This prerequisite establishes a baseline for providing a minimum amount of outdoor air to buildings in order to maintain good indoor air quality and keep occupants comfortable and healthy. This prerequisite references ASHRAE 62.1-2007 (with errata but without addenda) and is often more stringent than local building codes, although it is not likely to entail any added costs.
The compliance paths for mechanically ventilated and naturally ventilated spaces, Case 1 and Case 2, are somewhat different and you may need to follow both paths for the same building. 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.
New construction additions 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.
The 2007 edition of ASHRAE 62.1 combines 62.1-2004 and the eight approved and published addenda to the 2004 edition. The new edition does the following:
If the building relies on the fans for daily ventilation, it is considered a mechanically ventilated building.
Testing in naturally ventilated spaces is not required per 62.1-2007 Sections 4-7 if the outdoor air quality adequately meets 62.1-2007, Table 4-1.
Both operable windows and vents can be used, but only the operable area within those elements can be counted towards the minimum percentage (4%) of net occupiable area.
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.
For mixed-mode and naturally ventilated spaces, the mechanical engineer should calculate the outdoor airflow rate and communicate the area requirements for operable wall or roof openings to the architect.
The mechanical engineer begins preliminary ventilation rate calculations during project programming in order to set ventilation quality goals for particular spaces and occupancies. The area of a given multi‐zone system should be broken down by ventilation zones, and all zones within that system must meet the minimum breathing zone ventilation air requirements as per ASHRAE 62.1‐2004. For a typical office space, the mechanical design consists of multiple ventilation zones for which compliance would need to be shown on an individual basis.
For mixed-mode ventilation, zone the plan into areas—mechanically ventilated and naturally ventilated—and follow separate compliance calculations for each area.
Determine the applicable floor area for operable wall or roof openings according to ASHRAE 62.1-2007 section 5.1.
Consider using Computational Fluid Dynamics (CFD) modeling to determine proper opening sizes and ensure proper airflow. Some energy modeling programs also have CFD analysis capabilities.
Expect upfront modeling fees for Computational Fluid Dynamics (CFD), but also consider the benefits of CFD modeling: a better-designed natural ventilation system that can bring short-term payback from reduced mechanical systems, and long-term operational savings.
At the first integrated design meeting during schematic design, develop a detailed natural ventilation strategy involving goals for windows, building orientation, space planning, use of atriums, and other access to natural ventilation. Natural ventilation systems may require a more robust and intense integrated design process, of several focused workshops analyzing several alternatives. Computer modeling may be necessary to test various design alternatives to determine which is most effective and efficient.
Hotel and multifamily projects may have difficulty achieving this prerequisite if they are naturally ventilated and have interior spaces that are further than 25 feet from an operable wall or roof opening. These projects might consider increased window areas, shallower floor plates, or using mixed-mode ventilation so that mechanically supplied outdoor air can support areas outside the 25-foot natural ventilation boundary.
The mechanical engineer continues to run ventilation rate calculations during the mechanical design process to inform design development and confirm compliance with this prerequisite. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2007. See the attached 62MZ calculator.
Continuing to use an integrated design approach among the mechanical engineer, architects, owners and end users will facilitate design decisions that impact the mechanical design. For example, space planning decisions will impact the architectural programming of the space as well as access to natural ventilation.
Strategically locate air intakes for mechanical or natural ventilation systems to avoid taking in contaminants and odors like vehicle exhaust from parking lots or fumes from garbage storage areas.
Incorporating operable windows into the design for natural and mixed-mode ventilation can help with an additional LEED point for EAc6.1: Controllability of Systems—Thermal Comfort.
Continue running ventilation rate calculations during the mechanical design process to confirm compliance with this credit and to inform the design. The ventilation rate procedure is explained in section 6 of ASHRAE 62.1-2007. See the 62MZ calculator.
Implement energy recovery systems, economizers, low-pressure-drop design, and efficient fans as appropriate to support ventilation rates meeting or exceeding the referenced ASHRAE standard without compromising energy performance.
Avoid oversizing mechanical equipment. Oversized equipment will often increase operating costs and reduce operational efficiency. The correct equipment size will depend on a number of factors, including local climate, total building area, insulation levels, air filtration medium, number of windows and doors, and occupant comfort preferences.
Spaces served by the same VAV (variable air volume) controller can be grouped together in the 62MZ calculator, but grouped spaces should have similar exterior exposure. For example, you can group two perimeter spaces that share a VAV controller, but would want to separate a non-perimeter space even if it shares the same VAV controller.
Laboratory facilities generally require very high ventilation rates. Consider installing separate mechanical systems for lab spaces to maximize return-air mixing. Other strategies may include using a heat exchanger to capture energy from laboratory exhaust, using low-flow or variable-flow fume hoods, minimizing ventilation rates during unoccupied times, or using a dedicated outdoor air system.
Integrating building automation systems can control mechanical systems efficiently and maintain desired ventilation rates while minimizing unscheduled maintenance.
The Ventilation Rate Procedure calculation includes occupancy counts based on space types.
Continue to run calculations and develop flow diagrams to inform the design process and confirm compliance. If you are using a natural ventilation modeler for the project, use the model as a tool to inform design development.
The calculation for operable openings will only apply to the floor area adjacent to the window—25 feet to either side and in front of the opening.
The surface area of window openings must, for compliance with ASHRAE 62.1, be equal to or greater than 4% of the occupied floor area that the design considers naturally ventilated. Multiple windows in aggregate can provide the operable area needed to meet the requirements.
In naturally ventilated multifamily buildings, air infiltration from a pressurized hallway or corridor can contribute to the Ventilation Rate Procedure calculation for areas that do not meet the requirements of ASHRAE 62.1, as long as the corridor is pressurized with outdoor air.
For mechanically ventilated spaces, run ventilation calculations to verify that the final design meets the minimum outside air rates equal to or exceeding the ASHRAE 62.1-2007 minimum.
For naturally ventilated spaces, confirm compliance with the requirements of ASHRAE 62.1-2007 section 5.1.
If natural ventilation strategies are integrated into the design, ensure that key elements of the natural ventilation system, such as operable windows, window actuators, controls, operable atrium elements, and solar chimneys, are not compromised during value engineering. Educate decision-makers about the natural ventilation design and the importance of maintaining all the key components. If these elements are altered in a way that compromises natural ventilation rates, the mechanical system may no longer be sized appropriately.
Fill out the LEED credit form and upload all supporting documents to LEED Online.
Use this checklist for naturally ventilated spaces prior to construction to review plans for prerequisite compliance:
Use this checklist for mechanical systems prior to construction to check prerequisite compliance:
Coordinate the installation of ventilation systems with the project’s commissioning process.
Use commissioning to confirm that installed systems are providing the outside air rates specified in the design.
Monitor outdoor air delivery periodically to confirm that minimum ventilation rates are being maintained. Implement a maintenance program to ensure that mechanical system components are functioning properly.
Test all dedicated building exhaust systems including chemical areas, bathroom, shower, kitchen, and parking exhaust systems to confirm proper fan speed, voltage, control sequences, and set points as applicable. Provide operations and maintenance personnel with manuals and educate them about any atypical maintenance requirements.
Getting feedback on ventilation performance from occupants through surveys can help to identify potential problems that may become expensive if they go unnoticed.
A documented ventilation performance plan can help ensure that systems reach the expected ventilation thresholds.
In projects with operable windows, occupants may not know when conditions are best for opening the windows. Implement a system so that occupants are informed of when to open and close the windows to achieve designed performance and optimal comfort.
Maintain a building operating plan (BOP) that establishes operating schedules and set points and regularly review these parameters against actual building needs. When developing these parameters, consider both time-of-day and time-of-year variations in optimal temperature requirements and be careful to avoid over-conditioning the building spaces with more ventilation, heating or cooling than is necessary.
Adjust reset and setback temperature settings and calibrate controls and sensors. A Building Automation System (BAS) will allow building managers to adjust, monitor and control temperature set points and air volumes throughout the building from a central location. Direct digital controls (DDC) utilized by the BAS will function more efficiently than older pneumatic controls and help to avoid unnecessary use of HVAC equipment during non-business hours and holidays.
Develop and implement a comprehensive Indoor Air Quality Management Plan using the EPA’s “Indoor Air Quality Building Education and Assessment Model” (I-BEAM).
Following the initial audit, the IAQ manager must make periodic inspections to uncover new IAQ issues and monitor the status of previous issues. The I-BEAM tool supplies inspection forms that can be tailored to the project building to facilitate this process.
Establish protocols to manage all significant pollutant sources referenced in I-BEAM that are applicable to the project building.
Ensure that procedures are in place for receiving and responding to IAQ complaints from building occupants. The I-BEAM tool provides sample forms and logs for fielding and recording occupant complaints as well as information about key principles for developing effective communication with building occupants regarding IAQ issues. Strategies for investigating and resolving the issues that trigger occupant complaints are covered by a variety of I-BEAM guidelines.
Excerpted from LEED 2009 for New Construction and Major Renovations
To establish minimum indoor air quality (IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors.) performance to enhance indoor air quality in buildings, thus contributing to the comfort and well-being of the occupants.
CASE 1. Mechanically Ventilated Spaces
Mechanical ventilation systems must be designed using the ventilation rate procedure as defined by ASHRAE 62.1-2007, or the applicable local code, whichever is more stringent.
Meet the minimum requirements of Sections 4 through 7 of ASHRAE Standard 62.1-2007, Ventilation for Acceptable Indoor Air Quality (with errata but without addenda). Projects outside the U.S. may use a local equivalent to Sections 4 through 7 of ASHRAE Standard 62.1-2007.
Projects outside the U.S. may earn this prerequisite by meeting the minimum requirements of Annex B of Comité Européen de Normalisation (CEN) Standard EN 15251: 2007, Indoor environmental input parameters for design and assessment of energy performance of buildings addressing indoor air quality, thermal environment, lighting and acoustics; and the requirements of CEN Standard EN 13779: 2007, Ventilation for nonresidential buildings, Performance requirements for ventilation and room conditioning systems, excluding Section 7.3 – Thermal environment, 7.6 – Acoustic Environment, A.16, and A.17.
CASE 2. Naturally Ventilated Spaces
Naturally ventilated buildings must comply with ASHRAE Standard 62.1-2007, Paragraph 5.1 (with errata but without addenda). Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
Design ventilation systems to meet or exceed the minimum outdoor air ventilation rates as described in the ASHRAE standard. Balance the impacts of ventilation rates on energy use and indoor air quality to optimize for energy efficiency and occupant comfort. Use the ASHRAE Standard 62.1-2007 Users Manual (with errata but without addenda1) for detailed guidance on meeting the referenced requirements.
1 Project teams wishing to use ASHRAE approved addenda for the purposes of this prerequisite may do so at their discretion. Addenda must be applied consistently across all LEED credits.
This updated version of the spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. Up to date, 2nd Edition.
ASHRAE 62.1-2007 should be referenced when designing outdoor airflow monitoring devices.
This spreadsheet categories dozens of specific space types according to how they should be applied under various IEQ credits. This document is essential if you have questions about how various unique space types should be treated. This is the 1st edition.
This Rocky Mountain Institute publication is a case study of the connection between worker productivity and indoor air quality.
This manual provides information on the technology and techniques for the design, operation, servicing, and balancing of environmental systems.
ASHRAE publishes widely used standards and publishes the ASHRAE Journal.
Labs21 is a voluntary partnership program dedicated to improving the environmental performance of U.S. laboratories.
IAQA is a nonprofit organization dedicated to promoting the exchange of indoor environmental information through education and research.
MSCA is a national trade association that provides educational resources and training programs on sustainable service and maintenance practices for HVACR contractors.
Located in London, this organization publishes a series of guides on ventilation, including natural ventilation.
This website contains reports from an extensive EPA modeling study that assessed the compatibilities and trade-offs between energy, indoor air quality, and thermal comfort objectives for HVAC systems and formulated strategies to achieve superior performance.
This is a Microsoft Excel calculator that accompanies the ASHRAE 62.1 reference standard. The calculator allows users to plug in variables for specific project types and run the Ventilation Rate Procedure.
Public domain software from NIST (National Institute of Standards and Technology) that has natural ventilation sizing tools, and flow models to analytically predict room-by-room airflows.
Public domain software from NIST (National Institute of Standards and
Technology) that has natural ventilation sizing tools, and flow models
to analytically predict room-by-room airflows.
ASHRAE released an app for iPhone, iPod touch, and iPad that allows you to perform comprehensive minimum ventilation calculations for a wide variety of commercial buildings based upon Standard 62.1, using either I-P or SI units. This app is based upon the 62MZCalc.xls. Now, you can make calculations at a meeting and know if your project meets IEQp1 or IEQc2.
This example ventilation rate table from 23 High Line provides guidance when developing prerequisite compliance documents for your project.
This example air riser diagram from 23 High Line shows the mechanical ventilation supply for the building. It is the ducted diagram showing how air will be supplied to building occupants. Use this as an example for how to document ventilation effectiveness compliance.
Use this example mechanical schedule created from 23 High Line for guidance when developing ventilation effectiveness compliance documents for your project.
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.
Can anyone please clarify which, if any, ventilation requirements are applicable to shower spaces whithin a sports facility (e.g. exhaust rate per shower) under ASHRAE 90.1 (2007)?
There is no requirement in 90.1. If you are concerned about energy use then you may want to ask the same question on the EA forums. As for this prerequisite, 62.1 does not specifically list showers but I always count them as the same as toilets. Also, if your project is in the United States then it is most likely required by your local building code (mechanical) under Chapter 4.
I'm working with a building that has 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. that supplies OA to a single room based on the numbers of people on that space. Is it acceptable to submit a regular excel spreadsheet with the Voz calculation instead of using the 62MZ spreadsheet?
Thanks in advance,
Is it a single zone 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. air handler or is your project scope only one VAV on a multizone variable system? If it's only a single zone VAV 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. then you should just use the template for ease. If it is a full system then you will probably have to model the whole system to show that your zone is getting the correct OA flow under all conditions.
I am sure that's not the answer you are looking for but it's the most correct answer in my opinion.
It is a very small building, we have a single office space per floor, with a single 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. per floor, each VAV supplies air to it's floor office only.
What do you mean by "use the template"? Are you referring to the 62MZ spreadsheet?
Noriko, your description sounds like it is a multi-zone 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. You did not actually describe the air handling unit type so that is what I am inferring. If this is the case then simply use the 62MZ spreadsheet. If it is one zone per air handling unit then use the template. By template, I mean the credit form on leedonline.com.
Thank you Andrew,
Your advice is very helpful.
To date I have never received a comment from a reviewer regarding required exhaust per Table 6-4. The reviews always focus on the supply side - Tables 6-1 and 6-2 and the ventilation rate procedure calculation. The prerequisite language states that the requirements of Sections 4-7 of the Standard are to be met. However it does not appear any emphasis is placed on exhaust requirements. Not meaning to open Pandora's box, but can anyone explain this?
In my case, the reviewer always ask for exhuast rate narrative based on table 6-4. So, it is less risky if you submit it along with 62MZ spreadsheet.
We've got a Hotel building that is designed acc. to local Standards (not ASHRAE 62.1). The guest rooms are mechanically ventilated and have also operable Windows. The Problem is, that neither the OA rate is enough to fulfill the requirments of ASHRAE 62.1, nor the Windows are large enough (smaller than 4% of the floor area).
The Ventilation System design Intention is to provide a base 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. through the mechanical ventiation with the Option for the guests to open the Windows additionaly.
I am unsure how to show compliance in this case. My first thought would be to separate the room into 1 the part near the window and Label it as naturally ventilated an 2 the part away from the window and Label it as mechanically ventilated.
Has anybody experience with this? What are your general thoughts? Do you think I can avoid an official request to the GBCI?
Johannes, there is no easy answer for your question. Unfortunately ASHRAE 62.1-2007 does not address hybrid ventilation. ASHRAE Fundamentals 2013 does provide a brief paragraph in Ch.16 about this but it does not offer any guidance except to follow IEA Report Annex 35. You can find that in the link below. If you are going to try to achieve this prerequisite using hybrid ventilation then I would recommend that you reference ASHRAE Fundamentals and the IEA Report in your alternative approach.
Sorry that I could not offer much help but ASHRAE 62 is pretty black or white on this. Either you meet one condition or the other. That being said, if you have a living area and sleeping area that are divided somehow, you could mechanically ventilate one and naturally ventilate the other.
I am working on a project that consists of a two-story office building attached to a warehouse. According to ASHRAE 62.1-2007, warehouses don't have a people outdoor air rate (Rp), only an area outdoor air rate (Ra) equal to 0.06 cfm/ft2. What if the warehouse is occupied at different times of the day? People work there moving merchandise and performing other administrative tasks. Would the Rp still be zero?
The occupancy category should be selected separately for every zone. If you have 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. in your warehouse, they will have to be ventilated. However, ASHRAE 62.1 exempts "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." So you need to determine when and for how long a space will be occupied.
If the zone in question is a warehouse then you will be fine to meet the minimum requirements by doing the Ra number only. The idea behind warehouses is that the Ra will be so much more restrictive than the Rp (high ratio of area:people) that the Rp is insignificant. If you think that the warehouse is being used in a way other than normal warehouse activities then you should apply an Rp equal to the most similar space use.
Thanks to both of you for your replies. The reasoning behind Rp being zero makes perfect sense, Andrew. We will make sure to meet the minimum requirements using the Ra value only.
We have a tricky situation. We have a dormitory with apartment-style dorms. There is a common living area/kitchenette with four student bedrooms (with private baths) off a common corridor. The bedrooms and living area/kitchenette meet ASHRAE 62.1-2007 reqs for naturally ventilated spaces.
Question 1: The students eat their meals at a common cafeteria and so the kitchenettes are equipped with an electric hot plate, microwave, and fridge and are used for preparing snacks, coffee, etc. Do we need to provide exhaust for the kitchenette? It is not a true kitchen/will be used sparingly and is part of a space being naturally ventilated.
Question 2: Do we need to provide mechanical exhaust for the bathrooms? Typically in residential applications we do provide mechanical exhaust, but in this case the client would like to omit the exhaust since it is not required by code and the bedrooms are being naturally ventilated.
Thank you for your insight.
Michael, table 6-4 requires exhaust of 0.30 cfm/sf in Kitchenettes and 25 or 50 cfm for private toilet rooms depending on whether the exhaust is continuous or intermittent. Also, make sure to check the ventilation section (normall Chapter 4) of your state mechanical code, there most likely is a requirement for bathroom exhaust.
Thanks for the response. This project is in Africa, so a lot of typical code requirements (and assumptions) don't apply.
LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. 10248 suggests that the kitchenette will not require mechanical exhaust since it is part of a naturally ventilated space. It looks like mechanical exhaust of the bathrooms will definitely be required.
Bathrooms do not need to be mechanically ventilated per the standard. Natural ventilation of bathrooms is acceptable. ASHRAE 62.1-2007 is set up so that it is possible to substitute the exhaust requirements of table 6-4 for natural ventilation. In michaels case however, it seems that mechanical ventilation of bathrooms that dont have operable windows to the outdoors would be required.
We got a review from a Project and there are 2 comments that we are concerned about:
1) The review team says "that corridors, storage spaces, and technical rooms with intermitente occupancy would require to comply with the requirements of IEQp1. A space shall be considered occupiable if it is expected that occupants will spend any extended period of time there even if it is only 15 minutes".
However, as far as we know, the requirements of IEQp1 are applicable only to the 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. which definition is "areas where one or more individuals normally spend time (MORE THATN ONE HOUR PER DAY PER PERSON ON AVERAGE) seated or standing as they work, study, or perform other focused activities inside a building".
Thus we don't see how corridors, storage spaces, and technical rooms with INTERMITENT occupancy are required to comply. If we go by this defintion every single space in any type of building would have to comply because eventually somebody is going to enter that space.
2) The review team is claiming that the total sum of the areas stated in IEQp1 has to be equal to the total building area stated in PIf3. However, only regularly occupied spaces must be listed in IEQp1 template. Therefore, not necessarily the sum of those spaces will be equal to the total building area, since not all spaces within the building are regularly occupied.
Would anybody know wether these comments are leget or if we have room to question them? Thanks!
In 62.1, the ventilation is required for "occupiable space" which has the follow definitions
occupiable space: 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.
So, storage and M&E do not require ventilaiton if you claimed the definition of occupiable space. However, the corridor must have ventilation.
You should also consider exhuast ventilation for spaces such as recycle rooms, lockers, chemical storage, restrooms, etc as mentioned in table 6-4.
Marcio, Iatuwat is correct and I am glad that he beat me to it so I don't have to type out the 62.1 definition of occupiable spaces. I don't know where you got your definition from. I have never seen a review that specified time periods or room types to determine if a space is occupied. I know that USGBC defines an occupied space as a place where someone sits or stands while working. I always use the ASHRAE definition. As far as the specific answers to your questions, please see below:
1. I agree with the reviewer that ALL spaces must comply with IEQp1. The compiance method used for storage spaces is to apply the exception noted in the definition of occupiable space. Corridor ventilation is deabatable. The 62.1 user guide has some instances where it says it is not required, however, I always ventilate them per the area requirement of equation 6-1.
2. Again, IEQp1 does need to address all spaces. That is not to say that all spaces must be included in the VRP calculation. I recently went through a terribly frustrating ordeal with the recurring comment where I made a separate spreadsheet to list all of the spaces not included n the VRP calcs. The sheet listed the space name, type, area, airflow and reason for exclusion. I then wrote a letter that addressed my approach and compared the total VRP and non-included spaces with the GSF from the PI forms. I also had to noted that the space calculated for ventilation is net space, not gross which is listed in the PI forms. The numbers should come out pretty close. It's kind of ridiculous that we must go into this much detail but I don't want to have to pay the $800 appeal fee either.
I hope this has helped.
There is a 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. definition that sets the use at 1 hour per day. It is in the IEQ Overview section. It occurs twice. To quote the BD+C 2009 Reference Guide, and is applicable to schools;
[b]Compliant Space Types for Indoor Environmental Quality Credits[/b]
The following list identifies school spaces considered to be regularly occupied for applicability to indoor environmental quality credits. [u]In these spaces, daylight, views, thermal comfort, and/or acoustics[/u] affect the quality of occupants’ regular use.
[b]Regularly Occupied Spaces: Classroom and Core Learning[/b]
This category consists of spaces that are used for at least 1 hour per day for educational activities where the primary functions are teaching and learning:
[b]Other Regularly Occupied Spaces[/b]
This category includes all nonlearning spaces that are used by occupants for 1 or more hours per day to perform work-related activities.
NOTE: The above refers to specific credits. ASHRAE 62.1 is not one of those credits.
Thanks everyone for the feedback.
Andrew, I got the definition from the EQ Space type matrix and is also in the overview of IEQc8.1 credit in LEED User as Hernando said. http://www.usgbc.org/resources/eq-space-type-matrix
I don't quite understand what you mean by "IEQp1 does need to address all spaces. That is not to say that all spaces must be included in the VRP calculation". Is there any field in IEQp1 template dedicated for the área of the non-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.? Or the only way for us to express that is via Special Circumstances? That is so unpractical! If they want us to give this information they should set up the template to receive the data...
Thanks for the reference. To clarify my statement, I do not think that we SHOULD have to but in my experience, the LEED reviewers have become more demanding about documentation. Since they always comment on the airflow and area not being equal to schedules, I now upload a separate sheet showing all rooms not included in the VRP and why. I think it's absolutely ridiculous and it falls outside of the scope of the required documentation but it has evolved into this over time. I just go ahead and upload the documentation as a separate file.
If you chose the other path, to upload the 62MZCalc calulations, you have the following documentation requirement: "LEED Documentation: If the sum of the area reported for all air handling units combined with the sum of all naturally ventilated spaces is less than 90% of the total gross area reported for the project, please provide a narrative documenting the non-occupiable spaces that are excluded from the calculations."
I guess this is when the reviewers ask you as well, although providing only the VRP calculation on the form.
I have two additional questions:
- Do you usually use the default ASHRAE occupancy no. for corridors (zero), or as it is occupiable, you determine a number and then use diversity so that the total number of people is not exceeded?
- Do you usually give a roombook to document the unoccupied areas, or do you think just listing the area types and the total square footage can also be enough?
I use zero occupants for corridors and I provide a list of individual spaces with area, type, airflow and reason why they are excluded from the VRP calculation.
Must Vbz be met for all zones in a multizone system? Section 6.2 states that the VRP procedure is for determining Vot and not Vbz.
Rudolph, the Ventilation Rate Procedure (in theory) should ensure that Vbz is met at all zones in a multizone system. This is why Vot is frequently a larger volume of air than the sum of all Vbz of all constituent zones.
Thank you. The Ev division at the end makes that true. It seems unfortunate that critical zones are not guaranteed their respective Vbz values when the system is at full blast. Related question: If a system is in compliance with the VRP Vot minimum, when the Vot is increased to assure that all zones meet the increased ventilation credit, could you potentially need a greater Vot than the supply air flow rate of the entire system? In other words, can the increased ventilation rate credit force a system to need more total supply air?
IEQ Prerequisite 1 Form:
I have a reoccurring error on my mechanical ventilation – Multiple Zone Chart that is reading “Would need over 100% OA Intake”. However, when you click on the calculate button this error disappears, showing that everything on the form is complete/compliant. The problem is when you leave the form and come back on the page at a later time the error reappears. The overall form always shows up as compliant even when the error is on the page. Has anyone had this error occur to them and do they know of possible solutions to make the error flag go away. (The system in use is an 100% OA ERV Unit with VRF’s used to condition the spaces.)
Ken, I have not encountered this error before. Which version of the IEQp1 form are you using? In my experience errors in the prerequisite form will not stop you from submitting your project, even if you are shown as not meeting the prerequisite. As long as the correct information is in the form, the reviewers will be able to award your team the prerequisite. You can even select the alternate compliance path option and specifically mention the error in the form if you like.
That said, because of problems like this, I recommend using the spreadsheet 62MZ calculators available through the "Credit Resources" link on the Credit Information page for this prerequisite on LEED Online.
If we use an exhuast fan for an office and have no clear location of OA intake, can we comply with 62.1? Assumed that the Ventilation Rate Procedure (with zone and system effectiveness) can be supported by an exhuast fan, adequately.
I dont see why not. So long as you can demonstrate how the air will enter the space and that it is clear of any contaminant sources.
I see somewhere in 62.1 mentioning the mandatory of "OA intake" which might conflict with exhuast ventilaiton. In exhuast ventilation, there is no clear intake location.
I am confused with the definition of the enclosed space. For instance, will a factory with the large area of a solid roof and metal grill (and from outdoor can flow in and out freely) count as an enclose space and need to comply with 62.1.
Another case is an atrium with roof but have no door and have some openning under the roof (the air can flow freely). Will it count as an enclose space and need to comply with 62.1.
Definition of enclosed space from ASHRAE 90.1: a volume substantially surrounded by solid surfaces such as walls, floors, roofs, and openable devices such as doors and operable windows.
Check out the difnition of "occupiable space" in ASHRAE 62.1 also.
The term "substantially" seems subjective. For instance, if we have a solid roof and have 1 wall but three sides are open. What will fit this definition? is it enclosed or not?
What if the rest are attached with metal grills and the air can easily pass around? Will it be enclosed?
Well, if you have only 1 wall and a solid roof, then you would definitely comply with the natural ventilation requirements of section 5.1 in 62.1. The same applies to the factory. The free area of the grills are what would be used to caculate the 4% free area requirement of section 5.1. If you do have a substantially surrounded space with ventilation grills on the roof, and you cannot comply with the openings requirements of section 5.1, then maybe you might be able to comply utilizing stack effect calculations.
If that is the case, what about the hotel balcony (outdoor) , open terrace, open court. I think these are not enclosed space. it seems strange if i have to apply 62.1 section 5.1 to these space. Am I right?
Yes. If they are obviously not substantially surrounded, I would not consider them.
Should the ductwork that is delivered to the jobsite for installation be wrapped at the fab shop on both ends or can the ends of the duct be wrapped onsite prior to unloading from the truck?
Niether ASHRAE 62.1 nor USGBC specify this. I would personally rather them be sealed at the fab shop.
Can an air conditioned space that has operable windows earn minimum IAQIndoor air quality: The quality and attributes of indoor air affecting the health and comfort building occupants. IAQ encompasses available fresh air, contaminant levels, acoustics and noise levels, lighting quality, and other factors. performance prerequisite by demonstrating the compliance with natural ventilation requirements?
Yes, for ASHRAE 62.1-2007, it is permissable. ASHRAE 62.1-2010 however, does not permit natural ventilation of a conditioned space.
Yes. I have taken this approach successfully with a group of LEED certified duplex dwelling units. The air conditioning unit provides heating and cooling. The windows provide the ventilation for LEED certification purposes. We also had continuous bathroom fan ventilation to meet Energy Star ventilation requirements, but the exhaust fan was not the method used to certify for LEED.
Can the make-up air (CFM) provided for a kitchen hood exhaust system be considered as part of the total OSA CFM, in the VRP calculation?
Does it make a difference if the make-up air is provided by a supply fan or a louver with no fan assist?
Yes you can use the makeup air as outdoor air supplied to the kitchen, but you'll need to use an appropriate ventilation efficiency (Ez) number for "zone air distribution effectiveness". Air introduced directly into a bypass hood would not count. In the exhaust only case, Ez is 0.8 for a louver on the opposite side of the room from the exhaust air inlet or 0.5 for a louver near the exhaust air inlet. If you have overhead 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. distributing makeup air from a supply fan, you will need to make a judgement on what number to use for Ez. You can find Table 6-B with appropriate Ez values in the ASHRAE 62.1 Users Manual, which should be available as a Credit Resource IEQp1 through LEED Online on the right side of the IEQp1 credit information screen. If you supply air that is never more than 15 degrees above room temperature through ceiling diffusers that are well away from the exhaust hood, you should be able to use 1.0 for Ez. For warm air in the same configuration, Ez=0.8. If the supply air is distributed only immediately next to the exhaust hood, I would use an Ez of 0.5.
Can someone help me with exception "b" of mandatory section 126.96.36.199 in 90.1.
What is meant by the following:
b. multiple zone systems without DDC of individual zones communicating with a central control panel.
Must my client install DCV in an auditorium that meets all of the requirements of section 188.8.131.52 if the auditorium is fed by a multizone 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 DDC control?
What damper would the DCV control?
If you have a normal 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 DDC control, exception b does not apply. Exception b could apply if you had a multi-zone system where each space with a thermostat had its own stand-alone control to modulate its damper, but did not have a VAV box controller communicating with a central DDC system.
Yes, unless any of the other exceptions apply (a, c, or d), DCV is required in an auditorium fed by a multizone DDC VAV system that fits the parameters of 184.108.40.206. of ASHRAE 90.1-2007.
A controls contractor I worked with recently said it normally works best to let the VAV box be controlled by temperature and use the DCV carbon dioxide sensor to control the outdoor air damper at the air handling unit. It can get tricky to satisfy both 90.1 and 62.1 while maintaining comfort conditions in the whole system, so the HVAC engineer should definitely look at the control sequence carefully. Depending on the envelope loads, etc. , it's possible the VAV zone damper for the auditorium would need to be forced open above minimum in some cases if the temperature is satisfied but the CO2Carbon dioxide sensor is reading high. Hopefully there is plenty of heating capacity in the AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition)
2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. and also reheat at the VAV box.
Kinda wierd to make an exception for a system that has stand alone controls for each zone that don't comunicate with the central control panel.
I.e. Just because you dont have one installed doesnt mean that you cant have savings if you do install 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. box with a communicating controller.
The exception seems to be saying that since its too expensive to install a communicating controller then you dont need to install it.
We are in the midst of certifying a Medical office core and shell building. Our scope includes the landscaping, parking lot, side walks, and building shellThe exterior walls, roof, and lowest floor of a building, which serve to separate and protect the interior from the elements (precipitation, sunlight, wind, temperature variations).. The tenant will be responsible for all interior buildouts including the MEP. The tenant has supplied us with their preliminary drawings for us to review and the design of the HVAC system is in accordance with the ANSI/ ASHRAE/ ASHE 170: Ventilation of Health Care Facilities. Can some one advise me if this design constitute compliance with the mininum 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. requirement if not exceed it?
The ASHRAE 62.1-2007 users manual (available through USGBC at http://www.usgbc.org/sites/default/files/62_1_2007_UM.pdf) says:
"While the scope of Standard 62.1-2007
includes laboratory, healthcare, and
industrial spaces, ASHRAE recognizes
that the minimum requirements of
Standard 62.1 may be inappropriate for
some spaces. For inst
safety or other standards may require the
use of special capture ventilation or
personal protective equipment that is not
covered in this Standard. These
ts relate only to
spaces with special processes and not to
(such as offices)
located within these facilities. The latter
are covered in the scope of the Standard
just like similar spaces in non-industrial
facilities. On the other hand, systems and
equipment requirements (e.g., drain pans
and airstream surfaces) apply to all space
ASHRAE 170-2008 (paragraph 7.1.1.b.) says: "Ventilation rates for many areas not specified here can be found in ANSI/ASHRAE Standard 62.1. Where areas with prescribed rates in both Standard 62.1-2007 and Table 7-1 of this standard exist, the higher of the two air change rates shall be used."
There is only a little overlap in the types of spaces covered by the two standards. ASHRAE 170 uses air changes based on room volume and does not have correction factors for air distribution effectiveness, whereas 62.1 uses number of occupants and floor area. I believe the appropriate thing to do is to require compliance with both standards.
I've never documented a health care space for IEQp1. I would think the offices, etc. would fall under ASHRAE 62.1, but the health care specialty areas would be covered under Special Circumstances. This must have come up before, so maybe there are some interpretations on this. And someone should have past experience with it too.
I am curious about implimenting natural ventilation in climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 6 where the winter temperatures can be very cold. Does LEED take into account climate zones when looking at natural ventilation, or can I just follow the general guidlines of 4% floor area and 20' to windows? Thanks.
LEED only says that you must comply with ASHRAE 62.1. ASHRAE makes no distinction for climate zones.
Blower Door TestA blower door test gives an overall value for airtightness of a space, and can help identify air leaks. The testing unit consists of a calibrated fan that is sealed onto the unit entrance. The fan creates a continuous flow of pressure into the unit (or out of the unit when using theatrical fog to locate leaks). Devices detect the rate of pressure retention and loss due to possible air leaks in the construction. for Non-Smoking Hotel
For a Hotel Project where the Owner has confirmed its policy to be entirely non-smoking, is the requirement to conduct blower door testing (IEQP2: ETSEnvironmental tobacco smoke (ETS), or secondhand smoke, consists of airborne particles emitted from the burning end of cigarettes, pipes, and cigars, and is exhaled by smokers. These particles contain about 4,000 compounds, up to 50 of which are known to cause cancer. Control) as given below no longer applicable.
“Demonstrate acceptable sealing of residential units by a blower door test conducted in accordance with ANSI/ASTMVoluntary standards development organization which creates source technical standards for materials, products, systems, and services-E779-03, Standard Test Method for Determining Air Leakage RateThe speed at which an appliance loses refrigerant, measured between refrigerant charges or over 12 months, whichever is shorter. The leakage rate is expressed in terms of the percentage of the appliance's full charge that would be lost over a 12-month period if the rate stabilized. (EPA Clean Air Act, Title VI, Rule 608). By Fan Pressurization.”
Thank you for the advices.
If the owner has declared that the entire building is non-smoking, then separation testing is not required for LEED. You should check the local codes to see if they have a required test for rooms, as some municipalities require blower door testing of a sample of hotel rooms.
Our project is to build a two-story office building in Indonesia. For cooling, the building will be served by AC using VRF system (ceiling cassette) in each designated space that has MERV6 filter. Since this project is located in a tropical climate region (climate zoneOne of five climatically distinct areas, defined by long-term weather conditions which affect the heating and cooling loads in buildings. The zones were determined according to the 45-year average (1931-1975) of the annual heating and cooling degree-days (base 65 degrees Fahrenheit). An individual building was assigned to a climate zone according to the 45-year average annual degree-days for its National Oceanic and Atmospheric Administration (NOAA) Division. 1), heating is not applicable.
For ventilation, there is no applicable local code or local equivalent, so we assume ASHRAE 62.1-2007 standard should stand. Our current design is to provide natural ventilation only and no mechanical ventilation.
However, I got confused with the following:
"the naturally ventilated spaces shall be permanently open to and within 8 m (25 ft) of operable wall or roof openings to the outdoors, the openable area of which is a minimum of 4% of the net occupiable floor area". I'm not familiar with ventilation, or let alone ASHRAE.
Operable wall and openable area above are two different things right? Are operable wall include windows only, or could include doors as well?
Subsequently, does the openable area can be in the shape of windows or doors as well?
Do the 4% of the openable area of naturally ventilated space must always be opened or can we close it?
Correct me if I'm wrong, but I got the impression from the statement above that the naturally ventilated space should have distance to the operable windows and have an openable area which is 4% of occupiable floor area
How about if our design is to provide the occupiable space (mainly the regularly occupied space) with operable windows that can be open directly to the outside air. That the openable area are the operable windows area. Can this be acceptable?
Based on the above information, we would likely to fill the leedonline form as follows :
1. Only checks "natural ventilation" and "mechanical condition" box
2. Tick NO for "Is the project located outside of the U.S. and pursuing Option 2 or a local equivalent in Option 1"
3. Filling the Table IEQp1-A5. Natural Ventilation - System Name and Number: (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. 1) with : Windows
Is this correct?
Yasir, your approach is correct. For clarification, "operable wall" is not a noun. operable is being used as and adjective to describe the opening. The openable area is the area that will be open to the outside when open. For example, a single hung window that is 2' wide x 4' high is an opening. The openable area would be half (2'x2' area that opens up). That would give you 4sf of area which is good for a 100sf space. I hope that helps.
The operable area just needs to be openable. It does not have to be open all the time. It can be closed when the occupants do not feel the need for ventilation.
Thank you Andrew and Julia for the explanation. I think I have a better understanding now. But I still have some concerns.
ASHRAE: "Naturally ventilated spaces shall be permanently open to and within 8 m (25 ft) of operable wall or roof openings to the outdoors, the openable area of which is a minimum of 4% of the net occupiable floor area"
For example, there's a 2,000 sf office room in our building that have operable windows area of around 40 sf (2%), then we just need to add more windows right?
But, how about if it turned out that there's a portion of that space (say, 1,100 sf) have distances more than 25' (8m) to the windows. It is useless to add more windows now, isn't it? How can we deal with this and is it possible to solve this issue without adding any mechanical ventilation? Does the presence of AC could helped?
Unoccupied areas don't need operable windows, but how about the non-regularly occupied space, such as storage, kitchen/pantry, etc. Do we still have to provide them with 4% of opening area or smaller than 4% can be ok?
Yasir, if you cannot be within 25' of the exterior wall then you could add some operable opening in the roof. I have only seen this in Europe myself. As for the occupied and unoccupied spaces, all occupiable spaces need to comply with the ventilation requirements. See the definitions section to determine if a space is occupiable or not.
For room that has direct opening, the openable area should be 4%, and has distance of 8 m. For interior room that is ventilated through adjoining room, openable area is 8%, but how far the distance for this?
When the case is that we couldn't add any opening to the roof, because it's located in the ground floor (there's another room above) and/or the construction of that room is almost finished, how can we deal with this?
There is a possibility that few occupiable rooms cannot comply with the requirements due to certain limiting conditions. Do you think the reviewer would be kind to give us any tolerance/leniency.
The distance and 4% to outside stays the same. The opening between rooms is 8% or no smaller than 25 sf. If you cannot meet these requirements then you need mechanical ventilation. There is no tolerance by the reviewer. You may be able to get a building permit but I do not think it will be LEED Certified.
I'm not sure if any of this will help in your situation, but here are some things to look in to:
* I believe that "an engineered natural ventilation system can show compliance with acceptable engineering calculations or multinodal bulk airflow simulation" even if parts of the spaces are farther than 25' from the openings. (ASHRAE 62.1-2007 Section 5.1 also has an exception for engineered natural ventilation systems when approved by the authority having jurisdiction...)
* There's a LEED InterpretationLEED Interpretations are official answers to technical inquiries about implementing LEED on a project. They help people understand how their projects can meet LEED requirements and provide clarity on existing options. LEED Interpretations are to be used by any project certifying under an applicable rating system. All project teams are required to adhere to all LEED Interpretations posted before their registration date. This also applies to other addenda. Adherence to rulings posted after a project registers is optional, but strongly encouraged. LEED Interpretations are published in a searchable database at usgbc.org. that may help. (http://www.usgbc.org/leed-interpretations?keys=10144)
* Also check out the addendums to the ASHRAE standard as there may also be some options there. (Ex. "Addendum n" - http://www.ashrae.org/File%20Library/docLib/Public/20100608_ad62_1_2007_...)
Good luck finding a solution to the prereq!
One more thought -- if you've got AC that's recirculating the air, perhaps you can add a fan to bring in more outside air, and then you've got a mechanically ventilated system (see LEED User Bird's Eye View above) which completely changes your analysis. Perhaps there's a way to use mechanical fans just to get the air to the few rooms that aren't meeting the requirements so those rooms could be considered mechanically ventilated while the rest of the building is naturally ventilated?
Michelle, the AC will use ceiling cassette type, and yes it recirculates the air, but I don't know about bringing outside air through fan, the team has concerns about the hot outside air that could bring discomfort to the occupant, and will create greater workload as well as power consumption.
When two or more fancoils meet the same area, can be considered as a single zone, correct?
As long as it is one ventilation zone (most likely an uninterrupted 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)) then the thermal zone divisions do not matter.
Principal, Director of Sustainability
Westlake Reed Leskosky
Mechanical and natural ventilation designs must comply with requirements to mitigate environmental tobacco smoke.
The amount of fresh air the HVAC system is designed to process has a direct correlation to the buildup of carbon dioxide.
Increasing the ventilation rates 30% above the ASHRAE standard will help teams gain IEQp1.
Do you know which LEED credits have the most LEED Interpretations and addenda, and which have none? The Missing Manual does. Check here first to see where you need to update yourself, and share the link with your team.
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