| ACH @50Pa | NLR @50 PA | |
|---|---|---|
| L/s/m2 | Cfm50/ft2 | |
| 7.0 | 1.52 | 0.30 |
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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To limit occupants’ exposure to indoor air pollutants by minimizing the transfer of air between units.
Requirements
Multifamily and Attached Single-Family Projects Only
Compartmentalize each residential unit to minimize leakage between units. Minimize uncontrolled pathways for environmental tobacco smoke and other indoor air pollutants between units by sealing penetrations in walls, ceilings, and floors and by sealing vertical chases (including utility chases, garbage chutes, mail drops, and elevator shafts) adjacent to the units.
Weather-strip all doors in the residential units leading to common hallways to minimize air leakage into the hallway. Weather-strip all exterior doors and operable windows to minimize leakage from outdoors.
Demonstrate acceptable sealing of residential units by a blower door test. Follow the procedure described by RESNET or the ENERGY STAR Multifamily High Rise Program Testing and Verification Protocols, Version 1.0, with an allowable maximum leakage of 0.23 cfm50 per square foot (0.07 cmm50 per square meter) of enclosure (i.e., all surfaces enclosing the apartment, including exterior and party walls, floors, and ceiling).
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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 »Frequently asked questions
See all forum discussions about this credit »Addenda
10/14/2019 – Updated: 10/14/2019
Regional ACP
Description of change:
Campus Applicable
No
Internationally Applicable:
Yes
7/8/2017
LEED Interpretation
Inquiry:
A multifamily project we are working on has relatively small units - average unit size of 900 square feet. We've found that meeting the 0.23 compartmentalization threshold is more challenging to meet as units get smaller. Because this project has small unit, can we instead meet the Midrise v2010 compartmentalization prerequisite threshold of 0.30?
Ruling:
Revised Ruling (Proposed changes*[]*):
Yes, multifamily buildings whose average unit size is less than 1,200 square feet (110 square meters) and single-family houses with less than 800 square feet (74 square meters) of conditioned floor area may meet the following:
For EQ prerequisite Compartmentalization and EQ prerequisite Environmental tobacco smoke control, demonstrate an allowable maximum leakage of 0.30 cfm50 per square foot of enclosure (i.e., all surfaces enclosing the apartment, including exterior and party walls, floors, and ceiling). **[For multifamily buildings whose average unit size is less than 500 square feet (46 square meters) of conditioned floor area, demonstrate an allowable minimum leakage of 0.40 cfm50 per square foot of enclosure.]**
For Midrise EQ credit Enhanced Compartmentalization, to earn all 3 points, the 0.15 cfm50 per square foot of enclosure area threshold must be met. But partial credit is available, for 1 point, demonstrate maximum leakage of 0.23 cfm50 per square foot of enclosure (i.e., all surfaces enclosing the apartment, including exterior and party walls, floors, and ceiling).
For Homes EQ credit Enhanced Compartmentalization, for 1 point, demonstrate maximum leakage of 0.23 cfm50 per square foot of enclosure (i.e., all surfaces enclosing the apartment, including exterior and party walls, floors, and ceiling).
***[Updated [insert date] to allow multifamily units less than 500 square feet to meet EQp Compartmentalization at a higher threshold.]**
Applicability: Remains the same (v4 Homes, v4 Midrise)
Campus Applicable
No
Internationally Applicable:
Yes
7/1/2016
LEED Interpretation
Inquiry:
There are very few HERS raters outside of North America. Can other professionals be considered qualified professionals?
Ruling:
Yes, for projects outside of the U.S. and Canada, individuals with the following qualifications will be considered a qualified professional:
1. Completion of one of the following forms of education-
An Associate or Bachelor’s degree program that includes coursework in applied building science. If performing blower door testing and/or duct leakage for the LEED project, the individual must provide evidence that the Associate’s or Bachelor’s degree coursework specifically covered these topics, or provide evidence of at least 4 hours of formal training for each relevant topic.
OR
At least 4 hours of formal training in each of the following: building science fundamentals, blower door testing (if being performed for the project), air sealing inspections, insulation inspections, and duct leakage testing (if being performed by the project).
2. Experience performing energy inspections and testing on at least two building projects with a similar scope of work.
3. At least three years of professional experience in residential construction.
Additionally, the individual may not be part of the design or construction team.
***Updated 7.10.2020 to include applicability to v2008***
**Updated 1.08.2021 to align terminology with "qualified professional". For projects outside of the U.S. and Canada, the qualified professional meeting the qualifications above may perform all tasks required to be performed by the HERS Rater (also referred to as the “qualified energy rater” in the LEED v4 Homes Reference Guide).
Campus Applicable
No
Internationally Applicable:
Yes
7/1/2016
LEED Interpretation
Inquiry:
There are few professionals who are trained to perform envelope leakage, compartmentalization, and duct leakage tests in residential projects outside of North America. Is there another approach that projects can take to demonstrate compliance?
Ruling:
06.03.24 IL
Updates in **[]**
Yes, projects outside of the U.S. and Canada may perform a visual inspection of the air sealing measures in lieu of performing envelope leakage, compartmentalization, and duct leakage testing.
The visual inspection must be performed by a qualified professional **[ as defined in LI 10443 https://www.usgbc.org/leedaddenda/10443)]**and demonstrate that each unit meets the requirements of the ENERGY STAR Thermal Enclosure Checklist (for Homes projects) or Multifamily Midrise Thermal Enclosure Checklist (for Midrise). Each item on the checklist must be documented with photo evidence. For multifamily units, all common walls, ceilings, and floors must be considered 'unconditioned spaces' when completing Section 5 - Air Sealing, of the checklist. Note that this visual inspection requires an insulation inspection site visit at a mid-construction phase, in addition to a final site visit when construction is complete.
If this approach is used, energy savings for tight construction cannot be claimed. This approach is not available for related credits such as EA credit Air infiltration and EQ credit Enhanced compartmentalization.
***Updated 7.10.2020 to include applicability to v2008***
***Updated 11.9.2020 to include additional detail regarding required site visits***
***Updated 1.08.2021 to align terminology with "qualified professional". For projects outside of the U.S. and Canada, the qualified professional meeting the qualifications above may perform all tasks required to be performed by the HERS Rater (also referred to as the “qualified energy rater” in the LEED v4 Homes Reference Guide).
***Updated 2.02.2024
Projects using visual verification in line with LEED Interpretation 10444 must use the ENERGY STAR Reference Design values for infiltration and duct leakage from the most current version and revision of the ENERGY STAR National Program Requirements available at the time of project registration. The Reference Design values should be used in the energy model for either infiltration and/or duct leakage testing, when visual verification is used in lieu of energy performance testing.
***Updated 06.03.24 [IL] to clarify that the qualified professional used must align with the requirements in LI 10443 and to expand applicability to v4.1 Single Family and v4.1 Multifamily.
Projects that use LEED Interpretation 10444 for compartmentalization must also use 0.30 cfm50 per square foot of enclosure in the energy model.
Campus Applicable
No
Internationally Applicable:
Yes
Documentation toolkit
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Intent
To limit occupants’ exposure to indoor air pollutants by minimizing the transfer of air between units.
Requirements
Multifamily and Attached Single-Family Projects Only
Compartmentalize each residential unit to minimize leakage between units. Minimize uncontrolled pathways for environmental tobacco smoke and other indoor air pollutants between units by sealing penetrations in walls, ceilings, and floors and by sealing vertical chases (including utility chases, garbage chutes, mail drops, and elevator shafts) adjacent to the units.
Weather-strip all doors in the residential units leading to common hallways to minimize air leakage into the hallway. Weather-strip all exterior doors and operable windows to minimize leakage from outdoors.
Demonstrate acceptable sealing of residential units by a blower door test. Follow the procedure described by RESNET or the ENERGY STAR Multifamily High Rise Program Testing and Verification Protocols, Version 1.0, with an allowable maximum leakage of 0.23 cfm50 per square foot (0.07 cmm50 per square meter) of enclosure (i.e., all surfaces enclosing the apartment, including exterior and party walls, floors, and ceiling).
