BUG rating method | U.S. Green Building Council
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BUG rating method

REQSS8o1-0 | Possible point

Requirements

Uplight
Option 1. BUG rating method

Do not exceed the following luminaire uplight ratings, based on the specific light source installed in the luminaire, as defined in IES TM-15-11, Addendum A.

Table 1. maximum uplight ratings for luminaires

MLO lighting zone Luminaire uplight rating
LZ0 U0
LZ1 U1
LZ2 U2
LZ3 U3
LZ4 U4

OR
Option 2. calculation method

Do not exceed the following percentages of total lumens emitted above horizontal.

Table 2. maximum percentage of total lumens emitted above horizontal, by lighting zone

MLO lighting zone Maximum allowed percentage of total luminaire lumens emitted above horizontal
LZ0 0%
LZ1 0%
LZ2 1.5%
LZ3 3%
LZ4 6%

AND
Light trespass
Option 1. BUG rating method

Do not exceed the following luminaire backlight and glare ratings (based on the specific light source installed in the luminaire), as defined in IES TM-15-11, Addendum A, based on the mounting location and distance from the lighting boundary.

Table 3. maximum backlight and glare ratings

  MLO lighting zone
Luminaire mounting LZ0 LZ1 LZ2 LZ3 LZ4
  Allowed backlight ratings
> 2 mounting heights from lighting boundary B1 B3 B4 B5 B5
1 to 2 mounting heights from lighting boundary and properly oriented B1 B2 B3 B4 B4
0.5 to 1 mounting height to lighting boundary and properly oriented B0 B1 B2 B3 B3
< 0.5 mounting height to lighting boundary and properly oriented B0 B0 B0 B1 B2
  Allowed glare ratings
Building-mounted > 2 mounting heights from any lighting boundary G0 G1 G2 G3 G4
Building-mounted 1–2 mounting heights from any lighting boundary G0 G0 G1 G1 G2
Building-mounted 0.5 to 1 mounting heights from any lighting boundary G0 G0 G0 G1 G1
Building-mounted < 0.5 mounting heights from any lighting boundary G0 G0 G0 G0 G1
All other luminaires G0 G1 G2 G3 G4

The lighting boundary is located at the property lines of the property, or properties, that the LEED project occupies. The lighting boundary can be modified under the following conditions:

  • When the property line abuts a public area that includes, but is not limited to, a walkway, bikeway, plaza, or parking lot, the lighting boundary may be moved to 5 feet (1.5 meters) beyond the property line.
  • When the property line abuts a public street, alley, or transit corridor, the lighting boundary may be moved to the center line of that street, alley, or corridor.
  • When there are additional properties owned by the same entity that are contiguous to the property, or properties, that the LEED project is within and have the same or higher MLO lighting zone designation as the LEED project, the lighting boundary may be expanded to include those properties.

Orient all luminaires less than two mounting heights from the lighting boundary such that the backlight points toward the nearest lighting boundary line. Building-mounted luminaires with the backlight oriented toward the building are exempt from the backlight rating requirement.

OR
Option 2. calculation method

Do not exceed the following vertical illuminances at the lighting boundary (use the definition of lighting boundary in Option 1). Calculation points may be no more than 5 feet (1.5 meters) apart. Vertical illuminances must be calculated on vertical planes running parallel to the lighting boundary, with the normal to each plane oriented toward the property and perpendicular to the lighting boundary, extending from grade level to 33 feet (10 meters) above the height of the highest luminaire.

Table 4. maximum vertical illuminance at lighting boundary, by lighting zone

MLO lighting zone Vertical illuminance
LZ0 0.05 fc (0.5 lux)
LZ1 0.05 fc (0.5 lux)
LZ2 0.10 fc (1 lux)
LZ3 0.20 fc (2 lux)
LZ4 0.60 fc (6 lux)

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