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Requirements
Meet the minimum requirements of Sections 6 through 8 of ASHRAE Standard 170-2008, Ventilation of Health Care Facilities (with errata but without addenda1).
Case 1. Mechanically ventilated spaces
Mechanical ventilation systems must be designed using the ventilation rates in Section 7 of the standard, the requirements of the 2010 FGI Guidelines for Design and Construction of Health Care Facilities (Table 2.1-2) or the applicable local code, whichever is more stringent.OR
Case 2. Naturally ventilated projects
Naturally ventilated buildings or portions of the buildings must comply with ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, Paragraph 5.1 (with errata but without addenda1). [Latin America ACP: Engineered Natural Ventilation Systems]1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
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 »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.
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Learn more about The Cost of LEED v4 »Frequently asked questions
See all forum discussions about this credit »Addenda
May we use a more current version of ASHRAE 62.1 and ASHRAE 55?
Yes, for ASHRAE 62.1, LEED v4.1 projects may use ASHRAE 62.1-2019 or ASHRAE 62.1-2020 in lieu of ASHRAE 62.1-2016 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 v4 projects may use ASHRAE 62.1-2013, ASHRAE 62.1-2016, ASHRAE 62.1-2019, or ASHRAE 62.1-2020 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, ASHRAE 62.1-2019, or ASHRAE 62.1-2020 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 v4.1 projects may use ASHRAE 55-2020 in lieu of ASHRAE 55-2017 for EQ Credit Thermal Comfort.
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.**
**Updated 7/25/2023 to update to include LEED v4.1 and ASHRAE 2022/2020 standards**
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?
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.)
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.
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.
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.
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.
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.
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.
We are meeting the IEQp1: Minimum Indoor Air Quality Performance with Option 2, CEN standards EN 15251:2007 and EN 13779:2007. The CEN standards provide minimum outdoor air requirements for most spaces but refer to local codes for certain specialty spaces such as parking garages. To meet the intent of the prerequisite, we propose using our local code requirements for garages, which is Teil 5 Garagen (“Section 5 – Parking Garages”) of the Verordnung über Bau und Betrieb von Sonderbauten - Nordrhein-Westfalen (“Local Law of North Rhine-Westphalia for the Construction and Operation of Specialty Buildings”), dated 17 November 2009 (SBauVO). To meet this local code, our design will use demand control ventilation with carbon monoxide (CO) detectors to limit the CO concentration. Is this approach acceptable?
**Update 10/01/2014: Ruling has been revised
Yes, garage demand control ventilation is an acceptable ventilation approach for parking garages. This approach is acceptable for projects pursuing Option 2 (EN 15251 and EN 13779) of EQ Prerequisite Minimum Indoor Air Quality Performance as well as the hazardous exhaust requirements in EQ Credit Indoor Chemical and Pollutant Source Control. The demand control ventilation strategy must meet the following requirements:
- • Consider the number of cars expected to be operating in the garage at any given time and the length of time a car remains in operation in the parking garage.
- • Consider the emission rates associated with the car exhaust for the average car.
- • Detect the primary contaminant(s) of concern in the parking garage (for example: carbon monoxide, particulates, VOCs, NO2, etc.).
- • Modulate airflow such that contaminant levels are maintained below a specified contaminant concentration limit and corresponding exposure period. All concentration limits must be based on local code or some other cognizant authority. If the contaminant is carbon monoxide, a concentration limit of 35 ppm time-weighted average (8 hours) and levels not to exceed 50 ppm at any time is recommended.
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© Copyright U.S. Green Building Council, Inc. All rights reserved.
Requirements
Meet the minimum requirements of Sections 6 through 8 of ASHRAE Standard 170-2008, Ventilation of Health Care Facilities (with errata but without addenda1).
Case 1. Mechanically ventilated spaces
Mechanical ventilation systems must be designed using the ventilation rates in Section 7 of the standard, the requirements of the 2010 FGI Guidelines for Design and Construction of Health Care Facilities (Table 2.1-2) or the applicable local code, whichever is more stringent.OR
Case 2. Naturally ventilated projects
Naturally ventilated buildings or portions of the buildings must comply with ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality, Paragraph 5.1 (with errata but without addenda1). [Latin America ACP: Engineered Natural Ventilation Systems]1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.