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 on a space-by-space basis. Spaces served only by natural ventilation 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 which alternate between natural or mechanical ventilation must follow the compliance path for mechanical ventilation, Case 1.
For additions and major renovations, confirm that all 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 buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, etc. systems do not meet the standard’s requirements, you will need to either increase ventilation rates to comply or provide detailed analysis documenting the constraints and explaining why the base building systems cannot be upgraded.
There’s some confusion in this language on whether mixed-mode refers to a ventilation design with both natural and mechanical ventilation all the time, which needs to be divided up to show compliance, or to a system where either is optional, in which case the worst-case design conditions are for when only the mechanical systems are used and window are shut.
Commercial interior projects 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 cannot be modified to meet the standard’s requirements, you will need to provide detailed analysis documenting the constraints and explaining why the base building systems cannot be upgraded. Systems must be able to provide at least 10 cfm per person to meet this prerequisite.
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.
Local codes may be used to meet the prerequisite if the project team can show equivalency with Sections 7 through 7 of ASHRAE Standard 62.1-2007. Projects outside the US can now also choose to comply with the minimum requirements of Annex B of CEN Standard EN 15251:2007 Ventilation for Nonresidential buildings.
Teams may choose to substitute ASHRAE 62.1-2010, Sections 6.4.1-6.4.2, for ASHRAE 62.1-2007, Section 5.1.1, to document compliance with IEQp1 for naturally ventilated buildings. ASHRAE 62.1-2010 adds geometric requirements that extend the allowed naturally ventilated floor area based on ceiling height and opening configuration.
For CI projects, calculations must be done at the system level for any AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. providing outside air to the tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space..
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. Documentation using the IAQ Procedure requires the quantification of contaminant source emissions rates and their reduction, and has historically not been accepted for this prerequisite because it is performance-based and difficult to compare across projects.
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 by evaluating which space planning and envelope design strategies will create effective natural ventilation. An airflow modeling professional may add some upfront costs, while likely improving system efficiency.
Airflow modeling can also help to determine compliance for an engineered natural ventilation system outside the prescriptive measures of ASHRAE 62.1-2007.
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.
Sample LEED Online forms for all rating systems and versions are available on the USGBC website.
Documentation for this credit can be part of a Design Phase submittal.
Has anyone had an issue with complying with ASHRAE 62.1 for natural ventilation of a space that is being used as a maintenance garage?
We have 3 garage doors that are open to a large garage type area (about 60' X 60'). There are other shops within the building that are mechanically ventilated with a fan because they do not have operable openings to the outdoors. But according to ASHRAE 62.1, we can only claim natural ventilation for a distance of 2H into the building, with H being the ceiling height. In my particular case, that distance is 27 feet. We are far exceeding the 4% requirement of operable openings to the outdoors based on our floor area.
The building is already complete and occupied. The garage area is the bulk of the building, with some work shops and office spaces making up the rest of the building. The shops are heated by a gas fired furnace and the offices are conditioned with small multi zone heat pumps. We just reviewed review comments back and got the comment about the garage area not complying with ASHRAE 62.1.
It seems like a waste of energy to install an additional fan into this large area, especially since it is a garage. We are hoping to appeal this based on the use of the space. I am hoping we aren't the first group to deal with this. Has anyone successfully appealed something like this?
Does anyone have an example of a LEED Form completed for natural ventilation they would be willing to share? There does not appear to be one in the "documentation toolkit".
Alternatively, can anyone describe how they did this? What was used for the "System Name and Number" vs the "Zone".
We have a 342-unit high-rise residential building, with 61 different apartment layouts. Do I need to list every apartment as a "System Name", and each room in the apartment as a "zone", or can I list each of the 61 unique types as a "System Name"? Can this done on a separate spreadsheet, or must it be done in the LEED Form? Should I be taking a different approach all together?
Before the excel spreadsheet introduction naturally ventilated spaces were referenced in the IEQp1 form. Where can those spaces be referenced in the spreadsheet? Thank you!
You are correct for LEEDv2009 Natural Ventilation compliance was shown by completing Table L-17. Natural Ventilation AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. Summary within the IEQp1 Form; these calculations were not included in the 62MZCalc spreadsheet. Unfortunately, with the new LEED Minimum Indoor Air Quality Performance Calculator (for v2009 or v4 projects) natural ventilation is still not included in the spreadsheet. For v4 projects complying with natural ventilation, the IEQ form does not provide a table for calculations and the project team must provide/upload external calculations that prove compliance.
For naturally ventilated spaces (and for mixed-mode systems when the mechanical ventilation is inactivated), determine the minimum outdoor air opening and space configuration requirements using the natural ventilation procedure from ASHRAE Standard 62.1–2010 or a local equivalent, whichever is more stringent.
We are planning to use local code to meet the prerequisite. There are a few space types for which the local requirement is less stringent. However, ventilation calculations shows that local code requires remarkably more outdoor air for the whole building than ASHRAE 62.1. Should we still meet the ASHRAE outdoor air requirements in those few space types?
Assuming that those spaces are apart of the same zone, then as long as you meet the overall minimum ventilation rate provide by the HVAC system serving that zone(s) you will comply with the requirements of 62.1. I would highly recommend that you preform outdoor air calculations using the LEED Minimum Indoor Air Quality Performance Calculator referenced here: http://www.usgbc.org/resources/minimum-indoor-air-quality-performance-ca... (this can be used for LEEDv2009 or LEEDv4 projects) Alternatively, this could also be provided from energy model outputs for ventilation calculations for verification.
I'm working on a Multifamily Highrise building. The bedrooms will not have operable windows, so it looks like they need to be mechanically ventilated. Would it suffice to dump all the fresh air the residential unit needs into the living room and allow the fresh air to flow under the doorcracks into the living room, or does the fresh air have to be ducted directly into the bedrooms? Is there a precedent for this?
Fresh air must be directly ducted to each dwelling unit. This can be achieved by providing a 100% outside air unit that can supply ventilation to the corridors and the living units. The ventilation supply diffuser/grille can be located in the unit common area (i.e. living room, dining room, etc.) Please note, transfer air cannot be used from the corridor/unit entryway doors via pressurization to comply with ventilation requirements.
The IMC requires that outdoor air be distributed to each habitable room by means such as individual inlets, separate duct systems, or a forced-air system. Conflictingly, in homes with exhaust-only ventilation systems without outdoor air inlets, the home must have a ducted forced-air heating system that communicates with all habitable rooms and the interior doors must be undercut to a minimum of ½ inches above the surface of the finish floor covering.
2012 IMC “403.2.2 Transfer air. ……The amount of transfer air and exhaust air shall be sufficient to provide the flow rates as specified in Section 403.3. The required outdoor airflow rates specified in Table 403.3 shall be introduced directly into such spaces or into the 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. from which air is transferred or a combination of both.”
The comment response in LEEDUser for NC-IEQp1 titled "Dorm Suite Ventilation" by Andrew Mictchell, Principal, Mitchell Gulledge Engineering, Inc. may be useful as well.
Just so I understand, fresh air does NOT have to be separately ducted into each individual room as long as it is supplied to the living room and the HVAC unit is in the living room and then ducted to all the spaces.
Is "v2009v4_Minimum 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 Calculator_v03" spreadsheet is the correct/right one for a project registered in February 2016 in LEED 2009?
Also, Is there any updated "62MZCalc.xls" (Revised April, 2011) for 62.1 - 2007? Should I be using the one for 62.1 - 2010 though? Is there significant difference?
Appreciate your time/help.
The "v2009v4_Minimum 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 Calculator_v03" allows for calculations for either 62.1-2007 (LEED 2009) and 62.1-2010 (LEED v4).
It can be downloaded here: http://www.usgbc.org/resources/minimum-indoor-air-quality-performance-ca...
Please note, that the USGBC LEED 62MZCalc has been retired and replaced with the Minimum Indoor Air Quality Performance Calculator as mentioned above. While you could still use the 62MZCalc.xls if you have access to the document (and your project is under v2009); it may be more beneficial to use the new performance calculator because it may have useful updates to make the documentation process easier. It also minimize the potential for reviewers to comment on use of an old version for compliance.
Hello LEEDuser community,
We're working on an innovation and wellness center which, among different types of spaces, has a Dental Office in which small procedures will be performed.
We're not sure whether to use the ventilation rate for offices stated in the ASHRAE 62.1-2007, ot to use the ventilation rate required by the ASHRAE 170 for a Class A operating/procedure room.
ASHRAE 62.1-2007 does provide some guidance for acceptable ventilation rates for these types of spaces outlined in NORMATIVE APPENDIX E
VENTILATION RATES FOR HEALTH CARE FACILITIES: Table E-1. For a patient room, a minimum of 25 cfm/person at 10 people/1000sf, and for an operating room a minimum of 30 cfm/person at 20 people/1000sf. If ASHRAE 170 is to be used as an alternative compliance for LEED it must at least meet the minimum ventilation rates listed in 62.1 or be greater. This approach would also require an additional narrative describing the exceptional calculation methodology.
I just want to be sure of one thing. It looks like Multi-Zone systems, you have the option of saying that not all zones the system serves are in the VRP calculation and then you have to manually enter the total floor area and populations the system serves as well as the average per-person and per-square foot OA cfm rates. Has it been ok to do that for LEED submissions? Have you ever gotten comments telling you to fill every room in?
I am aware you have to go about filling every single room in when dealing with 100% OA units in the same spreadsheet.
Do vestibules at the entrance of buildings require mechanical ventilation? As those spaces have lots of air exchange with the outdoors when people enter or leave the building, it seems to me that ventilation is not necessary.
Do interior stairs require ventilation? Should we consider stairs as corridors?
I know spaces not intended for common use do not need ventilation. There are however, some stairs that are called emergency stairs but used daily.
IEQp1 form v06 has a new requirement to describe "how critical zones are selected and how all occupiable zones are accounted for in the determination of the critical zone. A critical zone is defined as the zone which requires the largest fraction of outdoor air in the primary air stream."
Is this mandatory for 100% outside air systems or only for VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. systems? In addition, there is little reference to critical zones in 62.1-2007 standard. Thanks in advance.
The new calculator from USGBC is good to help understanding the different types of zone systems:
There are multiple zones, 100% OA, and single zones. Only multiple zones will require you to determine the critical zone. If you input all zones on a multiple zone calculator, the calculator will automatically look for the critical zone.
You can find an example of how to find the critical zone in the 62.1 user's manual: Example 6-M—Finding Critical Zones in Multiple Zone Recirculating Systems . . . . . . . . . . . 6-26
I recommend you get one. It is very helpful.
As per ASHRAE 62.1 parking areas are subject to requirements for exhaust air and not ventilation rates. Accordingly, parking areas are not included in IEQp1, are they? Thanks in advance!
IEQp1 in inclusive of the entire ASHRAE 62.1 Standard. You do not need to include parking garages in your 62MZ calculation, but you must design to the standard and account for the space. I always include a note that "xxxx" sf of space complies with Table 6-4 because it is "xxxx" type of space. This lets them know why your 62MZ calculated area does not equal the total building area.
I have project with a dedicated outside air system that introduces air directly to the spaces on all levels (i.e. neutral air). The project has more than 100 VRF units. Can all the spaces be put into one excel sheet or do they need to be split out? I am not a mechanical engineer. The MEP on the team said that the outside air is not ducted to any VRFs.
You can disregard my question. I got the commissioning agent to help on this. It turns out the MEP designer was being a bit...obtuse.
we have some doubts in Ez (ZONE AIR DISTRIBUTION EFFECTIVENESS) selection in ventilation design
we are supply fresh air using Fresh air fans, ERV, Treated fresh air units, Evaporative cooler units
what value we take for EZ in below cases
1.Fresh air fans (Direct outside air)
2.Treated fresh air units (below ambient air temperature)
3.Evaporative cooler units (below ambient air temperature)
4.ERV (below ambient air temperature)
Kindly tell the suitable EZ values for all above cases separately
You can find Ez values in Table 6-2 (I'm pretty sure you already know this).
Basically, you need to know if you are providing cool or warm air. If you have both systems, then heating is your worst case scenario. You also need to know your distribution configuration: ceiling/floor air supply and ceiling/floor air return.
Then, use table 6-2 to find your system's Ez.
For a mechanically ventilated building for which the project team has attempted compliance with IEQc6.2 with operable windows the reviewer has commented at IEQp1 that the project may demonstrate compliance with this prerequisite using a combination of mechanical and natural ventilation. From our past projects experience we have never been asked to prove such a condition in a mechanically ventilated space when operable windows are used not for natural ventilation but simply for thermal comfort control. Has anyone ever had a similar experience? Thanks.
I have never received this comment. However, I have been denied the ASHRAE 55 credit because I used operable windows for controllability and the reviewer said that since we cannot control the weather, we do not comply with ASHRAE 55.
Thanks Andrew, I guess that submitting a table with all openable windows confirming they exceed 4% of the net occupiable corresponding space would provided the requested clarification. As far as the ASHRAE 55 credit is concerned we have got a very weird comment indicating that operable windows have to be individually operable to count as a means of thermal comfort control. We have discussed this issue under IEQc6.2.
I am conducting a survey in affiliation with University of Cincinnati for my Master's thesis which would take just 10-15 minutes of your time. By answering the questions that are relevant to your experience, would help me in giving my research the required depth in understanding the achievability of the credit points in the Material and Resource category of LEED v2009 and v2013.
The following is the link to complete the web based questionnaire.
Thank you in advance for your time!
I have naturally ventilated apartment units. Apartment's inner most wall distance from the exterior window is 33’. Interior most side of the apartment has toilet and kitchenette. Both toilet and kitchen have continuous running exhaust fans. Would this satisfy IEQp1 requirements of ventilation?
Corridor units are served by makeup air units. Door undercuts will ensure outdoor air reaches spaces furthest from operable windows.
Would this situation satisfy IEQp1 requirements?
It is possible to comply with mixed mode ventilation. For instance, if the space was 10' wide, you could use the first 25' (250 sf) as naturally ventilated by the window. The excess 8' (80sf) could be mechanically ventilated using exhaust fans. Be sure to look up the effectiveness rating based on where the air is made up from and where the exhaust is relative to the ventilated space. It will be either 0.8 or 0.5.
Thank you Andrew for your response. Kitchen continuous exhaust CFM is 25 CFM for an apartment. Does the CFM necessarily has to be 50 CFM minimum? As mentioned, both kitchen and bathrooms have continuous exhaust. Corridor make-up air units have energy recovery (energy recovered from bathroom and toilet exhaust). Also apartments have combination of natural ventilation (operable windows) and mechanical ventilation (ducted outdoor air thru heat pumps). Would this situation satisfy minimum ventilation requirements? Any ideas will be helpful.
Hi Andrew, I would appreciate if you could share some ideas on the situation above. Thanks.
It is not a question that I can answer without construction documents and calculations. You need a minimum exhaust of 0.30 cfm/sf in a kitchenette or 50CFM continuous for a residential kitchen. I don't know which if you classify as a kitchen or kitchenette. Other than required exhaust, you need to go to ASHRAE 62.1 and calculate the required breathing zoneThe breathing zone is the region within an occupied space between 3 and 6 feet above the floor and more than 2 feet from walls or fixed air-conditioning equipment. (AHSRAE 62.12007) ventilation rates for any area outside of the naturally ventilated area. This is all information that the PE who signed and sealed the construction documents should be able to provide without any issue.
Thank you Andrew. If the corridors make up air units are recovering energy from toilet and kitchen exhausts. Would this air still be acceptable for ventilation thru door under-cuts? Thanks!
Yes. It is prudent to take into account any cross contamination or purge designed into the unit based on fan configuration and seals.
Our project is a big confectionary plant situated in Russia.
According to the local standards we are not allowed to lay air ducts and make supply ventilation for such premises as stair halls and elevator halls. We can only place there smoke ventilation for these premises. What I don't understand is whether we need to provide supply ventilation for this kind of spaces to comply with this prerequisite requirements or not as these premises are non-occupied.
Thank you in advance.
If they are not normally occupied corridors or stairwells, then they do not require ventilation. This would apply to ones that are used for emergency egress only.
There is a Smoke Free Illinois Act that bans smoking inside buildings or within 15' of a window, door, or ventilation system. We are working on a school project that falls under this law. Is there a way to avoid posting signage since we comply with the law? The owner would really like to eliminate signage if possible.
I believe that you should be asking thie in IEQp2. The LEED requirement is 25', so I do not think that the state law would qualify for the prerequisite requirements.
I concur with Andrew, EQp2 question and 25ft is required. (See LI #1967)
As for the bare minimum for the signage, i have previously asked this question of the GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). and here is there response:
"There is no firm answer to this as it depends on the overall context of the exterior smoking policy communication method on the site, but the exact language on the signage, its size, and location(s) are up to the project team (with one caveat for signage locations for v4 projects - see the end of my message below). That being said, the signage throughout the site must somehow effectively communicate the exterior smoking policy to all building occupants and visitors and it must be reasonably visible. For example, a single sign with a crossed-out cigarette and no text at one entrance may not be sufficient and could be misinterpreted as the interior smoking policy, but if such a sign is installed at multiple locations around the building exterior to communicate the extent of the non-smoking area or if there is additional signage to indicate the location of the designated smoking area, this would better communicate the exterior smoking policy. Another example of effective signage language is "Smoking is allowed in designated smoking areas only." Also, reviewers will take into consideration other methods of communicating the exterior smoking policy in conjunction with the signage, such as policing of non-smoking areas by security staff or regular communications with occupants about the smoking policy. If the client wants to do the bare minimum, one approach could be to place a sign only at the designated smoking area saying something such as "Smoking permitted in this area only" and supplementing that with regular communications with the occupants about the site smoking policy.
Also, I just wanted to note that in LEED v4, the prerequisite requirements require signage within 10 feet of all entrances in case this happens to be a v4 project."
hope this helps!
Thank you both. My mistake -- I absolutely posted this in the wrong forum. Only problem is I can't figure out how to delete it now?
How project teams applying combined a ventilation strategy(Mechanical + Natural) should proceed in order to meet the minimum requirements established in ASHRAE 62.1-2007, Table 6-4, for parking garages. ASHRAE 62.1 eliminates exhaustion necessity in cases where at least two sides of the parking garage are at least 50% open to the outside. However, for cases where openings do not meet these requirements ( 30% openings for example), is it possible to reduce the required mechanical ventilation flow rate based on designed opening areas?
Does anyone know if there is a LEED interpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. that allows exhaust-only ventilation in multifamily units under LEED-NC?
You can use exhaust only as mechanical ventilation. Look at the ventilation effectiveness schedule in Table 6-2 to determine how to apply this to your project.
Dear all experts!
I have a high-rise residential building which aim to comply with IEQ pre.1 by combining 2 ways.
1. Living room and dinning room will comply with natural ventilation: 4% operable window and within 25 feet.
2. Bedroom is completely closed, and not connect with any operable window, therefore we try to comply with IEQ pre.1 by trickle ventilation. It means that, we have Toilet exhaust fan (continously operated) and we want to prove that the bedroom will provide with fresh air through this exhaust fan (of course, we will calculate with Vbz=0.8).
=> The question is: is that complied with IEQ pre. 1 for all living room, dining room, and bedroom by the above methods?
=> and the next question is: that bedroom near the corridor (which is permanent open and connect with outdoor), so is this ok for providing fresh air through trickle ventilation by exhaust fan at toilet (as above mention) and fresh air taking from corridor which permanent open like that?
Looking forward to receiving your feedback. Thanks so much.
If the make-up air being drawn in by the exhaust fan is outside air, then you can use it as mechanical ventilation by exhaust fan. The effectiveness will be 0.5 or 0.8 based on where your exhaust fan is in relation to the ventilated space. See the table in chapter 6.
I have a project, which have two types of system:
1. OA system offering the fresh air to each room, and each room has an individual fan coil unit .
2. OA system offering the fresh air through chilled beams to each room.
Should I verify the ventilation by 62MZ calculator or single zone as IEQp1-A2 table?
I appreciate any comments for this.
If the OA system is variable volume, then you should you the MZcalc. If not, you can treat each one as a separate zone receiving a set amount of OA.
It is VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. for OA system. In MZcalc, should I include fan coil supply air (or chilled beam induced air) and outdoor air into the design supply air? It says primary plus local recirculated, just want to make sure. Thank you!
We have an electrical room on site that is not attached to the main building and will hold the electrical equipment for a diesel fueling station. Someone will be in the room twice a day just to turn the system on and then turn it off (less than a minute each time) each day. Am i right in assuming that this room can be considered not regularly occupied and thus can be excluded from having to abide by ASHRAE 62.1?
Client does not want to put any mechanical cooling or heating equipment.
The space you describe seems to be intended primarily for purposes other than human functions AND it is only occupied for very short periods of time.
The overview of the EQ credit category within the v4 Reference Guide lists "electrical rooms" as being unoccupied.
I would define this room as "unoccupied" hence not requiring ventilation.
Be sure to include a narrative within EQp1 explaining the use of the room and why it is considered "unoccupied".
Our project is single storied sewing factory in production area we have large size Exhaust fans in one side and opposite side of exhaust fan have cooling pad
Now the issue is we can't provide any fresh air fans to production area but fresh air is mandatory for IEQp1 credit
But fresh air is continuously coming to room via cooling pads due to continuous exhaust in opposite side
as per rule the amount of exhaust we take from room is automatically comes due to pressure variance in space
so can we assume the exhaust air quantity is equal to fresh outdoor air quantity enter from other openings and cooling pads and count the same in VRP calculation for production area where no fresh air supplied mechanically but have the cooling pad with exhaust fan in opposite side
is it acceptable manner if it is not accepted means why?
kindly assist us to solve this issue (is these space need mechanical fans to supply fresh air )
If you are drawing fresh air in from a known intake using exhaust fans, then you are mechanically ventilating the space. You need to decide which of the following you fall into:
Makeup supply drawn in near to the exhaust and/or return location. (Ez value of 0.5)
Makeup supply drawn in on the opposite side of the room from the exhaust and/or return. (Ez value of 0.8)
Also, I assume that when you say cooling pad, you are referring to evaporative cooling pads. If that is the case, keep the following requirement in mind:
5.9 Particulate Matter Removal. Particulate matter filters or air cleaners having a minimum efficiency reporting value (MERVMinimum Efficiency Reporting Value (MERV) rating is an American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) measurement scale which rates the effectiveness of air filters. ) of not less than 6 when rated in accordance with ANSI/ASHRAE Standard 52.2 shall be provided upstream of all cooling coils or other devices with wetted surfaces through which air is supplied to an occupiable space.
Hi! I'm working on a one-story dormitory project. The different spaces are naturally ventilated and are in compliance with ASHRAE 62.1 "All must be naturally ventilated spaces within 25 feet of ( and permanently open to) operable wall or roof openings to the outdoors ; Also the operable area must be at Least 4% of the space 's net floor area occupiable " .
How can I document the credit? On the credit format on LEED Online states: Provide documentation demonstrating the minimum outdoor air opening and space configurations meet or Exceed the the minimum values from the natural ventilation requirements outlined in ASHRAE 62.1-2007 , Section 5.1.1 .
If I only send a floor plan of the different spaces ,sections and dimensions of the operable windows, and also a narrative, would it be ok?
You will also be required a spreadsheet showing: operable window area, space floor area and access within 25ft for each space.
I have uploaded floor plans showing a scaled 25' line, with each operable opening tagged for area as well as a tag on each space showing floor area and required openings.
I have a lobby which has one side is open to outside. But the length of lobby is almost 40ft instead of 25ft. And their are 8 ceiling fans evenly. Could be this the case for engineered natural ventilation in IEQp1?
If you can document that the air circulation induces OA all the way to the back, then you can submit it. Otherwise, install a small inline fan in the ceiling to meet the requirements of the remaining 15 feet and submit under mixed mode ventilation.
Regarding your point about installing an "inline fan" to mitigate the 25' distance requirement, is this technique something that LEED has previously accepted? I have an occupied space that is 28' away and see this as a simple solution -- both for my current project, and for future designs.
I have not done this exactly, but I have used mixed mode ventilation successfully.
I am submitting for review a project outside the US, in Brazil.
The legislation of Brazil is very similar to that specified by ASHRAE 62.1. However, at the LEED Online I am instructed to prepare a new worksheet describing the service to credit according to local law, and may not use the VRP Compliance Calculator option or 62MZCalc spreadsheet. Would not it be more appropriate for the analysis team I ever use one of these presentation tools available? What is recommended in this case? Okay to me to continue the service through the VRP Compliance Calculator?
If I can use the VRP Compliance Calculator, should I mark "Is the project located outside of the U.S. and pursuing Option 2 or a local equivalent in Option 1?"
you are allowed to use the 62MZ calculator, i suggest you use this to document the minimum ventilation requirements are met.
we have a new addition added to an existing facility. The consultant has decided to pursuit NC for this project, therefore the question comes if there is an existing area within the LEED boundary with existing AC units that wont be modified, do these units need to comply with the minimum OA required as well? Would a Test and Balance be necessary or only plans?
In the case that they take these existing areas out of the LEED boundary, only the new equipment will need to be Tested and Balanced, correct?
i.First of all, there are two different concepts here: this prerequisite requires your project to have VENTILATION (natural, mechanical, engineered...) regardless of whether or not you have A/C.
ii.Every occupiable space within your LEED Project Boundary must be ventilated. I am pretty sure your reviewers will require you to demonstrate that.
iii.Regarding your 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. question I would ask in the EAp1 forum.
we have a new addition added to an existing facility. The consultant has decided to pursuit NC for this project, therefore the question comes if there is an existing area within the LEED boundary with existing AC units that wont be modified, do these units need to comply with the minimum OA required as well?
Every interior space within your LEED Project Boundary must comply with the ventilation requirements.
Regarding the TaB question, I am not pretty sure but I would test the existing equipment to guarantee the outdoor air required by the VRP is provided by your system.
Figured out my question. Please delete
There's several quality level for interior air in EN 15251 : category I to III. The reference guide doesn't enjoin a specific category, as you can see in this extract :
"To determine the ventilation rate: Use Table B.1 in Annex B of CEN Standard EN 15251:2007 to find the appropriate percentage of dissatisfied building occupants and select Category I, II, or III based on the building design and applicable local codes."
We hesitate to select the lower category (III). Do you have any feedback about this ?
Any idea ?
What does VRP stand for in the column IEQp1 of the space matrix? I've looked it up in the notes and definitions tab but it does not appear.
I do not think it stands for Ventilation Rate Procedure because there are other methodologies appart from that one (CIBSE, natural ventilation...)
Mitchell Gulledge Engineering, Inc.
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