Flood lighting can provide a wide range of light distribution or beam spread. Beam spread is classified into NEMA Types.
|Beam Spread (°)||NEMA Type||Description|
|10° - 18°||1||Very Narrow|
|> 18° - 29°||2||Narrow|
|> 29° - 46°||3||Medium Narrow|
|> 46° - 70°||4||Medium|
|> 70° - 100°||5||Medium Wide|
|> 100° - 130°||6||Wide|
|> 130°+||7||Very Wide|
NEMA indicates how wide or narrow the light is projected out of the flood light. Horizontal and vertical beam spread angles are used to distinguish NEMA types.
Example: If the horizonal beam spread is 120° and the vertical beam spread is 140°, then the NEMA type is 6 x 7.
General Flood Lighting Principles
- A narrower beam spread should be used if there is a large distance between the floodlight and the area being illuminated.
- Narrow beam flood lights have a lower percentage of beam lumens falling outside the area to be lighted than wide beam flood lights.
- NEMA type is determined by two angles (horizontal and vertical) where the light intensity is 10% of the maximum beam intensity.
Six Standard Beam Spreads
Narrow Spot 2 x 2
The narrow spot distribution is ideal for applications where a tighter beam is required. It is also excellent for applications with far setbacks or longer distances such as flagpoles or tall trees.
Narrow Flood 4 x 4
Ideal for accenting sculptures, landscape and facade lighting with farther setbacks, narrow flood distribution provides a tight and symmetrical concentrated beam.
Horizontal Flood 5 x 3
Horizontal flood provides a wide horizontal beam with a narrow vertical concentration. It is ideal for applications that require a wide horizontal coverage with a shorter setback. It is a great distribution for grazing and accentuating architecture.
Vertical Flood 3 x 5
Great for tall facades and signs with a limited setback, vertical flood provides tall, tight distribution.
Medium Flood 5 x 5
Designed for applications that require a wider uniform pattern with a medium setback, medium flood is ideal for facades, under canopies, signs and general landscape applications.
Wide Flood 6 x 6
Wide flood distribution provides a large and uniform light pattern. Good for applications that require a shorter setback, wide flood can be used for signs, large facades, and broad landscape foliage. it can also be used for pole mounted applications for general area lighting.
Sources: Lithonia Lighting and Hubbell Lighting