Please upgrade your browser. This site requires a newer version to work correctly. Read more
Our "watch" feature allows you to stay current on all aspects of this specific credit. In your account, you can control what you get updated on and how you receive your notifications. Hide

Outdoor air delivery monitoring

EQ1.2 | Possible point

Intent

To provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

To provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

Provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

To provide capacity for ventilation system monitoring to help sustain occupants’ comfort and well-being.

Provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

Provide additional outdoor air ventilation to improve indoor air quality for improved occupant comfort, well-being and productivity.

Provide capacity for ventilation system monitoring to help sustain long-term occupant comfort and well-being.

Provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

Provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

Provide capacity for indoor air quality (IAQ) monitoring to help sustain long-term occupant comfort and well-being.

Provide capacity for indoor air quality (IAQ) monitoring to sustain long-term occupant health and comfort.

To provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

Requirements

Install permanent, continuous monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain minimum outdoor airflow rates under all operating conditions.

AND

Case 1. Mechanical ventilation systems

Provide an outdoor airflow measurement device capable of measuring (and, if necessary, controlling) the minimum outdoor airflow rate at all expected system operating conditions within 15% of the design minimum outdoor air rate. Monitoring must be performed for at least 80% of the building’s total outdoor air intake flow serving occupied spaces.

The outdoor airflow measurement device(s) must take measurements at the system level (i.e., the air-handling unit). The device must be monitored by a control system that is configured to trend outdoor airflow in intervals no longer than 15 minutes for a period of no less than 6 months. The control system must be configured to generate an alarm visible to the system operator if the minimum outdoor air rate falls more than 15% below the design minimum rate.

All measurement devices must be calibrated within the manufacturer’s recommended interval.

Case 2. Mechanical ventilation systems that predominantly serve densely occupied spaces1

Have a CO2 sensor or sampling location for each densely occupied space and compare it with outdoor ambient CO2 concentrations. Each sampling location must be between 3 and 6 feet above the floor.

Test and calibrate CO2 sensors to have an accuracy of no less than 75 parts per million (ppm) or 5% of the reading, whichever is greater. Sensors must be tested and calibrated at least once every 5 years or per the manufacturer’s recommendation, whichever is shorter.

Monitor CO2 sensors with a system configured to trend CO2 concentrations in intervals no longer than 30 minutes. The system must generate an alarm visible to the system operator and, if desired, to building occupants if the CO2 concentration in any zone rises more than 15% above that corresponding to the minimum outdoor air rate required by IEQ Prerequisite 1.

CO2 sensors may be used for demand-controlled ventilation provided the control strategy complies with ASHRAE Standard 62.1-2007 ventilation rate procedure (see IEQ Prerequisite 1: Minimum Indoor Air Quality Performance, including maintaining the area-based component of the design ventilation rate).

Case 3. Natural ventilation systems

Locate CO2 sensors in the breathing zone of every densely populated room and every natural ventilation zone.

CO2 sensors must provide an audible or visual alarm to the occupants in the space and to the system operator if CO2 conditions are greater than 530 ppm above outdoor CO2 levels or 1,000 ppm absolute. The alarm signal must indicate that ventilation adjustments (e.g. opening windows) are required in the affected space.

All monitoring devices must be calibrated within the manufacturer’s recommended interval.

Permanently open areas must meet the requirements of ASHRAE 62.1-2007, Section 5.1 (with errata but without addenda2).

Exemptions: If the total square footage of all space served by natural ventilation systems is less than 5% of total occupied square footage, the project is exempt from the requirements of this section. Rooms smaller than 150 square feet are also exempt.

Install permanent monitoring systems to ensure that ventilation systems maintain design minimum requirements. Configure all monitoring equipment to generate an alarm when the airflow values or carbon dioxide (CO2) levels vary by 10% or more from the design values via either a building automation system alarm to the building operator or a visual or audible alert to the building occupants.

AND

Case 1. Mechanically ventilated spaces

Monitor CO2 concentrations within all densely occupied spaces i.e., those with a design occupant density of 25 people or more per 1,000 square feet (95 square meters). CO2 monitors must be between 3 and 6 feet (between 1 and 2 meters) above the floor.

Provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow with an accuracy of plus or minus 15% of the design minimum outdoor air rate, based on the value determined in IEQ Prerequisite 1: Minimum Indoor Air Quality Performance, for mechanical ventilation systems where 20% or more of the design supply airflow serves non-densely occupied spaces.

Case 2. Naturally ventilated spaces

Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitors must be between 3 and 6 feet feet (between 1 and 2 meters) above the floor. One CO2 sensor may be used to monitor multiple nondensely occupied spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

Install permanent monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain design minimum ventilation requirements. Configure all monitoring equipment to generate an alarm when the conditions vary by 10% or more from setpoint, via either a building automation system alarm to the building operator or via a visual or audible alert to the building occupants.

For mechanically ventilated spaces
  • Monitor carbon dioxide concentrations within all densely occupied spaces (those with a design occupant density greater than or equal to 25 people per 1000 sq.ft.). CO2 monitoring locations shall be between 3 feet and 6 feet above the floor.
  • For each mechanical ventilation system serving non-densely occupied spaces, provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor airflow rate with an accuracy of plus or minus 15% of the design minimum outdoor air rate, as defined by ASHRAE 62.1-2004.
For naturally ventilated spaces

Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitoring shall be located within the room between 3 feet and 6 feet above the floor. One CO2 sensor may be used to represent multiple spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

Install permanent, continuous monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain minimum outdoor airflow rates under all operating conditions.

For all mechanical ventilation systems:

Provide an outdoor airflow measurement device capable of measuring (and, if necessary, controlling) the minimum outdoor airflow rate at all expected system operating conditions within 15% of the design minimum outdoor air rate. Monitoring must be performed for at least 80% of the building’s total outdoor air intake flow serving occupied spaces.

The outdoor airflow measurement device(s) must take measurements at the system level (i.e., the air-handling unit). The device must be monitored by a control system that is configured to trend outdoor airflow in intervals no longer than 15 minutes for a period of no less than six months. The control system must be configured to generate an alarm visible to the system operator if the minimum outdoor air rate falls more than 15% below the design minimum rate.

All measurement devices must be calibrated within the manufacturer’s recommended interval.

For mechanical ventilation systems that predominantly serve densely occupied spaces:

Have a CO2 sensor or sampling location for each densely occupied space and compare it with outdoor ambient CO2 concentrations. Each sampling location must be between 3 feet and 6 feet above the floor.

Test and calibrate CO2 sensors to have an accuracy of no less than 75 ppm or 5% of the reading, whichever is greater. Sensors must be tested and calibrated at
least once every five years or per the manufacturer’s recommendation, whichever is shorter.
Monitor CO2 sensors with a system configured to trend CO2 concentrations in intervals no longer than 30 minutes.

The system must generate an alarm visible to the system operator and, if desired, to building occupants if the CO2 concentration in any zone rises more than 15% above that corresponding to the minimum outdoor air rate required by ASHRAE Standard 62 (see EQ Prerequisite 1).

CO2 sensors may be used for demand-controlled ventilation provided the control strategy complies with ASHRAE Standard 62 (see EQ Prerequisite 1), including maintaining the area-based component of the design ventilation rate.

Densely occupied space is defined as an area with a design occupant density greater than or equal to 25 people per 1,000 square feet (40 square feet per person). If the total square footage of all dense space is less than 5% of total occupied square footage, the project is exempt from the requirements of this section. Rooms smaller than 150 square feet are also exempt.

For natural ventilation systems:

Locate CO2 sensors in the breathing zone of every densely populated room and every natural ventilation zone.

CO2 sensors must provide an audible or visual alarm to the occupants in the space and to the system operator if CO2 conditions are greater than 530 parts per million above outdoor CO2 levels or 1,000 parts per million absolute. The alarm signal must indicate that ventilation adjustments (e.g. opening windows) are required in the affected space.

All monitoring devices must be calibrated within the manufacturer’s recommended interval.

Permanently open areas must meet the requirements of ASHRAE 62.1–2007, Section 5.1.

Exemptions: If the total square footage of all space served by natural ventilation systems is less than 5% of total occupied square footage, the project is exempt from the requirements of this section. Rooms smaller than 150 square feet are also exempt.

Install permanent monitoring and alarm systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain design minimum ventilation requirements in a form that affords operational adjustments:

  • For mechanical ventilation systems that predominantly serve densely occupied spaces (those with a design occupant density greater than or equal to 25 people per 1000 sq. ft), install a CO2 sensor within each densely occupied space.
  • For all other mechanical ventilation systems, provide an outdoor airflow measurement device capable of measuring the minimum outdoor airflow rate at all expected system operating conditions within 15% of the design minimum outdoor air rate.
  • For natural ventilation systems, install a CO2 sensor within each naturally ventilated space.
For mechanically ventilated spaces:

Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by ASHRAE 62.1-2004 as determined by EQ Prerequisite 1.

For naturally ventilated spaces:

Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Carbon Trust “Good Practice Guide 237” [1998]. Determine that natural ventilation is an effective strategy for the project by following the flow diagram process shown in Figure 1.18 of the CIBSE (The Chartered Institution of Building Services Engineers) “Applications Manual 10: 2005, Natural ventilation in non-domestic buildings.”

And either of the following;

  • Use diagrams and calculations to show that the design of the natural ventilation systems meets the recommendations set forth in the CIBSE “Applications Manual 10: 2005, Natural ventilation in non-domestic buildings.”
    OR
  • Use a macroscopic, multi-zone, analytic model to predict that room-by-room airflows will effectively naturally ventilate at least 90% of occupied spaces.

Install permanent monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain minimum ventilation rates.

Option A

For mechanical ventilation systems that predominantly serve densely occupied spaces (spaces with a design occupant density greater than or equal to 25 people per 1,000 square feet (40 square feet per person)), do the following:

  • Provide a CO2 sensor or sampling location for each densely occupied space, and compare with outdoor ambient CO2 concentrations.
  • Test and calibrate CO2 sensors to have an accuracy of no less than 75 ppm or 5% of the reading; whichever is greater. Sensors must be tested and calibrated at least once every five years or per manufacturers’ recommendation.
  • Monitor CO2 sensors by a system capable of and configured to trend CO2 concentrations on no more than 30 minute intervals.
  • Configure system capability to generate an alarm visible to a system operator and, if desired, to building occupants if the CO2 concentration in any zone rises more than 15% above that corresponding to the minimum outdoor air rate required by ASHRAE Standard 62 (see IEQ Prerequisite 1).
  • CO2 sensors may be used for demand-controlled ventilation provided the control strategy complies with ASHRAE Standard 62 (see IEQ Prerequisite 1), including maintaining the area-based component of the design ventilation rate.
Option B

For all other mechanical ventilation systems:

  • An outdoor airflow measurement device must be provided that is capable of measuring (and, if necessary, controlling) the minimum outdoor airflow rate at all expected system operating conditions within 15% of the design minimum outdoor air rate.
  • The outdoor airflow measurement device shall be monitored by a control system capable of and configured to trend outdoor airflow on no more that 15-minute intervals for a period of no less than six months.
  • The control system shall be capable and configured to generate an alarm visible to the system operator if the minimum outdoor air rate falls more than 15% below the design minimum rate.
Option C

For natural ventilation systems, provide the following:

  • CO2 sensors located in the breathing zone of every densely populated room.
  • CO2 sensors located in the breathing zone of every natural ventilation zone.
  • CO2 sensor(s) located outdoors.
  • CO2 sensors shall provide an audible or visual alarm to the occupants in the space and building management if CO2 conditions are greater than 530 parts per million above outdoor CO2 levels or 1,000 parts per million absolute. The alarm signal should indicate that ventilation adjustments (i.e. opening windows) are required in the affected space.
  • Operable windows areas must meet the requirements of ASHRAE 62.1-2004, section 5.1.

Install permanent monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain design minimum ventilation requirements. Configure all monitoring equipment to generate an alarm when the conditions vary by 10% or more from setpoint, via either a building automation system alarm to the building operator or via a visual or audible alert to the building occupants.

For mechanically ventilated spaces
  • Monitor carbon dioxide concentrations within all densely occupied spaces (those with a design occupant density greater than or equal to 25 people per 1000 sq.ft.). CO2 monitoring locations shall be between 3 feet and 6 feet above the floor.
  • For each mechanical ventilation system serving non-densely occupied spaces, provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor airflow rate with an accuracy of plus or minus 15% of the design minimum outdoor air rate, as defined by ASHRAE 62.1-2004.
For naturally ventilated spaces

Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitoring shall be located within the room between 3 feet and 6 feet above the floor. One CO2 sensor may be used to represent multiple spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

Install permanent monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain design minimum ventilation requirements. Configure all monitoring equipment to generate an alarm when the conditions vary by 10% or more from setpoint, via either a building automation system alarm to the building operator or via a visual or audible alert to the building occupants.

For mechanically ventilated spaces
  • For each mechanical ventilation system, provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor airflow rate with an accuracy of plus or minus 15% of the design minimum outdoor air rate, as defined by ASHRAE 62.1-2004.
For naturally ventilated spaces

Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitoring shall be located within the room between 3 feet and 6 feet above the floor. One CO2 sensor may be used to represent multiple spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

Install a permanent carbon dioxide (CO2) monitoring system that provides feedback on space ventilation performance in a form that affords operational adjustments. Refer to the CO2 differential for all types of occupancy in accordance with ASHRAE 62-2001, Appendix D.

Install permanent monitoring systems that provide feedback on ventilation system performance to ensure that ventilation systems maintain design minimum requirements. Configure all monitoring equipment to generate an alarm when the airflow values or carbon dioxide (CO2) levels vary by 10% or more from the design values via either a building automation system alarm to the building operator or a visual or audible alert to the building occupants.

AND

Case 1. Mechanically ventilated spaces

Monitor CO2 concentrations within all densely occupied spaces i.e., those with a design occupant density of 25 people or more per 1,000 square feet (95 square meters). CO2 monitors must be between 3 and 6 feet (between 1 and 2 meters) above the floor.

Provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow with an accuracy of plus or minus 15% of the design minimum outdoor air rate, based on the value determined in IEQ Prerequisite 1: Minimum Indoor Air Quality Performance, for mechanical ventilation systems where 20% or more of the design supply airflow serves non-densely occupied spaces.

Case 2. Naturally ventilated spaces

Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitors must be between 3 and 6 feet feet (between 1 and 2 meters) above the floor. One CO2 sensor may be used to monitor multiple nondensely occupied spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

Join LEEDuser

Ask questions, share tips, and get notified of new forum posts by joining LEEDuser, a tool developed by BuildingGreen and supported by USGBC!

  • Share on Twitter
  • Share on Facebook
  • Share on LinkedIn
  • Print to PDF
Sample forms
View sample forms