Table of Contents 1. Retain Appearance. Discomfort glare can be reduced by decreasing the luminance of the light source. For now it may be defined as glare that causes complaints.
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Table of Contents 1. Retain Appearance. Discomfort glare can be reduced by decreasing the luminance of the light source. For now it may be defined as glare that causes complaints. Disability glare veiling luminance is caused by stray light scattered withinihe eye.
This contrast reduction can be thought of as a "veil" of luminance over the objects. It is caused by hi. These differences present certain challenges not usually found in interior lighting. There are a number of other Recommended Practices RPs that provide design guidelines for specitlc outdoor lighting applications.
It will also aid in the establishment of community themes and area classifications. Low light level receptors have highly specific requirements to detect identify. When this need for darkness conflicts with other people's need for light. Nuisance or annoyance glare has not been quantified. Glare from streetlights. They can contribute to various forms of glare and thus impede "seeing" the surfaces of interest. Viewing dramatic scenery.
Night time visual clutter can be disturbing. Some of the technical factors that need to be considered when designing and evaluating an exterior lighting system include glare. Discomfort glare does not necessarily reduce. This document is not intended tb supersede these other applicable RPs. This Vision is generally associated with adaptation to a lurnlnance s 0. It is important to see the effect of lighting and to minimize the appearance of the source. The proper lighting of surfaces is the foundation of a good quality lighting design.
In order to minimize glare and provide a pleasant environment.. Lighted outdoor vertical surfaces such as people's faces and bodies. Courtesy of the International Dark Sky Association Lighted outdoor horizontal surfaces such as roadways. Surface luminance of all types adds interest and depth to outdoor scenes and is necessary for good visibility and security see Figure 2. Scotopic Vision is the human eye's response at very low light levels such as moonlight. Photopic Vision is the human eye's response at hiQh light levels whereby the cones account for.
At these levels. Stimuli from the rods are also responsible for peripheral vision. Luminaire luminance is derived from the light-emitting portion of the luminaire's lamp. Refer to Section 3. Wet roadway surfaces. This subjective response is termed "brightness. These vision categories are defined with reference to the adaptive state of the rod and cone pnotoreceptors. The height and location of poles. IESNA RP sources on brightness perception should not be confused with color rendering tasks or with color naming.
The quality of this visual information is critical for both traffic safety and for a pedestrian'S sense of security. This system may include lighting for streets. Special features and amenities of urban environments should be lighted to reveal their importance. Current researoh 1 indicates that less light is required with a light source rich in green and blue components metal halidefluorescent.
This vision is generally associated with adaptation to a luminance between 3 and 0. Exterior lighting design should take into account the prevalence of mesopic conditions.
In urban settings. Note: Lighting for safety involves ensuring proper level of Illumination to provide safe working conditions. Lighting for. The height and location of poles contributes to the hierarchy of exterior lighting equipment along this street in Kansas City.
Source color is usually important too.. HPS is a more efficacious source than metal halide for on-axis foveal tasks where acuity is important and for luminances of approximate'y 1.
Refer to Section 5. A hierarchy of public lighting connotes the relative importance and character of city-scapes and enhances their information-giving value. Metal halide or other white light sources should be considered whenever off-axis vision is required. Both the rods and the cones contribute to the visual response. When olarity. Objects seen under metal halide or white light sources will appear slightly "clearer" than under HPS for the same luminance. This includes color matching.
The following eight steps Sections 3. Quality outdoor lighting should communicate 'Visual order. Common themes in architecture and lighting equipment can help communities or special dlstrlcts establish unique identities. Urban landscape elements are also a great municipal asset. The Visual image is just as Important dur. Consistency and coordination applied to lightIng special features will strengthen a pUblic lighting design and can improve the sense of community.
The community theme can also help establish methods of approach for meeting the lighting needs of the community based on the levels of both vehicular and pedestrian activity.
EVen the placement of equipment should help determine much of the envirorrnent's visual character after dark.. The types of equipment selected can reinforce the sense of activity and excitement in an entertainment and shopping distrlct. Courtesy of Michael Muthlansky Here. These features. The streetscaoe or pedestrian spaces should appear conststent with the community theme. Outdoor ligi1ungshoulcj be uncluttered 2lnd well-integrated as demonstrated in this streetscape both during the day left and at night right.
In developing lighting guidelines and' to establish and promote a community theme. With careful coordination of such issues as decorative detailing.
This will help maintain a sense of quiet solitude in the wilderness where few cars and pedestrians can be expected. Pole-mounted "Lantern-style" luminaires help create a turn-of-the-century theme for this street. Reviewing local lighting ordinances and bylaws Figure Reviewing community concerns on light trespass and pollution. Courtesy of Clanton and Associates. To meet this higher lighting criteria. A typical family of luminaires exemplifying various pole heights and lurninalre configurations.
In contrast. These ratios should set the maximum permissible luminance levels between the site being illuminated and neighboring sites having a potential direct view. Ure 7. EXcessive luminaire luminance can be distracting. See Figure 7 for lumlnaire distribution types. Any type of lumjnaire. Type ll. Type III and Type V for parking The luminance of luminaires is an important consideration in determining the overall quality ota lighting installation.
A rural settlement may demand lower ratios to preserve lower lighting levels overall. Viewjng car headlights during the daytime is a good exampleot a situation involving high luminance but low brightness. Brightness is affected by the environment in which the luminaire resides. Due to the subjective nature of a lighting scene. As a general rule. The light distribution patterns typical ieo-iilumlnancs traces for seven different lumfnaire configurations used to provide coverage for roadways Type III.
Consider the. All luminaires provide some level of luminance. Any consideration of safety. A municipality may opt for lower or higher luminance ratios dependinq upon the community theme. As the background luminfl. When comparing average luminance and luminous intensity.
The intent of this Recommended Practice is to address the design issues related to outdoor lighting. It also outlines the environmental considerations of outdoor lighting especially related to sky glow and light trespass. Finally, this RP discusses community based design, and specific recommendations for lighting outdoor areas. Your Alert Profile lists the documents that will be monitored.
Lighting for Exterior Environments
This document has been replaced. View the most recent version. ICC A July Lighting for Exterior Environments. February Lighting for Exterior Environments.