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<br />'r. <br /> <br />. Basics of Outdoor Lighting <br /> <br />. Functions of lighting: <br />* Safety/security <br />* Identification <br />* Environmental integration <br />* Beautification <br />* Attraction <br />* Recreation <br /> <br />. Lumen: unit of measurement 'of the amount of light energy emitted by a light source. <br /> <br />. Watt: unit of measure of the amount of electrical energy consumed <br /> <br />. Efficacy: measure of how efficiently a light source converts electric power (watts) into light <br />energy (lumens). Calculation = lumens per watt <br /> <br />. Footcandle: basic measure to indicate level of illumination. One footcandle is equal to one <br />lumen distributed evenly over a one-square-foot surface area. <br /> <br />.. Bulb Life: amount of time that elapses before half the light sources ofa large test group fails. <br /> <br />. <br /> <br />. Color rendering index: measure of the ability of a light source to represent colors of objects. <br /> <br />. Color temperature: color appearance of the light coming from a light source. <br /> <br />. Glare: illumination that causes annoyance, discomfort or sometimes a briefloss of vision. <br /> <br />. Quality of light, includes: distribution of light, color rendition, and color temperature in an <br />area <br /> <br />. Electricity costs oflarnps for 1 year: (based on 8760 hours at a $.06 per KWH rate) <br />Wattage of lamp Cost . <br />100 watt $52.56 <br />75 watt $39.42 <br />18 watt $9.46 <br />15 watt $7.88 <br /> <br />. Where your lighting dollar goes: <br />$.86 - electricity <br />$.03 - lamp <br />$.11 -labor <br /> <br />. <br />