More fresh air means healthier buildings. Building on IEQp1: Minimum Indoor Air Quality Performance, this credit calls for exceeding by 30% the minimum outside air requirements set by ASHRAE 62.1-2007. This credit applies only to 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. of the building unlike EQp1, which applies to all the rooms as per by ASHRAE 62.1. This increased ventilation helps reduce concentrations of carbon dioxide produced by occupants, and pollutants produced by off-gassing of construction materials and furnishings. By addressing these problems, increased ventilation can help mitigate occupant health problems.
Your mechanical system may already be designed to accommodate increased ventilation, but in other cases, this credit may represent a tradeoff in energy consumption (conditioning more air along with increased fan power to distribute it), and may reduce overall energy consumption as measured in EAc1: Optimize Energy Performance. Projects that use displacement ventilationA system in which air slightly cooler than the desired room temperature is introduced at floor level and is lifted up by warmer air to exhaust outlets at the ceiling, increasing air circulation and removal of pollutants. are often able to achieve the credit with minimal increase in energy use. Demand-controlled ventilation systems are also a good way to minimize the energy cost, and also work well with IEQc1: Outdoor Air Delivery Monitoring.
For projects relying on operable windows to provide fresh air, this credit is largely unattainable because you cannot usually guarantee a 30% increase in fresh air without mechanical means. However, projects using natural ventilation do have a compliance path and a reference standard they can use to attempt compliance. Increased ventilation in general as well as natural ventilation strategies are best implemented in mild, relatively dry climates where relatively little energy is needed to condition outside air.
Each space must be provided with a 30% increase in ventilation rate.
Based on the definition provided for occupiable spaces and 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) in ASHRAE 62.1 Section 3, electrical rooms, telecommunication/data rooms, elevator equipment rooms, storage rooms and similar spaces would not require the per square foot ventilation indicated in Table 6-1 to be delivered to the space since they are unoccupied the majority of the time.
Evaluate and select ventilation strategies—natural, mechanical, or mixed-mode—during the pre-design phase
Evaluate each space in the building separately in order to determine air requirements. 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 room require more fresh air than other spaces. Explore whether individual spaces should be ventilated mechanically, naturally or mixed-mode.
Consider the potential cost implications of natural ventilation. This may reduce or eliminate the need for fans and mechanical systems, but will require operable windows and a floor plan—probably a relatively open one—that is conducive to passive ventilation.
Analyze life-cycle cost tradeoffs between natural and mechanical ventilation systems.
Naturally ventilated buildings may find this credit relatively difficult to achieve. If considered early in design, it’s possible to achieve the credit, but may take a concerted effort to increase the amount of outdoor air intake using larger and more numerous operable windows, and more sophisticated designs such as wind chimneys.
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 demonstrate 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.
Consider the potential cost implications and benefits of supplying an additional 30% of outdoor air. This may bring additional costs in the form of increased energy demand for conditioning greater air volumes and upsizing HVAC systems and fans. It is intended to bring more fresh air to occupants, potentially increasing their comfort and productivity.
Demand-controlled ventilation can significantly reduce energy use while providing large amounts of fresh air to occupants.
Review the requirements of the Carbon Trust Good Practice Guide 237 (1998) and the flow diagram process shown in Figure 18 of the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual 10-2005, Natural Ventilation in Non-Domestic Buildings.
The Carbon Trust guide offers guidelines on window sizes, spacing and placement for non-residential buildings. These guidelines can be used as a great starting point to ensure sufficient fresh air is provided to the building with natural ventilation. Reference the guide early in design will help maximize benefits and ensure compliance.
Review the air-flow modeling methodology and requirements in Volume A of the CIBSE Guide and ASHRAE 62.1-2007, Section 6.2. This section of ASHRAE 62.1 offers the modeling protocol for simulating air movement within the building. It is not difficult to follow and may be familiar to modeling consultant.
Use Computational Fluid Dynamics (CFD) modeling to determine the proper sizes for windows and openings and ensure proper air movement through interior spaces. Some energy modeling programs also have CFD analysis capabilities.
Early air flow modeling will help the team create the most effective ventilation design. This data can inform the team on space planning and building envelope design, among other things.
There may be upfront modeling fees for CFD modeling. However, CFD can help design a better natural ventilation system that will deliver short-term payback and long-term savings.
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 ventilation rates for particular spaces.
Begin preliminary ventilation rate calculations during project programming to help set goals for ventilation quality goals in particular spaces.
An integrated design approach among the mechanical engineer, architects, owners and end users will facilitate more informed decisions that can impact the mechanical system design. For example, space planning decisions will impact the architectural programming as well as access to natural ventilation.
For mixed-mode and naturally ventilated spaces, it is up to the mechanical engineer to calculate the outdoor airflow rate and communicate with the architect on application of CIBSE guide for naturally ventilated spaces.
Increased ventilation rates come with long-term cost benefits. Well-ventilated spaces bring a premium in rents as well as the benefits of having healthy, productive occupants.
Create separate zones in buildings with mixed-mode ventilation systems—one for natural ventilation and one for mechanical ventilation—and follow the appropriate compliance path for each area.
If you choose to pursue IEQc5: Indoor Chemical and Pollutant Source Control, relatively high MERV 13 filtration is required. Pursuing both credits may require you to increase duct size and fan power, and may even affect your system selection.
Determine the ratio of floor area to operable wall or roof openings for naturally ventilated spaces to see what floor areas can be ventilated by operable windows.
If using air flow modeling (Option 2), select a natural ventilation modeler and for the project and consult with them.
Space planning, building envelope and orientation to breezes will impact the effectiveness of natural ventilation systems.
At the first integrated design meeting during schematic design, develop a detailed natural ventilation strategy that includes goals for windows, building orientation, space planning and other sources of natural ventilation. In larger buildings, consider using an atrium to use the “stack effect”—allowing air to enter the building through exterior windows, cycle through the building into the atrium space and out through the top of atrium, using the natural buoyancy of warm air. Fans can be added, if necessary, to assist with stack-effect exhaust.
Multifamily residential projects may find it difficult to meet the credit unless the units are supplied with fresh air. Typically multifamily projects are naturally ventilated, and they can meet the IEQp1 requirements with operable windows. However, the additional outside air required for IEQc2 compliance may be difficult to provide unless they also duct in extra outside air.
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.
The mechanical engineer continues 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.
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.
Use building automation systems (BAS) to control mechanical systems efficiently and maintain desired ventilation rates while minimizing unscheduled maintenance.
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 might want to separate a non-perimeter space even if it shares the same VAV controller.
The Ventilation Rate Procedure calculation includes occupancy counts based on space types.
Laboratory facilities generally require very high ventilation rates. Consider installing separate mechanical systems for lab spaces and other 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.
Continue running ventilation calculations and develop flow diagrams to inform the design process and confirm credit compliance.
Natural ventilation systems may require a more robust and intense integrated design process, consisting 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.
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 be equal to or greater than 4% of the total floor area that the design considers naturally ventilated. Multiple windows 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 final ventilation calculations to verify that the design exceeds ASHRAE 62.1-2007 by 30%.
For naturally ventilated spaces, confirm compliance with the requirements of the CIBSE Applications Manual 10-2005, Natural Ventilation in Non-Domestic Buildings.
Fill out the LEED credit form and upload all supporting documents to LEED Online
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.
Use this checklist prior to construction for mechanical systems and credit compliance:
Coordinate the installation of mechanical 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 over time.
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.
Excerpted from LEED 2009 for New Construction and Major Renovations
To provide additional outdoor air ventilation to improve 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.) for improved occupant comfort, well-being and productivity.
Increase 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) outdoor air ventilation rates to all 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. by at least 30% above the minimum rates required by ASHRAE Standard 62.1-2007 (with errata but without addenda1) as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance. Projects outside the U.S. may use a local equivalent to ASHRAE Standard 62.1-2007, if the same is used for IEQ Prerequisite 1: Minimum Indoor Air Quality Performance.
Projects outside the U.S. may earn this credit by increasing breathing zone outdoor air ventilation rates to all occupied spaces by at least 30% above the minimum rates 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, as determined by IEQ Prerequisite 1: Minimum Indoor Air Quality Performance,
Determine whether natural ventilation is an effective strategy for the project by following the flow diagram process in Figure 2.8 of the Chartered Institution of Building Services Engineers (CIBSE) Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings.
Show that the natural ventilation systems design meets the recommendations set forth in the CIBSE manuals appropriate to the project space.
Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent.
Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent.
Use a macroscopic, multizone, analytic model to predict that room-by-room airflows will effectively naturally ventilate, defined as providing the minimum ventilation rates required by ASHRAE Standard 62.1-2007 section 6 (with errata but without addenda), at least 90% of occupied spaces. Projects outside the U.S. may use Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251: 2007, or a local equivalent to section 6 of ASHRAE Standard 62.1-2007 to define the minimum ventilation rates.
For mechanically ventilated spaces: Use heat recovery, where appropriate, to minimize the additional energy consumption associated with higher ventilation rates.
For naturally ventilated spaces: Follow the 8 design steps described in the Carbon Trust Good Practice Guide 237:
This is a best-practice design guide to natural ventilation.
The ASHRAE User's Manual accompanies the 62.1 ASHRAE reference standard. The manual offers detailed plans and examples of the requirements spelled out in the reference standard. (With access to LEED Online, the 62MZ calculator and the 62.1 User
This site contains research data and considerations EPA uses to study sick building syndrome.
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.
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.
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.
Use this example ventilation rate table from 23 High Line as guidance when developing compliance documents for your project for credit compliance.
This example air riser diagram from 23 High Line shows the mechanical ventilation supply for the building. It is the ducted diagram showing how air will be supplied to building occupants. Use this as an example for how to document ventilation effectiveness compliance.
Use this example mechanical schedule created from 23 High Line for guidance when developing ventilation effectiveness compliance documents for your project.
The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 IEQ credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.
Version 4 forms (newest):
Version 3 forms:
These links are posted by LEEDuser with USGBC's permission. USGBC has certain usage restrictions for these forms; for more information, visit LEED Online and click "Sample Forms Download."
Documentation for this credit can be part of a Design Phase submittal.
Hi all, I have a project that seems only slightly different than many of the others I've seen posted here. However, it seems like a common enough issue that I can't imagine it's unique, and I'm hoping someone has come across it before.
The project is an apartment/condo building. Each residential unit has a small air cooled heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source., and provides the maximum amount of ventilation air that is possible, per manufacturer recommendations.
Unfortunately, the mechanical ventilation only covers about 1/2 of the air that would be required for mechanical ventilation alone (ASHRAE 62.1-2007).
The residential units also have operable windows, but the openable area is not quite enough to assume the space is fully served by natural ventilation, either.
So we must assume the ventilation is met through Concurrent Mixed Mode ventilation, per CIBSE AM10 and AM13.
This is not something I've really seen before, but I think I'm ok with the design concept up to this point... And I think the description meets the requirements of ASHRAE 62.1-2007, IMC 2009, and LEED IEQp1.
My real question comes from the insistence of others that this qualifies for IEQc2, because, I'm told, it has been done in the past.
First; as I read through AM10, it appears that our single sided, single vented residential units can only claim natural ventilation up to 2x the ceiling height from the exterior wall: the condos have 10 ft ceilings, so natural ventilation serves the area up to 20 ft inside of the exterior walls. It would need to be assumed that the remainder of the space (open plan kitchen and foyer over 20 ft from the exterior) is ventilated by the mechanical system... In practice, I understand the idea that most homes are provided with much less ventilation, and the heat pump will circulate the OA. However, I do not intuitively see how this could meet the "letter of the law" requirements for Increased Ventilation.
LEED does not require the Natural Ventilation (Case 2) EXCEED any minimum levels, only that the design meet the recommendations of CIBSE AM10 or AM13.
Best I can tell, CIBSE AM10 only appears to be more stringent than ASHRAE 62.1 in the distance from the exterior wall: ASHRAE states a flat 25 ft, CIBSE states 2x the ceiling height (20 ft).
Reviewing the required area of window opening, it appears ASHRAE simply states that the openable area of the window/door must be at least 4% of the floor area served.
The buoyancy calculations in CIBSE AM10 appear to only require about 1/3 of what was required by ASHRAE for the prerequisite...
CIBSE AM10 was a little vague about the required air flow rates that should be used in the buoyancy calcs, so I assumed the airflow required by ASHRAE for mechanical ventilation. These air flow numbers turned out to be very close to the amount of ventilation required to maintain CO2Carbon dioxide concentration levels per CIBSE section 4.5: Reservoir Effect.
Bottom line, ASHRAE appears to require 12 sf of openable window area for the prerequisite, and CIBSE appears to require 3.5 sf of openable window area for "Increased Ventilation"...?
I'm at a loss. Am I missing something?
I have this Project, which main activity is store and move packages.
The main building consists in a 404300 sf Warehouse, whith 36 exhaust fans that move 1.621.100 cfm, but none ouside air intake fan, outside air will get into the warehouse through the multiple oppenings to the outside. The place is neither conditioned or heated.
So, as I understand, it consists in a Mixed Ventilated system.
The thing is, how may I prove that the system complies with Case 2, Options 1 or 2?,
I found this document on the Canadian Green Building Council site. See link below.
It title is similar to the Carbon Trust's document, but I suspect it may not be the same thing. It looks like it was put out by the UK Department of Environment Transport Regions. (DETR). Can someone verify if this is or is not the Carbon Trust document? If not others will not be lead astray. Thanks.
The document is a brief of a Natural Ventilation Application Manual (AM) created by CIBSE (sort of equivalent to ASHRAE in the UK, but includes all building services). The Application Manual is very detailed and comes with an excel calculator
or directly from the CIBSE website
So this is not the Carbon Trust Practical Guide then? From what I have seen below it is no longer available?
I am working on a residential apartment. Elevator lobby/corridor, which is used by 2~3 dwelling units per floor, are unconditioned and naturally ventilated (one window).
1. ASHRAE defines occupied space as an enclose space intended for human activities, excluding those spaces intended primarilary for other purposes, such as storage rooms and equipment rooms, that are only occupied occasionally and for short periods of time. Since elevator lobby/corridor has some human activitity of waiting for an elevator, I guess it's not reasonable to treat the elevator lobby as storage/equipment rooms. What's your thought on this?
2. Does CIBSE offer guideline for ventilating an unconditioned corridor/lobby?
Jim, seems to me like these spaces are "occupied."
Hi, We have an overall 30% ventilation above ASHRAE, for each individual space. IEQp1 says we comply and that we do meet the 30% over the minimum requirement; however in the Credit form for IEQc2, it doesn't acknowledge this and won't award us the credit. Has anyone come accross this before - is it a glitch in the system, or is there something we've missed?
Could definitely be a glitch in the system. Hit the feedback button and fill out a complain. If you need to submit your credits before they get back to you, you can submit by selecting "Alternative Compliance" and filling out the narrative explaining that the form is acting irregular.
I have had the same problem with this Template on various projects (three that I can recall). It is a glitch recognized by the GBCI whom we reported it to on a particular project.
I have a office project with 250 car parking facility, underground and mechanically ventilated. We are going for increased ventilation credit in all spaces. However, based on USGBC's IEQ space matrix and occupied space definition we have excluded car parking from this credit. The parking facility is also CO-constrolled and in action probably would not need that full ventilation more the a few hours in a week.
Ofter design application the reviever has, however, taken the side that car parking should be included and is demanding the 30 % increase in ventilation rates.
Could you share your opinions, should car parking be included in this IEQ 2 credit ?
Car parking lots are not regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building.. Are you increasing the ventilation of your electrical rooms? Storage rooms? LEEDUser defines regularly occupied spaces as a space where occupants spend an hour or more per day working, studying, etc.
Perhaps the reviewer is not clear about the usage of that space.
We have a four story office building with natural ventilation. All the rooms are single-sided. We want to show that the window area is big enough to exceed the ASHRAE requirements by 30%.
1. What case applies, the buoyancy or the wind driven one?
2. Where can I get the C and wind speed values from? Even if I had the weather data the wind speed will be different depending on the height and orientation of the room.
3. What kind of documentation is required in order to submit the credit?
Thanks for your help!
Shiva, buoyancy driven requirements would apply. Demonstrating compliance for natural ventialtion with this credit is challenging, particularly if you only have a single-sided configuration. You'd need to use a simulation tool that can calculate hourly airflows.
We have a building that is provided with a mechanical means of ventilation. However, provisions are provided to naturally ventilate during times of the year when feasible and desirable to help enable the building to achieve net-zero energy.
For mixed-mode systems, do we have to document compliance with Case 1. Mechanically ventilated buildings AND Case 2. Naturally ventilated buildings?
As noted in the strategies section in the reference guide, projects employing both mechanical and natural ventilation (mixed mode) must exceed the minimum ventilation rates required by ASHRAE 62.1-2007, Chapter 6, by at least 30%.
The IEQc2 LEED Online form version 4 will ask for indication that your project is both mechanically and naturally ventilated, in part. Once you do this, the form will show compliance with IEQc2 under Mechanical Ventilation (linked to the IEQp1), and then you'll select an option under Natural Ventilation. Please correct me if I'm wrong, but a mixed-mode system should automatically comply with IEQc2 Case 2 Option 2 - Minimum Ventilation Rates from ASHRAE Standard 62.1-2007 without having to create the analytic model.
Repair bayA bay is a component of a standard, rectilinear building design. It is the open area defined by a building element such as columns or a window. Typically, there are multiple identical bays in succession. do not have Ventilation requirement but they do have exhaust requirement. Per the increased ventilation credit would we have to exhaust 30% more outside air?
Based on the language of this credit, the emphasis is on supply side breathing-zone ventilation, rather than exhaust. Has anyone else on this forum had to provide 30% more exhaust to meet this credit?
The credit language does not mention exhaust. The increase in ventilation applied to only regularly occupied spacesRegularly occupied spaces are areas where one or more individuals normally spend time (more than one hour per person per day on average) seated or standing as they work, study, or perform other focused activities inside a building..That being said if the repair bayA bay is a component of a standard, rectilinear building design. It is the open area defined by a building element such as columns or a window. Typically, there are multiple identical bays in succession. is regularly occupied you may consider providing ventilation.
I have achieved this credits many times without providing information about the buildings exhaust systems.
We have an overall 30% ventilation above ASHRAE, but it is different in each spaces. Some spaces have 10% more and other have over 40% more. For credit compliance do we need 30% on the total ventilation, or do we need to have 30% for each individual zone?
Every space needs 30% over
FYI - This has been updated with the latest forms. Now you are able to enter just the total OSA for a system. This allows you to share OSA throughout the zones associated with each system.
However, you still need to be aware of your zone Zp (ratio of OSA to Minimum Supply Air in a zone) as it can significantly raise your OSA requirements for a system.
The USGBC has published a draft for additional guidance for international projects. That includes alternative compliance paths and even additional LEED online forms for international projects. This credit is included in the guideline. Find more here: http://www.leeduser.com/topic/international-projects-alternative-complia...
We are using 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. in some zones of the office building project we are building. When calculating the %-increase in ventilation for the IEQ c2, I wonder what VAV airvalue to use?
The VAV air handlers have 3 values of air, Max - Nominal - Basic. 62.1 in 18.104.22.168 gives directions for use of Basic air volume when calculating Primary Outdoor Air Fraction. My guess would be the Nominal air flow value should be used, this due to the increase in the air supply to theoffice when the KNX detector register an entrance.
One of the most confusing part of this credit is Primary Outdoor Air Fraction (Zp). And I believe LEED just updated their forms as well.
Zp refers to the ratio of the OSA requirement for a space divided by the minimum CFM supply setting (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. min box cfm) for that space – the understanding being that as supply air becomes more concentrated with OSA, that OSA is less effective and doesn’t get used by the people prior to being returned to the air handler.
The Ev (efficiency) calculation, is related to the Max Zp value of all the rooms served by a common air handler.
We have a canteen area in one of our projects that is to be naturally ventilated through open windows and ceiling fans. How can you calculate and show compliance with recommendations set forth in the CISBE application manual?
Udana, the CIBSE manual has a diagram process that I think should be clear to follow, if you have a copy. There are also some tips on meeting the credit requirements in the Checklists tab above.
You can also find the CIBSE excel spreadsheet Design Tool here
I know there is not an exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. for this credit per say, but I am working on a project where we will using 100% outside air...do you think we could attmept an ID point since we are going above and beyond the requirments? Anyone try such a thing before? THANKS!
Nena - it's my understanding that this credit has more to do with volume of delivered air, so 100% outside air still does not guarantee satisfaction of credit requirements. But if you find out otherwise, please let us know!
Erica is right, it is a matter of volume. You may be able to claim an exemplary performanceIn LEED, certain credits have established thresholds beyond basic credit achievement. Meeting these thresholds can earn additional points through Innovation in Design (ID) or Innovation in Operations (IO) points. As a general rule of thumb, ID credits for exemplary performance are awarded for doubling the credit requirements and/or achieving the next incremental percentage threshold. However, this rule varies on a case by case basis, so check the credit requirements. by supplying 60% more outside air then ASHRAE minimum. That would be double what the credit asks for.
We have a single space in our building (entrance lobby) that is being naturally ventilated through the revolving doors at the main building entrance. How can you calculate the room-by-room airflow in this case for compliance with Option 2 of this credit?
Or is there any prescription in CIBSE AM10 for such a case that we may use to show compliance with Option 1 of this credit?
Omer, could you provide more details on the lobby and the location of the project? I haven't seen a project try to comply with ASHRAE 62 using revolving doors in the past.
If we incorporate increased ventilation capacity into our hvac system, do we have to assume the increased ventilation rate for our design building in our energy modeling?
Yes, you do. This is the "energy tradeoff" discussed above under the "Bird's Eye View" tab.
Can I use the garage doors in a Fire Department Apparatus BayA bay is a component of a standard, rectilinear building design. It is the open area defined by a building element such as columns or a window. Typically, there are multiple identical bays in succession. as a window to calculate my ventilation for ASHRAE 62.1.? We have have exhaust louvers at the rear of the building.
Michael, I don't see an issue with using the garage doors as the operable area. ASHRAE 62.1-2007 (Section 5.1.1) solely refers to operable wall or roof openings, rather than windows only.
We intend to incorporate demand control ventilation in our project. AHSRAE 62.1 limit on CO2Carbon dioxide concentration is 700 ppmParts per million.. If we have to meet the 30% increase in ventilation air for subject credit, what should be the maximum CO2 concentration in the conditioned space? Our outdoor CO2 concentration is 400 ppm.
700 ppmParts per million. is still an appropriate target for demand controlled ventilation, regardless of the design ventilation rate. With a properly functioning system, the amount of ventilation air supplied to spaces with CO2Carbon dioxide sensors will end up matching occupant loading and will be decoupled from the peak design value (e.g. 20 cfm/person). Increased ventilation will have more of an impact on spaces that don’t have CO2 sensors and likely result in CO2 levels less than 700 ppm.
This is a question for ASHRAE 62.1 2007, and more specifically, we find the ASHRAE 62.1 2007 User’s Manual to be super helpful in navigating this credit. The credit addresses the system capacity to supply that 30% extra outside air. It doesn't stipulate CO2Carbon dioxide levels that trigger the call for more outdoor air -- that will depend on the ambient conditions and activity levels of your project. Roger is correct that CO2 sensors support demand control ventilation for some spaces while this credit intent is to include all spaces.
Check out the User's Manual (Appendix A) for CO2 set point and see if it's helpful.
The Carbon Trust Good Practice Guide 237 — Natural Ventilation in Non-Domestic Buildings — a Guide for Designers, Developers and Owners
I can't find it. Not in the links given or using google.
It no longer exists - it was put back into LEED 2009 accidentally. You want to look at the errata, which references CIBSE AM-10 "Natural Ventilation in Non-Domestic Buildings"
The LEED Reference Guidelines mentions "all 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." for this credit. Does this mean "regularly occupied" as in other credits like Daylighting? If you look at Standard 62.1, Table 6.1 includes spaces like UPS room or storage room, which would not be occupied (and which usually are not supplied with outdoor air via dedicated system). Does LEED expect us to show calculations for such spaces as well? Or for example we have an atrium in our building which is conditioned but which will only be used by people walking from one area to other. Does LEED expect this area to be included as well?
Omer, I agree that the definitions of occupied space gets confusing between different LEED credits. I would approach this issue by adhering to the definition of "occupied space" as defined by ASHRAE 62.1. In the old days of CIRs, the USGBC gave the same advice around this definition and ventilation rates. ASHRAE defines occupiable space as "an enclosed space intended for human activities, excluding those spaces intended primarily for other purposes, such as storage rooms and equipment rooms, that are only occupied occasionally and for short periods of time". The USP room in the project you described could be exempt if it is only a storage area. If people work in this area or if it is similar to a mail room, you would need to meet the ventilation rates. The atrium you described would also need to meet the ventilation rates prescribed in ASHRAE as the primary purpose is a hallway for human transit.
Omer, Just to add to the previous comment, this credit seems to use language that singles out "occupied" spaces. However, we still need to comply with the prerequisite, IEQp1, which basically says to follow ASHRAE 62.1. The interesting thing to note is that the 6.1 ASHRAE table for Minimum Ventilation Rates includes all spaces, even storage and electrical equipment room. While they acknowledge that the Rp People Outdoor Air Rate is zero, they still have an Area Outdoor Air Rate that is very small. So, you still need to make sure you are supplying outdoor air to these spaces in some form to meet EQp1.
Seema, thanks for your valuable inputs into the subject. Does it mean that we still need to feed fresh air into electrical rooms, storage rooms, machine rooms etc.?
I recently came across a document in ASHRAE website stating that these areas need not mandatorily comply with Table 6-1 requirements.
I am working on a building that is actually registered under v2.2 and using ASHRAE 62.1-2004 or local code for this credit which Mass State Building Code 7th ed. According to the engineers, the local code in Massachusetts exceeds 30% increase over ASHRAE 62.1-2004. Has USGBC/GBCI made any exceptions to this credit? It would not be feasible for use to design for 30% above the local code but we would qualify if it were 30% over ASHRAE.
Paul, It's a bit buried, but the Reference Guide does call for 30% above ASHRAE or local code, "whichever is more stringent." Since this credit is out of reach for you if you try to go 30% over local code, and since you're meeting the credit's intent as well as the fundamental requirements as stated in the credit language, I'd suggest you simply submit the credit as 30% over ASHRAE and see how it goes. I wouldn't submit the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide unless you have to after the GBCI/ USGBC review your submittal.
Thank you Seema. I think that is the approach that we are going to take at this time.
In reality the Mass code is going to be the threshold here whether it is attainable or not unless you can get access to a public ruling. THe credit is clear as "whiehevre is more stringent" and I would be shocked if this were not strictly applied. Sorry for the bad news.
Can someone tell me where the BD&C Reference Guide says ASHRAE 62 or local code "whichever is more stringent" for IEQc2? I know this is the case for IEQp1, but I just learned from GBCI that the intent with NC v2.2 is to require 30% above ASHRAE for EQc2, not local code. I just reviewed the Reference Guide and did not see the local code reference in IEQc2, leaving me to believe that this is the same for 2009. Which would be good new for Paul.
Thanks. We are actually applying under the v2.2 system but I don't think that this site covered it when I originally posted the question. We're planning to submit this credit under v2.2 with 30% above ASHRAE. I haven't looked close enough at 2009 Reference Guide to see if the language has changed. v2.2 was just misleading enough to throw off the design team on the intent.
I am asking the same question under NC-2009 and ASHRAE 62.1-2007. In NYS the local code (IMC-2006) is more stringent and we meet th local code for IEQp1. The prerequisite DOES have the wording to meet ASHRAE or the local code whichever is more stringent. However, IEQc2 does NOT have the "or the local code whichever is more stringent" wording. So am I right, is it possible to meet the local code for IEQp1 and use the same values for IEQc2 which exceed 30% over ASHRAE?
NYS MC (IMC 2006) also has an exception paragraph to 403.2 indicating "an registered professional demonstrates that an engineered ventilation system design will prevent the maximum concentration of contaminants from exceeding that obtainable by the rate of ventilation required by....."
this paragraph is generally interpreted by the state as allowing the use of ASHRAE 62.1 being equivalent to the state code when applied by a registered design professional. so it almost sounds like double talk - we can use the state code higher ventialtion, but say we are using ashrae for the credits since technically ashrae is allowed by exception for the state code. does this sound feasible?
Paul, regardless of the logic from your post about NYS, I think you understand the credit properly according to your first post, and should be all set.
Principal, Director of Sustainability
Westlake Reed Leskosky
Commissioning will verify that systems are operating efficiently and delivering required air volumes.
Mechanical system designs for effective ventilation will need to comply with requirements to stop
tobacco smoke exposure.
Supplying more fresh air reduces the buildup of carbon dioxide. A monitoring system can make
ventilation systems more effective and energy-efficient, when used with demand-control ventilation.
Increasing ventilation rates can increase energy demand. Use natural ventilation or effective ventilation design to offset this issue.
MERV 13 filtration required by this credit must be accounted for in fan power requirements, duct sizing, and equipment size and type, all of which must also be considered for increased ventilation.
If operable windows are part of a project’s natural ventilation design, they can count towards IEQc6.2.
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