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. The 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 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.
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.
Naturally ventilated core and shell projects must provide the potential for tenant build-out to meet requirements of this credit. When documenting the credit, you can provide an assumed tenant layout and default occupancy assumptions based on the LEED Reference Guide Appendix 1 to confirm that tenant spaces meet ASHRAE 62.1 requirements.
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.
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 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.
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.
For Core and Shell projects, the space occupant densities used to determine the number of full time equivalent (FTE) occupants should be consistent for this LEED credit as well as WEp1: Water Use Reduction, WEc2: Innovative Wastewater Technologies, WEc3: Water Use Reduction, and SSc4: Alternative Transportation.
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 Core and Shell Development
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.
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 addenda1). 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.
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda1).
Mechanical ventilation systems installed during core and shell construction must be capable of meeting projected ventilation levels based on anticipated future tenant 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.
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.
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 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 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.
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 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 CS-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.
Reviewer has comment that "Verify that outside air is modeled with zero flow in both cases during unoccupied period" when system is used with DCV.
Is their any effective way to answer.
We are working on an office building for LEED CS. Packaged terminal AC are used to supply hot/cold air for office spaces to meet cooling/heating demand, but no outdoor air is supplied mechanically. Fresh air is supposed to be provided through window openings, and exhaust air also releases naturally. Can this type of ventilation system be defined as natural ventilation, or mixed-mode ventilation, when we want to achieve IEQp1?
Lolita, it sounds like it is mixed-mode.
I'm concerned that the ventilation is under-designed (will windows be open year-round, 24/7, for example to provide outdoor air exchange?), so I'd be careful to make sure it complies with ASHRAE 62.
Hello, I have two specific questions, please help me working them out.
1. At the begining, there is a red exclamation mark that says this: ''the space occupant densities used to determine occupancy for this credit should be consistent with WEp1, WEc2, WEc3, and SSc4''. However I normally take these values from ASHRAE 62.1-2007 table 6.1, whose Occupant Density is different from the 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. calculations for the mentioned credits. So, I think that I only should follow ASHRAE because it gives me more stringent results (i mean more levels of ventilation). Is it correct?
2. The ventilation design includes 3 big supply fans that take outdoor airflow to all the future tenant spaces (offices), the issue is that most offices have three intakes for these fans, however when I try to fill out the form for this credit, each office is supposed to be supplied by only one fan. So, is it possible that I get an ''equivalent fan'' by summing the CFM per fan for all offices?
Thanks in advance.
Actually, I've read on page 410 of the Reference Guide that these occupant densities should be taken from the standard ASHRAE 62.1-2007 (table 6.1); besides in the IEQ p1 form, there is no a link between those occupancy values and the credits mentioned in the red exclamation mark (WEp1, WEc2, WEc3 and SSc4)
Part of our warehouse project consists of a space (100m*100m*40m) using a ASRS (automated storage and retrieval system). It allows to store goods without people occupying the space.
I checked with the supplier of this system, and they indicate that it does not require any operator inside the space. Only maintenance, on a basis of once a month for a few hours in average, or if one of the system breaks down (maintenance only).
In the IEQ matrix, it is said that 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. do not need to comply with the natural ventilation/mechanical ventilation requirements from ASHRAE 62.1. Indeed, the project got a waiver from local authorities stating it can be considered 'naturally ventilated'.
Can this space be considered as 'non-occupied' (even if maintenance occurs on a monthly basis)? Can it be exempted from this prerequisite (and IEQc2 if attempted)?
Thanks a lot.
Also, since ASRS allows to build less intermediate slabs compared to more traditional options, can we consider this item as an innovation in design? If the power requirement for this solution is less than a typical warehouse equipment load, can we consider those as savings in the energy modeling? Thanks.
Yes, seems like it can be considered nonoccupied space.
I think it would be a stretch to go for IDc1 (post your question there and read the guidance and forum comments for more thoughts), but you have the potential to document savings under EAp2.
Tristan, thanks for your answer.
I found a definition of 'non-occupied space' in the LEED 2009 Missing Manual that seems to confirm your answer, as the only occupancy that will happen in the space is for maintenance purposes only.
As that author of the Missing Manual I'm glad my answers are consistent! ;)
What has to be included in the tenant lease for the shopping mall spaces? Is it enough if we write the minimum fresh air volumes that the tenant has to provide for its spaces or do we have to write specificly that ASHRAE 62.1-2007 requirements have to be complied with (we'd prefer not to mention ASHRAE because this standard is not known by retail tenants here and it would be easier just to include minimum air volumes in the agreement)?
Adam, you could word it in a way that the tenants will understand, as long as it is technically sound.
The project we are working on is a shopping mall. We are calculating airflow rates according to ASHRAE standard. Can you tell me if the area surrounding all the shops inside the mall can be clasified as "Corridors" (ASHRAE 62.1-2007, Table 6-1) or should it be clasified as "Common mall areas". The thing is that requirements for "Common mall areas" are very strict, 40 people per 100square meters seems to be to much. Our designers were conducting their calculations for lower occupant densities.
And one more thing: what minimum ventilation rates should we use for cinemas?
We are always use mall common area for these, it seems The review team is agree with this always.
I agree that the "Common Mall Areas" space type is appropriate. The corridor definitions hould only be applied to back-of-house areas, where there is substantially less occupant traffic.
The thing is that occupant density for "mall common area" is very high - 40people per100m2. This is much more than we assumed in our project. Can we uncheck the default box under occupant density in the LEED online form (only for mall common area) and put a value that our designers are using based on data from previous similar projects that are already in use? For other spaces we would use default occupancy desities.
I'm reviewing our responses to review comments. We already did what the reviewers asked for; so this is just out of curiosity.
The building got several 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. running on 100% outdoor air and each serving multiple zones. We did the VRP calculation on the LEED Online credit template version 3. Now the reviewers told us that the v3 form is only applicable to single-zone systems.
As we already certified other projects with the same setup I am asking myself if this is true.
Any comments or similar experience?
Yes, the review team is always asked the project team to updating this credit's template form to the latese version v5.
Hello. I'm working on a C&S project and have a question regarding the documentation of the IEQp1 credit. During the design a single tenant was found to occupy the entire site (700k sf). We worked hand in hand to establish the 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./RTU outside air quantities. I do not have a plan indicating the tenant's layouts. I also am not documenting the distribution ductwork on the floors. My question is how exactly to document the ventilation. I am thinking that I can do the 62.1 calcs, using a generic set of rooms (conference rooms, offices, lobbies) and drafting a narrative to explain my assumptions. Is there an issue if I use the ventilation calcs that the fit out engineer has developed for their layouts instead?
Randy, if you haven't already checked out CS Appendix 4 in the LEED Reference Guide, I think that offers one piece of the puzzle here.
I have the same question as Randy I think.
If we do not account for the fit-out, and take the office space as a single zone, the fresh air requirements will be different than if we consider some meeting rooms etc. (with a probable fit out); I think that by taking in consideration that one 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. is supplying air to several rooms, meeting rooms can become critical spaces that will influence the minimum fresh air.
I don't think this case is addressed in the reference guide, where the fresh air and AHU is taken care of in the C&S scope, but the ducting and terminal units design is still unknown.
We are working on a Core & Shell project, it has retail spaces that consists of two levels each one. On the second level, openings will be included in order to ensure the needed ventilation air rates but on the first level nor openings exist or will be included. Can we consider the entrance door (due to it is always open during occupied hours) as the opening area required for ventilation? or, Do we have to make architectural changes in the retail spaces facade in order to fulfill the ventilation air rates?
Yes the first floor would need to meet the LEED ventilation requirements. It sounds like you are attempting achieve the requirements by Natural Ventilation. In this case you need to meet the requirements of ASHRAE Standard 62.1-2007, Paragraph 5.1. (Naturally ventilation spaces shall be within 25 ft of operable wall, the openable area shall be 4% of the net occupiable floor area...). Depending on the size of the space the entrance door may not be enough.
I'm working on a mixed-use CS project. It has retail area in some of the lower floors, it is expected to have mechanical ventilation in these areas but this is not in the scope of the CS project even though the base building will facilitate the installation of the necessary ventilation equipment in the building's shell.
The owner will force the tenants to comply with the requirements of ASHRAE 62.1 by stating it in the lease agreement.
The LEED Online PIf4 template asks for the lease agreement signed by the owner and the tenant, since no tenant has already leased the retail area and the LEED certification is expected before it occurs, should we only upload the lease agreement with the owner’s signature?
A lease agreement showning the 62.1 language should suffice. You didn't ask this question, but be aware that if the central air handling units within the CS scope will eventually serve the tenant areas, then 62.1 VRP calculations should be performed using the anticipated occupant assumptions.
Anthony, thanks for the answer and the advice.
Wondering how the IEQp1 form should be filled out for a project that will not have any ventilation upon initial completetion. We do know that the future tenants will have both office and warehouse space, but do not know what the distribution will be. We have made assumptions about this distribution in order to come up with default space usage and occupancy values. Should we complete the form with ventilation per 62.1 for the assumed space distributions, or just upload the tenant lease agreement stating the tenants will comply with 62.1 requirements? Is it accepable to use assumed space values when they're not known? It should be noted there is no core space for this project. Thanks,
Hi Tony, tenant requirements that mandate compliance with ASHRAE 62.1 should be sufficient to confirm compliance for shell spaces that do not have HVAC systems installed as part of the scope of work of the Core & Shell project.
We are wondering the very same things for our core & shell warehouse project with no anticipated tenant(s). We,too, will mandate overall ASHRAE compliance in the lease. But how do we fill out specific VRP information for systems that don't yet exist? Get a tenant who doesn't yet exist to sign the lease? And get the form signed off by a ventilation designer that doesn't yet exist?
Have you made any progress on this? Or perhaps queried GBCI?
Hi Michelle, if HVAC systems aren't in the scope, you don't need to perform VRP calcs, you just need to submit a (unsigned) copy of a lease stating that the requirements of ASHRAE 62.1 must be met (by future tenants).
Thanks that's reassuring and what I would expect in this situation. But why doesn't the credit form acknowledge this reality and give you that option? Speculative core & shell doesn't always have a tenant. I generally prefer to give the reviewers what they ask for and definitely like to see the forms document the point. Obviously this one won't without all the specifics it's asking for. Thanks for the response.
Unfortunately, the forms aren't updated as quickly as we would like, so it generally takes awhile before the latest guidance/exceptions get incorporated. The reviewers know this though, so a simple narrative explaining the circumstances is usually sufficient.
I’m working on a residential building pre-certified and the project has some areas naturally ventilated and others mechanically ventilated.
I’m a little confused by what we should consider as “mechanically ventilated area”. For example, the 'kids room' at the common area (an indoor playground for all kids from the building) has an ar-conditioning system with a heat exchanger. So it’s a mechanically ventilated space and the intake air flow should be the air rate from the air-conditioning device, right? What about the bathrooms and the kitchens with exhaustion systems, they must be considered as mechanically ventilated spaces for this prerequisite? The intake air flow should be the rate from the exhaustion device?
Thanks a lot!
Edit: question has already been answered in February 2012 here: http://www.leeduser.com/credit/CI-2009/EAp2
Didn't find it before, sorry for any confusion.
on several spots in the Ref Guide it is said "project teams wishing to use ASHRAE approved Addenda for the purpose of this credit may do so at their discretion. Addenda must be applied consistently across all LEED credits".
This means that project teams may use single addenda to the standard as long as they use it on all credits. they do not have to follow all addenda published for that standard. Is that correct?
Thanks in advance!
Does anyone know if the ventilation system/strategy of a LEED 2009 project can be designed according to ASHRAE 62.1-2010 instead of 62.1-2007?
I haven't looked at the 2010, but I heard the fresh air requirements are lower than the 2007 standard.
You must follow the standard as it is cited in the reference guide.
I'm working in a CS office building with a designed ceiling plenum natural ventilation system for tenant spaces. The owner of the project will be providing the louvered inlets and outlets needed for the system to work, but there has been some discussion regarding the installation of the ceiling in tenant spaces by the tenants or the owner.
The question is, if the owner doesn't provide the ceilings for the tenant spaces, but provide the rest of the system features and explains the tenants how to install the ceiling in order for the natural ventilation system to work will that be enough for compliance? Or a legally binding lease agreement would be needed in this case?
Thanks for the help
We are working on a CS muti-unit residential project. There will be infrastructure for residents to use splits in their units. According to the item 5.9 of ASHRAE 62.1-2007 the project has to comply with filters minimum efficiency of MervMinimum efficiency reporting value. 6. As we know that the high wall system do not comply with this mandatory, the residents would have to use cassettes in their units, which would be very hard considering the lack of roof space.
Considering the units are not in the core or shell of the building, and that it is a residential project, does the lease agreement has to be done for future residents to comply with filters minimum efficiency?
We have C&S office building where the majority of the spaces are shell spaces for future office space. Since at the moment we do not know what is going to be the exact distribution (offices, meeting rooms etc.),
1. would it be acceptable to apply the Ashrae default density for Office Areas. I would think applying the default density should account on average bases for the distribution mixture of high density and low density areas such as meeting rooms, corridors and storage areas in a typical office space.
2. Would it be appropriate to use 1 for system effectiveness, since we do not know the exact distribution of the different spaces.
3. Should we also submit lease agreements that require for the tenant design team to verify compliance with ASHRAE? In the LEED online form it's either IN SCOPE or NOT IN SCOPE. We are providing the base building system but not the tenant distribution.
I’m wondering about how to comply with this credit for a C&S building that, upon initial completion, will be just a big warehouse space with no ventilation and the only HVAC equipment will be unit heaters to maintain 55 DegF during the heating season. There will be various tenant build-outs in the future, but the number is unknown and those spaces are not delineated yet. There will be no RTUs or exhaust fans installed as part of the C&S project. I assume the only way we can get this credit is by using special circumstances and uploading a lease agreement with binding language about 62.1 compliance, etc. However, in order to complete the form, I have to check one of the options regarding whether the project is mechanically/naturally ventilated/conditioned, none of which would apply. Any advice on a way around this? Also, since there is no ventilation system we cannot enter a ventilation system designer. The other option is to do upload IEQp1-RS1 which asks for the following:
Provide a document with the required signatory statement, copied directly from the form, signed and dated on letterhead.
I have no idea what for they’re requesting here. Anyone done this before?
In general, without any method of ventilation at initial completion, will we be able to achieve this prerequisite?
Would greatly appreciate input anyone may have.
I have a very similar situation, did you ever get any advice or support on this question?
Let me confirm the following ASHRAE 62.1-2007 Zone Air Distribution Effectiveness (Ez) issue.
Our project utilizes total heat exchangers for ventilation. We wonder what Ez should we use in the cooling mode most critical situation.
Typical Summer conditions at the project site are indicated below:
Outdoor temperature: 34 degrees C
Indoor temperature: 26 degrees C
Supply air temperature: between 26 and 34 degrees C
These assumptions meet the following situation written in 62.1 Table 6-2:
“Ez=1.0: ceiling supply warm air less than 15 degrees F (8 degrees C) or more above space temperature and ceiling return provided that the 150pfm (0.8m/s) supply air jet reaches to within 4.5ft (1.4m) of floor level. Note: For lower velocity supply air, Ez=0.8."
Note 2: “Warm air" is warmer than space temperature.
We think it’s not acceptable to have air speed at 1.4m above the floor level, because the draft would impair occupants’ comfort. We can find the following statement in ASHRAE 55 section 22.214.171.124:
Draft is unwanted local cooling of the body caused by air movement.
...The maximum allowable air speed is specified in Figure 126.96.36.199 as a function of air temperature and turbulence intensity. Alternatively, the following equation may be used for determining the maximum allowable air speed. The predicted percentage of people dissatisfied due to annoyance by draft (DR) is given by ...”
According to the Figure 188.8.131.52, air speed faster than 0.4m/s seems unacceptable. We think that the situation described in Table 6-2 in 62.1 is not compatible with ASHRAE 55 requirement.
If we could interpret the following part of 62.1: “provided that the 150pfm (0.8m/s) supply air jet reaches to within 4.5ft (1.4m) of floor level” as “provided that the 0.8m/s supply air jet at the diffuser, and the air reaches to 1.4m of floor level”, it would be understandable.
We checked the errata and addenda of 62.1 (even though the IEQ p1 asks for compliance only to the errata, and not to the addenda), and found no changes to the Ez coefficients.
Please let us know which Ez value, 1.0 or 0.8 should be used for our project.
Any comments would be greatly appreciated.
What areas/rooms should we consider inside an appartment for the calculation of naturally ventilated spaces? For example, the master bedroom has a dressing room and a bathroom, should we consider all these spaces?
What about circulation? Usually, it doesn't have any openings to the exterior, but doors to the other rooms. What about the kitchen, laundry rooms and the other bathrooms?
And the doors between two rooms can be considered as an "unobstructed opening"?
Hi to all of you,
as per Standard 62.1-2007, in Section 5.9, one of the minimum requirements for mechanically ventilated spaces, a MERVMinimum efficiency reporting value. 6 filter shall be provided upstream of all cooling coils. ...,
How strict is this situation if the units are VRF evaporators?, since they have very little pressure available and the filters would cause a big drop of it.
We have run into this on a number of projects. As this is a pre-req we have not pushed back on this requirement and always included at least MERVMinimum efficiency reporting value. 6, but usually MERV 8 filters.
Oversizing the ductwork (if there is any) will help reduce pressure drop,
creating an oversized plenum filter box to reduce the FPM across the filter, or
select a higher static VRF unit.
For a C&S project there are default 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. occupancy figures that shoudl be used for water calcs, bicycle racks etc where the final occupancy is not known. These are I believe average occupancy figures that represent an average number of occupants on a typical day and are less than what we would expet to be the peak occupancy. While FTE are ok for the average usage and water/bicycle number types of calcs I don't belive they should be used for the ASHRAE 62.1 fresh air calculations.
ASHRAE 62.1 has another set of default occupancy which are what I would descibe as the peak occupancy and the MEP designer will use these numbers in the MEP calcualtions NOT the FTE numbers.
Has anyone encountered this issue and dealt with the fact all the online forms are trying to use the same occupancy for Fresh air calcs as the FTE?
I think we should be able to use different occupancy in this case (as would the MEP designer) and that FTE should not be used fo this credit.
The ASHRAE occupancy numbers are numbers you can use for your 62.1 calculations if you don't have exact occupancy numbers (e.g. seats on a floor plan). 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. is strictly a LEED number and doesn't have to be used for the 62.1 calculations. I've never had my occupancy numbers questioned before, but if your quantities are way off of the FTE numbers then you may be asked to explain yourself in a narrative.
You have a really important question to calculate required OA of 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 appropriatly.
Refer to equation in the definitions on the page 22 of ASHRAE Standard 62.1-2007; Occupant Diversity,
D = Ps/ΣPz
Pz: Zone Population, the largest number of people
expected to occupy the zone during typical usage,
the ASHRAE occupancy numbers you mentioned.
Ps: System Population, it should vary by less than 10% from the peak population density reported(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.+transient) for LEED submittal.
Less 'Ps', less 'Vot'.
(but Ps is limited not to be over sum of Pz)
We are working on a natural ventilated CS office building. The entire building is going to be natural ventilated with no AC. The bathrooms are the only areas with an air extraction system, but we haven´t been able to understand if this system belongs to a mechanical ventilation system?
The air extraction system simply take out the air from the bathrooms and transports it to the outside of the building.
Could anyone help us with this?
Regarding my question above, maybe some details will shed some light in our inquiry:
As I stated above, the only mechanical ventilation in the project will be an exhaust ventilation system in the bathrooms. The LEED online form's Table "Ventilation Rate Procedure" doesn't seem to be designed for exhaust systems, since it asks for information such as Rp, Ra, Ez and Ev that is not included in ASHRAE's Table 6-4 (the table to be followed by air exhaust systems, according to ASHRAE 62.1 paragraph 6.2.8).
The form doesn't seem to include a table specifically for exhaust systems. So, any idea on how should we proceed? Should we exclude this exhaust system from our calculations? Should we mark the Special Circumstances Box and upload our own table, using Table 6-4's information?
Once again, thanks for your help.
You do not need to include the exhaust system in your calculations for this pre-req. Having an exhaust system does not count as Mechanical Ventilation for LEED purposes.
As a naturally ventilated building you must comply with ASHRAE Standard 62.1-2007, paragraph 5.1.
Thanks for the answer Dylan, it's been really helpful.
I appreciate your interpretations on the ASHRAE 62.1 regarding the requirement for naturally ventilated spaces:
5.1.1 Location and Size of Openings: Naturally ventilated
spaces shall be permanently open to and within 8 m
(25 ft) of operable wall or roof openings to the outdoors...
Does that mean that a residential studio (with no partitions) that is 30 feet long with an operable opening at one end would, would not, or would partially meet the distance requirement? My dillema is this: Technically, The studio is one big open space that is within 25 feet from an opening - then, it is compliant as per the ASHRAE wording. However, the last 5 feet of the studio are over 25 foot away form the opening- then, the area limited by the 5 feet length and the width of the studio may not qualify. Any thoughts on this?
Technically, I think you're correct, but this may not be a good idea for good air quality. Note that ASHRAE 62.1-2010 now has more restrictive guidance on the location of openings in section 6.4. For example, with a single opening, the maximum distance coverage is 2H, where H is the ceiling height.
We are dealing with project with underground garage, where adjacent spaces are technical rooms. Can we transfer the air from the garage to the technical rooms to ventilate them? Do we need to keep positive pressure in these rooms if they are not 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.?
Thanks for help
Could you provide clarification on what you mean by technical rooms? Parking garage is classified as Class 2 air, so you can't transfer to Class 1 spaces, which includes data rooms.
ASHRAE 62.1 excludes equipment rooms and storage rooms from the definition of occupiable spaces. If your technical rooms are within this definition, they don't need to be ventilated.
We are working on a office building applying for LEED CS. The building is going to be naturally ventilated. we haven't been able to understand if naturally ventilated spaces are considered conditioned or unconditioned, or somewhere in between. Regrettably, ASHRAE is not very clear with info and definitions regarding natural ventilation. Could anyone help us with this?
Thank you all
Luis, could you clarify how you're using the definition of conditioned versus unconditioned in your LEED submission?
Well, we haven't designated any space yet, but since the ASHRAE defines a conditioned space as "a cooled space,heated space, or indirectly conditioned space" and our building is naturally ventilated as a whole (and therefore there aren't any cooling or heating system), we think that everyone of the building spaces are considered unconditioned. What do you think Roger?
This covers more than just ventilation but as this is the most important I put all facts and questions down here.
An existing building from the 1970s is undergoing construction works. The client would like to certify the building and is seeking our advice. The works will mainly comprise a complete facade replacement and some work on none load-bearing walls. All HVAC systems and plants, distribution and so on will remain unchanged as far as possible.
According to the definitions in the Rating System Selection Guidance June 2011 this is a major renovation and the project would certify under CS Major Renovations.
Probably some of the systems are not compliant to ASHRAE 90.1-2007, but in most sections there are exceptions for existing systems that are not replaced or altered. So there seems to be no problem here, correct me please if I'm wrong.
We are sure that the ventilation rates are not compliant to ASHRAE 62.1-2007 in some places. There will most probably be no space to upgrade the system to ASHRAE 62.1, especially in the case of 5 underground parking decks. I can't find an exception similar to 90.1 in the 62.1.
Does anybody know of exceptions especially to ASHRAE 62.1 or a USGBC document / policy that allow the certification of this building (assuming all MPR and other prerequisites plus enough credits are met)? Or is this a project that just cannot be certified at all?
Jens, there are no exceptions. All prerequisites need to be met.
For our LEED CSv2.0 project, we have been asked to provide a proposed tenant layout for approximately 6 office spaces. There are (2) office spaces and (1) corridor space for each of (3) Roof Top Air Handling Units. As the programming of each office has not been decided as they will be individual and seperate office spaces, we are unable to provide a realistic expected program for each office. Fortunately the OA design for these units are large enough to accomodate the office spaces in a worst case scenario for an office (100% conference / meeting space has the highest occupancy values and OA rate requirements per person). Has anyone had any experience or have any comments on instead of providing an office specific programming layout to provide a narrative and associated ASHRAE 62 calculators showing that the RTU's are capable of handling the office space in these conditions?
Even if programming hasn't been completed, it should be possible to present a tenant layout plan that would be one of several possible options. The goal here is to show what might reasonably be built, and how the systems would perform for such a potential layout. It's mainly a test fit of a generic space plan to show the system meets the requirements with that case.
All we know about the spaces is that they will be office spaces, so if we show that we are able to exceed our OA requirement in the worst case scenario with the most OA required, shouldn't this be an acceptable method instead of pretending we know what the future layout could be, and as a result possibly undersizing the OA required for the space?
I am working on a project with similar spaces repeating on each floor. I know LEED allows one to group spaces in some credits. However, the LEED online template says "Complete the following table for each mechanically ventilated space in the project building." The key word being "each". The reference manual doesn't seem to suggest that spaces can be grouped and the ventilation rates be added for simplifying documentation. Typically, do you group such repetitive spaces then?
Some time ago but this still might help. I have a project where floors 3 to 33 are essentially the same. I wrote a narrative explaining this fact and filled the table with one examplary floor and all non standard floors. This approach was accepted in Desing Review.
We are working on a natural ventilated CS office building. The Leedonline form asks to fill in a table with the operable window area, in order to calculate ratio of window to occupiable area.
This building's natural ventilation system consist in ceiling duct system with openings to the outside thus creating a windflow that ventilates the offices. This offices have operable openings to regulate the inflow of air. Do you thinks we should include these operable openings' areas in the window area of the table?
Thanks for your help
instead of a window area, you probably need to use the area of the openings on the outside of the building, since this is the "inlet" area that is delivering the outside air. That open area needs to be at least 4% of the floor area it serves.
We are working on a C&S project but in the middle of the design phase we learned that a gym will lease three floors.
Air handling units will be installed on all floors except in the gym.
The gym will install their own AHU´s.
Do we need to include the ASHRAE ventilation requirements in the lease agreement?
ASHRAE 62.1 compliance is required for any space in the building. So yes, if the owner is not installing the ventilation system as part of the C&S than the lease agreement needs to require the gym to comply with ASHRAE.
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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