This prerequisite establishes a baseline for providing a minimum amount of outdoor air to buildings in order to maintain good indoor air quality and keep occupants comfortable and healthy. This prerequisite references ASHRAE 62.1-2007 (with errata but without addenda) and is often more stringent than local building codes, although it is not likely to entail any added costs.
The compliance paths for mechanically ventilated and naturally ventilated spaces, Case 1 and Case 2, are somewhat different and you may need to follow both paths for the same building. Naturally ventilated spaces must follow the distinct requirements set out in Case 2, even if other spaces in the same building are mechanically ventilated and are following Case 1. Mixed-mode spaces (with both mechanical and natural ventilation) must follow the compliance path for mechanical ventilation, Case 1.
New construction additions will need to confirm that any ventilation systems serving the project meet the ventilation rates required by ASHRAE 62.1 2007, even if the ventilation system design itself is outside the scope of the project. If base building systems do not meet the standard’s requirements, you will need to either modify the base building system or provide detailed analysis documenting the constraints and explaining why the base building systems cannot be upgraded.
The 2007 edition of ASHRAE 62.1 combines 62.1-2004 and the eight approved and published addenda to the 2004 edition. The new edition does the following:
If the building relies on the fans for daily ventilation, it is considered a mechanically ventilated building.
Testing in naturally ventilated spaces is not required per 62.1-2007 Sections 4-7 if the outdoor air quality adequately meets 62.1-2007, Table 4-1.
Both operable windows and vents can be used, but only the operable area within those elements can be counted towards the minimum percentage (4%) of net occupiable area.
Determine likely ventilation strategies during preliminary programming: natural, mechanical, or mixed-mode ventilation. This prerequisite is attainable with any of these strategies.
This prerequisite is paired with IEQc2: Increased Ventilation. If ventilation rates are targeted above the 30% ASHRAE requirement, projects can gain both the prerequisite and a point for EQc2. Projects pursuing IEQc2 may follow the compliance path for natural ventilation found in Chapter 2 of The CIBSE Applications Manual 10 (AM10) for both the prerequisite and for the credit.
Many of the strategies that contribute to meeting this prerequisite also support earning other indoor environmental quality credits and should be explored as integrated solutions. See LEEDuser's guidance on the rest of the IEQ section for ideas.
Natural ventilation strategies can reduce costs. Natural ventilation in particular can reduce the need for mechanical equipment as well as operational costs. Displacement ventilation, in which air is delivered at or near floor level at a low velocity, can also reduce ducting and improve equipment efficiency. In choosing a system, analyze life cycle cost tradeoffs.
Check local building codes to determine requirements. The project must either meet ASHRAE 62.1-2007, or local codes if they are more stringent. Since ASHRAE 62.1-2007 is often more stringent than local codes, be sure to review and be familiar with its requirements.
This prerequisite is not likely to require added costs.
Review the Ventilation Rate Procedure methodology in ASHRAE 62.1-2007 Section 6.2 and the associated Table 6-1.
ASHRAE 62.1 recognizes two procedures to prove IAQ compliance: the IAQ Procedure methodology and the Ventilation Rate Procedure. The Ventilation Rate Procedure is easier to apply and is the prescribed path for this LEED prerequisite.
If you are pursuing IEQc5: Indoor Chemical and Pollutant Source Control, you must incorporate MERV 13 filters into your filtration system. These relatively tight filters may affect the fan power and fan sizes necessary to provide the required quantities of air. Involve the engineer early if pursuing IEQc5.
Demand-controlled ventilation can greatly reduce energy use while providing large amounts of fresh air to occupants.
Determine whether natural ventilation is feasible based on the project type, use, and climate. Study the natural conditions of the site, such as prevailing wind direction, and orient the building to maximize airflow.
Review the prescriptive requirements for natural ventilation in ASHRAE 62.1-2007 Paragraph 5.1 (with errata but without addenda).
An integrated design meeting will help determine whether natural ventilation is a high priority and should be a primary driver of the design process.
Airflow modeling early in the design process can help teams create a more effective natural ventilation design. If the data is used early in the design to help inform team on such thing as space planning and building envelope design. An airflow modeling professional may add some upfront costs, while likely improving system efficiency and effectiveness.
Consider the cost implications of natural ventilation. Passive strategies may reduce or eliminate the need for fans and HVAC equipment, but they may also require high quantities of operable windows and a floor plan that is conducive to passive ventilation. Natural ventilation often requires the cooperation of occupants, to open and close windows when appropriate, for example, be sure that your project is likely to succeed in this respect.
Determine the required ventilation rates for indoor spaces based on occupancy and space types. ASHRAE 62.1-2007 tables 6-1 and 6-4 list minimum requirements for particular spaces.
Separately evaluate each space to determine air requirements and what type of ventilation will be best. Metabolic rate of the space activities and the occupant density are factors that determine the amount of fresh air needed in a space. For example, exercise rooms and conference rooms require more fresh air than offices.
An integrated design approach among the mechanical engineer, architects, owners and occupants will facilitate design decisions that impact the HVAC design. For example, space planning decisions will impact the architectural programming of the space as well as access to natural ventilation.
Increasing a project’s ventilation rate brings long-term cost benefits. Good indoor air quality can lower operational costs by increasing occupants’ health and productivity as well as the value and marketability of the building.
For mixed-mode and naturally ventilated spaces, the mechanical engineer should calculate the outdoor airflow rate and communicate the area requirements for operable wall or roof openings to the architect.
The mechanical engineer begins preliminary ventilation rate calculations during project programming in order to set ventilation quality goals for particular spaces and occupancies. The area of a given multi‐zone system should be broken down by ventilation zones, and all zones within that system must meet the minimum breathing zone ventilation air requirements as per ASHRAE 62.1‐2004. For a typical office space, the mechanical design consists of multiple ventilation zones for which compliance would need to be shown on an individual basis.
For mixed-mode ventilation, zone the plan into areas—mechanically ventilated and naturally ventilated—and follow separate compliance calculations for each area.
Determine the applicable floor area for operable wall or roof openings according to ASHRAE 62.1-2007 section 5.1.
Consider using Computational Fluid Dynamics (CFD) modeling to determine proper opening sizes and ensure proper airflow. Some energy modeling programs also have CFD analysis capabilities.
Expect upfront modeling fees for Computational Fluid Dynamics (CFD), but also consider the benefits of CFD modeling: a better-designed natural ventilation system that can bring short-term payback from reduced mechanical systems, and long-term operational savings.
At the first integrated design meeting during schematic design, develop a detailed natural ventilation strategy involving goals for windows, building orientation, space planning, use of atriums, and other access to natural ventilation. Natural ventilation systems may require a more robust and intense integrated design process, of several focused workshops analyzing several alternatives. Computer modeling may be necessary to test various design alternatives to determine which is most effective and efficient.
Hotel and multifamily projects may have difficulty achieving this prerequisite if they are naturally ventilated and have interior spaces that are further than 25 feet from an operable wall or roof opening. These projects might consider increased window areas, shallower floor plates, or using mixed-mode ventilation so that mechanically supplied outdoor air can support areas outside the 25-foot natural ventilation boundary.
The mechanical engineer continues to run ventilation rate calculations during the mechanical design process to inform design development and confirm compliance with this prerequisite. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2007. See the attached 62MZ calculator.
Continuing to use an integrated design approach among the mechanical engineer, architects, owners and end users will facilitate design decisions that impact the mechanical design. For example, space planning decisions will impact the architectural programming of the space as well as access to natural ventilation.
Strategically locate air intakes for mechanical or natural ventilation systems to avoid taking in contaminants and odors like vehicle exhaust from parking lots or fumes from garbage storage areas.
Incorporating operable windows into the design for natural and mixed-mode ventilation can help with an additional LEED point for EAc6.1: Controllability of Systems—Thermal Comfort.
Continue running ventilation rate calculations during the mechanical design process to confirm compliance with this credit and to inform the design. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2007. See the 62MZ calculator.
Implement energy recovery systems, economizers, low-pressure-drop design, and efficient fans as appropriate to support ventilation rates meeting or exceeding the referenced ASHRAE standard without compromising energy performance.
Avoid oversizing mechanical equipment. Oversized equipment will often increase operating costs and reduce operational efficiency. The correct equipment size will depend on a number of factors, including local climate, total building area, insulation levels, air filtration medium, number of windows and doors, and occupant comfort preferences.
Spaces served by the same VAV (variable air volume) controller can be grouped together in the 62MZ calculator, but grouped spaces should have similar exterior exposure. For example, you can group two perimeter spaces that share a VAV controller, but would want to separate a non-perimeter space even if it shares the same VAV controller.
Laboratory facilities generally require very high ventilation rates. Consider installing separate mechanical systems for lab spaces to maximize return-air mixing. Other strategies may include using a heat exchanger to capture energy from laboratory exhaust, using low-flow or variable-flow fume hoods, minimizing ventilation rates during unoccupied times, or using a dedicated outdoor air system.
Integrating building automation systems can control mechanical systems efficiently and maintain desired ventilation rates while minimizing unscheduled maintenance.
The Ventilation Rate Procedure calculation includes occupancy counts based on space types.
Continue to run calculations and develop flow diagrams to inform the design process and confirm compliance. If you are using a natural ventilation modeler for the project, use the model as a tool to inform design development.
The calculation for operable openings will only apply to the floor area adjacent to the window—25 feet to either side and in front of the opening.
The surface area of window openings must, for compliance with ASHRAE 62.1, be equal to or greater than 4% of the occupied floor area that the design considers naturally ventilated. Multiple windows in aggregate can provide the operable area needed to meet the requirements.
In naturally ventilated multifamily buildings, air infiltration from a pressurized hallway or corridor can contribute to the Ventilation Rate Procedure calculation for areas that do not meet the requirements of ASHRAE 62.1, as long as the corridor is pressurized with outdoor air.
For mechanically ventilated spaces, run ventilation calculations to verify that the final design meets the minimum outside air rates equal to or exceeding the ASHRAE 62.1-2007 minimum.
For naturally ventilated spaces, confirm compliance with the requirements of ASHRAE 62.1-2007 section 5.1.
If natural ventilation strategies are integrated into the design, ensure that key elements of the natural ventilation system, such as operable windows, window actuators, controls, operable atrium elements, and solar chimneys, are not compromised during value engineering. Educate decision-makers about the natural ventilation design and the importance of maintaining all the key components. If these elements are altered in a way that compromises natural ventilation rates, the mechanical system may no longer be sized appropriately.
Fill out the LEED credit form and upload all supporting documents to LEED Online.
Use this checklist for naturally ventilated spaces prior to construction to review plans for prerequisite compliance:
Use this checklist for mechanical systems prior to construction to check prerequisite compliance:
Coordinate the installation of ventilation systems with the project’s commissioning process.
Use commissioning to confirm that installed systems are providing the outside air rates specified in the design.
Monitor outdoor air delivery periodically to confirm that minimum ventilation rates are being maintained. Implement a maintenance program to ensure that mechanical system components are functioning properly.
Test all dedicated building exhaust systems including chemical areas, bathroom, shower, kitchen, and parking exhaust systems to confirm proper fan speed, voltage, control sequences, and set points as applicable. Provide operations and maintenance personnel with manuals and educate them about any atypical maintenance requirements.
Getting feedback on ventilation performance from occupants through surveys can help to identify potential problems that may become expensive if they go unnoticed.
A documented ventilation performance plan can help ensure that systems reach the expected ventilation thresholds.
In projects with operable windows, occupants may not know when conditions are best for opening the windows. Implement a system so that occupants are informed of when to open and close the windows to achieve designed performance and optimal comfort.
Maintain a building operating plan (BOP) that establishes operating schedules and set points and regularly review these parameters against actual building needs. When developing these parameters, consider both time-of-day and time-of-year variations in optimal temperature requirements and be careful to avoid over-conditioning the building spaces with more ventilation, heating or cooling than is necessary.
Adjust reset and setback temperature settings and calibrate controls and sensors. A Building Automation System (BAS) will allow building managers to adjust, monitor and control temperature set points and air volumes throughout the building from a central location. Direct digital controls (DDC) utilized by the BAS will function more efficiently than older pneumatic controls and help to avoid unnecessary use of HVAC equipment during non-business hours and holidays.
Develop and implement a comprehensive Indoor Air Quality Management Plan using the EPA’s “Indoor Air Quality Building Education and Assessment Model” (I-BEAM).
Following the initial audit, the IAQ manager must make periodic inspections to uncover new IAQ issues and monitor the status of previous issues. The I-BEAM tool supplies inspection forms that can be tailored to the project building to facilitate this process.
Establish protocols to manage all significant pollutant sources referenced in I-BEAM that are applicable to the project building.
Ensure that procedures are in place for receiving and responding to IAQ complaints from building occupants. The I-BEAM tool provides sample forms and logs for fielding and recording occupant complaints as well as information about key principles for developing effective communication with building occupants regarding IAQ issues. Strategies for investigating and resolving the issues that trigger occupant complaints are covered by a variety of I-BEAM guidelines.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish minimum indoor air quality (IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors.) performance to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of the occupants.
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.
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.
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.
CASE 2. Naturally Ventilated Spaces
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda). 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.
Design ventilation systems to meet or exceed the minimum outdoor air ventilation rates as described in the ASHRAE standard. Balance the impacts of ventilation rates on energy use and indoor air quality to optimize for energy efficiency and occupant comfort. Use the ASHRAE Standard 62.1-2007 Users Manual (with errata but without addenda1) for detailed guidance on meeting the referenced requirements.
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.
This updated version of the spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. Up to date, 2nd Edition.
ASHRAE 62.1-2007 should be referenced when designing outdoor airflow monitoring devices.
This spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. This is the 1st edition.
This Rocky Mountain Institute publication is a case study of the connection between worker productivity and indoor air quality.
This manual provides information on the technology and techniques for the design, operation, servicing, and balancing of environmental systems.
ASHRAE publishes widely used standards and publishes the ASHRAE Journal.
Labs21 is a voluntary partnership program dedicated to improving the environmental performance of U.S. laboratories.
IAQA is a nonprofit organization dedicated to promoting the exchange of indoor environmental information through education and research.
MSCA is a national trade association that provides educational resources and training programs on sustainable service and maintenance practices for HVACR contractors.
Located in London, this organization publishes a series of guides on ventilation, including natural ventilation.
This website contains reports from an extensive EPA modeling study that assessed the compatibilities and trade-offs between energy, indoor air quality, and thermal comfort objectives for HVAC systems and formulated strategies to achieve superior performance.
This is a Microsoft Excel calculator that accompanies the ASHRAE 62.1 reference standard. The calculator allows users to plug in variables for specific project types and run the Ventilation Rate Procedure.
Public domain software from NIST (National Institute of Standards and Technology) that has natural ventilation sizing tools, and flow models to analytically predict room-by-room airflows.
Public domain software from NIST (National Institute of Standards and
Technology) that has natural ventilation sizing tools, and flow models
to analytically predict room-by-room airflows.
ASHRAE released an app for iPhone, iPod touch, and iPad that allows you to perform comprehensive minimum ventilation calculations for a wide variety of commercial buildings based upon Standard 62.1, using either I-P or SI units. This app is based upon the 62MZCalc.xls. Now, you can make calculations at a meeting and know if your project meets IEQp1 or IEQc2.
This example ventilation rate table from 23 High Line provides guidance when developing prerequisite compliance documents for your project.
This example air riser diagram from 23 High Line shows the mechanical ventilation supply for the building. It is the ducted diagram showing how air will be supplied to building occupants. Use this as an example for how to document ventilation effectiveness compliance.
Use this example mechanical schedule created from 23 High Line for guidance when developing ventilation effectiveness compliance documents for your project.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 IEQ credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
Documentation for this credit can be part of a Design Phase submittal.
We are working on a residential building that has common areas which are conditioned with split system heat pumps and heat recovery ventilators for fresh air. Normally I would consider this a single zone system, but the HRU's serve multiple zones and systems (there are 4 HRU's and 10 split system heat pumps). Fresh air is ducted to each zone from the HRU, but there is only one return grill. Would I still treat this as a single zone system - or do I have to go to the multi-zone?
Nancy, you should treat this as a 100% outdoor air system, as long as a split system heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. does not serve more than one zone.
Our project is use VRF system to keep the space cool. We also provide dedicated injection fan (DOAS) as to meet 62.1 requirement. Most space will have indoor cassette unit. OA ventilation were provided from injection fan (DOAS) to each VRF system.
In IEQP1 form, we use VRP Compliance Calculate found in Appendix 1 for submission.
Some spaces such as a small area of lift lobby or storage room (aka files room), we only cater OA (from the same DOAS) and not cooling.
Do this area consider as "mechanical ventilated 100% OA" ?
If you are supplying the space with OA from a DOAS then it is mechanically ventilated.
According to the IEQ space matrix bathrooms and storage rooms are excluded from VRP calculations for IEQp1, would they still be excluded from 100% OA systems?
You will have to comply with either natural ventilation or required exhaust rates regardless of your system type.
While what Andrew says is true, unoccupied storage rooms do not require outdoor air and may not require exhaust depending on whether chemicals, etc. are to be stored in the closet. Also in my experience, even though the exhaust is required in restrooms by ASHRAE 62.1-2007, you normally don't have to include any reference to restroom exhaust in your IEQp1 ventilation calculations.
The same spaces that are excluded from VRP calculation requirements are also excluded from 100% outdoor air system tabulations, yes.
Julie, thank you for your clarifications! We will remove the storage and bathrooms from our 100%OA system tabulation.
We are working on a Project, in which most of the rooms are complying with the ASHRAE 62.1-2007 Natural Ventilation requirements, stated under the IEQ Prerequisite 1 – Minimum Indoor Air Quality Performance. And there are few rooms which are not qualifying as per the requirement. The Engineer is proposing Exhaust systems in the rooms which are not qualifying following the Natural Ventilation approach. This exhaust system will create a negative pressure in the Non-qualifying room, which will suck the air from the adjacent Qualifying rooms.
The queries are as follows:
1. Will installation of the exhaust system help to comply as per the requirement?
2. Can the openings at the bottom of the door be provided to help us qualify the credit?
3. Is there any requirement of CFM for the exhaust systems to comply with the LEED requirement? Do we need to consider the exhaust CFM as per Section 6 of ASHRAE 62.1-2007?
Thanks in advance!
1. No. Not if you are not ducting fresh air that will be used as make-up air.
2. Only if you can prove that the make-up air into that room is OA.
3. You would have to comply with the ventilation rate procedure with a ventilation effectiveness of 0.5.
1. Will installation of the exhaust system help to comply as per the requirement?
2. Can the openings at the bottom of the door be provided to help us qualify the credit?
3. Is there any requirement of CFM for the exhaust systems to comply with the LEED requirement? Do we need to consider the exhaust CFM as per Section 6 of ASHRAE 62.1-2007?
Thanking you in advance.
You may utilize transfer air induced by exhaust fans to comply with ASHRAE 62.1-2007, but the following must be considered:
1) Air class - this is described in the standard. There are 4 classes, with 1 being the cleanest air and 4 being exhaust from contaminated sources, like fume hoods.
2) Ventilation effectiveness - when utilizing transfer air, there is a de-rating factor you need to account for, typically more than 50%.
3) The exhaust airflow rate is dictated within ASHRAE 62.1.
Note there is a limit to how much air can be transferred through an undercut door. This is typically limited to residential applications where air volumes are relatively small.
I am working on a residential building, the venilation system consists of 4 AHUs that supply air to corridors. The corridors are pressurized and therefore push the fresh air through grills in the ceiling to the apartments. There is no ducting between the corridors and the apartments. Therefore the air transfers through the plenum basically. There is sufficient air flow, but would the system be approved by USGBC ?
I have worked on a similar design. The only way that I could be sure to get approval was to have an exhaust fan that draws the ventilation air into the living spaces. You have to use a ventilation effectiveness of 0.5. If you are simply counting on a pressurized corridor leaking ventilation air into each space at a uniform rate, it will probably not be approved by the LEED reviewer.
Thanks Andrew for the reply. Originally, we submitted a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide with this system asking if it is going to be feasible, and the USGBC replied it would be approved. However, in our CIR we added that there will be transfer ducts between the corridor and the apartment, but the project cannot include those ducts due to the fire system in the building. We are trying to find a different approach to solve the issue. Natural ventilation did not work either (small windows).
We have designed project that was built recently under local code compliance that refers to Ashrae 62.1-2007, however the project was registered for LEEDv2 a while ago, therefore we designed based on 2007 but according to the comments from USGBC we need to comply with the more strict 2004 version of Ashrae 62.1. Is there a CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide that would allow compliance by meeting local ordinances?
Catalina, you are allowed to use local ordinances but only if they are more stringent than the ASHRAE standard cited in the requirements. What is the specific requirement that's more strict in the 2004 standard?
residential units are required to provide more outside air (per room) while ashrae 62.-2007 requires a general ventilation for the complete dwelling unit. The difference is only like 10 cfm for us but we have 72 units
I am consulting on a big project which has small electrical rooms (~30 sq.ft) in the mechanically ventilated parking basement. The Engineers are claiming that it's not practical to provide a fresh air duct to these rooms (too much ductwork that has to pass from one size of the parking all the way to the other side, just for several small rooms like this).
The Engineers are proposing having an exhaust fan in each of these small rooms, along with a Fresh Air Transfer Grill in the room, which will ensure that sufficient amount of fresh air enters the room. The parking is mechanically ventilated with 100% fresh air & exhaust fans.
Would this be acceptable for the prerequisite? Do we need additional calculations from the engineers regarding the amount of fresh air entering these small rooms?
Omar, since these are not considered to be occupiable spaces, they do not need ventilation. You can simply provide cooling as necessary for the equipment inside.
However ASHRAE 62,1-2007 Table 6-1 has an area outdoor air rate of 0.06 cfm/ft2
The way I understood this is that even if an electrical room isn't occupied (which is true in almost all cases), you still need to provide fresh air.
Isn't this the case?
No, this is not the case. See the definition of Occupiable Space in ASHRAE 62.1.
Andrew, I know that these electrical rooms do not qualify as occupiable space, but still, why does Table 6-1 include ventilation requirements for electrical rooms?
You have to understand that the 62.1 Standard is meant to be applied to your building according to actual occupancy and use. There are some electrical rooms in the world that are occupied. Your electrical rooms (according to your description) are not. Therefore, you should utilize the exception found in the definition of an Occupiable Space. I hope that helps.
Okay now it's clear, thanks Andrew :)
To clarify things, the ventilation requirements for "Electrical equipment rooms" and "Elevator machine rooms" were stricken from ASHRAE 62.1-2007 with Addendum d. At the same time they modified the language for 'storage rooms' to list "Occupiable storage rooms for liquids or gels", along with a separate listing for "Occupiable storage rooms for dry materials", which have both been significantly helpful.
Good to know, thanks Richard!
My project is in design mid-review period, the reviewer gave a comment on IEQp1 which could be simplied as: “The total project area that is provided outdoor air is 10000 square meters (7000m2 for Phase I and 3000m2 for Phase 2); however, the ventilation calculations provided in the form indicate a total area of only 7000m2. Please provide a supplemental narrative and/or revised ventilation calculations to verify that all occupiable spaces have been considered to meet the requirements of ASHRAE Standard 62.1-2007.”
The 3000m2 is part of building and reserved for phase 2 of project, this area is estimated by project owner and there is no detail design on this part, what should I do for the credit compliance? Do I need a project owner’s letter for clarifying these areas would be designed according to ASHRAE Standard 62.1-2007 in phase 2 ??
Make sure that the alternate space which is not being built is outside of your LEED boundary. If it is make reference to the boundary. If the area is not outside of the boundary then just highlight one of the sheets tat shows it as an alternate or future space and add a narrative about the fact that it is not going to be built. Either one of these methods should suffice.
Thank you Andrew, the areas should be accounted as "incomplete space" through LI#10102, I'm following the indications in that ruling, think it works.
Make the space between and, which is not outside the limits of your LEED requirements. This should be referred. If it is not the area outside the border, choose one or another of Cicero shows such a feel good story about the next, that they do not add in building. Of these, one was enough.
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In Florida, we are constantly dealing with the Natural Ventilation section in ASHRAE 62.1-2007. We consistently have significant issues with confusion on the part of project teams on this subject. In my opinion, the USGBC has not done a great job clarifying this in general and offering some guidelines on what compliance paths will and won't be accepted. Their guidance is buried in CIRs that are usually project specific, and can be a bit confusing and rambling. Fortunately much of this is cleared up in future versions!
To try to guide our teams better I have prepared the following notes. I see these questions pop up on this forum a lot too, so I wanted to share it here as well. Of course, if I have misinterpreted anything as well, please offer me some feedback and discussion.
Hi Joe. Thanks for the post. Have you had experience with the 2010 version of 62.1? Specifically will direct kitchen exhaust be required for multi family, hot/humid, mid rise pursuing the natural ventilation approach to compliance with IEQ Ventilation prereq.?
Jason, I saw your question and would like to know if you are trying to certify under LEED v4 or LEED v3. Under v3, you only need to meet the ASHRAE 62.1 2007 standard. In that case, the kitchen exhaust is allowed to be deleted in the case of natural ventilation according to 62.1-2007.
LEED v4 requires you to use ASHRAE 62.1 - 2010. The big difference here (assuming you are not low rise residential) is that natural ventilation is only allowed if there is no heating or cooling equipmentThe equipment used for cooling room air in a building for human comfort. or if the ventilation openings are permanently open (they can also be controlled to open whenever occupants are present).
Basically, ASHRAE 62.1 -2010 kills almost all hopes of using natural ventilation in occupied buildings, especially in hot climates. Also, if you are using LEEDv4, then you the v4 forum would be a good place to go for more information during your certification process. I hope this helps.
Thanks Andrew. I was hoping to use V4, however the owner is dead set against ducting O/A into air handler closets... They could be convinced to provide kitchen exhaust to the exterior instead of re circulating hoods and CO2Carbon dioxide sensors/alarms but the O/A ducted to the unit seems to be a non starter for this client (based on humidity / mold concerns) . The project is in Miami, mid rise condos and has a 20' wide floor plate with 9'10 ceiling heights and operable openings in every regularly occupied area. In your opinion, Is there a path forward for a project like this?
Thank you for your input.
If you can comply with ASHRAE 62.1-2007 naturaql ventilation then certification under LEEDv3 is certainly possible. LEEDv4 seems impossible without design changes.
On another note, ducted OA from an OA unit (conditioned) would help prevent any mold/mildew problems. I work in Florida and we do a lot of work for UM. We always recommend pressurizing buildings with conditioned OA in order to minimize mold problems.
In our project, we have 2 different ventilation system. 1 is a recirculation ventilation system , using only 10% OA, while another system which located in a mechanical room, using 100% OA .
In recent comment from GBCI they mentioned this "The VRP calculations have been provided for multiple zone systems; however, it is unclear if these systems are 100% outdoor air systems that directly serve each ventilation zone. The calculations for multiple zone systems utilize several variables that are only applicable to multiple zone recirculating systems and cannot be used for 100% outdoor air systems"
What am i missing?anyone can assist?
We are pursuing for Fresh Air calculations for a Building with Natural Ventilation, as per the ASHRAE 62.1-2007 requirement, stated under the IEQ Prerequisite 1 – Minimum Indoor Air Quality Performance.
Few Zones in the Building have openable windows and also comply as per the 4% (Openable Area/Carpet Area) requirement. The Project has used a combination of exhaust fans and doors to comply the requirement, as per the local code.
Following are my queries:
1. Will installation of ceiling fans/exhaust fans help to achieve this credit? If yes, is there any specification for the fans?
2. Are spaces like Corridor, Foyer, Pantry, Electrical/Mechanical room and IT room to be counted as occupiable spaces and should Fresh Air calculations be done for these areas?
Kindly advice and thanks in advance.
JP, first of all, if I understand you correctly, most of your zones do not meet the natural ventilation requirements. This will be a major problem with achieving LEED certification. If you do not comply with the prescriptive requirements then you will need to show mechanical ventilation. You can do this with an exhaust fan by pulling in make-up air but you effectiveness will be 0.5. You need to make sure that the air is 100% OA. As for the second question, I would consider all of those to be non-occupied spacesOccupied Spaces are defined as enclosed spaces that can accommodate human activities. Occupied spaces are further classified as regularly occupied or non-regularly occupied spaces based on the duration of the occupancy, individual or multi-occupant based on the quantity of occupants, and densely or non-densely occupied spaces based upon the concentration of occupants in the space. with the exception of the foyer. Most foyers are not a separate room but are part of a living area. If it is separate then you may try to consider it non-occupied.
I am working on a data center and not sure about ASHRAE 62.1-2007 outside air requirement. Table 6.1 list 2 types: Computer lab at 10 CFM/ person and 0.12 CFM/Sqf and Computer no printing at 0.06 CFM/Sqf only.
it is not really clear where the data center will fall.
Any help will be appreciated.
When you say data center it is unclear what type of room you are referring to. The first thing that comes to my mind is a server room. For the most part, these are unoccupied spaces and do not require ventilation; much like an electrical room. You need to pay special attention to whether or not you have a UPS system in the same space and also if you determine that there are any local contaminants that will need to be exhausted from the room.
I am working on a Tier III data center with the same question. Our server room will be occupied for a few years with between 1 to 5 FTEFull-time equivalent (FTE) represents a regular building occupant who spends 8 hours a day (40 hours a week) in the project building. Part-time or overtime occupants have FTE values based on their hours per day divided by 8 (or hours per week divided by 40). Transient Occupants can be reported as either daily totals or as part of the FTE. Residential occupancy should be estimated based on the number and size of units. Core and Shell projects should refer to the default occupancy table in the Reference Guide appendix. All occupant assumptions must be consistent across all credits in all categories.'s working on daily basis. FTE's will taper off over time as server space is leased. I am therefore wondering what is correct CFM? Our UPS is outside the space.
yes its a server room, UPS is located in a separate room with its own system.
the room will be unoccupied just for maintenance. we have decided to bring outside air for pressurization. that will be close to the 0.06 CFM / Sqf.
Kimberly, in your case I would use the same rates as a computer room without printing.
Houcine, you will be fine with a small amount of pressurization air. You are simply doing more than what is required.
We are working on a multifamily building with naturally ventilated interior kitchens located next to the living/dining rooms that have operable windows. The kitchens meet 62.1-2007 section 5.1.1, having unobstructed openings to the living/dining rooms exceeding 8% of kitchen area and 25 SF. However, IEQp1 form v5.0 doesn't have a table where these rooms can be entered. There is a table for naturally ventilated rooms within 25 feet of operable windows, but not for the interior rooms that are ventilated through adjoining rooms. How can these areas be represented in the LEED form? Thanks.
Are the kitchens themselves also within the 25'?
Joseph, the kitchens themselves aren't within 25 feet of the windows. From the wording in Section 5.1.1, it doesn't seem it's required that the interior rooms need to be within 25 feet, but do you think that is a requirement?
Erika, I have always considered the language to mean that all spaces must be within the 25'. I have seen LEED review comments that agree with this interpretation.
Erika, I am in agreement with Andrew. The way I see it is that it wouldn't totally make sense if an "adjoining room" outside 25' could comply, but spaces beyond 25' within the same room wouldn't comply because they were beyond 25'. I too have seen reviews where this was interpreted like this.
Joseph, Andrew, thank you for your responses. I do have some interior rooms that are within 25' from the window, how would those be entered in the LEED form? I am thinking of entering both the interior room and it's adjoining room with the window as one large room in Table IEQp1-A5 and provide a narrative explaining that they are two separate rooms. Do you think I can submit something better?
I think that would be fine as long as you have the narrative. Remember that you are sure to get a comment along the lines of "The 25' dimension may not be impeded by walls." I always upload a plan showing a dimensioned line from the openable area to the furthest occupied corner.
We have a multifamily building where the naturally ventilated kitchens are interior rooms, located next to the living/dining rooms that have operable windows. The kitchens meet the requirement of 62.1-2007 Section 5.1.1, having unobstructed openings to the living/dining rooms with free area exceeding 8% of kitchen area and 25 SF+. However, we are not sure how to input this information in the LEED IEQp1 form v5.0. Under natural ventilation in that form, there is a table to input the rooms that have operable windows within 25 ft, but no table for the interior rooms that are ventilated through adjoining rooms, like the kitchens in our project. How should these kitchens be entered in the LEED form? Thanks.
I'm working on the certification of a completed project in Russia. Russian standards for OA requirements are 60 CFM/person, so I know that there is 'enough' total OA for the occupants (both for IEQp1 and c2). Our challenge arises in a couple of corridors that are designated 'critical zones' in the 62MZ calculators. In most cases, these corridors are only used by service people to access electrical closets and other service/'back of the house' areas.
The building is already built, so putting in additional ductwork, etc. ain't gonna happen. (BTW, the design and as-builts showed the necessary equipment in place, but during Cx1. Commissioning (Cx) is the process of verifying and documenting that a building and all of its systems and assemblies are planned, designed, installed, tested, operated, and maintained to meet the owner's project requirements.
2. The process of checking the performance of a building against the owner's goals during design, construction, and occupancy. At a minimum, mechanical and electrical equipment are tested, although much more extensive testing may also be included.--now on pause--we found the discrepancy)
First question, Do these seldom-used areas need to comply with the p1/c2 requirements?
Second question, What are folks' thoughts about suggested fixes?
One idea is to install some louvers in doors of adjacent rooms that have net negative air flow so that the corridors will receive the necessary air flow. If we use this strategy, would the use of louvers affect the air flow & how would we account for this?
Another idea is to install a small exhaust fan at the end of the corridors to pull additional air in. In all cases, the corridors are partially adjacent to spaces with significant 'extra' supply air.
Thanks in advance for any ideas.
Non-occupiable spaces do not require ventilation. The best description for this is provided by the ASHRAE 62.1 User's Manual. From the 2007 Manual:
Only "occupiable spaces" are required by the Standard to be ventilated. By definition, this excludes "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." So if an equipment room, for example, is expected to be occupied only occasionally (e.g. for servicing equipment), ventilation is not required...stairs and corridors that are used primarily for emergency egress do not have to be ventilated...
Thanks, Hernando, I think we should be able to demonstrate that these spaces should qualify as 'non-occupiable' by the ASHRAE definition.
Rob, your claim the corridors are not regularly occupied would be strengthened if you can provide a plan view showing that no access is provided to any regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building.. I included the statement about emergency egress stairs and corridors from the ASHRAE 62.1 User's Manual (2007 version) because that could prove to be useful to you and other people who use LEEDuser.com.
The quote from the User's Manual I provided comes from: "Example 6-E—Occasionally Occupied Spaces" on page 6-14.
in this project, each regularly occupied space have ventilation grill and OA grill - separately.
in the LEED form, should i determine the Vdzd are both the ventilation CFM and OA CFM?
Your question is quite confusing. What is the make-up of the air coming out of each grille?
sorry to confuse you. for example, in a meeting room, we have dedicated FCU unit and dedicated OA grille .
Even when FCU were off, the OA still fill up the room.
Is the value for Vdzd are the combination of FCU and OA CFM?
No, you should use the OA flow as the Vdzd. It seems from your description that if you require anything less than 100% OA using that method then you are fine. Make sure that your Ez is 1.0 if you are not supplying hot air through the dedicated vent.
I'm confused with two items on table 6-4: "Locker/dressing rooms" and "Locker rooms". The later requires twice the exhaust rate of the first item. Would it be accurate to say that locker rooms at sport facilities would require more exhaust while locker rooms at offices would require less exhaust?
Thanks in advance.
It isn't exactly clear in the minimum exhaust rate table what the difference between a locker room and a locker/dressing room is, is it?
I would interpret it as a Locker Room (with the greater exhaust rate required) as being a locker room with showers. Whereas a locker/dressing room would be a place for changing clothes but not for showering. This would explain the difference in the two exhaust rates, and I notice there is no separate line in the table for shower rooms.
Thank you very much!
Do we need to ventilate the locker room or by introducing sufficient exhaust flow rate will be ok?
Did anyone had ever to explain to the reviewers discrepancy between the area documented in IEQp1 and the total area in PIf3?
We had 33% of the total area that were NOT documented in IEQp1. Which is quite a lot and we are now listing all the unoccupied spaces in our response:
- this project is a manufacturing plant with large inactive and unoccupied areas that represent 20% of the total area.
- There are "unfinished spaces" that are unoccupied and represent 3% of the total area
We are dealing with a remaining of 10% that represent elevators, stairs for egress, small mechanical shaft and rooms etc...
We are unsure if a 10% discrepancy is ok? has anyone had experience with this type of comment?
Yes, I have listed all of the space in the building that were not included in the calculation and then demonstrated that the left over discrepancy area is walls and such since PIf3 is gsf and EQp1 is nsf. Explain it clearly and you will be fine.
Thanks Andrew, do you remember the difference in % you had between gsf and nsf?
I think it was around 5%.
Dear LEED Team,
just calculated the ventilation rate according the ashrae 62.1.2007 for a office building and now really wonder about the low outdoor air rate:
Density: 100 ft²/person (net occupiable area in zone)
OA per person: 5 cfm
OA per m²: 0,6 cfm/ft²
Combined OA per person: 5 cfm + 0,06 cfm/ft² x 100 ft² = 11 cfm/person
Compared to the European standard with around 20 cfm this seems to be very less. In cubicle offices with lower density it even gets worse. At the same time the ASHRAE recommends a CO2Carbon dioxide level of 1000ppm - which is not reachable with the given 11 cfm/person.
So, how can this be explained?
Although still widely cited, the 1,000 ppmParts per million. CO2Carbon dioxide concentration is an old ASHRAE reference from 62.1-1989.
I don't believe 62.1-2007 refers to that CO2 level. ASHRAE has converted to a dual component method of recommended minimum ventilation rates, based on air flow per unit area plus air flow per person. Apparently, the new ventilation rates recommended are considered adequate even though they can result in CO2 concentrations well above 1000 ppm.
Principal, Director of Sustainability
Westlake Reed Leskosky
Mechanical and natural ventilation designs must comply with requirements to mitigate environmental tobacco smoke.
The amount of fresh air the HVAC system is designed to process has a direct correlation to the buildup of carbon dioxide.
Increasing the ventilation rates 30% above the ASHRAE standard will help teams gain IEQp1.
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