The type I distribution is great for lighting walkways, paths, and sidewalks. This type of lighting is designed to be placed near the center of the pathway. This provides good lighting for narrower paths or roadway.

The type II distribution is used for wide walkways, on ramps and entrance roadways, as well as other long, narrow lighting. This type is meant for lighting larger areas and usually is located near the roadside. You’ll find this type of lighting mostly on smaller side streets or jogging paths.

The type III distribution is meant for general roadway lighting, parking areas and other areas where a larger area of lighting is required. Type III lighting needs to be placed to the side of the area, allowing the light to project outward and fill the area. Its throw is taller than Type II but its side to side throw is shorter.

The type IV distribution produces a semicircular light meant for mounting on the sides of buildings and walls. It’s best for illuminating the perimeter of parking areas and businesses. The intensity of the Type IV lighting has the same intensity at angles from 90 degrees to 270 degrees.

Type V produces a circular 360°distribution that has equal light distribution at all positions. This distribution has a circular symmetry of foot candles that is essentially the same at all viewing angles. It is intended for luminaire mounting at or near the center of roadways, center islands of the parkway, and intersections. Type V distribution is great for parking areas or flooding large areas of light directly in front of the fixture. It is one of the most common distribution types available today.

Type VS produces a square 360°distribution that has the same intensity at all angles. This distribution has a square symmetry of candlepower that is essentially the same at all lateral angles. It is intended for luminaire mounting at or near the center of roadways, center islands of the parkway, and intersections. It is also meant for large, commercial parking lot lighting as well as areas where sufficient, evenly distributed light is necessary. Type VS is used where the light pattern needs a more defined edge.

To determine your luminary’s NEMA classifications for an asymmetrical beam spread, complete the following equation:

Asymmetrical Beam Spread = Xº H (Horizontal Spread) by  Xº V (Vertical Spread)

Based on these 7 beam types, if the fixture you are considering has the specifications of NEMA Type 6×5, then its horizontal beam spread would be 100°-130° and its vertical beam spread would be 70°-100°, classifying it as a wide flood.

The IESNA and NEMA classification designations often provided in the product data sheets from many manufacturers, such as IES files, LDT files, may give the designer enough information to determine whether or not the fixture will meet the requirements of the intended application.Photometric reports, also available from many manufacturers, give a more detailed description of the illumination including brightness levels within the light distribution pattern.

With the above basic knowledge, it makes selecting the fixture distribution type easy. LONGSUN LED specializes in the sourcing of LED lighting systems for a variety of industrial applications.