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LEED v4.1

Schools – New Construction

Indoor Environmental Quality
Interior Lighting

LEED CREDIT

Schools-NC-v4.1 EQc6: Interior lighting 1-2 points

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View the LEED v4 version of this credit »

SPECIAL REPORT

LEEDuser expert

Kera Lagios

M.Arch, LEED AP BD+C, Assoc. IALD

atelier fos
Founder

SPECIAL REPORT

LEEDuser’s viewpoint

Explore this LEED credit

Post your questions on this credit in the forum, and click on the credit language tab to review to the LEED requirements.

Credit language

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To promote occupants’ productivity, comfort, and well-being by providing high-quality lighting.

Requirements

Meet 1 strategy for 1 point. Meet 3 strategies total for 2 points.

1. Glare Control

For all regularly occupied spaces, meet one of the following requirements:

  • Use light fixtures with a luminance of less than 7,000 candela per square meter (cd/m)2 between 45 and 90 degrees from nadir. OR
  • Achieve a Unified Glare Rating (UGR) rating of
Exceptions include wallwash fixtures properly aimed at walls, as specified by manufacturer’s data, indirect uplighting fixtures, provided there is no view down into these uplights from a regularly occupied space above, and any other specific applications (i.e. adjustable fixtures).
2. Color Rendering

For all regularly occupied spaces meet one of the following requirements:

  • Use light sources that have a Color Rendering Index (CRI) of at least 90.
  • Use light sources that have a Color Fidelity Index greater than or equal to 78 and a gamut index between 97 and 110, determined in accordance with Illuminating Engineering Society (IES) TM-30.
3. Lighting Control

Provide dimmable or multilevel lighting for 90% of occupant spaces.

4. Surface Reflectivity

For at least 90% regularly occupied spaces, use interior finishes with a surface reflectance greater or equal to 80% for ceilings and 55% for walls. If included in the project scope, use furniture finishes with a surface reflectance greater or equal to 45% for work surfaces and 50% for movable partitions.

India ACP: Interior Lighting
I. Projects in India may, in all regularly occupied spaces, meet or exceed the lower illuminance levels listed in the Bureau of Indian Standards (BIS) code -- IS 3646 (Part 1): 1992, Table 1- Recommended Illumination. See all forum discussions about this credit »

What does it cost?

Cost estimates for this credit

On each BD+C v4 credit, LEEDuser offers the wisdom of a team of architects, engineers, cost estimators, and LEED experts with hundreds of LEED projects between then. They analyzed the sustainable design strategies associated with each LEED credit, but also to assign actual costs to those strategies.

Our tab contains overall cost guidance, notes on what “soft costs” to expect, and a strategy-by-strategy breakdown of what to consider and what it might cost, in percentage premiums, actual costs, or both.

This information is also available in a full PDF download in The Cost of LEED v4 report.

Learn more about The Cost of LEED v4 »

Addenda

11/9/2020Updated: 11/30/2020
Reference Guide Correction
Description of change:
replace "There are no substantive changes to the credit requirements; refer to the LEED v4 reference guide, with the following addition:" with "Behind the Intent
Beta Update
The interior lighting credit has been overhauled to prioritize strategies identified by industry lighting experts as most critical and impactful for new construction LEED projects.
Lighting quality strategies for lamp life, direct overhead lighting, surface illuminance ratio have been removed.
The threshold for light fixture luminance has been decreased from 2,500 candela per square meter (cd/m2) to 7,000 cd/m2. An alternative metric Unified Glare Rating has been added as a new option.
The threshold for Color rendering index has been increased from CRI of 80 to CRI of 90. An alternative metric Color Fidelity Index has been added as a new option.
The previous option for lighting control has been simplified to a single requirement for dimmable or multilevel lighting in occupied spaces.
The surface reflectance requirements have been combined, requirements for floors are removed and the thresholds have been decreased from 85% for ceilings and 60% for walls to 80% for ceilings and 55% for walls.

Step-by-Step Guidance

Step 1. Establish Lighting Needs

Work with the owner to understand occupant’s lighting needs and desires.
• Document the types of tasks that will occur in each space and the tools or equipment that occupants use regularly, and determine appropriate light levels for tasks.
• Identify the level of control that occupants should have and the characteristics of the occupant population.
• Select measures that are appropriate for the project. Some options require attention during early design phases because achievement depends on luminare selection and configuration and architectural surface specifications.

Step 2. For Projects Pursuing Glare Control
 For the light fixtures, review luminaire cutsheets, Illuminating Engineering Society photometric files, or other documentation to identify luminance between 45 degrees and 90 degrees from nadir and select products that meet the credit requirements.
 Alternatively, select fixtures so that the spaces meet the UGR rating requirements.
 Exceptions include wallwash fixtures properly aimed at walls, as specified by manufacturer’s data, indirect uplighting fixtures, provided there is no view down into these uplights from a regularly occupied space above, and any other specific applications (i.e. adjustable fixtures).
 Exclude shipping and receiving, warehouse, and distribution centers where projects need to meet IES recommended foot-candles while maintaining clearance for forklifts and other tall equipment.

Step 3. For Projects Pursuing Color Rendering
Specify all light sources to meet the credit requirements for color rendering index or color fidelity index.
 Exceptions include lamps or fixtures specifically designed to provide colored lighting for effect, site lighting, and lamps or fixtures designed for some other special use.
 For the light sources, determine the CRI, not to be confused with correlated color temperature (CCT) which refers to the spectrum of warm to cool. A light source can have a high or low CRI regardless of CCT.

Step 4. For Projects Pursuing Lighting Control
Specify all light sources to meet the credit requirements for color rendering index or color fidelity index.
 Identify all occupant spaces in the project.
 Design lighting controls for each of these spaces to meet the credit requirements.

Step 5. For Projects Pursuing Surface Reflectivity
Select or specify high-reflective finish materials. Before construction begins, review manufacturer’s cutsheets to identify reflectance typically expressed as a fraction or percentage LR (light reflectance) or LRV (light reflectance value). If manufacturers’ data do not include reflectance, measure the reflectance of product samples (before construction) or the installed product (post-construction) using the methodology described in IES Lighting Handbook, or use reflectance charts such as Lighting Guide 11, Surface Reflectance and Color.
For work surfaces and movable partitions compliance is limited to the opaque surfaces of the partition; transparent or partially transparent surfaces are excluded.
If each surface is unable to comply with the reflectance requirement a weighted average surface reflectance calculation can be performed.

Step 6. Confirm Compliance
Compile documentation that confirms compliance with the selected strategies.

Under Further Explanation, add:

"Required Documentation
 Table of occupied spaces and associated lighting details
 Lighting details, including manufacturer and model, results of estimations, or in situ or laboratory photometric tests
 Surface Reflectivity:
o List of ceiling and wall surfaces, work surfaces (if in project scopes), movable partitions (if in project scope), and their associated surface reflectance values
Average surface reflectance calculations (if needed)
"
Campus Applicable
No
Internationally Applicable:
No
11/9/2020Updated: 11/30/2020
Rating System Correction
Description of change:
Replace Option 1 and Option 2 requirements with the following:
Meet 1 strategy for 1 point. Meet 3 strategies total for 2 points.

1. Glare Control
For all regularly occupied spaces, meet one of the following requirements:
• Use light fixtures with a luminance of less than 7,000 candela per square meter (cd/m)2 between 45 and 90 degrees from nadir. OR
• Achieve a Unified Glare Rating (UGR) rating of
Exceptions include wallwash fixtures properly aimed at walls, as specified by manufacturer’s data, indirect uplighting fixtures, provided there is no view down into these uplights from a regularly occupied space above, and any other specific applications (i.e. adjustable fixtures).


2. Color Rendering
For all regularly occupied spaces meet one of the following requirements:
• Use light sources that have a Color Rendering Index (CRI) of at least 90.
• Use light sources that have a Color Fidelity Index greater than or equal to 78 and a gamut index between 97 and 110, determined in accordance with Illuminating Engineering Society (IES) TM-30.

3. Lighting Control
Provide dimmable or multilevel lighting for 90% of occupant spaces.

4. Surface Reflectivity
For at least 90% regularly occupied spaces, use interior finishes with a surface reflectance greater or equal to 80% for ceilings and 55% for walls. If included in the project scope, use furniture finishes with a surface reflectance greater or equal to 45% for work surfaces and 50% for movable partitions.
Campus Applicable
No
Internationally Applicable:
No
See all forum discussions about this credit »

Documentation toolkit

The motherlode of cheat sheets

LEEDuser’s Documentation Toolkit is loaded with calculators to help assess credit compliance, tracking spreadsheets for materials, sample templates to help guide your narratives and LEED Online submissions, and examples of actual submissions from certified LEED projects for you to check your work against. To get your plaque, start with the right toolkit.

LEEDuser expert

Kera Lagios

M.Arch, LEED AP BD+C, Assoc. IALD

atelier fos
Founder

USGBC logo

© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To promote occupants’ productivity, comfort, and well-being by providing high-quality lighting.

Requirements

Meet 1 strategy for 1 point. Meet 3 strategies total for 2 points.

1. Glare Control

For all regularly occupied spaces, meet one of the following requirements:

  • Use light fixtures with a luminance of less than 7,000 candela per square meter (cd/m)2 between 45 and 90 degrees from nadir. OR
  • Achieve a Unified Glare Rating (UGR) rating of
Exceptions include wallwash fixtures properly aimed at walls, as specified by manufacturer’s data, indirect uplighting fixtures, provided there is no view down into these uplights from a regularly occupied space above, and any other specific applications (i.e. adjustable fixtures).
2. Color Rendering

For all regularly occupied spaces meet one of the following requirements:

  • Use light sources that have a Color Rendering Index (CRI) of at least 90.
  • Use light sources that have a Color Fidelity Index greater than or equal to 78 and a gamut index between 97 and 110, determined in accordance with Illuminating Engineering Society (IES) TM-30.
3. Lighting Control

Provide dimmable or multilevel lighting for 90% of occupant spaces.

4. Surface Reflectivity

For at least 90% regularly occupied spaces, use interior finishes with a surface reflectance greater or equal to 80% for ceilings and 55% for walls. If included in the project scope, use furniture finishes with a surface reflectance greater or equal to 45% for work surfaces and 50% for movable partitions.

India ACP: Interior Lighting
I. Projects in India may, in all regularly occupied spaces, meet or exceed the lower illuminance levels listed in the Bureau of Indian Standards (BIS) code -- IS 3646 (Part 1): 1992, Table 1- Recommended Illumination.

LEEDuser expert

Kera Lagios

M.Arch, LEED AP BD+C, Assoc. IALD

atelier fos
Founder

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