The prerequisite of best outdoor street lighting is considering the LED distribution types and pattern imposed by Illuminating Engineering Society of North America (IESNA). In many bidding documents of LED replacement for metal halide, halogen, mercury or high-pressure sodium street lamps, the contactors are required to provide the flood lights satisfying Type I, Type II, Type III, Type IV or Type V light distribution, which is related to IES diagrams. For instance, Type I & V is symmetrical lighting pattern for narrow sidewalks, crossroad or pavement such kind of longitudinal uniformity street lighting, and tennis court, basketball court or football field lighting; while Type II, III & IV are asymmetrical outdoor IESNA LED lighting distribution for alley, parking lot, warehouse or building facades. This chapter shares with you what are the LED distribution types and their classification.
Type I LED Distribution
This type I pattern offers oval, narrow shape of LED distribution for outdoor sidewalks, or walkways. The light source is at the center of illumination. You can observe the longitudinal and symmetrical lighting for streets. The bi-directional illuminance is uniformity distributed across the two side of the light pole. We may need a relatively lower power, ranged from 30W, 40W, 50 watt or 60 watt LED lights to light up these area.
Type II Distribution
Comparing to type I LED pattern, type II illumination accommodates wider footpath or car roads. The point light source is inclined to one side to have asymmetric LED distribution type. To have type II pattern, IESNA claims the ratio between width of footpath and height of luminary should be less than 1.75.
Type III LED Distribution Pattern
This type has a wider illumination area if you make a direct comparison to type II LED distribution. If is adopted to light up the highways, parking lot, garage, driveway, as well as sports fields – football pitch, tennis, basketball, volleyball and more. It has asymmetric arrangement as well. The ratio between width of illumination area and height of pole should be less than 2.75. Since we need to light a large outdoor area, we need to buy higher power LED lights for garage.
Type IV LED Arrangement
LED distribution Type IV is best fit for outdoor building façade, billboard lighting, highways and suspension bridge. The standard ratio (width to height) is 3.7. The power requirement for type IV LED pattern is more demanding, we will need up to 100 watt, 200 watt, 300 watt, or up to 400 watt LED lights to light up the bridge and façade.
Type V Pattern
Circular, omni-directional LED distribution can be observed for type V LED pattern. It is suitable for crossroad, roadway center. In fact, there is also a type VS LED distribution for commercial parking lots. The major difference is that the illumination of type VS has a more defined angle which fits for the special requirement of the lighting projects.
Since we are LED lighting manufacture, we supply IESNA-compatible, low cost flood lamps and streetlights that are compatible to type I, II, III, IV & V LED distribution requirement. If you are interested to get the IES files and quotes, please feel free to contact us at email beatus@ledsmaster.com