F L O O D L I G H T I N G T E R M I N O L O G Y
-Floodlighting Terminology
-NEMA [IES] Classifications
F L O O D L I G H T I N G T E R M I N O L O G Y
Ever wonder how NEMA (H x V) Classifications are derived, or how they relate to the performance and design application of a floodlighting distribution? How about beam and field angles, and maximum candela values?
-Maximum Candela is defined as the maximum candela value emitted from the luminaire in any given direction.
-Beam angle is defined as the included angle between points of 50% of Maximum Candela.
-Field Angle is defined as the included angle between points of 10% of Maximum Candela.
As an example, a distribution with a 50,000 Cd maximum candela value
as shown in the intensity distribution graph to the right (FIG. 1) would have a Beam Angle defined by the included angle of 25,000 Cd values, and a Field Angle defined by the included angle of 5,000 Cd values.
E X A M P L E
Max Candela = 50,000 Cd
Candela Value defining Beam Angle = (50% * 50,000 Cd) = 25,000 Cd Candela Value defining Field Angle = (10% * 50,000 Cd) = 5,000 Cd Beam Angle = 90°
Field Angle = 120°
N E M A [ I E S ] C L A S S I F I C A T I O N S
FIG. 1
90°
80°
70°
60°
50°
45°
40°
30°
20°
10°
5 |
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| d | |
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Field |
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10,000 cd | ||||||
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15, | 000 cd | |||||
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20, | 00 | 0 cd | ||||
25 |
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,00 | ||||||
Beam | Angle | |||||
30 |
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,00 | ||||||
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35 | ,000 cd | |||||
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4 | 0,000 | |||||
d | ||||||
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4 | 5,000 | |||||
5 |
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0,000 | ||||||
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20°
10°
90°
80°
70°
60°
50°
45°
40°
30°
NEMA classifications are extrapolated from the table below and are determined by a distribution’s Field Angle. This relative classification is used to describe the general shape and application of a distribution. NEMA classifications are used to classify both the horizontal and vertical components of a floodlight distribution.
The example distribution in FIG. 1 above would have a NEMA Classification of 6 as the 120° Field Angle falls between the
NEMA Beam | Field Angle | Description + |
Classification | Range | Setback |
1 | Narrowest Beam, Long Setback | |
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2 | Narrow Beam, Long Setback | |
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3 | Narrow Beam, Long Setback | |
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4 | Medium Beam, Medium Setback | |
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5 | Medium Beam, Medium Setback | |
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6 | Wide Beam, Shorter Setback | |
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7 | Widest Beam, Short Setback | |
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4
V I S I O N F L O O D A r c h i t e c t u r a l F l o o d L u m i n a i r e
