Warehouses-EBOM-v4 SSc4: Light pollution reduction

  • Flexibility in demonstrating compliance

    This credit has two compliance options, which means your team has some flexibility in how it chooses to demonstrate compliance.

    Option 1 deals directly with your exterior fixtures (both luminaires and illuminated signage) and the lamps you use. Option 2 assesses your building’s contribution to light pollution through nighttime illumination measurements taken around the project boundary.

    If some of your exterior fixtures can’t comply with Option 1, there’s still a chance that your building can comply with Option 2. Unfortunately, there’s no good way to know whether you’ll comply with Option 2 except to perform the actual measurements, so teams often try to comply with Option 1 first.

    This credit is easier to earn compared to LEED 2009, as the interior lighting component has been removed entirely. Teams now need to be concerned with lights on the building exterior only.

    What’s New in LEED v4

    • The interior lighting requirements have been removed from this credit.
    • Projects can no longer demonstrate compliance with the exterior lighting requirement by meeting maximum footcandle levels (per IESNA RP-33). (The option to show a difference in illumination levels of no more than 20% between lights-on and light-off levels, at each measurement point, is still available.)

    Readiness Review Questions

    • Are exterior fixtures shielded? Can you determine the lumen1. A lumen is a unit of luminous flux equal to the light emitted in a unit solid angle by a uniform point source of 1 candle intensity. 2. A measurement of light output. value of currently installed lamps to confirm if fixtures exceed 2,500 lumens?
    • Are there opportunities to reduce exterior lighting levels? Can unnecessary fixtures be removed or de-lamped?
    • Is light trespass at the LEED project boundary minimal, likely qualifying the project for Option 2? 


    We have parking garage signs on the building exterior. We’re attempting Option 1 Fixture Shielding. Does the parking signage need to meet the requirements too?

    Yes. For Option 1, illuminated signage on the building exterior must have compliant shielding unless the sum of the mean lamp lumens is under 2,500. If you have exterior signage that doesn’t meet either of those requirements (and you can’t perform retrofits), you can still potentially earn the credit by pursuing Option 2 Perimeter Measurements.

    What about lights on the roof? Do they have to comply?

    Yes. Exterior roof lighting must comply with the credit requirements.

    What about exterior lighting owned by tenants?

    All exterior lighting and illuminated signage must comply with the credit requirements, even if is not owned or controlled by the building management. Option 2 can be used to demonstrate compliance if some or all of your exterior lighting cannot meet the requirements of Option 1. 

  • SS Credit 4: Light pollution reduction


    To increase night sky access, improve nighttime visibility, and reduce the consequences of development for wildlife and people.



    Option 1. Fixture Shielding

    Shield all exterior fixtures (where the sum of the mean lamp lumens for that fixture exceeds 2,500) such that the installed fixtures do not directly emit any light at a vertical angle more than 90 degrees from straight down.


    Option 2. Perimeter Measurements

    Measure the night illumination levels at regularly spaced points on the project boundary, taking the measurements with the building’s exterior and site lights both on and off. At least eight measurements are required, at a maximum spacing of 100 feet (30 meters) apart. The illumination level measured with the lights on must not be more than 20% above the level measured with the lights off.



Fixture Shielding

Option 1

Demonstrate compliance with Option 1 through compliant outdoor fixture shieldingShielding is a nontechnical term that describes devices or techniques that are used as part of a luminaire or lamp to limit glare, light trespass, or sky glow., as documented with manufacturer cutsheets.

Perimeter Measurements

Option 2

While a report is not required, this template can help ensure you include all required information for Option 2 in your submittal. The report template summarizes key measurement protocols, includes a scaled site plan example, and provides space for measurement results.

Perimeter Measurements

Option 2

Use a scaled site plan to show the project boundary and the location of all illumination measurement points around the boundary. Maintain records of measurement protocols and data points.


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Aug 22 2017
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