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F X'?s With Offices Throughout The Midwest www.dlz.com LIGHTING LAMP REPORT La Salle Street Bridge Renovation Date: November 25, 2003 By:. Wally Lopez Project: St. Joseph County - LaSalle Street Bridge DLZ #0261-2291-90 GENERAL The purpose of this report is to inform of the life span, color rendering and temperature of the various types of lamps to be considered for the lighting renovation for this project. There are four areas to this report and they are as follows: A. Performance characteristics of color temperature and color rendering. B. Brief explanation of five lamp types: • Clear -Metal Halide • Phosphor coated -Metal Halide • Ceramalux Comfort -High pressure Sodium • Ceramalux-High Pressure Sodium • QL Induction lamp C. Color temperature and a lamp specification chart. D. Lamp specifications. ITEM 'A'— PERFORMANCE CHARACTERISTICS The actual color appearance of the light that comes from a light source is called color temperature or chromaticity. Also referred to as Correlated Color temperature (CCT) and it's measured in degrees Kelvin or "K," Color temperature creates the mood or ambiance of the space you are lighting. Imagining a piece of iron in a fire can help you visualize color temperature. At first the iron becomes "red hot." Reddish-yellow is the color of the light being generated by the metal at this temperature. In describing color temperatures, this color corresponds to a "warm" appearance such as in High Pressure Lamps at 2100-2200 Kelvin. Continuing to heat the metal makes it "white hot," such as in cool white fluorescent lamps operating at 4100 Kelvin. Heating it further would cause it to become "blue -hot" (like flash bulbs), corresponding to daylight such as in 5K metal halide sources at 5000 Kelvin. The ability of a light source to represent colors in objects is called its Color Rendering Index or CRI. Based on a relative measurement which rates light sources on a scale of 0 to 100, the higher the CRI, the more vibrant or closer to natural the colors appear. Light from lamps with good (70— 80 CRI) and excellent (80+ CRI) color rendering properties is said to be "high quality light" because objects and people look more appealing and the light level itself is perceived to be higher.