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More fresh air means healthier buildings
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.
There may be an energy tradeoff
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.
Tough to do with natural ventilation
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.
FAQs for IEQc2
Does each individual zone need a 30% increase in ventilation, or can a weighted average be used for the building?
Each space must be provided with a 30% increase in ventilation rate.
Do spaces which are not regularly occupied require increased ventilation?
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.
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USGBC
Excerpted from LEED 2009 for New Construction and Major Renovations
IEQ Credit 2: Increased ventilation
1 Point
Intent
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.
Requirements
Case 1. Mechanically vented spaces
Option 1. ASHRAE standard 62.1-2007 or non-U.S. equivalent
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.
OR
Option 2. CEN Standard EN 15251: 2007
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,
Case 2. Naturally vented spaces
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.
AND
Option 1. CIBSE or non-U.S. equivalent
Show that the natural ventilation systems design meets the recommendations set forth in the CIBSE manuals appropriate to the project space.
Path 1
Use CIBSE Applications Manual 10: 2005, Natural Ventilation in Non-domestic Buildings. Projects outside the U.S. may use a local equivalent.
Path 2
Use CIBSE AM 13:2000, Mixed Mode Ventilation. Projects outside the U.S. may use a local equivalent.
OR
Option 2. Airflow Model
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.
Potential Technologies & Strategies
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:
- Develop design requirements.
- Plan airflow paths.
Technical Guides
Chartered Institution of Building Services Engineers (CIBSE) Applications Manual 10: 2005, Natural Ventilation in Non-Domestic Buildings
This is a best-practice design guide to natural ventilation.
ASHRAE 62.1 User's Manual
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
Building Assessment, Survey, and Evaluation Study (U.S. EPA)
This site contains research data and considerations EPA uses to study sick building syndrome.
IEQ Space Matrix
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.
Organizations
CIBSE Applications Manual 10-2005
Located in London, this organization publishes a series of guides on ventilation, including natural ventilation.
American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE)
ASHRAE publishes widely used standards and publishes the ASHRAE Journal.
Labs for the 21st Century (Labs 21)
Labs21 is a voluntary partnership program dedicated to improving the environmental performance of U.S. laboratories.
Software Tools
62MZ Calculator: Ventilation Rate Procedure
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.
CONTAM 3.0 Multizone Modeling Software
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.
Loop DA Multizone Modeling Software
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 62.1 iPhone App
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.
Publications
Greening the Building and the Bottom Line
This Rocky Mountain Institute publication is a case study of the connection between worker productivity and indoor air quality.
Ventilation Rate Table
Use this example ventilation rate table from 23 High Line as guidance when developing compliance documents for your project for credit compliance.
Air Riser Diagram
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.
Mechanical Systems Schedule
Use this example mechanical schedule created from 23 High Line for guidance when developing ventilation effectiveness compliance documents for your project.
LEED Online Forms: NC-2009 IEQ
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):
- IEQp1: Minimum IAQ Performance
- IEQp2: ETS Control
- IEQc1: Outdoor Air Delivery Monitoring
- IEQc2: Increased Ventilation
- IEQc5: Indoor Chem. & Pollutant Source Control
- IEQc6.1: Control. of Systems—Lighting
- IEQc6.2: Control. of Systems—Thermal Comfort
- IEQc7.1: Thermal Comfort—Design
- IEQc8.1: Daylight & Views—Daylight
- IEQc8.2: Daylight & Views—Views
Version 3 forms:
- IEQp1: Minimum IAQ Performance
- IEQp2: ETS Control
- IEQc1: Outdoor Air Delivery Monitoring
- IEQc2: Increased Ventilation
- IEQc3.1: Const. IAQ Mngt.—During Const.
- IEQc3.2: Const. IAQ Mngt.—Before Occupancy
- IEQc4.1: Low-Emitting Mats.—Paints & Coatings
- IEQc4.2: Low-Emitting Mats.—Adhesives & Sealants
- IEQc4.3: Low-Emitting Mats.—Flooring
- IEQc4.4: Low-Emitting Mats.—Composite Wood
- IEQc5: Indoor Chem.l & Pollutant Source Control
- IEQc6.1: Control. of Systems—Lighting
- IEQc6.2: Control. of Systems—Thermal Comfort
- IEQc7.1: Thermal Comfort—Design
- IEQc7.2: Thermal Comfort—Verification
- IEQc8.1: Daylight & Views—Daylight
- IEQc8.2: Daylight & Views—Views
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."
Design Submittal
Documentation for this credit can be part of a Design Phase submittal.
LEEDuser is produced by BuildingGreen, Inc., with YR&G authoring most of the original content. LEEDuser enjoys ongoing collaboration with USGBC.
55 Comments
Mixed Mode Natural & Mechanical Ventilation...?
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?
Mixed Ventilation
Hello Everybody,
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?,
Thank you
Carbon Trust Good Practice Guide 237?
I found this document on the Canadian Green Building Council site. See link below.
http://www.cagbc.org/AM/PDF/GoodPracticeGuide237.pdf
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
http://www.google.com/url?sa=t&rct=j&q=cibse+am10+excel&source=web&cd=1&...
or directly from the CIBSE website
http://www.cibse.org/index.cfm?go=page.view&item=507
So this is not the Carbon Trust Practical Guide then? From what I have seen below it is no longer available?
is an elevator lobby/corridor considered as a occupied spaces
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?
Thank you
Jim, seems to me like these spaces are "occupied."
IEQc2 - Why haven't we been awarded the credit?
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?
Thanks
Mairead,
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.
Car parking and increased ventilation
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.
Natural Ventilation
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.
Mixed-mode ventilation systems
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?
Hi Cindy,
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 Bays
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.
30% for all spaces individually or for the total ?
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.
Alternative Compliance path for international projects
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...
Increase in Ventilation - Precentage
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 6.2.5.1 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.
Compliance through natural ventilation
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
www.cibse.org/docs/AM10CalcToolv5.xls
ID credit for 100% outside air
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.
Outdoor Air through Revolving Doors
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?
Thanks.
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.
Increased ventilation and energy modeling
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.
Ventilation in a Fire Station Apparatus bay
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.
IEQc2: Increased Ventilation
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.
Hi Conrado
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.
Good luck
The Carbon Trust Good Practice Guide 237 — Natural Ventilation
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"
http://www.cibse.org/index.cfm?go=publications.view&item=297
Which Spaces Should Be Included?
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?
Thank you.
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.
www.ashrae.org/File%20Library/.../20100203_ic_621200716.pdf
ashrae.org/File%20Library/docLib/.../20100203_ic_621200717.pdf
7th ed. Massachusetts Building Code and ASHRAE 62.1-2004
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.
Thanks
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.
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