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LEED v2009
New Construction
Indoor Environmental Quality
Minimum IAQ Performance

LEED CREDIT

NC-2009 IEQp1: Minimum IAQ Performance Required

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Andrew Mitchell, P.E.

Mitchell Gulledge Engineering, Inc.
Principal

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Credit language

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

Intent

To establish minimum indoor air quality (IAQ) performance to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of the occupants.

Requirements

Case 1. Mechanically ventilated spaces
Mechanical ventilation systems must be designed using the ventilation rate procedure as defined by ASHRAE 62.1-2007, or the applicable local code, whichever is more stringent.
Option 1. ASHRAE standard 62.1-2007 or non-U.S. equivalent
Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda1). Projects outside the U.S. may use a local equivalent to Sections 4 through 7 of ASHRAE Standard 62.1-2007.

OR

Option 2. CEN standards EN 15251: 2007 and EN 13779: 2007
Projects outside the U.S. may earn this prerequisite by meeting the minimum 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 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.

OR

Case 2. Naturally ventilated spaces
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda1). [Europe ACP: Arbeitsstaettenrichtlinie ASR 5] [Latin America ACP: Engineered Natural Ventilation Systems]

Alternative Compliance Paths (ACPs)

Europe ACP: Arbeitsstaettenrichtlinie ASR 5
Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 or ASR A3.6 as a local equivalent to ASHRAE Standard 62.1-2007, paragraph 5.1.
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).
Credit substitution available
You may use the LEED v4 version of this credit on v2009 projects. For more information check out this article.
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Frequently asked questions

Which units should be included in the calculations for this prerequisite?

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Is outdoor air quality testing required in a space using natural ventilation?

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For a space designed to be naturally ventilated, can operable windows or vents be used to satisfy the 62.1-2007 requirements?

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What options are available to projects outside the US to meet this prerequisite?

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Can LEED 2009 projects elect to follow ASHRAE 62.1-2010 for this prerequisite?

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Addenda

7/8/2017Updated: 11/6/2020
Regional ACP
Description of change:
Revise the Europe ACP to the following:
"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."
Campus Applicable
No
Internationally Applicable:
No
4/5/2016Updated: 1/8/2020
Regional ACP
Description of change:
Under Naturally Ventilated Spaces 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)."
Campus Applicable
No
Internationally Applicable:
Yes
4/1/2015Updated: 4/1/2015
Regional ACP
Description of change:
Add the following after the text for Case 2:

"Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 as a local equivalent to ASHRAE Standard 62.1-2007, paragraph 5.1."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Case 1, Option 1 should read: "Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda). Projects outside the U.S. may use a local equivalent to Sections 4 through 7 of ASHRAE Standard 62.1-2007."
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 language under Case 1: "Mechanical ventilation systems must be designed using the ventilation rate procedure as defined by ASHRAE 62.1-2007, or the applicable local code, whichever is more stringent."
Campus Applicable
No
Internationally Applicable:
Yes
1/8/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Reformat the requirements section as indicated in the supplemental document.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Delete current language under "Requirements" and "Case 1"
Campus Applicable
No
Internationally Applicable:
Yes
10/1/2014Updated: 2/14/2015
Form Update
Description of change:
New calculator for projects performing the ASHRAE 62.1 ventilation rate procedure calculations required for EQ Prerequisite Minimum Indoor Air Quality Performance. This optional calculator can be used for LEED 2009 and LEED v4 projects and is an alternative to the ASHRAE 62.1 62MZCalc and previous 100% outdoor air and single zone calculators.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Option title to read: "OPTION 2. CEN Standards EN 15251: 2007 and EN 13779: 2007"
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Option title to read: "OPTION 1. ASHRAE Standard 62.1-2007 or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
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
1/8/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Reformat the requirements section as indicated in the supplemental document.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Case title to read: "CASE 1. Mechanically Ventilated Spaces"
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following language under Case 1, Option 2: "Projects outside the U.S. may earn this prerequisite by meeting the minimum requirements of Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
2/12/2008
LEED Interpretation
Inquiry:

Description We are planning to construct an apparel factory for LEED certification. The planned factory will have 1000 sewing machines and few finishing equipments among others. The entire space will be air conditioned to maintain ASHRAE comfort levels. The occupation density is 20-25 persons per 1000 square feet. Proposal Since there is no specified category in ASHRAE 62.1-2004 \'Ventilation for Acceptable Indoor Air Quality\' for apparel industry, we are proposing to use \'data entry\' category listed under office buildings which is similar (200W sewing machine with operator seated similar to data entry). This allows 5cfm per person with 0.06cfm per square feet. Please rule on the acceptability of this approach.

Ruling:

The CIR is asking for verification that they have selected the appropriate Occupancy Category for their project, given that it does not fall precisely within the categories listed in ASHRAE 62.1-2004. ASHRAE instructs that if the occupancy category for a proposed space or zone is not listed, the requirements for the listed occupancy category that is most similar in terms of occupant density, activities and building construction shall be used. It is up to the discretion of the design team to select the most appropriate alternative. It would be beneficial to the LEED reviewer if, included with the prerequisite submission, the applicant provides an explanation of their rationale for the selection. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
10/1/2015
LEED Interpretation
Inquiry:

Can cold storage areas conditioned below 32°F (0 °C) be excluded from the minimum ventilation requirements in the prerequisite Minimum Indoor Air Quality Performance? These spaces should be excluded for three reasons, 1. There are few contaminant sources in these spaces, 2. The introduction of outside air into these spaces is problematic, and 3. The storage areas are intended for storage of frozen goods and are uninhabitable environments, only occupied occasionally and for short periods of time, as dictated by OSHA requirements.

Ruling:

Yes, frozen cold storage areas conditioned below 32 °F (0 °C) do not need to meet ASHRAE 62.1 for the purposes of the Minimum Indoor Air Quality Prerequisite. This exception is not allowed for cold storage areas that can be adjusted from below 32 °F (0 °C) to above 32 °F (0 °C). It is also not allowed if combustion equipment (such as gas-operated forklifts) is operated in the space.

Campus Applicable
No
Internationally Applicable:
No
11/1/2011
LEED Interpretation
Inquiry:

How do naturally ventilated projects, such as high rise residential projects, that do not qualify with the requirements of the Ventilation Rate Procedure, or ASHRAE 62.1 Section 5.1, or CIBSE Applications Manual 10 meet IEQp1 for v2 and 2009 rating systems?

Ruling:

For projects that do not qualify with the requirements of the Ventilation Rate Procedure, or ASHRAE 62.1 Section 5.1, or CIBSE Applications Manual 10, and are pursuing an engineered ventilation system (e.g. a combination of natural ventilation with mechanical exhaust, or some other means of assisting the outside airflow through the openings and circulating it through the occupiable space), the following expectations apply:Compliance when the local ventilation code governing the project is ASHRAE 62.1-2007 (or 2004 for LEED-v2 projects): We understand that many local jurisdictions would not be willing to provide confirmation that your engineered natural ventilation approach meets the intent of ASHRAE 62.1-2007. Therefore, in locations where ASHRAE 62.1-2007 is required for local ventilation code compliance, it would be sufficient to document that the plans and specifications that use the engineered natural ventilation approach have been approved by the local code authority in order to show compliance with EQ Prerequisite 1. The documentation required for EQp1 would include confirmation that all of the mandatory requirements of ASHRAE 62.1 have been met, a narrative describing the engineered ventilation modeling approach, evidence documenting that the plans have been approved by the local code authority, and some form of evidence that ASHRAE 62.1-2007 (or a later version of ASHRAE 62.1) is required for local building code compliance.Compliance when the local ventilation code governing the project can be documented to be at least as stringent as ASHRAE 62.1-2007 (or 2004 for LEED-v2 projects):If the local code requirements relative to ventilation are governed by an alternate code (any code other than ASHRAE 62.1-2007 (2004 for LEED-v2) or a later version of ASHRAE 62.1), then the project team must provide evidence that this alternate code is at least as stringent than ASHRAE 62.1-2007 (2004 for LEED-NCv2) in its entirety. If this documentation could be provided, then the approval of the local code authority would be sufficient to document compliance with the prerequisite requirements. Using this methodology, the documentation required for EQp1 would include documentation showing that the alternate code is at least as stringent than ASHRAE 62.1-2007 (2004 for LEED-v2) in its entirety, confirmation that all of the mandatory requirements of the alternate code have been met, a narrative describing the engineered ventilation modeling approach, and evidence documenting that the plans have been approved by the local code authority. Compliance when the local ventilation code governing the project cannot be documented to be at least as stringent as ASHRAE 62.1-2007: If the documentation described above cannot be provided, then, for purposes of LEED Certification, USGBC/GBCI would serve as the Authority Having Jurisdiction [since the local code authority does not have jurisdiction over ASHRAE 62.1-2007 (2004 for LEED-v2) or a ventilation standard of equivalent stringency]. In this case, the project team would be required to submit documentation showing that the intent of ASHRAE 62.1-2007 (2004 for LEED-v2) has been met with the project\'s engineered natural ventilation system. This documentation must clearly identify how the natural ventilation requirements stipulated in ASHRAE 62.1-2007 (2004 for LEED-v2) Section 5.1 have not been met (e.g. smaller operable window area, larger distance from operable windows or openings, etc.). The documentation must also clearly identify how the ventilation design has been engineered to meet the intent of ASHRAE 62.1 where the requirements of Section 5.1 have not been met. For example, if the distance from windows or openings is more than 25 feet, is there an exhaust air fan located at the furthest distance from the windows that is inducing the outdoor air to flow through the space; is that exhaust fan flow equivalent to the outside airflow that would be required for the space if the Ventilation Rate Procedure were used? If the window area is less than 4% of the floor area, is the space designed with cross-ventilation to ensure adequate airflow? Drawings and some calculations or air flow analyses will be required in addition to the narrative describing the engineered ventilation approach to justify this approach. For projects that have not yet entered the review process, it is highly recommended that this be provided in a project-specific credit interpretation request in order to achieve prior approval of the engineered natural ventilation approach rather than waiting until the system has been fully designed to pursue approval of this method.Below are some specific examples of the types of documentation that would be required if using this compliance approach; but these examples are not intended to apply to every possible engineered ventilation solution:For example, in high rise residential, the team must identify any occupiable spaces (excluding coat closets and entry vestibules) in the residential units that are more than 25 feet away from the operable windows, that are interior spaces with unobstructed free area from adjacent rooms that is less than 8% of the area of the interior room, or that have operable window openings that totals less than 4% of the total naturally ventilated floor area. A narrative and/or calculations should be provided explaining how mechanical ventilation or a combination of mechanical ventilation and natural ventilation are used to meet the ventilation requirements for those spaces. For spaces or portions of spaces that are ventilated using mechanical ventilation or a combination of mechanical and natural ventilation, the documentation must show compliance with the ventilation rates indicated in Table 6-1 of ASHRAE 62.1-2007 (2004 for LEED-v2) and the Ventilation Rate Procedure calculations indicated in Section 6.2, using appropriate values for zone air distribution effectiveness (Ez.)For high-rise residential projects attempting to show compliance for EQp1 using positively pressurized corridors that are provided with excess outdoor air [above ASHRAE 62.1-2007 (2004 for LEED-v2) minimum requirements] that is to be transferred into each living unit either via undercuts in the entry doors, transfer air grilles, or some other means, the project team must document that all mechanically ventilated spaces will meet the minimum ventilation requirements of ASHRAE 62.1-2007 (2004 for LEED-v2) Section 6.2. For projects utilizing bathroom or other exhaust to negatively pressurize the unit to draw in excess ventilation air from the corridors, if the primary makeup air source for the unit exhaust is designed to be provided through the apartment entrance/vestibule, the project team should sufficiently demonstrate that the makeup air is outdoor air and not relief air (or previously "used" outside air) from other occupied spaces in the building and that the exhaust operates continuously. Additionally, note that for the case of makeup air provided from the apartment entrance, the makeup air may substantially short-circuit the space requiring mechanical ventilation depending on the location of the air entry point and the exhaust grilles, and therefore an appropriate air distribution effectiveness (Table 6-2) must be considered (see example 6-H from the ASHRAE 62.1-2007 User\'s Manual - p. 6-20, where a zone air distribution effectiveness of 0.5 is utilized.)

Campus Applicable
No
Internationally Applicable:
No
10/1/2012
LEED Interpretation
Inquiry:

Our project is a mixed use facility with a combination of a high-rise (21-story) and mid-rise (6-story) residential apartment building. Our project utilizes all electric cooking appliances; there is no gas within the dwelling units. Table 6-4 of ASHRAE 62.1-2007 indicates 100 CFM of intermittent exhaust should be provided for residential kitchens. However, Table 6-4 also indicates that residential kitchen exhaust is Class 2 air, and ASHRAE 62.1-2007 section 5.17.3.2 indicates that Class 2 air can be re-circulated within the space. Please confirm that re-circulating kitchen hoods meet the IEQp1 prerequisite (which requires the 100 CFM of intermittent exhaust). We would also like to know if re-circulating hoods are acceptable for both mechanically ventilated and naturally ventilated apartments, since we may have both in our project. We believe re-circulated hoods should be acceptable to meet the exhaust requirements based on ASHRAE 62.1-2007 section 5.17.3.2, but wanted to confirm since this is a prerequisite.

Ruling:

The applicant is requesting confirmation that recirculating kitchen hoods meet the kitchen exhaust requirements of ASHRAE 62.1-2007 for IEQp1 in both mechanically and naturally ventilated kitchens. For mechanically ventilated kitchens, the exhaust rates listed in Table 6-4 of ASHRAE 62.1-2007 are by definition required to be discharged to outside the building (per Section 3 air, exhaust: air removed from a space and discharged to outside the building). Although recirculation of Class 2/3 air is permissible per section 5.17.3.2/5.17.3.3, the Table 6-4 exhaust requirements must still be provided (to outside the building) to meet the minimum requirements of Section 6 of ASHRAE 62.1-2007. Therefore recirculating hoods alone do not meet the exhaust requirements of Table 6-4 of the standard for mechanically ventilated kitchens. Additionally, LEED Interpretation 2208 (CIR ruling dated 6/25/2008) referenced in the inquiry, is indicated within the LEED Interpretation database as NOT applicable to the LEED NCv2009 rating system.In regards to naturally ventilated kitchens, natural ventilation systems designed in accordance with Section 5.1 of the standard do not need to meet the mechanical ventilation (exhaust) requirements of Table 6-4. Note, the exhaust requirements of Table 6-4 were clarified by ASHRAE through addendum O, which states "...exhaust requirements apply to all zones and/or systems regardless of the method used to determine minimum outdoor airflow rates (Ventilation Rate Procedure, IAQ Procedure, or Natural Ventilation Procedure)." Projects have the option to follow the ASHRAE 62.1-2007 addendum but it is not required.

Campus Applicable
No
Internationally Applicable:
No
3/25/2008
LEED Interpretation
Inquiry:

The project is designed to have about 60% of the building footprint as future tenant occupied datacenter space with the rest as support offices, shipping & handling office, corridors, restrooms, mechanical and electrical rooms. The datacenter will not be regularly occupied. The datacenter space will not have permanent or temporary workstations for the technicians. It is most similar in nature to an electrical or mechanical equipment room - technicians will be required to enter for short periods on an occasional basis for maintenance, etc. Additionally, the data center will be a sensitive area with access control (security), such that only authorized personnel may even enter the space. We would like to know if the datacenter space could be defined as a non-regularly occupied space & whether the proposed occupancy count for a datacenter space is appropriate. For LEED points concerning regularly occupied spaces: As per CIR Ruling 1/29/2008 (referred in LEED NC 2.2 credit EQ 6.2) & ASHRAE 62.1 2004, page 4 - definition of occupied space: "An enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms and equipment rooms, that are only occupied occasionally and for short periods of time." & As per CIR Ruling 1/29/2008 (referred in LEED NC 2.2 for credit EQ 8.1) - We consider the datacenter space as a non-regularly occupied space. We propose to exclude the datacenter space from the calculations of the following points: 1. EQ Prereq 1: Minimum IAQ Performance 2. EQ credit 1: Outdoor Air Delivery Monitoring 3. EQ credit 2: Increased Ventilation 4. EQ credit 6: Controllability of Systems, Thermal Comfort 5. EQ credit 7: Thermal Comfort, Compliance with ASHRAE 55-2004 (The data center will be designed to meet ASHRAE TC9.9 recommendations on Thermal Guidelines for Data Processing Environments.) 6. EQ credit 8.1: Daylight & Views Is datacenter a non-regularly occupied space? And, would the exclusion for the above points, be allowed? For datacenter occupancy count: As per LEED CS Appendix, default occupancy for a datacenter space is not listed. The technicians will enter the datacenter space occasionally and for short periods of time. Typically, we anticipate 1 technician for duration of 2 hours for 1 day, biweekly. At peak we anticipate 2 technicians for the same duration. So at any given time in the year there will be no more then 2 technicians in the datacenter space. We propose to: 1. Add the peak 2 datacenter occupants to the average transient occupancy & FTE for the regularly occupied areas for purposes of SS credit 4 calculations. 2. Add 2 transient occupants to the transient occupancy & FTE for the regularly occupied areas for purposes for WE credit 2 & 3 calculations. Is the above acceptable?

Ruling:

The applicant is asking to exclude an area of the project, a datacenter that can be considered non-regularly occupied, from the calculations of various prerequisites and credits under LEED-CS. 1. EQ Prerequisite 1: Minimum IAQ Performance- No it cannot be excluded. 2. EQ Credit 1: Outdoor Air Delivery Monitoring- No it cannot be excluded. 3. EQ Credit 2: Increased Ventilation- No it cannot be excluded. 4. EQ Credit 6: Controllability of Systems, Thermal Comfort- Yes, non-regularly occupied spaces are not applicable to this credit. 5. EQ Credit 7: Thermal Comfort, Compliance with ASHRAE 55-2004 (The data center will be designed to meet ASHRAE TC9.9 recommendations on Thermal Guidelines for Data Processing Environments.)- Yes, this approach is acceptable. 6. EQ Credit 8.1: Daylight & Views- Yes, non-regularly occupied spaces are not applicable to this credit. The applicant is also seeking guidance for how to account for the occupancy of the datacenter space in LEED credit calculations. Based upon Appendix 1 of the LEED-CS Reference Guide, if the total tenant occupancy is known, this must be used for all calculations, as long as the gross square footage per employee is not greater than that in the default occupancy count. If the total tenant occupancy count is not known, the Appendix 1 guidelines can be used. However, these occupancy counts are provided for typical core and shell project types. Project types and circumstances not covered in the Appendix will be considered on a case-by-case basis. For this project, the proposed methodology is acceptable.

Campus Applicable
No
Internationally Applicable:
No
7/1/2015
LEED Interpretation
Inquiry:

May we use a more current version of ASHRAE 62.1 and ASHRAE 55?

Ruling:

Yes, for ASHRAE 62.1, LEED v4 projects may use ASHRAE 62.1-2013, ASHRAE 62.1-2016 or ASHRAE 62.1-2019 in lieu of ASHRAE 62.1-2010 for EQ Prerequisite Minimum Indoor Air Quality Performance and EQ Credit Enhanced Indoor Air Quality Strategies. The same standard must be used for both credits.

LEED 2009 projects may use ASHRAE 62.1-2010, ASHRAE 62.1-2013, or ASHRAE 62.1-2016, or ASHRAE 62.1-2019 in lieu of ASHRAE 62.1-2007 for EQ Prerequisite Minimum Indoor Air Quality Performance and EQ Credit Increased Ventilation. The same standard must be used for both credits.

For ASHRAE 55, LEED v4 projects may use ASHRAE 55-2013 in lieu of ASHRAE 55-2010 for EQ Credit Thermal Comfort.

LEED 2009 projects may use ASHRAE 55-2010 or ASHRAE 55-2013 in lieu of ASHRAE 55-2004 for EQ Credit Thermal Comfort- Design.

**Updated 7/10/2020 to include ASHRAE 62.1-2016 and ASHRAE 62.1-2019 as applicable standards.**

Campus Applicable
No
Internationally Applicable:
No
8/1/2011
LEED Interpretation
Inquiry:

This project is a renovation of an existing building on a university campus. This building is one of a series of buildings constructed in the early 1960\'s, and the University is attempting to maintain the character and cohesiveness of the campus by preserving the existing structures and facades. Preserving the buildings also contributes to our sustainable design efforts, but it has resulted in an issue with the prerequisite for indoor air quality. The basement and first floor levels are mechanically ventilated in accordance with ASHRAE 62.1, and do not present a problem. However, running ductwork to the upper floors did prove problematic, so the design team is relying upon natural ventilation for the second and third floors. After calculating the window ventilation areas, all but three of the rooms comply with ASHRAE 62.1 for natural ventilation. The three rooms in question obtain 74%, 77% and 78% of the required ventilation area for operable windows.In order to meet University requirements and LEED Criteria all windows will be replaced with new, energy star models, to match the size and appearance of the existing windows. As previously mentioned, these new windows will generally provide 100% opening requirements, except in the three cases noted.It is the University\'s intent, as the Authority Having Jurisdiction, to grant a waiver for the minimum ventilation requirement in only these three rooms, thereby permitting the maximum use of the facility, while maintaining the historic appearance of the building.The University has therefore requested an interpretation from USGBC that this waiver for reduced ventilation requirements will be acceptable for obtaining LEED Certification for these facilities.

Ruling:

The applicant is requesting a waiver from the ASHRAE 62.1-2007 Section 5.1 natural ventilation prescriptive requirements for three rooms within the existing building. The new window areas are insufficient to meet the prescriptive requirements and are specified and installed per university requirements. ASHRAE 62.1-2007 exempts engineered natural ventilation systems when approved by the authority having jurisdiction. The natural ventilation system, as described, does not appear to be an engineered system. In this case, the prescriptive requirements could not be waived.

Campus Applicable
No
Internationally Applicable:
No
4/1/2012
LEED Interpretation
Inquiry:

Can projects use the natural ventilation prescriptive dimensional requirements written in 62.1-2010, instead of those in ASHRAE 62.1-2007? This would allow some spaces to comply with the requirements where they may otherwise not if 62.1-2007 is applied. If so, are we required to comply with the standard as a whole? Applying the standard as whole would have serious implications for new construction or existing projects attempting to comply with the Natural Ventilation Procedure because in some instances mechanical ventilation systems would have to be installed to meet the prerequisite.

Ruling:

For LEED 2009 projects where ASHRAE 62.1-2007 is the applicable standard for compliance with IEQp1, project teams may substitute the geometric requirements of ASHRAE 62.1-2010 sections 6.4.1 through 6.4.2 in place of ASHRAE 62.1-2007 section 5.1.1.
**Update October 1, 2013: This ruling also applies to EQp1 in LEED 2009 for Schools.

Campus Applicable
No
Internationally Applicable:
No
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Mitchell Gulledge Engineering, Inc.
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Intent

To establish minimum indoor air quality (IAQ) performance to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of the occupants.

Requirements

Case 1. Mechanically ventilated spaces
Mechanical ventilation systems must be designed using the ventilation rate procedure as defined by ASHRAE 62.1-2007, or the applicable local code, whichever is more stringent.
Option 1. ASHRAE standard 62.1-2007 or non-U.S. equivalent
Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda1). Projects outside the U.S. may use a local equivalent to Sections 4 through 7 of ASHRAE Standard 62.1-2007.

OR

Option 2. CEN standards EN 15251: 2007 and EN 13779: 2007
Projects outside the U.S. may earn this prerequisite by meeting the minimum 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 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.

OR

Case 2. Naturally ventilated spaces
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda1). [Europe ACP: Arbeitsstaettenrichtlinie ASR 5] [Latin America ACP: Engineered Natural Ventilation Systems]

Alternative Compliance Paths (ACPs)

Europe ACP: Arbeitsstaettenrichtlinie ASR 5
Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 or ASR A3.6 as a local equivalent to ASHRAE Standard 62.1-2007, paragraph 5.1.
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).
Credit substitution available
You may use the LEED v4 version of this credit on v2009 projects. For more information check out this article.

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7/8/2017Updated: 11/6/2020
Regional ACP
Description of change:
Revise the Europe ACP to the following:
"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."
Campus Applicable
No
Internationally Applicable:
No
4/5/2016Updated: 1/8/2020
Regional ACP
Description of change:
Under Naturally Ventilated Spaces 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)."
Campus Applicable
No
Internationally Applicable:
Yes
4/1/2015Updated: 4/1/2015
Regional ACP
Description of change:
Add the following after the text for Case 2:

"Projects in Europe may use Arbeitsstaettenrichtlinie ASR 5 as a local equivalent to ASHRAE Standard 62.1-2007, paragraph 5.1."
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Case 1, Option 1 should read: "Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda). Projects outside the U.S. may use a local equivalent to Sections 4 through 7 of ASHRAE Standard 62.1-2007."
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 language under Case 1: "Mechanical ventilation systems must be designed using the ventilation rate procedure as defined by ASHRAE 62.1-2007, or the applicable local code, whichever is more stringent."
Campus Applicable
No
Internationally Applicable:
Yes
1/8/2010Updated: 2/14/2015
Rating System Correction
Description of change:
Reformat the requirements section as indicated in the supplemental document.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Delete current language under "Requirements" and "Case 1"
Campus Applicable
No
Internationally Applicable:
Yes
10/1/2014Updated: 2/14/2015
Form Update
Description of change:
New calculator for projects performing the ASHRAE 62.1 ventilation rate procedure calculations required for EQ Prerequisite Minimum Indoor Air Quality Performance. This optional calculator can be used for LEED 2009 and LEED v4 projects and is an alternative to the ASHRAE 62.1 62MZCalc and previous 100% outdoor air and single zone calculators.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Option title to read: "OPTION 2. CEN Standards EN 15251: 2007 and EN 13779: 2007"
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Option title to read: "OPTION 1. ASHRAE Standard 62.1-2007 or Non-U.S. Equivalent"
Campus Applicable
No
Internationally Applicable:
Yes
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
1/8/2010Updated: 2/14/2015
Reference Guide Correction
Description of change:
Reformat the requirements section as indicated in the supplemental document.
Campus Applicable
No
Internationally Applicable:
No
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add a new Case title to read: "CASE 1. Mechanically Ventilated Spaces"
Campus Applicable
No
Internationally Applicable:
Yes
7/6/2012Updated: 2/14/2015
Global ACP
Description of change:
Add the following language under Case 1, Option 2: "Projects outside the U.S. may earn this prerequisite by meeting the minimum requirements of Annex B of Comit
Campus Applicable
No
Internationally Applicable:
Yes
2/12/2008
LEED Interpretation
Inquiry:

Description We are planning to construct an apparel factory for LEED certification. The planned factory will have 1000 sewing machines and few finishing equipments among others. The entire space will be air conditioned to maintain ASHRAE comfort levels. The occupation density is 20-25 persons per 1000 square feet. Proposal Since there is no specified category in ASHRAE 62.1-2004 \'Ventilation for Acceptable Indoor Air Quality\' for apparel industry, we are proposing to use \'data entry\' category listed under office buildings which is similar (200W sewing machine with operator seated similar to data entry). This allows 5cfm per person with 0.06cfm per square feet. Please rule on the acceptability of this approach.

Ruling:

The CIR is asking for verification that they have selected the appropriate Occupancy Category for their project, given that it does not fall precisely within the categories listed in ASHRAE 62.1-2004. ASHRAE instructs that if the occupancy category for a proposed space or zone is not listed, the requirements for the listed occupancy category that is most similar in terms of occupant density, activities and building construction shall be used. It is up to the discretion of the design team to select the most appropriate alternative. It would be beneficial to the LEED reviewer if, included with the prerequisite submission, the applicant provides an explanation of their rationale for the selection. Applicable Internationally.

Campus Applicable
No
Internationally Applicable:
Yes
10/1/2015
LEED Interpretation
Inquiry:

Can cold storage areas conditioned below 32°F (0 °C) be excluded from the minimum ventilation requirements in the prerequisite Minimum Indoor Air Quality Performance? These spaces should be excluded for three reasons, 1. There are few contaminant sources in these spaces, 2. The introduction of outside air into these spaces is problematic, and 3. The storage areas are intended for storage of frozen goods and are uninhabitable environments, only occupied occasionally and for short periods of time, as dictated by OSHA requirements.

Ruling:

Yes, frozen cold storage areas conditioned below 32 °F (0 °C) do not need to meet ASHRAE 62.1 for the purposes of the Minimum Indoor Air Quality Prerequisite. This exception is not allowed for cold storage areas that can be adjusted from below 32 °F (0 °C) to above 32 °F (0 °C). It is also not allowed if combustion equipment (such as gas-operated forklifts) is operated in the space.

Campus Applicable
No
Internationally Applicable:
No
11/1/2011
LEED Interpretation
Inquiry:

How do naturally ventilated projects, such as high rise residential projects, that do not qualify with the requirements of the Ventilation Rate Procedure, or ASHRAE 62.1 Section 5.1, or CIBSE Applications Manual 10 meet IEQp1 for v2 and 2009 rating systems?

Ruling:

For projects that do not qualify with the requirements of the Ventilation Rate Procedure, or ASHRAE 62.1 Section 5.1, or CIBSE Applications Manual 10, and are pursuing an engineered ventilation system (e.g. a combination of natural ventilation with mechanical exhaust, or some other means of assisting the outside airflow through the openings and circulating it through the occupiable space), the following expectations apply:Compliance when the local ventilation code governing the project is ASHRAE 62.1-2007 (or 2004 for LEED-v2 projects): We understand that many local jurisdictions would not be willing to provide confirmation that your engineered natural ventilation approach meets the intent of ASHRAE 62.1-2007. Therefore, in locations where ASHRAE 62.1-2007 is required for local ventilation code compliance, it would be sufficient to document that the plans and specifications that use the engineered natural ventilation approach have been approved by the local code authority in order to show compliance with EQ Prerequisite 1. The documentation required for EQp1 would include confirmation that all of the mandatory requirements of ASHRAE 62.1 have been met, a narrative describing the engineered ventilation modeling approach, evidence documenting that the plans have been approved by the local code authority, and some form of evidence that ASHRAE 62.1-2007 (or a later version of ASHRAE 62.1) is required for local building code compliance.Compliance when the local ventilation code governing the project can be documented to be at least as stringent as ASHRAE 62.1-2007 (or 2004 for LEED-v2 projects):If the local code requirements relative to ventilation are governed by an alternate code (any code other than ASHRAE 62.1-2007 (2004 for LEED-v2) or a later version of ASHRAE 62.1), then the project team must provide evidence that this alternate code is at least as stringent than ASHRAE 62.1-2007 (2004 for LEED-NCv2) in its entirety. If this documentation could be provided, then the approval of the local code authority would be sufficient to document compliance with the prerequisite requirements. Using this methodology, the documentation required for EQp1 would include documentation showing that the alternate code is at least as stringent than ASHRAE 62.1-2007 (2004 for LEED-v2) in its entirety, confirmation that all of the mandatory requirements of the alternate code have been met, a narrative describing the engineered ventilation modeling approach, and evidence documenting that the plans have been approved by the local code authority. Compliance when the local ventilation code governing the project cannot be documented to be at least as stringent as ASHRAE 62.1-2007: If the documentation described above cannot be provided, then, for purposes of LEED Certification, USGBC/GBCI would serve as the Authority Having Jurisdiction [since the local code authority does not have jurisdiction over ASHRAE 62.1-2007 (2004 for LEED-v2) or a ventilation standard of equivalent stringency]. In this case, the project team would be required to submit documentation showing that the intent of ASHRAE 62.1-2007 (2004 for LEED-v2) has been met with the project\'s engineered natural ventilation system. This documentation must clearly identify how the natural ventilation requirements stipulated in ASHRAE 62.1-2007 (2004 for LEED-v2) Section 5.1 have not been met (e.g. smaller operable window area, larger distance from operable windows or openings, etc.). The documentation must also clearly identify how the ventilation design has been engineered to meet the intent of ASHRAE 62.1 where the requirements of Section 5.1 have not been met. For example, if the distance from windows or openings is more than 25 feet, is there an exhaust air fan located at the furthest distance from the windows that is inducing the outdoor air to flow through the space; is that exhaust fan flow equivalent to the outside airflow that would be required for the space if the Ventilation Rate Procedure were used? If the window area is less than 4% of the floor area, is the space designed with cross-ventilation to ensure adequate airflow? Drawings and some calculations or air flow analyses will be required in addition to the narrative describing the engineered ventilation approach to justify this approach. For projects that have not yet entered the review process, it is highly recommended that this be provided in a project-specific credit interpretation request in order to achieve prior approval of the engineered natural ventilation approach rather than waiting until the system has been fully designed to pursue approval of this method.Below are some specific examples of the types of documentation that would be required if using this compliance approach; but these examples are not intended to apply to every possible engineered ventilation solution:For example, in high rise residential, the team must identify any occupiable spaces (excluding coat closets and entry vestibules) in the residential units that are more than 25 feet away from the operable windows, that are interior spaces with unobstructed free area from adjacent rooms that is less than 8% of the area of the interior room, or that have operable window openings that totals less than 4% of the total naturally ventilated floor area. A narrative and/or calculations should be provided explaining how mechanical ventilation or a combination of mechanical ventilation and natural ventilation are used to meet the ventilation requirements for those spaces. For spaces or portions of spaces that are ventilated using mechanical ventilation or a combination of mechanical and natural ventilation, the documentation must show compliance with the ventilation rates indicated in Table 6-1 of ASHRAE 62.1-2007 (2004 for LEED-v2) and the Ventilation Rate Procedure calculations indicated in Section 6.2, using appropriate values for zone air distribution effectiveness (Ez.)For high-rise residential projects attempting to show compliance for EQp1 using positively pressurized corridors that are provided with excess outdoor air [above ASHRAE 62.1-2007 (2004 for LEED-v2) minimum requirements] that is to be transferred into each living unit either via undercuts in the entry doors, transfer air grilles, or some other means, the project team must document that all mechanically ventilated spaces will meet the minimum ventilation requirements of ASHRAE 62.1-2007 (2004 for LEED-v2) Section 6.2. For projects utilizing bathroom or other exhaust to negatively pressurize the unit to draw in excess ventilation air from the corridors, if the primary makeup air source for the unit exhaust is designed to be provided through the apartment entrance/vestibule, the project team should sufficiently demonstrate that the makeup air is outdoor air and not relief air (or previously "used" outside air) from other occupied spaces in the building and that the exhaust operates continuously. Additionally, note that for the case of makeup air provided from the apartment entrance, the makeup air may substantially short-circuit the space requiring mechanical ventilation depending on the location of the air entry point and the exhaust grilles, and therefore an appropriate air distribution effectiveness (Table 6-2) must be considered (see example 6-H from the ASHRAE 62.1-2007 User\'s Manual - p. 6-20, where a zone air distribution effectiveness of 0.5 is utilized.)

Campus Applicable
No
Internationally Applicable:
No
10/1/2012
LEED Interpretation
Inquiry:

Our project is a mixed use facility with a combination of a high-rise (21-story) and mid-rise (6-story) residential apartment building. Our project utilizes all electric cooking appliances; there is no gas within the dwelling units. Table 6-4 of ASHRAE 62.1-2007 indicates 100 CFM of intermittent exhaust should be provided for residential kitchens. However, Table 6-4 also indicates that residential kitchen exhaust is Class 2 air, and ASHRAE 62.1-2007 section 5.17.3.2 indicates that Class 2 air can be re-circulated within the space. Please confirm that re-circulating kitchen hoods meet the IEQp1 prerequisite (which requires the 100 CFM of intermittent exhaust). We would also like to know if re-circulating hoods are acceptable for both mechanically ventilated and naturally ventilated apartments, since we may have both in our project. We believe re-circulated hoods should be acceptable to meet the exhaust requirements based on ASHRAE 62.1-2007 section 5.17.3.2, but wanted to confirm since this is a prerequisite.

Ruling:

The applicant is requesting confirmation that recirculating kitchen hoods meet the kitchen exhaust requirements of ASHRAE 62.1-2007 for IEQp1 in both mechanically and naturally ventilated kitchens. For mechanically ventilated kitchens, the exhaust rates listed in Table 6-4 of ASHRAE 62.1-2007 are by definition required to be discharged to outside the building (per Section 3 air, exhaust: air removed from a space and discharged to outside the building). Although recirculation of Class 2/3 air is permissible per section 5.17.3.2/5.17.3.3, the Table 6-4 exhaust requirements must still be provided (to outside the building) to meet the minimum requirements of Section 6 of ASHRAE 62.1-2007. Therefore recirculating hoods alone do not meet the exhaust requirements of Table 6-4 of the standard for mechanically ventilated kitchens. Additionally, LEED Interpretation 2208 (CIR ruling dated 6/25/2008) referenced in the inquiry, is indicated within the LEED Interpretation database as NOT applicable to the LEED NCv2009 rating system.In regards to naturally ventilated kitchens, natural ventilation systems designed in accordance with Section 5.1 of the standard do not need to meet the mechanical ventilation (exhaust) requirements of Table 6-4. Note, the exhaust requirements of Table 6-4 were clarified by ASHRAE through addendum O, which states "...exhaust requirements apply to all zones and/or systems regardless of the method used to determine minimum outdoor airflow rates (Ventilation Rate Procedure, IAQ Procedure, or Natural Ventilation Procedure)." Projects have the option to follow the ASHRAE 62.1-2007 addendum but it is not required.

Campus Applicable
No
Internationally Applicable:
No
3/25/2008
LEED Interpretation
Inquiry:

The project is designed to have about 60% of the building footprint as future tenant occupied datacenter space with the rest as support offices, shipping & handling office, corridors, restrooms, mechanical and electrical rooms. The datacenter will not be regularly occupied. The datacenter space will not have permanent or temporary workstations for the technicians. It is most similar in nature to an electrical or mechanical equipment room - technicians will be required to enter for short periods on an occasional basis for maintenance, etc. Additionally, the data center will be a sensitive area with access control (security), such that only authorized personnel may even enter the space. We would like to know if the datacenter space could be defined as a non-regularly occupied space & whether the proposed occupancy count for a datacenter space is appropriate. For LEED points concerning regularly occupied spaces: As per CIR Ruling 1/29/2008 (referred in LEED NC 2.2 credit EQ 6.2) & ASHRAE 62.1 2004, page 4 - definition of occupied space: "An enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms and equipment rooms, that are only occupied occasionally and for short periods of time." & As per CIR Ruling 1/29/2008 (referred in LEED NC 2.2 for credit EQ 8.1) - We consider the datacenter space as a non-regularly occupied space. We propose to exclude the datacenter space from the calculations of the following points: 1. EQ Prereq 1: Minimum IAQ Performance 2. EQ credit 1: Outdoor Air Delivery Monitoring 3. EQ credit 2: Increased Ventilation 4. EQ credit 6: Controllability of Systems, Thermal Comfort 5. EQ credit 7: Thermal Comfort, Compliance with ASHRAE 55-2004 (The data center will be designed to meet ASHRAE TC9.9 recommendations on Thermal Guidelines for Data Processing Environments.) 6. EQ credit 8.1: Daylight & Views Is datacenter a non-regularly occupied space? And, would the exclusion for the above points, be allowed? For datacenter occupancy count: As per LEED CS Appendix, default occupancy for a datacenter space is not listed. The technicians will enter the datacenter space occasionally and for short periods of time. Typically, we anticipate 1 technician for duration of 2 hours for 1 day, biweekly. At peak we anticipate 2 technicians for the same duration. So at any given time in the year there will be no more then 2 technicians in the datacenter space. We propose to: 1. Add the peak 2 datacenter occupants to the average transient occupancy & FTE for the regularly occupied areas for purposes of SS credit 4 calculations. 2. Add 2 transient occupants to the transient occupancy & FTE for the regularly occupied areas for purposes for WE credit 2 & 3 calculations. Is the above acceptable?

Ruling:

The applicant is asking to exclude an area of the project, a datacenter that can be considered non-regularly occupied, from the calculations of various prerequisites and credits under LEED-CS. 1. EQ Prerequisite 1: Minimum IAQ Performance- No it cannot be excluded. 2. EQ Credit 1: Outdoor Air Delivery Monitoring- No it cannot be excluded. 3. EQ Credit 2: Increased Ventilation- No it cannot be excluded. 4. EQ Credit 6: Controllability of Systems, Thermal Comfort- Yes, non-regularly occupied spaces are not applicable to this credit. 5. EQ Credit 7: Thermal Comfort, Compliance with ASHRAE 55-2004 (The data center will be designed to meet ASHRAE TC9.9 recommendations on Thermal Guidelines for Data Processing Environments.)- Yes, this approach is acceptable. 6. EQ Credit 8.1: Daylight & Views- Yes, non-regularly occupied spaces are not applicable to this credit. The applicant is also seeking guidance for how to account for the occupancy of the datacenter space in LEED credit calculations. Based upon Appendix 1 of the LEED-CS Reference Guide, if the total tenant occupancy is known, this must be used for all calculations, as long as the gross square footage per employee is not greater than that in the default occupancy count. If the total tenant occupancy count is not known, the Appendix 1 guidelines can be used. However, these occupancy counts are provided for typical core and shell project types. Project types and circumstances not covered in the Appendix will be considered on a case-by-case basis. For this project, the proposed methodology is acceptable.

Campus Applicable
No
Internationally Applicable:
No
7/1/2015
LEED Interpretation
Inquiry:

May we use a more current version of ASHRAE 62.1 and ASHRAE 55?

Ruling:

Yes, for ASHRAE 62.1, LEED v4 projects may use ASHRAE 62.1-2013, ASHRAE 62.1-2016 or ASHRAE 62.1-2019 in lieu of ASHRAE 62.1-2010 for EQ Prerequisite Minimum Indoor Air Quality Performance and EQ Credit Enhanced Indoor Air Quality Strategies. The same standard must be used for both credits.

LEED 2009 projects may use ASHRAE 62.1-2010, ASHRAE 62.1-2013, or ASHRAE 62.1-2016, or ASHRAE 62.1-2019 in lieu of ASHRAE 62.1-2007 for EQ Prerequisite Minimum Indoor Air Quality Performance and EQ Credit Increased Ventilation. The same standard must be used for both credits.

For ASHRAE 55, LEED v4 projects may use ASHRAE 55-2013 in lieu of ASHRAE 55-2010 for EQ Credit Thermal Comfort.

LEED 2009 projects may use ASHRAE 55-2010 or ASHRAE 55-2013 in lieu of ASHRAE 55-2004 for EQ Credit Thermal Comfort- Design.

**Updated 7/10/2020 to include ASHRAE 62.1-2016 and ASHRAE 62.1-2019 as applicable standards.**

Campus Applicable
No
Internationally Applicable:
No
8/1/2011
LEED Interpretation
Inquiry:

This project is a renovation of an existing building on a university campus. This building is one of a series of buildings constructed in the early 1960\'s, and the University is attempting to maintain the character and cohesiveness of the campus by preserving the existing structures and facades. Preserving the buildings also contributes to our sustainable design efforts, but it has resulted in an issue with the prerequisite for indoor air quality. The basement and first floor levels are mechanically ventilated in accordance with ASHRAE 62.1, and do not present a problem. However, running ductwork to the upper floors did prove problematic, so the design team is relying upon natural ventilation for the second and third floors. After calculating the window ventilation areas, all but three of the rooms comply with ASHRAE 62.1 for natural ventilation. The three rooms in question obtain 74%, 77% and 78% of the required ventilation area for operable windows.In order to meet University requirements and LEED Criteria all windows will be replaced with new, energy star models, to match the size and appearance of the existing windows. As previously mentioned, these new windows will generally provide 100% opening requirements, except in the three cases noted.It is the University\'s intent, as the Authority Having Jurisdiction, to grant a waiver for the minimum ventilation requirement in only these three rooms, thereby permitting the maximum use of the facility, while maintaining the historic appearance of the building.The University has therefore requested an interpretation from USGBC that this waiver for reduced ventilation requirements will be acceptable for obtaining LEED Certification for these facilities.

Ruling:

The applicant is requesting a waiver from the ASHRAE 62.1-2007 Section 5.1 natural ventilation prescriptive requirements for three rooms within the existing building. The new window areas are insufficient to meet the prescriptive requirements and are specified and installed per university requirements. ASHRAE 62.1-2007 exempts engineered natural ventilation systems when approved by the authority having jurisdiction. The natural ventilation system, as described, does not appear to be an engineered system. In this case, the prescriptive requirements could not be waived.

Campus Applicable
No
Internationally Applicable:
No
4/1/2012
LEED Interpretation
Inquiry:

Can projects use the natural ventilation prescriptive dimensional requirements written in 62.1-2010, instead of those in ASHRAE 62.1-2007? This would allow some spaces to comply with the requirements where they may otherwise not if 62.1-2007 is applied. If so, are we required to comply with the standard as a whole? Applying the standard as whole would have serious implications for new construction or existing projects attempting to comply with the Natural Ventilation Procedure because in some instances mechanical ventilation systems would have to be installed to meet the prerequisite.

Ruling:

For LEED 2009 projects where ASHRAE 62.1-2007 is the applicable standard for compliance with IEQp1, project teams may substitute the geometric requirements of ASHRAE 62.1-2010 sections 6.4.1 through 6.4.2 in place of ASHRAE 62.1-2007 section 5.1.1.
**Update October 1, 2013: This ruling also applies to EQp1 in LEED 2009 for Schools.

Campus Applicable
No
Internationally Applicable:
No

LEEDuser expert

Andrew Mitchell, P.E.

Mitchell Gulledge Engineering, Inc.
Principal

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