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
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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. |
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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. |
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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. |
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Vertical Flood 3 x 5 Great for tall facades and signs with a limited setback, vertical flood provides tall, tight distribution. |
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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. |
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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