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LEED v4.1

Commercial Interiors
Indoor Environmental Quality
Minimum Indoor Air Quality Performance

LEED CREDIT

CI-v4.1 EQp1: Minimum indoor air quality performance Required

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

Intent

To contribute to the comfort and well-being of all building occupants by establishing minimum standards for indoor air quality (IAQ).

Requirements

Mechanically Ventilated Spaces
Case 1. Systems Able to Meet Required Outdoor Airflow Rates
For mechanically ventilated spaces, meet the requirements of ASHRAE Standard 62.1–2016, Sections 4, 5, 6.2, 6.5, and 7 or a local equivalent, whichever is more stringent.
Case 2. Systems Unable to Meet Required Outdoor Airflow Rates
If meeting the outdoor airflow rates in Case 1 is not feasible because of the physical constraints of the existing ventilation system, complete an engineering assessment of the system’s maximum outdoor air delivery rate. Supply the maximum possible to reach the minimum setpoint in Case 1 and not less than 10 cubic feet per minute (5 liters per second) of outdoor air per person.

AND

Provide outdoor air monitors for all mechanical ventilation systems in the project scope of work with outdoor air intake flow greater than 1000 cfm (472 L/s). The monitoring device must be capable of measuring the minimum outdoor air intake flow and be capable of measuring the design minimum outdoor air intake flow with an accuracy of +/–10%. An alarm must indicate when the outdoor airflow value varies by 15% or more from the outdoor airflow setpoint.

Alternatively, for constant-volume systems included in the project scope of work, that do not employ demand control ventilation, provide an indicator capable of confirming the intake damper is open to the position needed to maintain the design minimum outdoor airflow as determined during the system startup and balancing.

Naturally Ventilated Spaces
For naturally ventilated spaces, meet one of the following ventilation requirements.
Natural Ventilation
  • Option 1. ASHRAE prescriptive natural ventilation compliance path
    Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.1, 6.4.3, 6.4.4, and 6.5.
    • OR
  • Option 2. ASHRAE Engineered natural ventilation system compliance path
    Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.2, 6.4.3, 6.4.4 and 6.5
    • OR
  • Option 3. Existing building using ASHRAE prescriptive natural ventilation path
    This option is available to projects located in an existing building. Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.1.1-6.4.1.6, 6.4.2, 6.4.3, 6.4.4, and 6.5.

AND

Comply with at least one of the following monitoring strategies.
  • Provide a direct exhaust airflow measurement device capable of measuring the exhaust airflow with an accuracy of +/–10% of the design minimum exhaust airflow rate. An alarm must indicate when airflow values vary by 15% or more from the exhaust airflow setpoint. This strategy is not allowed for projects using Natural Ventilation Option 3. Existing building.
  • Provide automatic indication devices on all natural ventilation openings intended to meet the minimum opening requirements. An alarm must indicate when any one of the openings is closed during occupied hours.
  • Monitor carbon dioxide (CO2) concentrations within each thermal zone. CO2 monitors must be between 3 and 6 feet (900 and 1 800 millimeters) above the floor and within the thermal zone. CO2 monitors must have an audible or visual indicator or alert the building automation system if the sensed CO2 concentration exceeds the setpoint by more than 10%. Calculate appropriate CO2 setpoints by using the methods in ASHRAE 62.1–2016, Appendix D.
All Spaces
The indoor air quality procedure defined in ASHRAE Standard 62.1–2016, Section 6.3 may not be used to comply with this prerequisite.
Europe ACP: Naturally Ventilated Spaces
Projects in Europe may use the following approach:
  • Design the spaces for natural ventilation. Consider typical site-specific local weather conditions, site location and terrain, outdoor environmental impacts (noise, car or industrial emissions, etc.), and the comfort and well-being of the occupants.
  • Perform a design study for the building owner and building users comparing the advantages and disadvantages of the natural ventilation concept with a mechanical ventilation concept.
  • Comply with the following minimum ventilation areas per person:
    • Table 1. Minimum ventilation area

    Continuous ventilation

    Intermittent ventilation

    Single-sided

    0,35 m² / person

    1,05 m² / 10 m² room area

    Cross-ventilation

    0,2 m² / person

    0,6 m² / 10 m² room area

    The provided areas are the sum of supply an exhaust areas for an applicable room depth up to 10m. For the calculations use the number of people in the ventilation zone during use. To calculate ventilation area, if the window is covered with louvers, insect screens, or otherwise obstructed, the openable area must be based on the free unobstructed area through the opening. Additionally, comply with the monitoring requirements outlined in the credit. Submittal Documentation for Europe ACP: Provide a narrative demonstrating the natural ventilation concept can contribute to the comfort and well-being of the occupants. Include the following information:
    • Design studies which compare the natural ventilation concept with a mechanical ventilation concept along with a description of the advantages and disadvantages for the building owner and building user.
    • Description of the principal natural ventilation concept (single-sided or cross-ventilation). If the design proposes a mix of the two, provide plans and/or sections with highlighted areas for each of the natural ventilation modes.
    • Description of the proposed façade openings (type of windows, louvers, etc.) and their opening mechanisms
    Latin America ACP: Engineered Natural Ventilation Systems
    Projects in Latin America may follow the Verification Protocol for Engineered Natural Ventilation Systems in Equatorial Climates and receive a design review and approval from the Colombian Professional Association of Air-conditioning, Ventilation and Refrigeration (ACAIRE).
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Addenda

2/1/2021 – Updated: 7/17/2024
Regional ACP
Description of change:
Projects outside the U.S. may instead meet the requirements of ISO Standard 17772-1:2017, Section 6.3, using Method 1—Perceived air quality with Category I or II and local standard for ventilation system design such as EN Standard 16798-3: 2017, Sections 7-10.  

**Made applicable to v4.1 O+M Projects on 2/6/23
Campus Applicable
No
Internationally Applicable:
Yes
4/21/2023 – Updated: 5/9/2023
Rating System Correction
Description of change:
Under Option 2, delete "6.4.4.5"

For BDC Only:

Under CS Only, delete "installed during core and shell construction"

Revise Residential Only section to read as follows:
"In addition to the requirements above, if the project building contains residential units, each dwelling unit must meet all of the following requirements:
• Design and install a dwelling-unit mechanical ventilation system that complies with ASHRAE 62.2-2016, Sections 4, 6.7, and 6.8, or a local equivalent, whichever is more stringent. Supply and balanced mechanical ventilation systems must be designed and constructed to provide ventilation air directly from the outdoors. Mechanical ventilation systems are not required when the project meets the exception to Section 4.1.1 of ASHRAE 62.2-2016.
• Design and install local mechanical exhaust systems in each kitchen and bathroom (including half-baths) that comply with ASHRAE 62.2-2016, Sections 5 and 7 or local equivalent, whichever is more stringent. Exhaust air to the outdoors. Do not route exhaust ducts to terminate in attics or interstitial spaces. Recirculating range hoods or recirculating over-the-range microwaves do not satisfy the kitchen exhaust requirements. For exhaust hood systems capable of exhausting in excess of 400 cubic feet per minute (188 liters per second), provide makeup air at a rate approximately equal to the exhaust air rate. Makeup air systems must have a means of closure and be automatically controlled to start and operate simultaneously with the exhaust system. Use ENERGY STAR–labeled bathroom exhaust fans in all bathrooms (including half-baths) or performance equivalent for projects outside the U.S. A heat recovery ventilator (HRV) or energy recovery ventilator (ERV) may be used to exhaust single or multiple bathrooms if it has an efficacy level meeting the ENERGY STAR Technical Specifications for Residential Heat-Recovery Ventilators and Energy-Recovery Ventilators (H/ERVs) Version 2.0 as certified by the Home Ventilating Institute (HVI).
• Unvented combustion appliances (ovens and ranges excluded) are not allowed.
• Carbon monoxide (CO) monitor must be installed on each floor of each dwelling unit, hard-wired with a battery backup. CO monitors are required in all types of units, regardless of the type of equipment installed in the unit.
• Any indoor fireplaces and woodstoves must have solid glass enclosures or doors that seal when closed.
• Any indoor fireplaces and woodstoves that are not closed combustion or power-vented must pass a backdraft potential test to ensure that depressurization of the combustion appliance zone is less than 5 Pa.
• Space- and water-heating equipment that involves combustion must be designed and installed with closed combustion (i.e., sealed supply air and exhaust ducting) or with power-vented exhaust, or located in a detached utility building or open-air facility.


Campus Applicable
No
Internationally Applicable:
No
4/9/2021 – Updated: 4/19/2021
Rating System Correction
Description of change:
Revise credit intent to read: "To contribute to the comfort and well-being of all building occupants by establishing minimum standards for indoor air quality (IAQ). "
Campus Applicable
No
Internationally Applicable:
No
11/9/2020 – Updated: 2/3/2021
Form Update
Description of change:
Updated to align with v4.1 November 2020 addenda
Campus Applicable
No
Internationally Applicable:
No
11/9/2020 – Updated: 11/25/2020
Reference Guide Correction
Description of change:
Under Behind the Intent, Beta update, replace the first paragraph with:
The ASHRAE standards have been updated to newer versions:
 ASHRAE 62.1-2010-> ASHRAE 62.1-2016 (updated version)
 ASHRAE 170-2008 and FGI 2010 -> ASHRAE 170-2017 (updated version)
Option 2 is available for use through regional compliance pathways.
 EN 13779-2007 ->EN 16798-3:2017 (local applicability)

and revise the third paragraph with:
Credit language for natural ventilation pathway is revised to incorporate ASHRAE 62.1-2016 addendum l and to reflect better which specific sections from 62.1-2016 need to be met for naturally ventilated spaces, for engineered natural ventilation or for ventilation of projects registered as historic buildings (since existing historic buildings may be limited in their ability to alter the building envelope to include additional ventilation systems/adjust openings).

Under Step-by-Step Guidance
replace step 1 with "Step 1. Evaluate Outdoor Air Quality: For evaluation of outdoor air quality, follow the specific sections 4.5, 6.2, 6.5 and 7 per the latest version of ASHRAE 62.1-2016. ", delete step 3, and add the following after step 1: Steps 2-4. Refer to LEED v4 reference guide.

Under "mechanically ventilated spaces (and Mixed-Mode spaces when a mechanical ventilation is active)" add the following above step 4:

Steps 1. Refer to LEED v4 reference guide
Step 2-3. Refer to the LEED v4 reference guide. Note: The indoor air quality procedure (defined in ASHRAE Standard 62.1–2016, Section 6.3) may not be used to comply with this prerequisite. For projects interested in using this section must pursue the pilot credit Performance-based indoor air quality design and assessment."

Under "Naturally ventilated spaces (and mixed mode systems when mechanical ventilation is inactivated)" and "Steps 1-2. Refer to LEED v4 reference guide" above step 3 and "Step 4. Refer to LEED v4 reference guide" above step 5.

Under Further explanation, required documentation, replace the bullets with:
 For Option 1, Option 2 and mixed mode, confirm that project meets minimum requirements of applicable sections of ASHRAE 62.1- 2016.
 For naturally ventilated and mixed mode ventilated projects, confirmation that projects meets requirements of the applicable sections in ASHRAE 62.1-2016.

For IDC only:
delete section:

"Healthcare:
Confirmation that project meets minimum requirements of ASHRAE 170-2017, Sections 6-10"



Campus Applicable
No
Internationally Applicable:
No
11/9/2020 – Updated: 11/25/2020
Rating System Correction
Description of change:
Under requirements, mechanically ventilated spaces section,

delete "For mechanically ventilated spaces (and for mixed-mode systems when the mechanical ventilation is activated), meet the requirements for both ventilation (Case 1 Option 1 or Option 2 or Case 2) and monitoring."

delete "Mechanical Ventilation" header

delete header text: "Option 1. ASHRAE Standard 62.1–2016"
Revise the sentence under Option 1, to read as " For mechanically ventilated spaces, meet the requirements of ASHRAE...."
delete "OR" above Option 2
delete Option 2 " Option 2.  ISO 17772-1:2017 and EN 16798-3: 2017 and  Projects outside the U.S. may instead meet the requirements of ISO Standard 17772-1:2017, Section 6.3, using Method 1—Perceived air quality with Category I or II and local standard for ventilation system design such as EN Standard 16798-3: 2017, Sections 7-10.
delete header "Monitoring for mechanical ventilation systems" and replace with "AND"

Under naturally ventilated spaces

replace the language that starts with: "(and for mixed-mode systems when the mechanical ventilation is inactivated), confirm that natural ventilation is an effective strategy for the project by following the flow diagram in the ...." with "meet one of the following ventilation requirements."

delete header "Natural ventilation"
rename Option 1 header to "Option 1. ASHRAE prescriptive natural ventilation compliance path"
Under Option 1 add "with addendum I" after ASHRAE 62.1-2016, and replace "6.4" with "6.4.1, 6.4.3,6.4.4"

rename Option 2 header to "ASHRAE Engineered natural ventilation system compliance path
Under Option 2 add "with addendum I" after ASHRAE 62.1-2016, and after Sections 4 add ", 6.4.2, 6.4.4.5, 6.4.3, 6.4.4 "
delete "and have an engineered natural ventilation system approved by the authority having jurisdiction (per exception 1 of ASHRAE 62.1-2016 section 6.4)"

rename Option 3 header to "Historic building using ASHRAE prescriptive natural ventilation path"
Under Option 3 add "with addendum I" after ASHRAE 62.1-2016, replace "6.4.1" with ".1-6.4.1.6", delete 6.4.2, and add "6.4.4" after 6.4.3
replace "Monitoring for natural ventilation systems" with AND
add "monitoring strategies" so the sentence reads "Comply with at least one of the following monitoring strategies"
Campus Applicable
No
Internationally Applicable:
No
4/10/2020 – Updated: 11/12/2020
Regional ACP
Description of change:
Projects in Japan may use JIS filter standard as alternative to ASHRAE 52.2 MERV requirements, as follows:
E(4) 25%, as defined by JIS B 9908:2011 as alternative to MERV 6
E(4) 60%, as defined by JIS B 9908:2011, as alternative to MERV 8
ePM2.5 36%, as defined by JIS B 9908: 2018, as alternative to MERV 11
ePM1 49%, as defiend by JIS B 9908:2018 as alternative to MERV 13
Campus Applicable
No
Internationally Applicable:
Yes
11/14/2019 – Updated: 11/14/2019
Form Update
Description of change:
Indoor Air Quality Performance Calculator updated to include LEED v4.1 rating systems.
Campus Applicable
No
Internationally Applicable:
Yes
7/25/2019 – Updated: 7/29/2019
Rating System Correction
Description of change:
1. Under monitoring for natural ventilation systems, revise the last sentence of the first bullet to read "This strategy is not allowed for projects using Natural Ventilation Option 3. Historic building." for BD+C rating system, and "This strategy is not allowed for projects using Natural Ventilation Option 3. Existing building." for ID+C rating system

2. Further explanation, Required Documentation section, replace the bullets under "Healthcare documentation only" with "Confirmation that project meets minimum requirements of ASHRAE 170-2017, Sections 6-10. "
Campus Applicable
No
Internationally Applicable:
No
7/25/2019 – Updated: 7/29/2019
Reference Guide Correction
Description of change:
1. Under monitoring for natural ventilation systems, revise the last sentence of the first bullet to read "This strategy is not allowed for projects using Natural Ventilation Option 3. Historic building." for BD+C rating system, and "This strategy is not allowed for projects using Natural Ventilation Option 3. Existing building." for ID+C rating system

2. Further explanation, Required Documentation section, replace the bullets under "Healthcare documentation only" with "Confirmation that project meets minimum requirements of ASHRAE 170-2017, Sections 6-10. "
Campus Applicable
No
Internationally Applicable:
No
4/9/2019 – Updated: 4/9/2019
Rating System Correction
Description of change:
At the end of the sentence, replace ASHRAE 62.2-2016 with ASHRAE 62.1-2016, so requirement reads:

Meet the requirements of ASHRAE 62.1-2016, Sections 4 and 6.5, and have an engineered natural ventilation system approved by the authority having jurisdiction (per exception 1 of ASHRAE 62.1-2016 section 6.4).
Campus Applicable
No
Internationally Applicable:
No
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© Copyright U.S. Green Building Council, Inc. All rights reserved.

Intent

To contribute to the comfort and well-being of all building occupants by establishing minimum standards for indoor air quality (IAQ).

Requirements

Mechanically Ventilated Spaces
Case 1. Systems Able to Meet Required Outdoor Airflow Rates
For mechanically ventilated spaces, meet the requirements of ASHRAE Standard 62.1–2016, Sections 4, 5, 6.2, 6.5, and 7 or a local equivalent, whichever is more stringent.
Case 2. Systems Unable to Meet Required Outdoor Airflow Rates
If meeting the outdoor airflow rates in Case 1 is not feasible because of the physical constraints of the existing ventilation system, complete an engineering assessment of the system’s maximum outdoor air delivery rate. Supply the maximum possible to reach the minimum setpoint in Case 1 and not less than 10 cubic feet per minute (5 liters per second) of outdoor air per person.

AND

Provide outdoor air monitors for all mechanical ventilation systems in the project scope of work with outdoor air intake flow greater than 1000 cfm (472 L/s). The monitoring device must be capable of measuring the minimum outdoor air intake flow and be capable of measuring the design minimum outdoor air intake flow with an accuracy of +/–10%. An alarm must indicate when the outdoor airflow value varies by 15% or more from the outdoor airflow setpoint.

Alternatively, for constant-volume systems included in the project scope of work, that do not employ demand control ventilation, provide an indicator capable of confirming the intake damper is open to the position needed to maintain the design minimum outdoor airflow as determined during the system startup and balancing.

Naturally Ventilated Spaces
For naturally ventilated spaces, meet one of the following ventilation requirements.
Natural Ventilation
  • Option 1. ASHRAE prescriptive natural ventilation compliance path
    Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.1, 6.4.3, 6.4.4, and 6.5.
    • OR
  • Option 2. ASHRAE Engineered natural ventilation system compliance path
    Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.2, 6.4.3, 6.4.4 and 6.5
    • OR
  • Option 3. Existing building using ASHRAE prescriptive natural ventilation path
    This option is available to projects located in an existing building. Meet the requirements of ASHRAE 62.1-2016 with addendum l, Sections 4, 6.4.1.1-6.4.1.6, 6.4.2, 6.4.3, 6.4.4, and 6.5.

AND

Comply with at least one of the following monitoring strategies.
  • Provide a direct exhaust airflow measurement device capable of measuring the exhaust airflow with an accuracy of +/–10% of the design minimum exhaust airflow rate. An alarm must indicate when airflow values vary by 15% or more from the exhaust airflow setpoint. This strategy is not allowed for projects using Natural Ventilation Option 3. Existing building.
  • Provide automatic indication devices on all natural ventilation openings intended to meet the minimum opening requirements. An alarm must indicate when any one of the openings is closed during occupied hours.
  • Monitor carbon dioxide (CO2) concentrations within each thermal zone. CO2 monitors must be between 3 and 6 feet (900 and 1 800 millimeters) above the floor and within the thermal zone. CO2 monitors must have an audible or visual indicator or alert the building automation system if the sensed CO2 concentration exceeds the setpoint by more than 10%. Calculate appropriate CO2 setpoints by using the methods in ASHRAE 62.1–2016, Appendix D.
All Spaces
The indoor air quality procedure defined in ASHRAE Standard 62.1–2016, Section 6.3 may not be used to comply with this prerequisite.
Europe ACP: Naturally Ventilated Spaces
Projects in Europe may use the following approach:
  • Design the spaces for natural ventilation. Consider typical site-specific local weather conditions, site location and terrain, outdoor environmental impacts (noise, car or industrial emissions, etc.), and the comfort and well-being of the occupants.
  • Perform a design study for the building owner and building users comparing the advantages and disadvantages of the natural ventilation concept with a mechanical ventilation concept.
  • Comply with the following minimum ventilation areas per person:
    • Table 1. Minimum ventilation area

    Continuous ventilation

    Intermittent ventilation

    Single-sided

    0,35 m² / person

    1,05 m² / 10 m² room area

    Cross-ventilation

    0,2 m² / person

    0,6 m² / 10 m² room area

    The provided areas are the sum of supply an exhaust areas for an applicable room depth up to 10m. For the calculations use the number of people in the ventilation zone during use. To calculate ventilation area, if the window is covered with louvers, insect screens, or otherwise obstructed, the openable area must be based on the free unobstructed area through the opening. Additionally, comply with the monitoring requirements outlined in the credit. Submittal Documentation for Europe ACP: Provide a narrative demonstrating the natural ventilation concept can contribute to the comfort and well-being of the occupants. Include the following information:
    • Design studies which compare the natural ventilation concept with a mechanical ventilation concept along with a description of the advantages and disadvantages for the building owner and building user.
    • Description of the principal natural ventilation concept (single-sided or cross-ventilation). If the design proposes a mix of the two, provide plans and/or sections with highlighted areas for each of the natural ventilation modes.
    • Description of the proposed façade openings (type of windows, louvers, etc.) and their opening mechanisms
    Latin America ACP: Engineered Natural Ventilation Systems
    Projects in Latin America may follow the Verification Protocol for Engineered Natural Ventilation Systems in Equatorial Climates and receive a design review and approval from the Colombian Professional Association of Air-conditioning, Ventilation and Refrigeration (ACAIRE).

LEEDuser expert

headshot

Ben Stanley

WSP - Built Ecology
Senior Sustainability Manager

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