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 follow the distinct requirements set out in Case 2, even if other spaces in the same building are mechanically ventilated and are following Case 1. Mixed-mode spaces (with both mechanical and natural ventilation) must follow the compliance path for mechanical ventilation, Case 1.
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 do not meet the standard’s requirements, you will need to either modify the base building system or provide detailed analysis documenting the constraints and explaining why the base building systems cannot be upgraded.
Determine likely ventilation strategies during preliminary programming: natural, mechanical, or mixed-mode ventilation. This prerequisite is attainable with any of these strategies.
This prerequisite is paired with IEQc2: Increased Ventilation. If ventilation rates are targeted above the 30% ASHRAE requirement, projects can gain both the prerequisite and a point for EQc2. Projects pursuing IEQc2 may follow the compliance path for natural ventilation found in Chapter 2 of The CIBSE Applications Manual 10 (AM10) for both the prerequisite and for the credit.
Many of the strategies that contribute to meeting this prerequisite also support earning other indoor environmental quality credits and should be explored as integrated solutions. See LEEDuser's guidance on the rest of the IEQ section for ideas.
Natural ventilation strategies can reduce costs. Natural ventilation in particular can reduce the need for mechanical equipment as well as operational costs. Displacement ventilation, in which air is delivered at or near floor level at a low velocity, can also reduce ducting and improve equipment efficiency. In choosing a system, analyze life cycle cost tradeoffs.
Check local building codes to determine requirements. The project must either meet ASHRAE 62.1-2007, or local codes if they are more stringent. Since ASHRAE 62.1-2007 is often more stringent than local codes, be sure to review and be familiar with its requirements.
This prerequisite is not likely to require added costs.
Review the Ventilation Rate Procedure methodology in ASHRAE 62.1-2007 Section 6.2 and the associated Table 6-1.
ASHRAE 62.1 recognizes two procedures to prove IAQ compliance: the IAQ Procedure methodology and the Ventilation Rate Procedure. The Ventilation Rate Procedure is easier to apply and is the prescribed path for this LEED prerequisite.
If you are pursuing IEQc5: Indoor Chemical and Pollutant Source Control, you must incorporate MERV 13 filters into your filtration system. These relatively tight filters may affect the fan power and fan sizes necessary to provide the required quantities of air. Involve the engineer early if pursuing IEQc5.
Demand-controlled ventilation can greatly reduce energy use while providing large amounts of fresh air to occupants.
Determine whether natural ventilation is feasible based on the project type, use, and climate. Study the natural conditions of the site, such as prevailing wind direction, and orient the building to maximize airflow.
Review the prescriptive requirements for natural ventilation in ASHRAE 62.1-2007 Paragraph 5.1 (with errata but without addenda).
An integrated design meeting will help determine whether natural ventilation is a high priority and should be a primary driver of the design process.
Airflow modeling early in the design process can help teams create a more effective natural ventilation design. If the data is used early in the design to help inform team on such thing as space planning and building envelope design. An airflow modeling professional may add some upfront costs, while likely improving system efficiency and effectiveness.
Consider the cost implications of natural ventilation. Passive strategies may reduce or eliminate the need for fans and HVAC equipment, but they may also require high quantities of operable windows and a floor plan that is conducive to passive ventilation. Natural ventilation often requires the cooperation of occupants, to open and close windows when appropriate, for example, be sure that your project is likely to succeed in this respect.
Determine the required ventilation rates for indoor spaces based on occupancy and space types. ASHRAE 62.1-2007 tables 6-1 and 6-4 list minimum requirements for particular spaces.
Separately evaluate each space to determine air requirements and what type of ventilation will be best. Metabolic rate of the space activities and the occupant density are factors that determine the amount of fresh air needed in a space. For example, exercise rooms and conference rooms require more fresh air than offices.
An integrated design approach among the mechanical engineer, architects, owners and occupants will facilitate design decisions that impact the HVAC design. For example, space planning decisions will impact the architectural programming of the space as well as access to natural ventilation.
Increasing a project’s ventilation rate brings long-term cost benefits. Good indoor air quality can lower operational costs by increasing occupants’ health and productivity as well as the value and marketability of the building.
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.
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 Commercial Interiors
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 perform according to the ventilation rate procedure.
Modify or maintain existing building outside-air ventilation distribution system to supply at least the outdoor air ventilation rate required by ASHRAE Standard 62.1-2007 (with errata but without addenda1). Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007 for 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) minimum ventilation rates.
Projects outside the U.S. may modify or maintain each outside air intake, supply air fan and/or ventilation distribution system to supply at least the outdoor air ventilation rate required by 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.
If the project team cannot meet the outside air requirements of the above standards, document the space and system constraints that make it not possible, complete an engineering assessment of the system’s maximum cubic feet per minute (cfm) capability toward meeting the requirements of the above standards, and achieve those levels, with a minimum of 10 cfm (0.28 cubic meters per minute) per person. All other requirements must be met.
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda1).
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.
Located in London, this organization publishes a series of guides on ventilation, including natural ventilation.
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 Rocky Mountain Institute publication is a case study of the connection between worker productivity and indoor air quality.
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.
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 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.
Complete documentation for achievement of IEQp1 on a LEED-CI 2009 project.
Documentation for this credit can be part of a Design Phase submittal.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each CI-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."
Our project has one primary ventilation system for the entire project space served by the base building AHUs. In addition, several rooms could be served by the newly installed split units for the "after-hours" use, whenever necessary. Do I need to enter info on the supplementary "after-hours" system too in addition to the primary one? Thanks in advance!
I have a question about the occupancy value of VRP calculation. We normally use default occupancy value (that is the occupancy rate in the ASHRAE 62.1) or use design occupancy value, if the design occupancy value is larger than default value.
However, if our design occupancy value is smaller than the default value, can we still use the design value for LEED-CI IEQp1 calculation?
We have a studio room in the project, the default occupancy rate of studio room is 70ppl / 1000ft. However, our design is just 20ppl / 1000ft.
If we use the default occupancy rate, the calculation can't comply with the pre-requisite requirement. Does anyone have the experience of this?
Thank you very much.
Go with the design perimeters. This same discussion is happening at the NC forum here:
I have two short questions:
1. Would an IT Room require a minimum ventilation rate if it is an infrequently occupied space? Technicians will enter the room only if they suspect a piece of equipment is not working properly - probably a couple of times a day, for less than 20 minutes each time.
2. In case it does, would the IT Room be categorized as an "Electrical Equipment Room" in Table 6-1 of Standard 62.1-2007?
Thanks for your help!
Typically an IT Room would not be considered a regularly occupied space, therefore no need to include it in your calculations.
Does this mean that IEQp2 only applies to regularly occupied areas?
We are working in a project pursuing LEED-CI certification, and some of the base building 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.'s were short on supplying air in order to meet the demand of lay-out spaces, so the interior HVAC designer install new back up AHU´s connected to the main air supply duct of the Core&Shell system and returning the air for the interior AHU with no outdoor air. The argument of the HVAC interior designer is that the base building system already has outdoor air supply connected to return complying to ASHRAE 62.1, so according to him, the back up AHU do not need to meet the requirements of the prerequisite. I understand that all new AHU´s installed as part of the tenant scope will also need to meet the requirements, Am I Right?.
Thank you for your response.
I'm not quite clear on how the systems are set up from your description. If the C&S system was designed with sufficient outdoor air capacity for the CI spaces, you should be able to demonstrate that the CI system will provide the required outdoor air by drawing it from the C&S supply.
If the project spaces are served by a large 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. system which has mixing of central Outside air inlet and recirculation air, but the VAV system is also serving other tenant spaces. How can we do the calculation if we cannot get space use info in other tenant spaces which are served by same VAV system?
This is a bit tricky, we tend to try to find the data for the other tenant spaces just to be sure. Sometimes you can get this information from the building engineerA qualified engineering professional with relevant and sufficient expertise who oversees and is responsible for the operation and maintenance of mechanical, electrical and plumbing systems in the project building. or manager.
If not, the CI version of this form allows you to only input the critical zones. "Describe how critical zones are selected and how all occupied 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."
If we don't have the data from all the zones, we will typically input all of the zones within the project scope then explain that the other zones are similar in the narrative (also private offices and conference rooms, etc).
We are working on a project where the HVAC system is VRV unit.
Air distribution system has a treated fresh air unit.
When the fresh air unit is turned on, whether the meeting rooms are occupied or not, whether the indoor unit is turned or not, the fresh air will be supplied to meeting rooms.
The same scenario is repeated in office space.
Can I consider air distribution system as a constant air volume system and report Ds as 100%.
Appreciate your inputs and suggestions.
Sriman, this should be considered a 100% outside air application due to use of a make-up air (fresh air) unit. Ds should be 100%.
Do you have a definition for Ds(%)? ASHRAE 62.1 does not have such a variable. There is a D for diversity, which seems to be the inverse of this Ds based upon experimentation. Can anyone advise?
D is the same as Ds. The s is a subscript to represent diversity at the system level. D is described in Chapter 6 of ASHRAE 62.1.
I think there is some confusion here. D is not the same as Ds.
D=Diversity. Either in regards to the population served by the system vs 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. or the sum of all your zone maximum supply quantities vs your system capacity.
Your office spaces has a ventilation design capacity of 50 people and your conference rooms have a design capacity of 50 people. But your FTE is only 50 people. Your population D=50%. This reduces your outdoor air intake requirements.
Ds=Percentage of total design airflow rate at conditioned analyzed.
You have a 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. system with a 50% turn down for heating mode. Ds = 50%. Ds is typically the turn down at the terminal (for the design condition). For a VAV system, it is typically between 30-50%. For a constant volume system, Ds=100%. A lower Ds will give you a lower Ev coefficient, resulting in higher OA intake requirements.
On LEEDOnline, go to the main page for IEQp1. Then on the right, under quick links is a link to "Credit Resources." Download the "62MZCalc" excel file. Although it may confuse you more, at least there are some directions and definitions in that file.
We have 4 questions listed below regarding IEQ Prerequisite 1 - Minimum Indoor Air Quality Performance.
Question 1: Requirements, Case 1, Paragraph 3: We are seeking clarification or guidance concerning the last sentence stating “All other requirements must be met.”
We are renovating two floors of a 13 story building. We cannot verify the amount of ventilation air due to lack of air flow measuring stations or similar means to directly measure the quantity of outside vs. quantity of return air as the variable air volume controls modulate to meet the space loads. Case 1 allows an exception if we can, through engineering judgment, determine that the system provides at least 10 cfm per person.
However the last sentence of Case 1 paragraph 3 appears to then still require that we have to have controllability per ASHRAE 62.1-2007 paragraph 5.2.1 and paragraph 5.4. The question is then does Case 1 paragraph 3 actually provide an exception?
Question 2: Are there recommended methods and approved documentation approaches that are suitable to prove the systems meet 10 cfm per person for the entire building?
Question 3: Is an approach of measuring temperatures of return and outside air and resulting mixed air temperatures acceptable means to indirectly predict the ventilation air quantity? Can this be data and calculated amounts be obtained via a sampling of measurements at specific times of the year representing peak heating, cooling and mid season values?
Question 4: Can we extrapolate data from the renovation of our two floors to use as the basis for occupancy and ventilation rates for the rest of the facility? The TI work on our floors is the first renovation project; other floors are anticipated to be improved but no specific data or plans are available to make more specific estimates of the eventual renovation and resulting occupancy totals.
I would like to ask if there's any requirement regarding outdoor air suplly to a kitchen located in an office area? In ASHRAE 62.1-2007 Table 6-1 a kitchen is not mentioned. However in 62MZCalc file you can choose "Kitchen (cooking)" as a zone type. What is the requirement for kitchens regarding amount of resh air?
My client has an office where there is a kitchen (around 12 square meters) without outdoor air supply, there's only exhaust installation. I'm not sure what to do about this. Does it mean that the requirements of this prerequisite are not complied with.
Kitchens have an exhaust air requirement (Table 6-4) rather than an outdoor air requirement. The kitchen you're referring to sounds more like the kitchenette occupancy category than a commercial kitchen, so the exhaust rate would likely need to meet the 0.3 cfm/sf requirement in Table 6-4. As stated in Section 6.2.8, the exhaust makeup air does not need to be outdoor air, but can be any combination of outdoor air, recirculated air, and transfer air.
Our design has four Dual Duct 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. units that share common plenum return that is recirculated thru both hot and cold deck of each unit. Each unit has it's own OA intake. We've done separate calcs for each unit w/ zones associated to each unit. The reviewer had stated that the AHUs should be combined as one multi-zone recirculating unit for these calcs. I'm drawing a blank as to how to calculate this in the 62 calculator or why it would be necessary.
In Dual Duct unit in the Heating Calc sheet, would I assume the fully occupied Interior Classrooms or conference rooms to be in cooling within the heating calcs for the unit? So this unit's calculation for heating would be a mixture of zones in heating and/or cooling? being these rooms not likely to set Ev.
thanks in advance!
IEQc1 requires confirmation that the building services have been designed in accordance with ASHRAE. A statement from the mechanical engineer is required to demonstrate this.
We have provided a statement from our mechanical engineer for the supplementary systems in the project, however not for the base building mechanical systems.
The company who designed and installed the base building systems is no longer in business. We have received email confirmation from the current contractor that his inspection of the systems confirms they were designed in line with ASHRAE standards, however he is reluctant to sign a statement along these lines.
Therefore we would like confirmation on the best approach for the LEED submission:
1. Do we submit his email confirmation which verifies he has checked the installed systems and they meet the requirements of ASHRAE, OR
2. Do we submit a statement from our mechanical engineer stating that according to information provided by the contractor, the system installed meets the requirements of ASHRAE
Thank you in Advance!
We have a small mechanical equipment room that contains a backup diesel generator. It is being ventilated to remove exhaust and excess heat. However, ventilation rates do not meet those required per ASHRAE 62.1-2007 for an 'electrical equipment room' which seems like the closest possible space category in ASHRAE 62.1. It is unclear to me whether this is the appropriate classification, as our understanding is this classification is intended to apply to rooms with transformers and other purely electrical equipment. If not, is there a more appropriate category of space, or should we just the space to meet engineering and code requirements and not worry about ASHRAE 62.1 for that particular space?
I agree with your interpretation of what the 'electrical equipment room' classification is intended to apply to, and I would not use that classification for this space. In fact, I would say that this type of space is outside of the scope of ASHRAE 62.1-2007, as this space is likely not intended for human occupancy. However, this does not mean that it shouldn't be exhausted, you would just need to demonstrate compliance with the applicable code requirement.
We are working on a office interior design project. LEED CI IEQp1 says the requirement is "Meet the minimum requirements of Section 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality". My question is:
1 If only the system and equipments related to our LEED CI project scope has to meet this requirement or the whole building that the office located has to meet it?
2 If only the " Ventilation for Acceptable Indoor Air Quality" of Section 4 through 7 of ASHRAE 62.1-2007 has to be met? Or the whole Section 4 through 7 of ASHRAE Standard 62.1-2007 has to be met?
Thanks a lot!
Only the components that impact your CI scope need to meet Standard 62.1-2007. The entirety of Section 4 through 7 applies. I'm not sure what distinction you mean by Ventilation for Acceptable Indoor Air Quality versus other parts is.
In the 62MZ calc, i created zones that have heating and potentially critically zones, but im having an issue with the results; for Vdzd, i enter the airflow rate that corresponds to the minimum 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. damper position, which is 30% of the rated airflow of the VAV, then in the Ds field, i enter '30%', but the results for the 'outdoor air intake required for system' shows an error.Im using the April 2011 version of the calc.and also downloaded a fresh version, but ended up with errors again. Anyone else experienced this? If i change Vdzd to the max/total airflow for the zone/VAV and set Ds to 30%, i do not get an error, but not sure if this is the right approach. I've been scratching my head on this one for a while and would greatly appreciate any inputs on this, or if anyone has a sample calc.for the 62MZ calc, that would really help.
I have experienced this, and it seems like the reduced airflow should only be accounted for by modifying Ds rather than Vdzd. Otherwise the calculator is essentially applying the 30% twice, resulting in a supply airflow equal to 9% of the rated value. I would leave Vdzd at the rated value and only adjust Ds.
I'm working in a project that has operable windows in the toilets. I would like to know if those windows comply with the item mandatory 5.18.5 Exhaust System of ASHRAE 62.1-2007 or do I need to install a mechanical exhaust system to comply with the mandatory?
You'll need to use a mechanical exhaust system. Operable windows only apply to ventilation.
I am new to the ASHRAE MZ62 calculator and I am not clear on how to write the narrative regarding :
Ds - If not all zones are entered, provide a description of how the system Ds value was calculated, and confirm that it accounts for the percent of total design airflow to each zone at the condition analyzed (zone Ds), and the primary air fraction of supply air to each zone (Ep) at the condition analyzed.
I have a 3 story non-residential building, and 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.'s on each floor are served by individual air handling units. If i want to use the 62-MZ ASHRAE calculator to document Vot for multiple zone units, would i total up the airflow for all three units and input that amount as Vpsd, then include all zones (in the bldg) in the calculator and submit 1 spreadsheet calc or would i need to have 3 separate Vot spreadsheet calcs. for each system?
Any input would be greatly appreciated.
Bobby, you'll want to have one separate spreadsheet per system.
I am working on LEED CI 2009 Retail Shop. This shop is using existing wall, roof and floors and existing AC units in a shopping mall. In this shop there is window provision and surrounded by other shops also. There is no provision to provide window or making any opening for Fresh air required by ASHRAE 62.1-2007. Also in this mall there is Fresh air handling unit to provide fresh air in any shop so in this shop also there is no provison for mechanical ventilation. In both case mentioned above there is no chance to provide Fresh air required by ASHRAE 62.1-2007.
In this case, can this pre-requistes exempted? or is there any other way to comply with this prerequisite?
There is no exemption. You need to comply with ASHRAE 62.1-2007. If there's a fresh air system serving the mall, you'll want to work with the mall operators to see if adjustments can be made to supply enough ventilation air to the retail shop.
Office floor of a high rise building trying to obtain LEED sliver. Floor is served by 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., which serves 30 other floors not in scope. 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.'s serve multiple zones on this floor. Even if CO2Carbon dioxide sensors were added to every room it does not seem feasible to obtain this prerequisite considering there is no way to modulate the O.A the air handler. Any thoughts?
We have a project which the outdoor air supply is limited from the base building HVAC system (out of our boundary) and we are not sure if the project will be able to meet the ASHRAE 62.1 requirements due to this. Has anyone gone down the compliance path when one or more AHUs are unable to meet the ASHRAE 62.1 requirement and had their credit approved? I'm wondering what GBCI considers qualifying 'space and system constraints' and requires for documentation.
If there are space and system constraints, you can go down to 10 cfm per person, but no less. There's no way around this, without violating the original intent of this pre-requisite.
we had received following comments from GBCI for final design review for IEQP1 credit: Revised documentation has been provided including a response narrative, revised Ventilation Rate Procedure (VRP) calculations, and an updated LEED Prerequisite Form to address the issues outlined in the Preliminary Review. The 62MZCalc spreadsheet has been used which is appropriate for the multiple-zone re-circulating system. The system ventilation efficiency (Ev) has been determined based on the critical zone parameters. However, three issues remain outstanding. Outstanding Issues: 1. Preliminary ReviewComment #1 and ;#2 requested;a separate;VRP calculation be performed for each
ventilation system. However, the VRP calculations provided combining all ventilation systems (AHU1 to AHU12) in one VRP calculation. Additionally, the mechanical schedule;and anarrative describing the ventilation system and system design outdoor airflow for each system has not been provided as requested. It is unclear whether the ventilation requirements have been met at the systemlevel for each system. 2. Preliminary Review Comment #3
requested the VRP calculations be revised to account for the total system population, area, supply air, and outdoor air volumes for systems also serve spaces outside the project scope. However, it appears from the revised VRP calculations, the zone area and zone population for other spaces in the building have not been included, and no justifications have been provided. 3. Preliminary Review Comment #4 requested the VRP calculations be performance based on the worst-case condition, which includes revising the zone air distribution effectiveness (Ez) to 0.8 for zones that are provided with heating and using the terminal box minimum supply flow to zone in the calculations. ;However, the zone air distribution effectiveness (Ez) used in the revised VRP calculations is still 1.0, and the Ds value of 100% has been used, with no justifications provided. Note that Ds is used to calculate the"; percent of total design air flow rate at conditioned analyzed” and shall be determined based on terminal box minimum supply flow to zone to represent the worst case condition. Failure to adjust Ds results in an inaccurate value of system ventilation efficiency Ev value. The documentation dose not demonstrate prerequisite compliance.
Please help us on the comment, we are unable to understand comments received, please let us know how can we reply to GBCI.
I recommend working with your mechanical engineering consultant to resolve these issues. Overall, a separate calculation needs to be performed for each air-handling unit system, so you'll end up with 12 spreadsheets. The Ez value needs to be selected carefully - the value of 0.8 is typical for a heating condition for most air distribution systems. The adjustment of Ds allows you to simulate turndown of the system in heating mode.
I have a 400 sq ft office in an existing building without an existing A/C system. We installed a mini split system (no outside air) for mechanical conditioning, and there are 2 existing windows but are usually closed. What is the best approach for complying with this prerequisite? Can the mechanical approach be used if the equipment doesn't have an outside air intake? Or should I take the natural ventilation approach? Thanks!
Roberto, it sounds like you should use the prescriptive natural ventilation approach, which requires a certain 4% of operable vent area as a fraction of floor area, as well as a maximum distance from occupant to vent. Section 6.4 of ASHRAE 62.1 provides addition details.
We have a small LEED:CI project in a CS certified shopping mall. We don't have any direct outdoor air intakes, we take the air from the main atrium and give it to our space. The base building has even achieved increased ventilation credit by natural ventilation, so air in atrium is quite acceptable.
How can we document compliance with this prerequiste?
Aaron, you'll want to see if you can find out the outside air percentage in the air distributed to the atrium. ASHRAE 62 does allow you to use transfer air to meet ventilation requirements in certain cases, with a zone air distribution effectiveness of 0.8 if you're transferring air from the opening of the store to the back of the store.
All HVAC mechanical systems were existing. Only the ductwork was installed. There is Engineer for this project is there a way to comply without the signature?
All HVAC mechanical systems were existing. Only the ductwork was installed. There isnt an Engineer for this project is there a way to copmly without the signature
We had a similar case and were able to successfully get the credit approved by having the architect sign and provide a narrative explaining there was no engineer on the project. However, you still must provide all the proper documentation and calculations to show compliance.
Does technical rooms, as IDFs rooms needs to have outside air renovation? As it is not intended for human occupancy, we understand that it is not necessary to consider these kind of rooms as a project zone. Is that correct?
In ASHRAE 62.1-2010, Telephone Closets are specifically shown with having 0 ventilation requirement.
We have a CI project with multiple zone units and 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. system. We are using template VRP compliance calculator. For filling it, there are no instructions on the template or in ASHRAE on what "Vdzd" means. 62MZ Calc, states that Vdzd is the "Design total supply to zone (primary plus local recirculated)". The Refence Guide states that "for VAV systems, Vpz is the minimum expected primary airflow for design purposes", and we understand that these statements are conflicting. Wich volume is correct to consider? It seems that the VRP calculator already takes in consideration the Vpz minimum airflow. Is this correct?
In the VRP calculator we are using the total supply air in the zone as described for Vdzd, and considering Ds as 100%. Is that correct?
Ds should be adjusted to consider the heating design flow rate, which will usually be significantly less than the cooling design flow rate. Vdzd is the total supply air.
Does anyone know if for ventilation requirements Title 24 - 2005 is acceptable in lieu of ASHRAE 62.1-2007? I know for EAc1 Title 24 - 2005 is seen as equivalent to ASHRAE 90.1- 2007. Additionally, it is written in the book that "local code can be used in lieu of ASHRAE when the local code is more stringent."
This one is challenging to answer, because T24-2005 doesn't include the same procedures as ASHRAE 62.1 for multi-zone recirculating systems (e.g. 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.). If you're working with a dedicated outdoor air system and the effective airflow rates are greater per person than ASHRAE 62.1, then I think it's fine to use T24.
We received a comment back on a CI project stating:
"Demonstrate the system serving the special occupancy space is capable of modulating system and zone minimum supply volume below 0.30 cubic feet per minute per square foot of supply volume."
It then goes on to say:
"Confirm the mandatory requirements of ASHRAE 90.1-2007 and ASHRAE 62.1-2007 are met."
The ASHRAE 62.1-2007 calculation uses the minimum expected primary airflow. Now that there is a requirement to reduce the min airflow in this intermittently occupied space to 0.3 cfm/sf, the minimum expected airflow no longer meets the requirements of ASHRAE 62.1-2007. The purpose of ASHRAE 62.1 is to provide indoor air quality that is acceptable to human occupants. Here I seem to be getting penalized for not providing enough air to a space that is unoccupied.
I do not want to submit the 62.1 calc for IEQp1 at the minimum expected occupied design conditions to have the reviewer look at my schedule and see the 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. box min value (which has been set lower due to the intermittent unoccupied conditions) was not used, but I do not see a place in the IEQp1 form to note that this space has intermittent occupancy (the diversity variable is only applied at a system level, not per zone)
Rick, I've never seen a requirement specifically in ASHRAE 62.1 to modulate down to 0.3 cfm/sf. Is this a project specific requirement? Even an intermittently occupied space benefits from ventilation to combat off-gassing of materials within the space. I would provide a detailed response narrative, rather than trying to adjust the form to accommodate a specific condition.
The Template calculates Vot by dividing Voz by Ev. ASHRAE 62.1 2007 arrives at Vot by dividing Vou by Ev, not Voz. This matters because Voz has already been corrected to account for the zone air distribution effiectiveness where Vou has not. This results in Vot being much higher than anticipated. Is this a known error in the credit template that I can simply bypass by asking for the most recent update of the template? Has anybody else ran into this error?
I should note that this is a multizone recirculating system.
It sounds like you are using an older version of the form, and yes you are correct, this error does result in an over-exaggerated value for Vot. GBCI is aware of this error, which has been corrected in subsequent versions of the form which have separate sections for single-zone, multiple-zone, and 100% outdoor air systems. You can either request the most recent version of the form or complete the calculations using the ASHRAE 62MZCalc spreadsheets.
In the reference book, under IEQc1 point 4. Implementation, it states that "This prerequisite is not limited to the project scope of work." Could someone please clarify exactly what this is referring to?
It refers to the building HVAC system supplying enough air, and also location of air intakes within this paragraph.
Currently I have a new system that is serving spaces that fall under the LEED scope, and spaces that do not. Do all spaces need to be included for compliance since the Ventilation Rate Procedure looks at both individual spaces, and the system as a whole? While spaces outside of the scope wouldn't count towards the credit, they could change the system ventilation efficiency.
Does anyone have an experience with this?
Michelle, you'll have to consider all spaces associated with the HVAC system, in order to determine the proper ventilation efficiency (Ev), as you mention. The main purpose of the comment in the reference book is that even if base building systems are outside of project scope, the project still needs to comply with ASHRAE 62.
I understand that the project spaces need to comply with ASHRAE 62.1, if the systems serving the space was installed as part of the LEED scope or not.
Are you saying that a project would need to perform a calc on each and every space that is served by an existing system? I am working on a job where the base building system serves 10 other floors of the building, it seems unreasonable to think that our engineers would need to first understand the distribution system throughout the rest of the building and then to calculate the ventilation rate in all of those spaces...for a pre req????
Is it the system or the zone that must comply with the ventilation requirements?
In May 2011 the USGBC updated the calculator for v2 projects (v3 doesn't appear to be updated) to check for compliance only at the system level... Our previous understanding was that each zone has to meet the thresholds for credit compliance (EQp1 = equal or better, EQc2 = 30% higher or better), but the new calculator only requests OA flow at the system level and then on a separate sheet only examines the system for compliance, not each individual zone.
My understanding of this is that each zone has to comply.
We have an office project (LEED CI 2.0) in an exsitng small building about 3500 s.f. The building is served by one existing central system that provides OA to the space. The layout of the space is very open, almost no doors, the second floor is a mezzanine that is open to the first. Basically all the outdoor air coming in is shared between spaces due to transfer and openness,etc. In addition there are two very large ceiling fans that circulate air throughout the open space. Although there are different "spaces" designated (open office, coffee area, materials storage, etc.) it doesn't seem appropriate to analyize these separately as "zones" for this credit due to the open nature of the plan. Would it be possible to analyze the space at the building level as one "zone?"
Greg, could you provide more detail on how the OA is brought into the space? Are there multiple injection points?
The OA comes into the space through multiple points. I'd estmate about 30 or so dispersed throughout the building(a combination of floor grills and ceiling diffusersIn an HVAC context, diffusers disperse heating, cooling, or ventilation air as it enters a room, ideally preventing uncomfortable direct currents and in many cases, reducing energy costs and improving indoor air quality (IAQ). In light fixtures, diffusers filter and disperse light.).
Greg, you should be fine treating the space as one zone, given your description of the OA distribution.
I have a technical question about LEED Online and inputting information into the Adobe Form for IEQp1. The issue I am having is the amount of time required to document a building that has several zones.
Currently, the only way I know how to document IEQp1 is to actively enter each zone, line by line online. However, each time I input a value, the whole form pauses and I believe, re-calculates every value in the table. This pause greatly slows the process of inputting information and for buildings with well over 40 zones can increase our documentation time by several hours.
Has anyone run into this issue with online documentation and found a better method? Are there ways to download and then upload adobe templates with LEED Online v3? Or any other process that I might try? Thanks.
Shannon, see response from Kimberly below. I recommend using a spreadsheet approach for projects with more than 25 zones. Make sure that you have all of the data from the LEED template in your spreadsheet, at minimum. It can be helpful to also submit the formal ASHRAE developed 62 calculation spreadsheet as a separate check of compliance.
Do we have to use the template table or can we upload our own spreadsheet using the same calcs? The template spreadsheet takes much more time than our spreadsheet that is used during the design phase.
If you are uploading your own spreadsheet, make sure you still include the information required in the template (i.e. for each ventilation zone, the amount of outside air required by ASHRAE 62.1-2007 and the actual amount of outside air provided to that zone). Just showing the outside air volume required and provided on a system level (per air handling unit) for multi-zone systems is not sufficient.
ASHRAE 62's Ev value is determined by either the ASHRAE Standard 62 Appendix A (lowest calculated method value of the zone efficiency Evz) or per ASHRAE's Table 6-3 "System Ventilation Efficiency". The Ez method deteremined from these methods are used as a system Value is determined from the space airflow fractions... However, the LEED Online "Ventilation Rate Procedure" Table appears to divide HVAC units into spaces covered by the unit and the Ez value for each space is required. Should the values entered in this table be entered by each space (each having it's own Ez), or should the calculated system Ez value be used for each space?
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