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LEED v4
New Construction
Indoor Environmental Quality

Enhanced indoor air quality strategies

LEED CREDIT

NC-v4 EQc1: Enhanced indoor air quality strategies 1-2 points

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Requirements

Option 1. Enhanced IAQ strategies (1 point)
Comply with the following requirements, as applicable.
Mechanically ventilated spaces:
A. entryway systems;
B. interior cross-contamination prevention; and
C. filtration.

Naturally ventilated spaces:
A. entryway systems; and
D. natural ventilation design calculations.

Mixed-mode systems:
A. entryway systems;
B. interior cross-contamination prevention;
C. filtration;
D. natural ventilation design calculations; and
E. mixed-mode design calculations.

A. Entryway systems
Install permanent entryway systems at least 10 feet (3 meters) long in the primary direction of travel to capture dirt and particulates entering the building at regularly used exterior entrances. Acceptable entryway systems include permanently installed grates, grilles, slotted systems that allow for cleaning underneath, rollout mats, and any other materials manufactured as entryway systems with equivalent or better performance. Maintain all on a weekly basis.

B. Interior cross-contamination prevention
Sufficiently exhaust each space where hazardous gases or chemicals may be present or used (e.g., garages, housekeeping and laundry areas, copying and printing rooms), using the exhaust rates determined in EQ Prerequisite Minimum Indoor Air Quality Performance or a minimum of 0.50 cfm per square foot (2.54 l/s per square meter), to create negative pressure with respect to adjacent spaces when the doors to the room are closed. For each of these spaces, provide self-closing doors and deck-to-deck partitions or a hard-lid ceiling.

C. Filtration
Each ventilation system that supplies outdoor air to occupied spaces must have particle filters or air-cleaning devices that meet one of the following filtration media requirements:
  • minimum efficiency reporting value (MERV) of 13 or higher, in accordance with ASHRAE Standard 52.2–2007; or
  • Class F7 or higher as defined by CEN Standard EN 779–2002, Particulate Air Filters for General Ventilation, Determination of the Filtration Performance.
  • [East Asia ACP: Filtration Media]
  • Replace all air filtration media after completion of construction and before occupancy.

    D. Natural ventilation design calculations
    Demonstrate that the system design for occupied spaces employs the appropriate strategies in Chartered Institution of Building Services Engineers (CIBSE) Applications Manual AM10, March 2005, Natural Ventilation in Non-Domestic Buildings, Section 2.4. [Latin America ACP: Engineered Natural Ventilation Systems]

    E. Mixed-mode design calculations
    Demonstrate that the system design for occupied spaces complies with CIBSE Applications Manual 13–2000, Mixed Mode Ventilation.
    Option 2. Additional enhanced IAQ strategies (1 point)

    Comply with the following requirements, as applicable.

    Mechanically ventilated spaces (select one):
    A. exterior contamination prevention;
    B. increased ventilation;
    C. carbon dioxide monitoring; or
    D. additional source control and monitoring.

    Naturally ventilated spaces (select one):
    A. exterior contamination prevention;
    D. additional source control and monitoring; or
    E. natural ventilation room by room calculations.

    Mixed-mode systems (select one):
    A. exterior contamination prevention;
    B. increased ventilation;
    D. additional source control and monitoring; or
    E. natural ventilation room-by-room calculations.

    A. Exterior contamination prevention
    Design the project to minimize and control the entry of pollutants into the building. Ensure through the results of computational fluid dynamics modeling, Gaussian dispersion analyses, wind tunnel modeling, or tracer gas modeling that outdoor air contaminant concentrations at outdoor air intakes are below the thresholds listed in Table 1 (or local equivalent for projects outside the U.S., whichever is more stringent).

    Table 1. Maximum concentrations of pollutants at outdoor air intakes

    Pollutants

    Maximum concentration

    Standard

    Those regulated by National Ambient Air Quality Standards (NAAQS)

    Allowable annual average
    OR
    8-hour or 24-hour average where an annual standard does not exist
    OR
    Rolling 3-month average

    National Ambient Air Quality Standards (NAAQS)

    B. Increased ventilation
    Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates as determined in EQ Prerequisite Minimum Indoor Air Quality Performance.

    C. Carbon dioxide monitoring
    Monitor CO2 concentrations within all densely occupied spaces. CO2 monitors must be between 3 and 6 feet (900 and 1 800 millimeters) above the floor. 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 using methods in ASHRAE 62.1–2010, Appendix C.

    D. Additional source control and monitoring
    For spaces where air contaminants are likely, evaluate potential sources of additional air contaminants besides CO2. Develop and implement a materials-handling plan to reduce the likelihood of contaminant release. Install monitoring systems with sensors designed to detect the specific contaminants. An alarm must indicate any unusual or unsafe conditions.

    E. Natural ventilation room-by-room calculations
    Follow CIBSE AM10, Section 4, Design Calculations, to predict that room-by-room airflows will provide effective natural ventilation. [Latin America ACP: Engineered Natural Ventilation Systems]

    Alternative Compliance Paths (ACPs)

    IAQ-HIGH">East Asia ACP: Filtration Media
    Projects in East Asia may use filtration media classified as high efficiency (高中效过滤器) or higher as defined by Chinese standard GB/T 14295-2008 (空气过滤器).
    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). 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 »

    Frequently asked questions

    Do I have to achieve Option 1 if I want to pursue Option 2?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    Has the pressure differential requirement of at least 5 pascals for LEED 2009 EQc5: Indoor and Chemical Source Pollutant Control been eliminated from the requirement of this credit?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    How can a Core & Shell (CS) project to comply with the credit requirements if they are not in the project scope?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    See all forum discussions about this credit »

    Addenda

    4/5/2016Updated: 1/8/2020
    Regional ACP
    Description of change:
    For LEED v4 projects using the Enhanced Indoor Air Quality credit:
    Under Option 1, Strategy D. Natural ventilation design calculations in the rating system, add the following language: "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)."

    Under Option 2, Strategy E. natural ventilation room-by-room calculations in the rating system, add the following language: "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)."

    For LEED 2009 projects using EQc2 - Increased Ventilation:
    Under Case 2, Naturally Ventilated Spaces, add the following language after the first paragraph: "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)."
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    4/1/2015Updated: 3/29/2018
    Regional ACP
    Description of change:
    In option C, add the following language under the third bullet: “Projects in East Asia may use filtration media classified as high efficiency (高中效过滤器) or higher as defined by Chinese standard GB/T 14295-2008 (空气过滤器).”
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    10/1/2014Updated: 9/15/2017
    Reference Guide Correction
    Description of change:
    BD+C:
    Option 1, under naturally ventilated spaces, change B to D
    Option 2, 2,under naturally ventilated spaces, change B to D and C to E.

    ID+C:
    Option 1, under naturally ventilated spaces, change B to D
    Option 2, under naturally ventilated spaces, change B to D and C to E; under mixed-mode systems, change C to D and D to E.
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    7/1/2014Updated: 9/15/2017
    Reference Guide Correction
    Description of change:
    In the third sentence change ‘high-volume exterior entrance’ to ‘regularly used exterior entrance' to read: "However, if the project scope includes an entrance that would qualify as regularly used exterior entrance, then the team must ensure that appropriate entryway systems are also installed."
    Campus Applicable
    Yes
    Internationally Applicable:
    Yes
    1/27/2017Updated: 2/9/2017
    Reference Guide Correction
    Description of change:
    Add the following at the end of step 3: Note, if you comply with these natural ventilation room-by-room calculations, you automatically comply with the ventilation requirements for naturally ventilated spaces in EQ Prerequisite Minimum Indoor Air Quality Performance. The monitoring requirements in the prerequisite must still be met.
    Campus Applicable
    No
    Internationally Applicable:
    No
    See all forum discussions about this credit »

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    Senior Consultant

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    USGBC logo

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

    Requirements

    Option 1. Enhanced IAQ strategies (1 point)
    Comply with the following requirements, as applicable.
    Mechanically ventilated spaces:
    A. entryway systems;
    B. interior cross-contamination prevention; and
    C. filtration.

    Naturally ventilated spaces:
    A. entryway systems; and
    D. natural ventilation design calculations.

    Mixed-mode systems:
    A. entryway systems;
    B. interior cross-contamination prevention;
    C. filtration;
    D. natural ventilation design calculations; and
    E. mixed-mode design calculations.

    A. Entryway systems
    Install permanent entryway systems at least 10 feet (3 meters) long in the primary direction of travel to capture dirt and particulates entering the building at regularly used exterior entrances. Acceptable entryway systems include permanently installed grates, grilles, slotted systems that allow for cleaning underneath, rollout mats, and any other materials manufactured as entryway systems with equivalent or better performance. Maintain all on a weekly basis.

    B. Interior cross-contamination prevention
    Sufficiently exhaust each space where hazardous gases or chemicals may be present or used (e.g., garages, housekeeping and laundry areas, copying and printing rooms), using the exhaust rates determined in EQ Prerequisite Minimum Indoor Air Quality Performance or a minimum of 0.50 cfm per square foot (2.54 l/s per square meter), to create negative pressure with respect to adjacent spaces when the doors to the room are closed. For each of these spaces, provide self-closing doors and deck-to-deck partitions or a hard-lid ceiling.

    C. Filtration
    Each ventilation system that supplies outdoor air to occupied spaces must have particle filters or air-cleaning devices that meet one of the following filtration media requirements:
    • minimum efficiency reporting value (MERV) of 13 or higher, in accordance with ASHRAE Standard 52.2–2007; or
    • Class F7 or higher as defined by CEN Standard EN 779–2002, Particulate Air Filters for General Ventilation, Determination of the Filtration Performance.
  • [East Asia ACP: Filtration Media]
  • Replace all air filtration media after completion of construction and before occupancy.

    D. Natural ventilation design calculations
    Demonstrate that the system design for occupied spaces employs the appropriate strategies in Chartered Institution of Building Services Engineers (CIBSE) Applications Manual AM10, March 2005, Natural Ventilation in Non-Domestic Buildings, Section 2.4. [Latin America ACP: Engineered Natural Ventilation Systems]

    E. Mixed-mode design calculations
    Demonstrate that the system design for occupied spaces complies with CIBSE Applications Manual 13–2000, Mixed Mode Ventilation.
    Option 2. Additional enhanced IAQ strategies (1 point)

    Comply with the following requirements, as applicable.

    Mechanically ventilated spaces (select one):
    A. exterior contamination prevention;
    B. increased ventilation;
    C. carbon dioxide monitoring; or
    D. additional source control and monitoring.

    Naturally ventilated spaces (select one):
    A. exterior contamination prevention;
    D. additional source control and monitoring; or
    E. natural ventilation room by room calculations.

    Mixed-mode systems (select one):
    A. exterior contamination prevention;
    B. increased ventilation;
    D. additional source control and monitoring; or
    E. natural ventilation room-by-room calculations.

    A. Exterior contamination prevention
    Design the project to minimize and control the entry of pollutants into the building. Ensure through the results of computational fluid dynamics modeling, Gaussian dispersion analyses, wind tunnel modeling, or tracer gas modeling that outdoor air contaminant concentrations at outdoor air intakes are below the thresholds listed in Table 1 (or local equivalent for projects outside the U.S., whichever is more stringent).

    Table 1. Maximum concentrations of pollutants at outdoor air intakes

    Pollutants

    Maximum concentration

    Standard

    Those regulated by National Ambient Air Quality Standards (NAAQS)

    Allowable annual average
    OR
    8-hour or 24-hour average where an annual standard does not exist
    OR
    Rolling 3-month average

    National Ambient Air Quality Standards (NAAQS)

    B. Increased ventilation
    Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates as determined in EQ Prerequisite Minimum Indoor Air Quality Performance.

    C. Carbon dioxide monitoring
    Monitor CO2 concentrations within all densely occupied spaces. CO2 monitors must be between 3 and 6 feet (900 and 1 800 millimeters) above the floor. 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 using methods in ASHRAE 62.1–2010, Appendix C.

    D. Additional source control and monitoring
    For spaces where air contaminants are likely, evaluate potential sources of additional air contaminants besides CO2. Develop and implement a materials-handling plan to reduce the likelihood of contaminant release. Install monitoring systems with sensors designed to detect the specific contaminants. An alarm must indicate any unusual or unsafe conditions.

    E. Natural ventilation room-by-room calculations
    Follow CIBSE AM10, Section 4, Design Calculations, to predict that room-by-room airflows will provide effective natural ventilation. [Latin America ACP: Engineered Natural Ventilation Systems]

    Alternative Compliance Paths (ACPs)

    IAQ-HIGH">East Asia ACP: Filtration Media
    Projects in East Asia may use filtration media classified as high efficiency (高中效过滤器) or higher as defined by Chinese standard GB/T 14295-2008 (空气过滤器).
    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).

    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 »

    In the end, LEED is all about documentation. LEEDuser’s Documentation Toolkit, for premium members only, saves you time and helps you avoid mistakes with:

    • Calculators to help assess credit compliance.
    • Tracking spreadsheets for materials purchases.
    • Spreadsheets and forms to give to subs and other team members.
    • Guidance documents on arcane LEED issues.
    • Sample templates to help guide your narratives and LEED Online submissions.
    • Examples of actual submissions from certified LEED projects.

    Do I have to achieve Option 1 if I want to pursue Option 2?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    Has the pressure differential requirement of at least 5 pascals for LEED 2009 EQc5: Indoor and Chemical Source Pollutant Control been eliminated from the requirement of this credit?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    How can a Core & Shell (CS) project to comply with the credit requirements if they are not in the project scope?

    The answer to this question is available to LEEDuser premium members. Start a free trial »

    (If you're already a premium member, log in here.)

    4/5/2016Updated: 1/8/2020
    Regional ACP
    Description of change:
    For LEED v4 projects using the Enhanced Indoor Air Quality credit:
    Under Option 1, Strategy D. Natural ventilation design calculations in the rating system, add the following language: "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)."

    Under Option 2, Strategy E. natural ventilation room-by-room calculations in the rating system, add the following language: "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)."

    For LEED 2009 projects using EQc2 - Increased Ventilation:
    Under Case 2, Naturally Ventilated Spaces, add the following language after the first paragraph: "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)."
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    4/1/2015Updated: 3/29/2018
    Regional ACP
    Description of change:
    In option C, add the following language under the third bullet: “Projects in East Asia may use filtration media classified as high efficiency (高中效过滤器) or higher as defined by Chinese standard GB/T 14295-2008 (空气过滤器).”
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    10/1/2014Updated: 9/15/2017
    Reference Guide Correction
    Description of change:
    BD+C:
    Option 1, under naturally ventilated spaces, change B to D
    Option 2, 2,under naturally ventilated spaces, change B to D and C to E.

    ID+C:
    Option 1, under naturally ventilated spaces, change B to D
    Option 2, under naturally ventilated spaces, change B to D and C to E; under mixed-mode systems, change C to D and D to E.
    Campus Applicable
    No
    Internationally Applicable:
    Yes
    7/1/2014Updated: 9/15/2017
    Reference Guide Correction
    Description of change:
    In the third sentence change ‘high-volume exterior entrance’ to ‘regularly used exterior entrance' to read: "However, if the project scope includes an entrance that would qualify as regularly used exterior entrance, then the team must ensure that appropriate entryway systems are also installed."
    Campus Applicable
    Yes
    Internationally Applicable:
    Yes
    1/27/2017Updated: 2/9/2017
    Reference Guide Correction
    Description of change:
    Add the following at the end of step 3: Note, if you comply with these natural ventilation room-by-room calculations, you automatically comply with the ventilation requirements for naturally ventilated spaces in EQ Prerequisite Minimum Indoor Air Quality Performance. The monitoring requirements in the prerequisite must still be met.
    Campus Applicable
    No
    Internationally Applicable:
    No

    LEEDuser expert

    Mohammad H Abbasi

    WSP
    Senior Consultant

    See all LEEDuser forum discussions about this credit » Subscribe to new discussions about NC-v4 EQc1 View the LEED v4.1 version of this credit