Schools–NC-v4 EQp1: Minimum indoor air quality performance

  • Baseline for outdoor air ventilation

    This prerequisite establishes a baseline for providing a minimum amount of outdoor air to buildings in order to maintain good indoor air quality and keep occupants comfortable and healthy. 

    The referenced standard is ASHRAE 62.1-2010, which is a newer version than that referenced in LEED 2009. ASHRAE 62.1-2010 is often more stringent than local building codes, although it is not likely to entail any added costs.

    The prerequisite has different compliance paths for mechanically ventilated and naturally ventilated spaces, and you may need to follow both paths for the same building on a space-by-space basis. In fact, teams should beware that ASHRAE 62.1-2010 effectively prohibits natural ventilation via operable openings as a stand-alone strategy. This is because the standard requires spaces to be mechanically ventilated whenever the operable windows are closed. Multifamily residential buildings may be most impacted by this type of scenario.

    What’s New in LEED v4

    • The prerequisite now references ASHRAE Standard 62.1 version 2010.
    • Window configuration and ceiling height are now considered in ASHRAE 62.1-2010 natural ventilation calculations.
    • Supplementary mechanical ventilation systems for naturally ventilated spaces are required by ASHRAE 62.1-2010 in some cases.
    • USGBC requires project teams to confirm the appropriate use of natural ventilation through the flow chart in CIBSE AM10, Figure 2.8.
    • CEN requirements, instead of ASHRAE 62.1-2010, are now allowed for demonstrating achievement.
    • EQc1: Outdoor Air Delivery Monitoring is now included in this prerequisite. Additionally, USGBC distinguishes between variable air volume and constant volume systems in its monitoring requirements.
    • LEED now includes specific requirements for residential projects for this prerequisite, which were largely taken from LEED for Homes EQc2, Combustion Venting.

    FAQs

    A building has fan-assisted ventilation and no mechanical cooling system. Does this qualify as natural ventilation?

    If the building relies on the fans for daily ventilation, it is considered a mechanically ventilated building. 

    What options are available to mechanically ventilated projects outside the U.S. to meet this prerequisite?

    Local codes may be used to meet the prerequisite if you can show equivalency with Sections 4 through 7 of ASHRAE Standard 62.1-2010. Alternatively, international projects can choose to comply with the minimum requirements of Annex B of CEN Standard EN 15251–2007, and meet the requirements of CEN Standard EN 13779–2007 excluding Sections 7.3, 7.6, A.16, and A.17.

  • EQ Prerequisite 1: Minimum indoor air quality performance

    Intent

    To contribute to the comfort and well-being of building occupants by establishing minimum standards for indoor air quality (IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors.).

    Requirements

    Meet the requirements for both ventilation and monitoring.

    Ventilation
    Mechanically ventilated spaces
    Option 1. ASHRAE Standard 62.1–2010

    For mechanically ventilated spaces (and for mixed-mode systems when the mechanical ventilation is activated), determine the minimum outdoor air intake flow for mechanical ventilation systems using the ventilation rate procedure from ASHRAE 62.1–2010 or a local equivalent, whichever is more stringent.

    Meet the minimum requirements of ASHRAE Standard 62.1–2010, Sections 4–7, Ventilation for Acceptable Indoor Air Quality (with errata), or a local equivalent, whichever is more stringent.

    Option 2. CEN Standards EN 15251–2007 and EN 13779–2007

    Projects outside the U.S. may instead meet the minimum outdoor air requirements of Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251–2007, Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics; and meet the requirements of CEN Standard EN 13779–2007, Ventilation for nonresidential buildings, Performance requirements for ventilation and room conditioning systems, excluding Section 7.3, Thermal environment; 7.6, Acoustic environment; A.16; and A.17.

    Naturally ventilated spaces

    For naturally ventilated spaces (and for mixed-mode systems when the mechanical ventilation is inactivated), determine the minimum outdoor air opening and space configuration requirements using the natural ventilation procedure from ASHRAE Standard 62.1–2010 or a local equivalent, whichever is more stringent. Confirm that natural ventilation is an effective strategy for the project by following the flow diagram in the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual AM10, March 2005, Natural Ventilation in Nondomestic Buildings, Figure 2.8, and meet the requirements of ASHRAE Standard 62.1–2010, Section 4, or a local equivalent, whichever is more stringent. [Europe ACP: Arbeitsstaettenrichtlinie ASR 5] [Latin America ACP: Engineered Natural Ventilation Systems]

    All spaces

    The indoor air quality procedure defined in ASHRAE Standard 62.1–2010 may not be used to comply with this prerequisite.

    Monitoring
    Mechanically ventilated spaces

    For mechanically ventilated spaces (and for mixed-mode systems when the mechanical ventilation is activated), monitor outdoor air intake flow as follows:

    • For variable air volume systems, provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow. This device must measure the minimum outdoor air intake flow with an accuracy of +/–10% of the design minimum outdoor airflow rate, as defined by the ventilation requirements above. An alarm must indicate when the outdoor airflow value varies by 15% or more from the outdoor airflow setpoint.
    • For constant-volume systems, balance outdoor airflow to the design minimum outdoor airflow rate defined by ASHRAE Standard 62.1–2010 (with errata), or higher. Install a current transducer on the supply fan, an airflow switch, or similar monitoring device.
    Naturally ventilated spaces

    For naturally ventilated spaces (and for mixed-mode systems when the mechanical ventilation is inactivated), comply with at least one of the following strategies.

    • Provide a direct exhaust airflow measurement device capable of measuring the exhaust airflow. This device must measure 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.
    • 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 (CO2Carbon dioxide) 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 setpointsSetpoints are normal operating ranges for building systems and indoor environmental quality. When the building systems are outside of their normal operating range, action is taken by the building operator or automation system. using the methods in ASHRAE 62.1–2010, Appendix C.
    Residential only

    In addition to the requirements above, if the project building contains residential units, each dwelling unit must meet all of the following requirements.

    • Unvented combustion appliances (e.g., decorative logs) are not allowed.
    • Carbon monoxide monitors must be installed on each floor of each unit.
    • All 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.
    • For projects in high-risk areas for radon, EPA Radon Zone 1 (or local equivalent for project outside the U.S.), design and construct any dwelling unit on levels one through four above grade with radon-resistant construction techniques. Follow the techniques prescribed in EPA Building Radon Out; NFPA 5000, Chapter 49; International Residential Code, Appendix F; CABO, Appendix F; ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services E1465; or a local equivalent, whichever is most stringent [Canada ACP].
      • Alternative Compliance Paths (ACPs)

        Canada ACP - Radon

        Cities in Canada that have been proven to have an average radon concentration of 4 pCi/L (150 Bq/m3) or less through testing in accordance with the Health Canada Guide for Radon Measurements in Dwellings (with a minimum of 50 tests) are considered equivalent to EPA Radon Zone 2, and therefore are exempted from the radon requirements of this prerequisite.

        Europe ACP: Arbeitsstaettenrichtlinie ASR 5

        Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 as a local equivalent to ASHRAE Standard 62.1-2010, natural ventilation procedure.

        Latin America ACP: Engineered Natural Ventilation Systems

        Projects in Latin America may follow the Verification Protocol for Engineered Natural Ventilation Systems in Equitorial Climates and receive a design review and approval from the Colombian Professional Association of Air-conditioning, Ventilation and Refrigeration (ACAIRE).

Minimum Indoor Air Quality Performance Calculator

The Minimum Indoor Air Quality Performance Calculator can be used for projects using ASHRAE 62.1 to comply with LEED BD+C, ID+C and O+M EQ Prerequisite Minimum Indoor Air Quality Performance, EQ Credit Increased Ventilation, and EQ Credit Enhanced Indoor Air Quality Strategies, Option 2, Strategy B: Increased Ventilation, as well as LEED Homes and Multifamily Midrise EQ Prerequisite Ventilation. The calculator accommodates all ventilation types (multiple zone, single-zone, 100% outside air) in one spreadsheet. Assumptions for occupancy categories are from ASHRAE 62.1-2010 (for LEED v4 projects) and ASHRAE 62.1-2007 (for LEED 2009 projects).

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Jul 26 2017
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