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LEED v2009
New Construction
Indoor Environmental Quality
Increased Ventilation

LEED CREDIT

NC-2009 IEQc2: Increased Ventilation 1 point

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LEEDuser expert

Dylan Connelly

Integral Group
Mechanical Engineer

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Credit language

USGBC logo

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

Intent

To provide additional outdoor air ventilation to improve indoor air quality (IAQ) for improved occupant comfort, well-being and productivity.

Requirements

Case 1. Mechanically ventilated spaces
Option 1. ASHRAE standard 62.1-2007 or non-U.S. equivalent
Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by ASHRAE Standard 62.1-2007 (with errata but without addenda1) as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007, if the same is used for IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. OR
Option 2. CEN Standard EN 15251: 2007
Projects outside the U.S. may earn this credit by increasing breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by 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, as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance,
Case 2. Naturally ventilated spaces
Determine whether natural ventilation is an effective strategy for the project by following the flow diagram process in Figure 2.8 of the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. [Latin America ACP: Engineered Natural Ventilation Systems]

AND

Option 1. CIBSE or non-U.S. equivalent
Show that the natural ventilation systems design meets the recommendations set forth in the CIBSE manuals appropriate to the project space.
Path 1
Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent.
Path 2
Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent.

OR

Option 2. Airflow Model
Use a macroscopic, multizone, analytic model to predict that room-by-room airflows will effectively naturally ventilate, defined as providing the minimum ventilation rates required by ASHRAE Standard 62.1-2007 section 6 (with errata but without addenda), at least 90% of occupied spaces. Projects outside the U.S. may use Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251: 2007, or a local equivalent to section 6 of ASHRAE Standard 62.1-2007 to define the minimum ventilation rates.

Alternative Compliance Paths (ACPs)

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 »

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Frequently asked questions

Does each individual zone need a 30% increase in ventilation, or can a weighted average be used for the building?

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Do spaces which are not regularly occupied require increased ventilation?

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

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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
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Path 2 should read: "PATH 2. Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following sentence to the end of the paragraph: "Projects outside the U.S. may use Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the fourth line of the paragraph, replace the text "1.18" with "2.8."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Option 1 should be titled: "OPTION 1. CIBSE or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the paragraph text with: Show that the natural ventilation systems design meets therecommendations set forth in the CIBSE manuals appropriate to the projectspace.PATH 1. CIBSE Applications Manual 10: 2005, Natural Ventilation in NondomesticBuildings.PATH 2. CIBSE AM 13:2000, Mixed Mode Ventilation.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following title after Case 1, Option 1: "OPTION 2. CEN Standards EN 15251: 2007 and EN 13779: 2007"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the fourth line of the paragraph, replace the text "1.18" with "2.8."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Option 2 should read: "OPTION 2. Airflow Model"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
Replace the paragraph text with: Show that the natural ventilation systems design meets therecommendations set forth in the CIBSE manuals appropriate to the projectspace.PATH 1. CIBSE Applications Manual 10: 2005, Natural Ventilation in NondomesticBuildings.PATH 2. CIBSE AM 13:2000, Mixed Mode Ventilation.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Delete the Alternative Compliance Path for Projects Outside the U.S.
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Path 1 should read: "PATH 1. Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following title immediately following Case 1: "OPTION 1. ASHRAE Standard 62.1-2007 or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first paragraph, remove the text "Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Carbon Trust "Good Practice Guide 237" (1998)."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following paragraph: "Projects outside the U.S. may earn this credit by increasing breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
4/14/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the text with "Breathing zone is the region within an occupiedspace between 3 and 6 feet above the floor. Note that this definitionvaries from that of ASHRAE 62.1-2007, which states that the breathingzone is between 3 inches and 6 feet from the floor, and 2 feet from thewalls as well as fixed air conditioning equipment."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following sentence to the end of the paragraph: "Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007 if the same is used for IEQ Prerequisite 1: Minimum Indoor Air Quality Performance."
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the first paragraph, remove the text "Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Carbon Trust "Good Practice Guide 237" (1998)."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
In the first sentence, replace "Chapter" with "section" after "ASHRAE Standard 62.1-2007"
Campus Applicable
No
Internationally Applicable:
Yes
3/2/2009
LEED Interpretation
Inquiry:

Background: The project is a multi-building complex on a military reservation that includes 256,000 square feet of buildings. Included in this total are two office buildings totaling approximately 160,000 square feet, two vehicle maintenance facilities that total approximately 61,000 square feet and four warehouses that total approximately 36,000 square feet. The protocol used in conjunction with the LEED V2.2 Rating System is the LEED-NC Application Guide for Multiple Buildings and On-Campus Building Projects. Issue: This CIR relates to the vehicle maintenance building. Employing the Ventilation Rate Procedure (as opposed to the Indoor Air Quality Procedure) for a facility classed as a "repair garage" in ASHRAE 62.1-2004 appears to result in unnecessarily large ventilation requirements. The energy use for the resulting continuous ventilation is significant, and does not appear to be justified based on the results achieved. Discussion: The ASHRAE 62.1 ventilation rate procedure for a "repair garage" requires 1.5 CFM per square foot. To achieve a 30% increase in ventilation, the airflow would be 1.95 CFM per square foot. Based on calculated occupancy, this results in between about 390 to 500 cfm/person. Additionally, each repair bay is equipped with a vehicle exhaust pickup (1,400 CFM each) and its own large individual overhead door. The space is heated to 55 degrees with radiant heaters. Each maintenance area is designed for a single-zone 100% outside air system. Operational data for four similar vehicle maintenance facilities at the same reservation was collected. Four years of operational history are available. The outside air ambient condition at these facilities is the same as the proposed installation. The existing facilities are equipped with a full energy management system that permits monitoring of fan run time and indoor air quality (CO and CO2) data. The area ventilation fans for these facilities activate when high CO or CO2 was measured. The measured conditions for the three facilities with occupancy similar to the proposed facility showed CO and CO2 levels were at or near outside air ambient conditions over 95% of the time. The CO levels never exceeded 5 PPM, the CO2 levels never exceeded 800 PPM. The data from these existing facilities indicates that continuous ventilation of 1.5 CFM per square foot or higher would not provide a significant improvement in indoor air quality over demand-controlled (intermittent) ventilation. LEED requires documentation for the increased ventilation credit to be prepared using the ventilation rate procedure in accordance with ASHRAE 62.1-2004. Because the similar building performance data is available, we propose to provide documentation for this project in accordance with the "indoor air quality procedure", also in compliance with ASHRAE 62.1-2004, documented IAW paragraph 6.3.2, "Documentation", as follows: ".If the design is based on an approach that has proved successful for similar buildings, the documentation shall include the basis for concluding that the design approach was successful." . This is addressed in the LEED V2.2 Reference Guide but not used because it is somewhat more problematic to document. Providing control to a reduced level of contaminants would produce exceptional air quality for these maintenance bays and fulfill the intent of increased ventilation, while providing reduced energy use and less embodied energy in construction materials. It is also the standard of practice for maintenance facilities. Request: Document increased ventilation in accordance with ASHRAE 62.1-2004, "Indoor Air Quality Procedure". Provide increased ventilation via demand-controlled (intermittent) ventilation systems with DDC controls similar to the existing facilities for control of CO2 to 800 PPM and CO to 12 PPM. Both of these concentrations are at least 30% less than conventional criteria, and far less than regulatory levels defined in ASHRAE 62.1.

Ruling:

There are two questions raised by this CIR: 1. Can ventilation rates be determined using the Indoor Air Quality Procedure instead of the Ventilation Rate Procedure in Standard 62.1? No. As stated in EQ Prerequisite 1, the Ventilation Rate Procedure must be used to size the ventilation system. Hence for "auto repair rooms," the exhaust rate must be 1.5 CFM per square foot per Table 6-4. However, demand controlled ventilation using CO concentration may be used to modulate the exhaust rate down when CO levels are low. (See Appendix B in Standard 62.1 for guidelines of maximum CO concentration.) 2. Does the exhaust rate in the auto repair room have to be increased by 30% to meet EQ Credit 2? No. This credit requires that breathing zone ventilation rates required by Standard 62.1 be increased by at least 30%. Breathing zone rates are listed in Table 6-1, so it is those rates that must be increased by 30%. The exhaust rates in Table 6-4 need not be increased to achieve this credit.Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues.

Campus Applicable
No
Internationally Applicable:
No
See all forum discussions about this credit »

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Credit achievement rate

XX%

Upgrade to LEEDuser Premium to see how many projects achieved this credit. Try it free »

LEEDuser expert

Dylan Connelly

Integral Group
Mechanical Engineer

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USGBC logo

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

Intent

To provide additional outdoor air ventilation to improve indoor air quality (IAQ) for improved occupant comfort, well-being and productivity.

Requirements

Case 1. Mechanically ventilated spaces
Option 1. ASHRAE standard 62.1-2007 or non-U.S. equivalent
Increase breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by ASHRAE Standard 62.1-2007 (with errata but without addenda1) as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007, if the same is used for IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. OR
Option 2. CEN Standard EN 15251: 2007
Projects outside the U.S. may earn this credit by increasing breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by 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, as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance,
Case 2. Naturally ventilated spaces
Determine whether natural ventilation is an effective strategy for the project by following the flow diagram process in Figure 2.8 of the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. [Latin America ACP: Engineered Natural Ventilation Systems]

AND

Option 1. CIBSE or non-U.S. equivalent
Show that the natural ventilation systems design meets the recommendations set forth in the CIBSE manuals appropriate to the project space.
Path 1
Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent.
Path 2
Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent.

OR

Option 2. Airflow Model
Use a macroscopic, multizone, analytic model to predict that room-by-room airflows will effectively naturally ventilate, defined as providing the minimum ventilation rates required by ASHRAE Standard 62.1-2007 section 6 (with errata but without addenda), at least 90% of occupied spaces. Projects outside the U.S. may use Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251: 2007, or a local equivalent to section 6 of ASHRAE Standard 62.1-2007 to define the minimum ventilation rates.

Alternative Compliance Paths (ACPs)

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).

XX%

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Does each individual zone need a 30% increase in ventilation, or can a weighted average be used for the building?

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.)

Do spaces which are not regularly occupied require increased ventilation?

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
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Path 2 should read: "PATH 2. Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following sentence to the end of the paragraph: "Projects outside the U.S. may use Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the fourth line of the paragraph, replace the text "1.18" with "2.8."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Option 1 should be titled: "OPTION 1. CIBSE or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the paragraph text with: Show that the natural ventilation systems design meets therecommendations set forth in the CIBSE manuals appropriate to the projectspace.PATH 1. CIBSE Applications Manual 10: 2005, Natural Ventilation in NondomesticBuildings.PATH 2. CIBSE AM 13:2000, Mixed Mode Ventilation.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following title after Case 1, Option 1: "OPTION 2. CEN Standards EN 15251: 2007 and EN 13779: 2007"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the fourth line of the paragraph, replace the text "1.18" with "2.8."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Option 2 should read: "OPTION 2. Airflow Model"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
Replace the paragraph text with: Show that the natural ventilation systems design meets therecommendations set forth in the CIBSE manuals appropriate to the projectspace.PATH 1. CIBSE Applications Manual 10: 2005, Natural Ventilation in NondomesticBuildings.PATH 2. CIBSE AM 13:2000, Mixed Mode Ventilation.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Delete the Alternative Compliance Path for Projects Outside the U.S.
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Path 1 should read: "PATH 1. Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following title immediately following Case 1: "OPTION 1. ASHRAE Standard 62.1-2007 or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Reference Guide Correction
Description of change:
In the first paragraph, remove the text "Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Carbon Trust "Good Practice Guide 237" (1998)."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following paragraph: "Projects outside the U.S. may earn this credit by increasing breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates required by Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
4/14/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Replace the text with "Breathing zone is the region within an occupiedspace between 3 and 6 feet above the floor. Note that this definitionvaries from that of ASHRAE 62.1-2007, which states that the breathingzone is between 3 inches and 6 feet from the floor, and 2 feet from thewalls as well as fixed air conditioning equipment."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following sentence to the end of the paragraph: "Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007 if the same is used for IEQ Prerequisite 1: Minimum Indoor Air Quality Performance."
Campus Applicable
No
Internationally Applicable:
Yes
12/2/2009Updated: 2/14/2015
Rating System Correction
Description of change:
In the first paragraph, remove the text "Design natural ventilation systems for occupied spaces to meet the recommendations set forth in the Carbon Trust "Good Practice Guide 237" (1998)."
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
In the first sentence, replace "Chapter" with "section" after "ASHRAE Standard 62.1-2007"
Campus Applicable
No
Internationally Applicable:
Yes
3/2/2009
LEED Interpretation
Inquiry:

Background: The project is a multi-building complex on a military reservation that includes 256,000 square feet of buildings. Included in this total are two office buildings totaling approximately 160,000 square feet, two vehicle maintenance facilities that total approximately 61,000 square feet and four warehouses that total approximately 36,000 square feet. The protocol used in conjunction with the LEED V2.2 Rating System is the LEED-NC Application Guide for Multiple Buildings and On-Campus Building Projects. Issue: This CIR relates to the vehicle maintenance building. Employing the Ventilation Rate Procedure (as opposed to the Indoor Air Quality Procedure) for a facility classed as a "repair garage" in ASHRAE 62.1-2004 appears to result in unnecessarily large ventilation requirements. The energy use for the resulting continuous ventilation is significant, and does not appear to be justified based on the results achieved. Discussion: The ASHRAE 62.1 ventilation rate procedure for a "repair garage" requires 1.5 CFM per square foot. To achieve a 30% increase in ventilation, the airflow would be 1.95 CFM per square foot. Based on calculated occupancy, this results in between about 390 to 500 cfm/person. Additionally, each repair bay is equipped with a vehicle exhaust pickup (1,400 CFM each) and its own large individual overhead door. The space is heated to 55 degrees with radiant heaters. Each maintenance area is designed for a single-zone 100% outside air system. Operational data for four similar vehicle maintenance facilities at the same reservation was collected. Four years of operational history are available. The outside air ambient condition at these facilities is the same as the proposed installation. The existing facilities are equipped with a full energy management system that permits monitoring of fan run time and indoor air quality (CO and CO2) data. The area ventilation fans for these facilities activate when high CO or CO2 was measured. The measured conditions for the three facilities with occupancy similar to the proposed facility showed CO and CO2 levels were at or near outside air ambient conditions over 95% of the time. The CO levels never exceeded 5 PPM, the CO2 levels never exceeded 800 PPM. The data from these existing facilities indicates that continuous ventilation of 1.5 CFM per square foot or higher would not provide a significant improvement in indoor air quality over demand-controlled (intermittent) ventilation. LEED requires documentation for the increased ventilation credit to be prepared using the ventilation rate procedure in accordance with ASHRAE 62.1-2004. Because the similar building performance data is available, we propose to provide documentation for this project in accordance with the "indoor air quality procedure", also in compliance with ASHRAE 62.1-2004, documented IAW paragraph 6.3.2, "Documentation", as follows: ".If the design is based on an approach that has proved successful for similar buildings, the documentation shall include the basis for concluding that the design approach was successful." . This is addressed in the LEED V2.2 Reference Guide but not used because it is somewhat more problematic to document. Providing control to a reduced level of contaminants would produce exceptional air quality for these maintenance bays and fulfill the intent of increased ventilation, while providing reduced energy use and less embodied energy in construction materials. It is also the standard of practice for maintenance facilities. Request: Document increased ventilation in accordance with ASHRAE 62.1-2004, "Indoor Air Quality Procedure". Provide increased ventilation via demand-controlled (intermittent) ventilation systems with DDC controls similar to the existing facilities for control of CO2 to 800 PPM and CO to 12 PPM. Both of these concentrations are at least 30% less than conventional criteria, and far less than regulatory levels defined in ASHRAE 62.1.

Ruling:

There are two questions raised by this CIR: 1. Can ventilation rates be determined using the Indoor Air Quality Procedure instead of the Ventilation Rate Procedure in Standard 62.1? No. As stated in EQ Prerequisite 1, the Ventilation Rate Procedure must be used to size the ventilation system. Hence for "auto repair rooms," the exhaust rate must be 1.5 CFM per square foot per Table 6-4. However, demand controlled ventilation using CO concentration may be used to modulate the exhaust rate down when CO levels are low. (See Appendix B in Standard 62.1 for guidelines of maximum CO concentration.) 2. Does the exhaust rate in the auto repair room have to be increased by 30% to meet EQ Credit 2? No. This credit requires that breathing zone ventilation rates required by Standard 62.1 be increased by at least 30%. Breathing zone rates are listed in Table 6-1, so it is those rates that must be increased by 30%. The exhaust rates in Table 6-4 need not be increased to achieve this credit.Update April 15, 2011: Please note that all 2009 projects in multiple building situations must follow the 2010 Application Guide for Multiple Buildings and On-Campus Building Projects, located here: https://www.usgbc.org/ShowFile.aspx?DocumentID=7987. 2009 project teams should check this document for up to date guidance on all multiple building issues.

Campus Applicable
No
Internationally Applicable:
No

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Dylan Connelly

Integral Group
Mechanical Engineer

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