(1) Calculate Distance between each Street Light Pole:
Example: Calculate Distance between each streetlight pole having following Details,
 Road Details: The width of road (w) is 11.5 Foot.
 Pole Details: The height of Pole is 26.5 Foot.
 Luminaire of each Pole: Wattage of Luminaries is 250 Watt, Lamp Out Put (LL) is 33200 Lumen, Required Lux Level (Eh) is 5 Lux, Coefficient of Utilization Factor (Cu) is 0.18, Lamp Lumen Depreciation Factor (LLD) is 0.8, Lamp Lumen Depreciation Factor (LLD) is 0.9.
 Space Height Ratio should be less than 3.
Calculation:
 Spacing between each Pole=(LL*CU*LLD*LDD) / Eh*W
 Spacing between each Pole=(33200×0.18×0.8×0.9) / (5×11.5)
 Spacing between each Pole= 75 Foot.
 Space Height Ratio = Distance between Pole / Road width
 Space Height Ratio = 3. Which is less than define value.

Spacing between each Pole is 75 Foot.
(2) Calculate Street Light Luminaire Watt:
Example: Calculate Streetlight Watt of each Luminaire of Street Light Pole having following Details,
 Road Details: The width of road (w) is 7 Meter. Distance between each Pole (D) is 50 Meter.
 Required Illumination Level for Street Light (L) is 6.46 Lux per Square Meter. Luminous efficacy is 24 Lumen/Watt.
 Maintenance Factor (mf) 0.29, Coefficient of Utilization Factor (Cu) is 0.9.
Calculation:
 Average Lumen of Lamp (Al) = 8663 Lumen.
 Average Lumen of Lamp (Al) =(LxWxD) / (mfxcu)
 Average Lumen of Lamp (Al)= (6.46x7x50) / (0.29×0.9)
 Average Lumen of Lamp (Al)=8663 Lumen.
 Watt of Each Street Light Luminar = Average Lumen of Lamp / Luminous efficacy
 Watt of Each Street Light Laminar = 8663 / 24

Watt of Each Street Light Luminaire = 361 Watt
(3) Calculate Required Power for Street Light Area:
Example: Calculate Streetlight Watt of following Street Light Area,
 Required Illumination Level for Street Light (L) is 6 Lux per Square Meter.
 Luminous efficacy (En) is 20 Lumen per Watt.
 Required Street Light Area to be illuminated (A) is 1 Square Meter.
Calculation:
 Required Streetlight Watt = (Lux per Sq.Meter X Surface Area of Street Light) / Lumen per Watt.
 Required Streetlight Watt = (6 X 1) / 20.

Required Streetlight Watt = 0.3 watt per Square Meter.
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