Selection for Street Light Luminar-(PART-2)
Classification of Street:
| Classification Roadway Traffic | ||
| Classification Number | Number of Vehicles per Hour | |
| Maximum Night Hour | Both Direction | |
| Very light traffic | Under | 150 |
| Light traffic | 150 | 500 |
| Medium traffic | 500 | 1200 |
| Heavy traffic | 1200 | 2400 |
| Very heavy traffic | 2400 | 4000 |
| Heavy traffic | Over | 4000 |
| Classification of Pedestrian Traffic | |
| Light or No Traffic | Residential, warehouse areas on express / elevated depressed roadways |
| Medium Traffic | Secondary business streets and some industrial roads |
| Heavy Traffic | Business streets. |
Mounting Height of Street Light Laminar:
- The distance the lamp is mounted above the roadway will affect the illumination intensity, uniformity of brightness, area covered, and relative glare of the unit.
- Higher mounted units will provide greater coverage, more uniformity, and reduction of glare, but a lower illumination level.
- It is necessary to weigh the effects of larger lamps against a greater number of smaller units at lower mounting heights with maximum glare potential.
- The height of luminaries above the roadway surface varies from 5 Meter to more than 20 Meter.
- Conventional roadway lighting utilized mounting height of 8 to 20 Meter. The lower mounting heights require the use of cutoff or semi-cutoff luminary’s distribution to minimize glare.
| Height of Pole | Application |
| 6 Meter | For streets ,alleys, public gardens and parking lots |
| 8 Meter | Urban traffic route, multiplicity of road junctions, |
| Narrow roads such as local access roads in residential areas in which a mounting height between 10 M or 12 M and 5 M or 6 M is required. | |
| 10 Meter | Urban traffic route, For wide heavily used routes where a large number of intersection, bends can lead to a short spacing making the use of 12 M mounting height uneconomical. |
| 12 Meter | Wide or heavily used routes where advantage can be taken of a longer spacing of luminaries. |
| 18 Meter and above | High mast lighting poles shall be installed at large-scale area such as airports, dockyards, large industrial areas, sports areas and road intersections |
| Type of Road | Pole | Pole Height | Laminar Watt | Type of Laminar |
| Rural | Aluminum or Steel Pole | 10 to 16 Meter | 250W to 400W | HPS |
| Urban | Aluminum | 10 to 13 Meter | 250W to 400W | HPS (Cut off or Semi Cut off) |
High Mast Lighting Systems:
- High mast lighting has 3 or 4 no’s of 1000 watt HPS luminaries mounted on poles /towers, at mounting heights (30 Meter). It develops a highly uniform light distribution.
- Advantage:
- Excellent uniformity of illumination, reduce glare with a substantially smaller number of pole locations.
- Application:
- Where continuous lighting is desirable such as lighting of toll plazas, rest areas ,parking areas, general area lighting, highways , traffic lanes.
- High mast lighting is also desirable where there is minimal residential area.
- High Mast used at remote location to eliminates the need for maintenance, vehicles obstructing traffic on the roadway.
- High Mast having symmetric or asymmetric distribution
- The design and installation of high mast lighting equipment is more complex than conventional lighting.
Correction Lamp Comparison Chart (Bureau of Energy Efficiency, Delhi) | |||||
| Lamp Type | Lamp ( Watts) | Efficacy (Lumens /Watt) | ColorRender
| LampLife (Hr) | Remarks |
| Incandescent (GLF) Lamps: | |||||
| (Incandescent bulbs) | 15,25,40,60,75,100,150,200, 300,500 (no ballast) | 8 to 17 | 100 | 1000 | |
| Tungsten Halogen | 75,100,150,500,1000,2000 (no ballast) | 13 to 25 | 100 | 2000 | |
| Fluorescent Tube lights(Argon filled) | 20,40,65, (32,51,79) | 31 to 58 | 67 to 77 | 5000 | |
| Fluorescent Tubular Lamp (T5) | 18,20,36,40,58,65 | 100 to 120 | Very Good | 15,000 to 20,000 | Energy-efficient,long lamp life, only available in low wattages |
| Compact Fluorescent Lamps (CFLs) | 5,7,9,11,18,24,36 | 26 to 64 | 85 | 8000 | |
| HID Lamps: | |||||
| High Pressure MercuryVapor (HPMV) | 80,125,250,400,1000,2000 | 25 to 60 | 45 (Fair) | 16,000 to 24,000 | High energy use,Poor lamp life |
| High Pressure Metal Halide Lamps (HPMH) | 70,150,250, 400,1000,2000 | 62 to 72 | 70 (Excellent) | 8000 to 12000 | High luminous efficacy, Poor lamp life |
| High Pressure SodiumVapor Lamps (HPSV) | 70,150,250,400,1000 | 69 to 108 | 25 to 60 (Fair) | 15000 to 24000 | Energy-efficient, poor color rendering |
| Low Pressure Sodium Vapor Lamps (LPSV) | 35,55,135 | 90 to 133 | Very Poor | 18000 to 24000 | Energy-efficient, very poor color rendering |
| Low Pressure Mercury Fluorescent TubularLamps (T8 & T12) | 35,55,135 | 30 to 90 | Good | 5000 to 10000 | Poor lamp life, medium energy use, only available in low wattages |
| LED Lamps | |||||
| Light Emitting Diode (LED) | 70 to 160 | Good | 40,000 to 90,000 | ||