Site Lighting: Optical Systems Design and Application Guide for Site and Roadways

Selecting the right type of site lighting enhances building design, efficiency, and safety
This course is no longer active
[ Page 11 of 13 ]  previous page Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 next page
Advertorial course provided by Kim Lighting

Figure 11: Typical Round vs. Square Overlap patterns

It should be noted that the effects of lamp orientation and lens configuration on house-side shields are dramatic. Main reflector distribution, street-side reflector brightness, and direct lamp visibility are factors that determine the effectiveness of house-side shields in reducing unwanted brightness on the house-side of the optical system. Horizontal lamp orientation presents the greatest challenge in designing effective shielding. Convex lenses allow more effective control, as the shielding device is able to better control direct arc tube brightness. Vertical lamp orientation provides even greater control, as the arc tube is already deeper in the optical system.

Reflector Orientation/Rotatable Optics
Orientation of luminaires is often controlled by available pole locations and a product's aesthetic design. The luminaire's head, arm, or yoke, however, may dictate an orientation that varies from the desired optical orientation. The ability to rotate optical systems provides a high degree of flexibility to tailor luminaire performance to specific applications, while maintaining the aesthetic continuity of the luminaires used. The combination of optical distributions in multiple luminaire applications produces additional unique "footprints," creating customized performance and/or increased illumination levels to suit a very wide range of needs. Figure 13 shows just a few examples based on a simple twin mounting arrangement.


Figure 12: House-side shields for cutoff and light control for different types of luminaires

Footnotes:

  1. ITL Reports using IES guidelines consider any crossing of the identified boundaries as definition of overall type, regardless of its impact or significance to applied performance. Classifications indicated do not consider minor deviations in classification of type shown.
  2. The "Very Short Range" identification is not an IES standard definition, but isused by ITL to identify distributions with ranges inside the 1.0 MH allowed in the "Short Range" definition established.
  3. Information shown is for illustrative purposes only and does not represent a specific luminaire's performance.
  4. Definition is extracted from IES Lighting Handbook, 8th edition.
  5. Definition has not been identified by the IES at this time. Definition shown is based on Kim Lighting research and development efforts and engineering of optical systems to improve applied performance.
  6. Distribution may be classified by ITL, using IES standard practices, as a Type IV
    distribution, due to a small portion of the 50% isocandela trace falling beyond the 2.75 MH line. This aberration in classification methodology conflicts with luminaire applied performance. Classification indicated more accurately represents actual luminaire usage.

Type II
Type III, Asymmetric
Type IV

Figure 13: Examples of optics that can be rotated within luminaires

 

[ Page 11 of 13 ]  previous page Page 1 Page 2 Page 3 Page 4 Page 5 Page 6 Page 7 Page 8 Page 9 Page 10 Page 11 Page 12 Page 13 next page
Originally published in Architectural Record.
Originally published in December 2005

Notice

Academies