. Shall comply with the above requirements. 109 2. Shall not be aimed onto adjoining properties. 110 111 Section 3. Exceptions to this ordinance 112 113 The following types of lighting shall be exempt from, and are not regulated by, this 114 ordinance but shall be placed and directed to minimize the detrimental effects of glare on 115 motorists, pedestrians and abutting lots: 116 117 (a) Lighting within the public right-of-way or easement for the principle purpose of 118 illuminating streets or roads. No exception shall apply to any lighting within the 119 public right-of-way or easement when the purpose of the luminaire is to illuminate 120 areas outside the public right-of-way or easement, unless regulated with a street 121 lighting ordinance. 122 (b) Lighting for public monuments or statuary. 123 (c) Lighting solely for signs as regulated under Section 20-4.3 -Sign Regulations. 124 @ Temporary lighting used on construction sites, where the hours during which 125 construction is permitted is permissible under the zoning ordinance or through 126 special provision approved by the City. 127 .liD. One partially shielded or unshielded luminaire at the main entry, which may not 128 exceed 420 lumens. 129 (0 Any other partly shielded or unshielded luminaires not exceeding 420 lumens. 130 (g) Low voltage landscape lighting aimed away from adjacent properties and not 131 exceeding 1,050 lumens. Page 3 of 4 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 (h) Shielded directional flood lighting aimed so that direct glare is not visible from adjacent properties and not exceeding 1,260 lumens. (i) Open flame gas lamps. CD Lighting installed with a vacancy sensor, where the sensor extinguishes the lights within 15 minutes after the area is vacated. (k) Repairs to existing luminaires provided the number of luminaries repaired does not exceed 25% of total installed luminaires. (1) Temporary lighting for theatrical, television, performance areas, or construction sites. (m) Underwater lighting in swimming pools and other water features. (n) Temporary lighting and seasonal lighting provided that individual lamps are less than 10 watts and 70 lumens. (0) Lighting that is used only under emergency conditions. (p) Low voltage landscape lighting controlled by an automatic device that is set to tum the lights off at one hour after the site is closed to the public or at a time established by the City. Section 4. Existing conditions Properties with existing lighting in violation at the time this ordinance goes into effect shall be allowed ninety (90) days after initial notification to comply. A partial or full waiver due to undue hardship may be granted by the City Commission. Section 5. This ordinance shall become effective immediately upon adoption. Passed and adopted this _ day of ____ 2012. ATTEST: City Clerk 1st Reading: 2nd Reading: READ AND APPROVED AS TO FORM, LANGUAGE, LEGALITY AND EXECUTION THEREOF CITY ATTORNEY Page 4 of 4 APPROVED: Mayor COMMISSION VOTE: Mayor Stoddard: Vice Mayor Liebman: Commissioner Newman: Commissioner Harris: Commissioner Welsh: , ,.' CITY OF SOUTH MIAMI PLANNING BOARD Regular MeetillgMinlltes Tuesd~y, Allg~st14~2012 CitYCommissiPrtQhurnbers ...... ......... 7:30·P.M. ... ....• . .. City of South Miami Ordinance No. 08-06-1876 requires all lobbyists before engaging in any lobbying activities to register with the City Clerk and pay an annual fee of$500 per Ordinance No. 44-08-1979. This applies to all persons who are retained (whether paid or not) to represent a business entity or organization to influence "City" action. "City" action is broadly described to include the ranking and selection of professional consultants, and virtually all-legislative, quasi-judicial and administrative action. I. Call to Order and the Pledge of Allegiance to the Flag Action: The meeting was called to order at 7:39PM Pledge of Allegiance was recited in unison II. Roll Call Action: Dr. Whitman requested a roll call. Board Members present constituting a quorum: Dr. Whitman (Chairman), Mr. Dundorf, Mr. Cruz (Vice-Chairman), Dr. Hauri, Dr. Philips and Mr. Vitalini Board Member absent: None City staff present: Mr. Christopher Brimo (Planning Director), Mr. Marcus Lightfoot (Permit Facilitator), Ms. Tiffany Hood (Office Support). City staff absent: None City Attorney: Mr. Thomas Pepe. III. Administrative Matters There will only be one meeting scheduled (tentatively) in the month of September. IV. Public Hearings 2. PB-12-027 -Applicant: City of South Miami An Ordinance amending Section 20-3.6(U), Outdoor lighting spillage; creating additional minimum standards for outdoor lighting in residential districts. Dr. Hauri read the item into the record. Mr. Brimo presented the item to the Board. The Chairman Opened the Public Hearing. NAME ADDRESS SUPPORT/OPPOSE Ryan Deveraux 5786 Prosper Road He stated his concern of the outdoor lighting spillage at South Miami Park during activities held at the park. Motion: Dr. Philips motioned for Commissioner Welsh to speak for five minutes. This motion was seconded by Mr. Cruz. Vote: Approved: 6 Opposed: 0 Dr. Whitman: Yes Dr. Philips: Yes Mr. Vitalini: Yes Mr. Cruz: Yes Mr. Dundorf: Yes Dr. Hauri: Yes Commissioner Welsh stated that there is neighbor that installed some powerful halogen lights that disturbs another neighbor. He then stated is there any way to quantify how many lumens a neighbor has at the borderline of their property and to adjust the measurements if necessary. The Chairman Closed the Public Hearing. Motion: Dr. Whitman motioned to amend the language of the ordinance Paragraph B outdoor lighting affecting residentially zoned districts RS, RT, RN and PUD-R shall be designed so that any over spill of lighting onto other properties shall not exceed, Paragraph D-l all outdoor lighting affecting residential zoning districts shall follow provisions in this ordinance. This was seconded by Mr. Cruz. Vote: Approved: 5 Opposed: 0 Dr. Whitman: Yes Dr. Philips: Yes Mr. Vitalini: Yes Mr. Hauri: Yes Mr. Dundorf: Absent for the vote Mr. Cruz: Yes Motion: Mr. Cruz motioned to add under G # 5 excluding sporting events. This motion was seconded by Dr. Hauri. Vote: Approved: 6 Opposed: 0 Dr. Whitman: Yes Dr. Philips: Yes Mr. Vitalini: Yes Mr. Hauri: Yes Mr. Dundorf: Absent for the vote Mr. Cruz: Yes Motion: Dr. Hauri motioned to approve the item as a whole. This motion was seconded by Mr. Cruz. Vote: Approved: 6 Opposed: 0 Dr. Whitman: Yes Dr. Philips: Yes Mr. Vitalini: Yes Mr. Hauri: Yes Mr. Dundorf: Absent for the vote Mr. Cruz: Yes International Dark-Sky Association The Nightscape Authority Simple Guidelines for Lighting Regulations for Small Communities, Urban Neighborhoods, and Subdivisions The purpose of the regulation is to: • Permit reasonable uses of outdoor lighting for nighttime safety, utility, security, and enjoyment while preserving the ambiance of the night; • Curtail and reverse any degradation of the nighttime visual environment and the night sky; • Minimize glare and obtrusive light by limiting outdoor lighting that is misdirected, excessive, or unnecessary; • Conserve energy and resources to the greatest extent possible; • Help protect the natural environment from the damaging effects of night lighting. All outdoor lighting fixtures (luminaires) shall be installed in conformance with this Regulation and with the provisions of the Building Code, the Electrical Code, and the Sign Code, as applicable and under permit and inspection, if such is required. Comment: Practical Considerations: 1. The idea that more light always results in better safety and security is a myth. One needs only the right amount of light, in the right place, at the right time. More light often means wasted light and energy. 2. Use the lowest wattage oflamp that is feasible. The maximum wattage for most commercial applications should be 250 watts of high intensity discharge lighting should be considered the maximum, but less is usually sufficient. 3. Whenever possible, turn off the lights or use motion sensor controlled lighting. 4. Incorporate curfews (i.e. turn lights off automatically after a certain hour when businesses close or traffic is minimal). This is an easy and fast way to initiate dark sky practices. Maximum Lamp Wattage and Required Luminaire or Lamp Shielding: All lighting installations shall be designed and installed to be fully shielded (full cutoff), except as in exceptions below, and shall have a maximum lamp wattage of 250 watts HID (or lumen equivalent) for commercial lighting, 100 watts incandescent, and 26 watts compact fluorescent for residential lighting (or approximately 1 ,600 lumens). In residential areas, light should be shielded such that the lamp itself or the lamp image is not directly visible outside the property perimeter. Lighting that is exempt from these regulations: 1. Lighting in swimming pools and other water features governed by Article 680 of the National Electrical Code. 2. Exit signs and other illumination required by building codes. 3. Lighting for stairs and ramps, as required by the building code. 4. Signs are regulated by the sign code, but all sign lighting is recommended to be fully shielded. 5. Holiday and temporary lighting (less than thirty days use in anyone year). 3225 North First Avenue • Tucson, AZ 85719 • USA (phone) + 1 (520) 2933918 • (fax) +1 (520) 2933192 ida@darksky.org • www.darksky.org International Dark-Sky Association The Nightscape Authority 6. Football, baseball, and softball field lighting; only with permit from the authority recognizing that steps have been taken to minimize glare and light trespass, and utilize sensible curfews. 7. Low voltage landscape lighting, but such lighting should be shielded in such a way as to eliminate glare and light trespass. Additional requirements: • Lighting attached to single-family home structures should not exceed the height of the eave. • Residential pole height restrictions can be considered to control light trespass on adjacent properties. Notes: 1. The general belief that more light means better safety and security is just a myth. All that is needed is the right amount, in the right place, at the right time. More light just means wasted light and energy. 2. Use the lowest wattage oflamp as possible. For cost saving purposes, consider compact fluorescent lamps rather than incandescent, as they use much less energy and have a much longer lifetime. 3. Whenever possible, turn off the lights. Definitions: • Glare: Intense and blinding light. Causes visual discomfort or disability. • Landscape lighting: Luminaries mounted in or at grade (but not more than 3 feet above grade) and used solely for landscape rather than any area lighting. • Obtrusive light: Spill light that causes glare, annoyance, discomfort, or loss of visual ability. Light Pollution. • Luminaire (light fixture): A complete lighting unit consisting of one or more electric lamps, the lamp holder, any reflector or lens, ballast (if any), and any other components and accessories. • Fully shielded (full cutoff) luminaire: A luminaire emitting no light above the horizontal plane. • Spill light: Light from a lighting installation that falls outside of the boundaries of the property on which it is located. Usually results in obtrusive light. Additional Resources for Establishing Outdoor Lighting Guidelines 1. Model Lighting Ordinance (MLO) 2. Recommended Outdoor Lighting Zones 3. IDA Lighting Code Handbook 4. Directory of Ordinances and Other Regulations 5. Glossary of Basic lighting Terms and Definitions 3225 North First Avenue • Tucson, AZ 85719 • USA (phone) + 1 (520) 2933918 • (fax) +1 (520) 2933192 ida@darksky.org • www.darksky.org Glossary of Basic Terms Page 1 of2 Login I Krp h I Frqw:lf;MXv I VMlllPds I Mcl::j I Uhqhz I Grqdm About IDA Outdoor Lighting Night Sky Conservation Education Resources Members Act Now GLOSSARY OF BASIC TERMS, LIGHTING We include in this glossary of definitions for a number of the basic terms and words used in the lighting community. For further information and formal definitions, see discussions in standard dictionaries, encydopedias, the IES Lighting Handbook, and other lighting industry books. Note that some of these definitions are quite subjective, and are offered here as a guidance, not as a formal definition. Accent lighting Ambient light: The general overall level of lighting in an area. Angstrom: A unit of wavelength often used in astronomy, equal to 10-10 meter or 0.1 nanometer. Baffle: An opaque or translucent element to shield a light source from direct view. Ballast: A device used with a discharge lamp to obtain the necessary voltage, current, and/or wave fonn for starting and operating the lamp. Beam spread: The angle between the two directions in the plane in which the intensity is equal to a given percentage (usually 10 percent) of the maximum beam intensity. Brightness: Strength of the sensation that results from viewing surfaces from which the light comes to the eye. Bulb or lamp: The source of electric light. To be distinguished from the whole assembly (see luminaire). Lamp often is used to denote the bulb and its housing. Candela (cd): Unit of luminous intensity. One candela is one lumen per steradian. Formerly called the candle. Candlepo'Wer distribution curve: A plot of the variation in luminous intensity of a lamp or luminaire. Candlepovver: Luminous intensity expressed in candelas. CIE: Commission Intemationale de l'Eclairage. The intemationallight commission. Sets most lighting standards. Coefficient of Utilization (eU): Ratio of luminous flux (lumens) from a luminaire received on the "work plane" [the area where the light is needed1 to the lumens emitted by the luminaire. Color rendering: Effect of a light source on the color appearance of objects in comparison with their color appearance under normal daylighting. Cones and rods: Retinal receptors. Cones dominate the response when the luminance level is high, and provide color perception. Rods dominate at low luminance levels. No rods are found in the central part of the fovea. Rods have no color perception ability. Conspicuity: The capacity of a signal to stand out in relation to its background so as to be readily discovered by the eye (as in lettering on a Sign, for example). Cosine law: Illuminance on a surface varies as the cosine of the angle of incidence of the light. The inverse square law and the cosine law can be combined. Cut off angle, of a luminaire: The angle, measured up from the nadir (Le. straight down), between the vertical axis and the first line of sight at which the bare source (the bulb or lamp) is not visible. Cutoff fixture: A fixture that provides a cutoff (shielding) of the emitted light. Dark adaptation: The process by which the eye becomes adapted to a luminance less than about 0.03 candela per square meter (0.01 footlambert). Disability glare: Glare resulting in reduced visual performance and visibility. It is often accompanied by discomfort. Discomfort glare: Glare that produces discomfort, but does not necessarily diminish visual performance. Efficacy: The ability of a lighting system to produce the desired result. Efficiency: A measure of the effective or useful output of a system compared to the input of the system. Electromagnetic (EM) spectrum: The distribution of energy emitted by a radiant source, arranged in order of wavelength or frequency. Includes gamma-ray, X-ray, ultraviolet, visual, infrared, and radio regions. Energy (radiant energy): Unit is erg, or joule, or kWh. Fixture: The assembly that holds the lamp in a lighting systl?m. It includes the elements designed to give light output control, such as a reflector (mirror) or refractor (lens), the ballast, housing, and the attachment parts. Floodlight: A fixture designed to "flood" a well defined area with light. Flux (radiant flux): Unit is erg/sec or watts. Footcandle: Illuminance produced on a surface one foot from a uniform point source of one candela. Footlambert: The average luminance of a surface emitting or reflecting light at a rate of one lumen per square foot. http://www .darksky .org/index. php?option=com _ content&view=article&id=532 9/27/2012 Glossary of Basic Terms Page 2 of2 Full~cutoff fixture: A fixture that allows no emission above a horizontal plane through the fixture. Glare: Intense and blinding light. Never helps visibility. HID lamp: In a discharge lamp, the emitted energy (light) is produced by the passage of an electric current through a gas. High-intensity discharge (HID) include mercury, metal halide, and high pressure sodium lamps. Other discharge lamps are LPS and fluorescent. Some such lamps have intemal coatings to convert some of the ultraviolet energy emitted by the gas discharge into visual output. High-Pressure Sodium (HPS) lamp: HID lamp where radiation is produced from sodium vapor at relatively high partial pressures (100 torr). HPS is essentially a "point source". Illuminance: Density of luminous flux incident on a surface. Unit is footcandle or lux. Illuminating Engineering Society of North America (IES or IESNA): The professional society of lighting engineers, induding those from manufacturing companies, and others professionally involved in lighting. Incandescent lamp: Ught is produced by a filament heated to a high temperature by electric current. Infrared radiation: EM radiation just to the long wavelength side of the visual. IntenSity: The degree or amount of energy or light. International Oark~Sky Association (IDA, Inc.): A non-profit organization whose goals are to build awareness of the value of dark skies, and of the need for quality lighting. Inverse·square law: Illuminance at a point varies directly with the intenSity, I, of a point source and inversely as the square of the distance, d, to the source. E ::; II d2 kWh: Kilowatt-hour: A unit of energy equal to the work done by one kilowatt (1000 watts) of power acting for one hour. Light pollution: Any adverse effect of manmade light. Often used to denote urban sky glow. Light trespass: Light falling where it is not wanted or needed. Spill light. Obtrusive light. Low-Pressure Sodium (LPS) lamp: A discharge lamp where the light is produced by radiation from sodium vapor at a relatively low partial pressure (about 0.001 torr). LPS is a "tube source". It is monochromatic light. Lumen: Unit of luminous flux; the flux emitted within a unit solid angle by a point source with a uniform luminous intensity of one candela. One footcandle is one lumen per square foot. One lux is one lumen per square meter. Lumen depreciation factor: Ught loss of a luminaire with time due to the lamp decreasing in efficiency, dirt accumulation, and any other factors that lower the effective output with time. Luminaire: The complete lighting unit, induding the lamp, the fixture, and other parts. Luminance: At a pOint and in a given direction, the luminous intensity in the given direction produced by an element of the surface surrounding the point divided by the area of the projection of the element on a plane perpendicular to the given direction. Units: candelas per unit area. Lux: One lumen per square meter. Unit of illuminance. Mercury lamp: An HID lamp where the light is produced by radiation from mercury vapor. Metal-halide lamp: An HID lamp where the light is produced by radiation from metal-halide vapors. Mounting height: The height of the fixture or lamp above the ground. Nanometer (nm): 10-9 meter. Often used as the unit for wavelength in the EM spectrum. Photometry: The quantitative measurement of light level and distribution. Quality of light: A subjective ratio of the pluses to the minuses of any lighting installation. Reflector: Controlling light output by means of reflection (mirror). Refractor: Controlling light output by means of refraction (lens). Semi-cutoff fixture: A fixture that provides some cutoff, but less than a full-cutoff fixture. Spotlight: A fixture designed to light only a small, well-defined area. Stray light: Emitted light that falls away from the area where it is needed or wanted. Light trespass. Task lighting: Lighting designed for a specific purpose or task. Ultraviolet "light": The energy output by a source which is of shorter wavelengths than the eye can see. Some photographic films are sensitive to ultraviolet energy, as are many electronic detectors. "Black Ught." Urban sky glow: The brightening of the night sky due to manmade lighting. Veiling luminance: A luminance produced by bright sources in the field-of-view superimposed on the image in the eye reducing contrast and hence visibility. Visibility: Being perceived by the eye. Seeing effectively. The goal of night lighting . . Lighting used to emphasize or draw attention to a special object or building. International Dark-Sky Association(lDA) 1 ©IDA 13223 N. First Avenue. Tucson, Arizona 85719, USA 1 Terms of Use 1 ~ http://www.darksky.org/index.php?option=com _ content&view=artic1e&id=532 9/27/2012