**Made applicable to v4.1 O+M Projects on 2/6/23
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Credit language
© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Maintain the ventilation system equipment and associated components based on Table 8.2 of ASHRAE 62.1-2016. Include information on ventilation system operation and preventative maintenance in the current facilities requirements and operations and maintenance plan required for compliance with EA prerequisite Energy Efficiency Best Management Practices.
For spaces with mechanical exhaust, test and confirm proper operation of the exhaust systems as outlined in the current facilities requirements and operations and maintenance plan.
Ventilate the project spaces mechanically or naturally as follows:
For mechanically ventilated spaces, measure the total quantity of outdoor air delivered and verify the results are within 10 percent of the rates outlined in the current facilities requirements and operations and maintenance plan. Measurements shall quantify the amount of outdoor air for each air handling unit serving the project. Measurements taken within five years prior to project submission are acceptable. The rates must meet the following minimum requirements for each air handling unit:
In I-P units:
Minimum outdoor air rate in cfm = 0.06 cfm/sf x gross building area (in sf) + people outdoor air rate from Table 1 (cfm/person) x building occupancy
In SI units:
Minimum outdoor air rate in L/s = 0.3 L/s*m2 x gross building area (in m2) + people outdoor air rate from Table 1 (L/s per person) x building occupancy
Table 1. People outdoor air rate
Occupancy category* | People outhoor air rate | |
---|---|---|
cfm per person | L/s per person | |
Auditorium seating area Libraries Office space Places of religious worship | 5 | 2.5 |
Mall common areas Museums | 7.5 | 3.8 |
Classrooms Daycare General manufacturing | 10 | 5 |
Health club/aerobics | 20 | 10 |
Alternatively, the rates may meet the Ventilation Rate Procedure outlined in Section 6.2 of ASHRAE 62.1 editions 2016, 2013, 2010, or 2007.
For naturally ventilated spaces, meet the minimum requirements in Table 2:Table 2. Minimum opening location and size requirements for naturally ventilated spaces*
Opening type | Location of opening | Size of opening |
---|---|---|
Maximum distance from operable openings** | Minimum opening area*** | |
Single side opening | 2 x ceiling height | 4% of floor area |
Double side opening | 5 x ceiling height | 4% of floor area |
Corner opening | 5 x ceiling height (along a line drawn between the two openings that are farthest apart.; for floor area outside line, comply with single side opening) | 4% of floor area |
*Adopted from Section 6.4.1 of ASHRAE 62.1-2016
**For ceilings that are increasing in height as distance from the openings is increased, the ceiling height shall be determined as the average height of the ceiling within 6 m (20 ft) from the operable openings.
***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.
Multifamily
For all common areas in the building, meet requirements above.
For residential units, have an operable window in each bedroom with the total openable window area a minimum of 4% of the room floor area or meet the following minimum requirements for the entire unit:
In I-P units:
Minimum outdoor air rate in cfm = 0.03 cfm/sf x dwelling unit floor area (in sf) + 7.5 cfm/person x (number of bedrooms + 1)
In SI units:
Minimum outdoor air rate in L/s = 0.15 L/s*m2 x dwelling unit floor area (in m2) + 7.5 cfm/person x (number of bedrooms + 1)
In each full bathroom, have either an exhaust fan that vents directly to the outdoors or an operable window.
Europe ACP: Arbeitsstaettenrichtlinie ASR 5
Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 or ASR A3.6 as a local equivalent to ASHRAE Standard 62.1-2010, natural ventilation procedure. 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
How do I find whether my project is located in a non-attainment area for particulate matter or exceeds the prerequisite ozone requirements? 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.) |
The outdoor air intake for our ventilation system is not accessible, and it’s not possible to measure the outdoor airflow directly. How can we determine the outdoor airflow for this system? 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.) |
What if our systems do not meet the required outside air when systems are tested at worst-case conditions? 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.) |
Our system cannot provide enough outdoor air due to design limitations. What should we do? 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.) |
My building has 80 AHUs providing ventilation to building spaces. Do I have to do the ventilation calculations and conduct outdoor air measurements for each one? 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.) |
What if after our Preliminary Review we have to revise the ventilation rate procedure calculations and find that we need to make corrections to the system in order to meet the prerequisite? Can we redo the outside air testing after making corrections? Would we need to update the performance period for all credits accordingly? 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.) |
Our building has a single fan that supplies outside air to multiple AHUs. Do we need to perform outside air testing at the supply fan or at all AHUs? 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.) |
We have a VAV system where single AHUs serve multiple zones. Do we need to take outside air measurements at each VAV box? 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.) |
Addenda
**Made applicable to v4.1 O+M Projects on 2/6/23
"Projects outside the U.S. may instead calculate minimum outdoor air requirements using 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 first bullet under Required Documentation
Add a second and third bullet under Required Documentation to read as:
"- For mechanically ventilated spaces
o Minimum indoor air quality calculator
o Measured outdoor airflows
o Description of the method or protocol used to measure the total quantity of outdoor air delivered and exhaust ventilation rates, as applicable. Explain the measurement device or system, its accuracy, and how and when the measurements were taken (if applicable)
- For naturally ventilated spaces: list of spaces with floor area, opening size, and opening locations and calculations showing compliance with Table 2
Documentation toolkit
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Maintain the ventilation system equipment and associated components based on Table 8.2 of ASHRAE 62.1-2016. Include information on ventilation system operation and preventative maintenance in the current facilities requirements and operations and maintenance plan required for compliance with EA prerequisite Energy Efficiency Best Management Practices.
For spaces with mechanical exhaust, test and confirm proper operation of the exhaust systems as outlined in the current facilities requirements and operations and maintenance plan.
Ventilate the project spaces mechanically or naturally as follows:
For mechanically ventilated spaces, measure the total quantity of outdoor air delivered and verify the results are within 10 percent of the rates outlined in the current facilities requirements and operations and maintenance plan. Measurements shall quantify the amount of outdoor air for each air handling unit serving the project. Measurements taken within five years prior to project submission are acceptable. The rates must meet the following minimum requirements for each air handling unit:
In I-P units:
Minimum outdoor air rate in cfm = 0.06 cfm/sf x gross building area (in sf) + people outdoor air rate from Table 1 (cfm/person) x building occupancy
In SI units:
Minimum outdoor air rate in L/s = 0.3 L/s*m2 x gross building area (in m2) + people outdoor air rate from Table 1 (L/s per person) x building occupancy
Table 1. People outdoor air rate
Occupancy category* | People outhoor air rate | |
---|---|---|
cfm per person | L/s per person | |
Auditorium seating area Libraries Office space Places of religious worship | 5 | 2.5 |
Mall common areas Museums | 7.5 | 3.8 |
Classrooms Daycare General manufacturing | 10 | 5 |
Health club/aerobics | 20 | 10 |
Alternatively, the rates may meet the Ventilation Rate Procedure outlined in Section 6.2 of ASHRAE 62.1 editions 2016, 2013, 2010, or 2007.
For naturally ventilated spaces, meet the minimum requirements in Table 2:Table 2. Minimum opening location and size requirements for naturally ventilated spaces*
Opening type | Location of opening | Size of opening |
---|---|---|
Maximum distance from operable openings** | Minimum opening area*** | |
Single side opening | 2 x ceiling height | 4% of floor area |
Double side opening | 5 x ceiling height | 4% of floor area |
Corner opening | 5 x ceiling height (along a line drawn between the two openings that are farthest apart.; for floor area outside line, comply with single side opening) | 4% of floor area |
*Adopted from Section 6.4.1 of ASHRAE 62.1-2016
**For ceilings that are increasing in height as distance from the openings is increased, the ceiling height shall be determined as the average height of the ceiling within 6 m (20 ft) from the operable openings.
***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.
Multifamily
For all common areas in the building, meet requirements above.
For residential units, have an operable window in each bedroom with the total openable window area a minimum of 4% of the room floor area or meet the following minimum requirements for the entire unit:
In I-P units:
Minimum outdoor air rate in cfm = 0.03 cfm/sf x dwelling unit floor area (in sf) + 7.5 cfm/person x (number of bedrooms + 1)
In SI units:
Minimum outdoor air rate in L/s = 0.15 L/s*m2 x dwelling unit floor area (in m2) + 7.5 cfm/person x (number of bedrooms + 1)
In each full bathroom, have either an exhaust fan that vents directly to the outdoors or an operable window.
Europe ACP: Arbeitsstaettenrichtlinie ASR 5
Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 or ASR A3.6 as a local equivalent to ASHRAE Standard 62.1-2010, natural ventilation procedure.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.
How do I find whether my project is located in a non-attainment area for particulate matter or exceeds the prerequisite ozone requirements? 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.) |
The outdoor air intake for our ventilation system is not accessible, and it’s not possible to measure the outdoor airflow directly. How can we determine the outdoor airflow for this system? 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.) |
What if our systems do not meet the required outside air when systems are tested at worst-case conditions? 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.) |
Our system cannot provide enough outdoor air due to design limitations. What should we do? 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.) |
My building has 80 AHUs providing ventilation to building spaces. Do I have to do the ventilation calculations and conduct outdoor air measurements for each one? 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.) |
What if after our Preliminary Review we have to revise the ventilation rate procedure calculations and find that we need to make corrections to the system in order to meet the prerequisite? Can we redo the outside air testing after making corrections? Would we need to update the performance period for all credits accordingly? 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.) |
Our building has a single fan that supplies outside air to multiple AHUs. Do we need to perform outside air testing at the supply fan or at all AHUs? 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.) |
We have a VAV system where single AHUs serve multiple zones. Do we need to take outside air measurements at each VAV box? 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.) |
**Made applicable to v4.1 O+M Projects on 2/6/23
"Projects outside the U.S. may instead calculate minimum outdoor air requirements using 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 first bullet under Required Documentation
Add a second and third bullet under Required Documentation to read as:
"- For mechanically ventilated spaces
o Minimum indoor air quality calculator
o Measured outdoor airflows
o Description of the method or protocol used to measure the total quantity of outdoor air delivered and exhaust ventilation rates, as applicable. Explain the measurement device or system, its accuracy, and how and when the measurements were taken (if applicable)
- For naturally ventilated spaces: list of spaces with floor area, opening size, and opening locations and calculations showing compliance with Table 2