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Lighting Chapter 5

Terms and Applications. Lighting Chapter 5. PowerPoint Cartoon. Security Lighting CH 5 P42. Term most often used in Crime Prevention lighting applications. Usually considered to be very brightly- lit areas surrounding a protected structure. Lighting Plan Elements.

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Lighting Chapter 5

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  1. Terms and Applications Lighting Chapter 5

  2. PowerPoint Cartoon

  3. Security Lighting CH 5 P42 • Term most often used in Crime Prevention lighting applications. • Usually considered to be very brightly- lit areas surrounding a protected structure.

  4. Lighting Plan Elements • Provide a clear view from a distance. • Enable anyone moving in or immediately around it to be easily seen. • Deny potential hiding spaces adjacent to frequently traveled foot routes. • Permit facial identification at a distance of at least 30’.

  5. Lighting Plan Elements (cont.) • Facilitate the proper use of other security devices. • Deter crime against persons or property. • Enhance the public’s feeling of comfort in accessing spaces and increase nighttime pedestrian traffic.

  6. Lighting Terms Ch 5 P42-44 • Illuminance • Color Rendering • Uniformity • Glare • Light Trespass • Footcandle • Lamp • Shadows

  7. Illuminance • Quantity - the amount of light arriving on a surface. • Affected by intensity, distance from source and angle.

  8. Color Rendering Index (CRI) • How well true colors are seen under a particular light source. • 0 – 100 CRI • 50+ allows accurate color identification.

  9. Uniformity • Avoids pools of bright light -interspaced with dark or shadows.

  10. Glare • Light which travels on a horizontal plane directly into the eye. • Affects the ability to see beyond the light source.

  11. Light Trespass • Light is distributed into areas - where it is not wanted.

  12. Footcandle • Unit measuring the amount of light reaching a surface or desired location. • Recommended levels are published by the Illuminating Engineering Society of North America (IESNA).

  13. Typical Lamp Types • Interior • Incandescent - filament • Fluorescent • LED • Exterior • Incandescent - filament • Mercury Vapor (Rare) • High Pressure Sodium • Low Pressure Sodium (Very Rare) • Metal Halide • LED

  14. Lamp Type CRI • Incandescent • 100 CRI • Fluorescent • 62-90 CRI • High Pressure Sodium • 22 CRI • Metal Halide • 65-90 CRI • LED • 72 CRI

  15. High Pressure vs. LED

  16. Cal-State Fullerton

  17. Shadows • Shadows • Reduce effectiveness of lighting distribution patterns. • May be annoying - discourages a feeling of safety. • Makes it difficult to maintain quality surveillance.

  18. Lighting and Crime Ch 5 P46-47 • How Much Light For Pedestrian Environs? • Provide necessary sense of security. • Recognize if a person is likely to be: • Friendly • Indifferent • Aggressive • Take an appropriate response: • Continue toward • RUN!

  19. Vertical Illuminance • Essential for facial identification. • Generally measured 5’ above grade. • If the illuminance behind the face exceeds 4:1 ratio of light on the face, the image will be in silhouette.

  20. Vertical Illuminance(cont.) • IESNA G-1-03 minimum of .5 fc semi-circle and .5 to .8 fc on face at 30 feet. • Background to face illuminance not exceeding a 4:1 ratio.

  21. Sample List from IESNA G-1-03

  22. Daylighting • Controlled admission of natural light into a space.

  23. Darkened Campus • 1973 San Antonio, TX School District • one of the first to try turning out the lights on a school campus as a crime prevention measure. • Vandalism costs dropped from $161,000 to $41,000. • East Side School District, San Jose, CA • saved $1,000,000 a year with no increase in vandalism, burglary or arson.

  24. Hillsborough County, FL • 13th Largest School District in the US. • “Lights Out” program in 1994 • Elementary schools from 8 pm to 6 am • Middle schools from 10 pm to 6 am • High schools from 12 pm to 6 am • First full year burglary and vandalism dropped while saving $450,000. • Currently saving over $1,000,000 a year.

  25. The End

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