CI-2009 IEQc1: Outdoor Air Delivery Monitoring

  • Fresh air and energy savings

    Outdoor air delivery monitoring ensures that the ventilation system, whether natural or mechanical, provides enough fresh air to occupants. The credit  requires carbon dioxide (CO2) and outdoor airflow monitors that signal when fresh air is needed according to minimum set points defined by ASHRAE 62.1-2007. Typical ventilation design (without monitors) tends to encourage increased ventilation that may result in increased energy use and added cost for conditioning increased amounts of outside air. However, the addition of sensors and monitors allows ventilation to be delivered on demand only when required, potentially saving a lot of energy during unoccupied hours in spaces with varying occupancy.

    Crowded auditoriumA space with high-density occupancy at different times of day can be a great fit for this credit.

    Good for buildings with varying occupancy rates

    For buildings with varying occupancy rates and centralized mechanical systems, like offices and schools, the added cost should be minimal, and the systems will probably reduce energy bills, offering good return on investment. High-density areas like conference rooms, theaters, and congregation spaces are a particularly good match for this credit.

    In multifamily or hotel projects, or any building with numerous isolated mechanical systems or natural ventilation, more sensors will be needed, making this credit relatively expensive to pursue.

    Use these questions to help explore this credit

    • Will the project have natural, mechanical or mixed-mode ventilation?
    • If the project is mechanically ventilated, will it be a centralized system? Centralized systems can achieve this credit more cost-effectively.
    • If naturally ventilated, will the project include designs that allow for adequate ventilation without human interaction?
    • Will the design include a BMS or demand control ventilation? These systems can make credit achievement easier.
    • What is the cost increase associated with CO2 sensors and outdoor air monitors?
    • Does the local utility offer any rebates on incentives on CO2 sensors, outdoor air flow monitors or demand control ventilation?
    • If the project is a hotel or multifamily, does installing CO2 sensors in each room seem cost-effective and beneficial?
    • If the project is a laboratory, can CO2 and other small particulates be monitored to provide ventilation only when needed? If so, this credit can be very cost-effective.
    • Are CO2 sensors or outdoor air monitors compatible with existing mechanical equipment and is the building owner willing to install these monitoring systems?
    • Which spaces are densely occupied and which are non-densely occupied?

    FAQs for IEQc1

    If my project is using air handlers that supply 100% outside air at a constant volume, do I still need to install an airflow monitoring device?

    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. #2099, issued 4/24/2008, allows the use of circuit transducers that measure fan status of 100% outside air and constant volume fan systems as an alternative to an airflow measuring station for this credit. For constant volume and 100% outside air systems that have been accurately balanced, monitoring the fan status is adequate to maintain proper outside air volumes. This is not an appropriate strategy for variable volume systems.

Legend

  • Best Practices
  • Gotcha
  • Action Steps
  • Cost Tip

Schematic Design

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  • Determine the best ventilation strategy for your building: natural, mechanical, or mixed-mode ventilation. The choice of ventilation system is more likely to be shaped by the LEED minimum ventilation prerequisite (IEQp1) and increased ventilation credit (IEQc2), not this credit.


  • Consider the impact of monitoring devices on space and design requirements. Issues to consider include the location of CO2 sensors, the inclusion of outdoor air monitors when designing the mechanical system, and whether to use a building management system (BMS), which allows your ventilation system to automatically respond to changing indoor situations.


  • Outdoor airflow monitoring devices are the single most costly component of this credit, ranging from $1,000–$5,000 per monitor, depending on size of the ducts and product type. You can reduce this cost by minimizing the number of supply ducts coming into the building. Centralized systems minimize these ducts, thereby minimizing cost.


  • CO2 sensors are not standard practice and typically cost $500–$1000 per sensor including installation. Installing CO2 sensors is becoming more common and this price may come down, however. Costs can add up quickly if several sensors are required. In applications with many densely occupied spaces and isolated mechanical systems, like hotels and multifamily, providing CO2 sensors and the associated controls for each unit could become costly, without much added benefit. However, in applications with larger, densely occupied spaces served by centralized mechanical systems—such as office spaces—CO2 sensors become significantly more cost-effective, as ventilation demand is matched to occupancy and the HVAC system operates only when the room is occupied or to meet established set points.


  • CO2 sensors are not the same as CO sensors. CO (carbon monoxide) sensors are much more common, inexpensive, and do not need to be hard wired. Make sure this distinction is clear when talking with the owner, mechanical engineer, and building operator.


  • Consider incorporating CO2 sensors or outdoor airflow monitors into the building design, as required by the credit. Discuss with the project team the indoor air quality (IAQ) and energy benefits of installing monitoring devices in the project.


  • Demand Control Ventilation (DCV) in conjunction with CO2 sensors can serve the dual purpose of energy conservation and improved indoor air quality. They provide the option of additional ventilation only when CO2 sensors indicate that it is necessary.


  • Outdoor air can contain contaminants that lead to unhealthy working or living conditions. You may need to assess the quality of the local outdoor air before bringing it indoors. HHigh efficiency MERV filters (13 or higher) are one solution to treating poor-quality outdoor air before supplying it to the indoors. This can be part of a strategy for achieving IEQc5: Indoor Chemical and Pollutant Source Control.


  • For Commercial Interiors projects, verify that any outdoor air monitoring devices or CO2 sensors are compatible with the existing mechanical equipment and will be able to provide the feedback and corrective action for credit requirements. Providing the appropriate feedback is typically more difficult for CI projects.


  • Continuous airflow and CO2 monitoring is required. Air balancing measures such as total airflow measurement and static pressurization measurements do not comply with the credit requirements.


  • Projects without ducted make-up air must follow Option 2 for natural ventilation, and should weigh the costs and benefits of installing monitoring devices. For example, in multifamily projects and hotels where outside air is only supplied through pressurized hallways and operable windows. Every apartment or unit will need one CO2 sensor per unit, and many projects find this to be too costly. Mechanically ventilated common areas such as hallways and lobbies will require outdoor airflow monitors instead of CO2 sensors.


  • CO2 sensors do not provide the same benefit in non-densely occupied spaces as they do in densely occupied spaces. It is important to remember that CO2 sensors measure only CO2 generated by human occupants and they are typically not a good way to indicate indoor air quality in non-densely occupied spaces. CO2 monitors cannot replace outdoor air monitors and are often incorrectly preferred because they are less expensive than outdoor air delivery monitoring.


  • Some utilities offer rebates for installing CO2 sensors in conjunction with demand-control ventilation. For example, the New York State Energy Research and Development Authority (NYSERDA) and Florida Power & Light have offered such incentives. Check with your local utility or DSIRE to see if rebates are available in your area (see Resources).


  • CO2 sensors will provide the highest return on investment in areas where the occupancy is intermittent or unpredictable. Examples include conference rooms and auditoriums, where ventilation rates will need to be high only when close to full occupancy and where ventilation rates can be low when the spaces are unoccupied.


  • Fees for engineering services may increase due to this credit, because of the need to develop controls sequences. That premium can be reduced if the engineer has experience with the credit in similar applications.


  • The cost of alarms and BMS equipment varies greatly and is dependent on the complexity of the system.

Design Development

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  • The project team and contractor work together to determine the feasibility and rough cost increase of including CO2 sensors or outdoor airflow measurement devices.


  • The owner, mechanical engineer and building operator should determine the best option for corrective action in the project. Options for corrective action include opening windows, adjusting air-handling units, alerting tenants, and increasing ventilation flow rates.


  • Use ASHRAE standard 62.1-2007 to determine outside air requirements.


  • The mechanical engineer and architect identify densely and non-densely occupied spaces as defined by LEED and determine the quantity and locations of all monitoring devices, and integrate them into the HVAC system. The mechanical engineer should verify that the monitors are designed to interface with a BMS system or trigger an audible or visual alarm if CO2 concentrations or ventilation rates fall outside of the required range.


  • All monitoring devices must be able to trigger an alarm or automated response when actual measurements vary by 10% or more in either direction from the design set points. The signal or alarm is most often relayed to a building management system that balances supply and return air volumes, monitors and controls minimum fresh air volumes, and provides a reliable reference point for commissioning of VAV systems. The alarm can be audible or visual and be relayed to building facility staff or directly to the occupants, to alert them to open windows.


  • The benefits of any monitoring device depend on the communication system, response and corrective action. Facility operators often find it very beneficial to automate the response by installing demand-control ventilation, which automatically regulates airflow as needed.


  • CO2 sensors can 1) measure the indoor concentrations of CO2 and compare them against ASHRAE 62.1-2007 limits or, 2) measure the indoor concentrations of CO2 and compare them against outdoor CO2 concentrations. If you choose the second option, you will need to install outdoor CO2 monitors as well.


  • Naturally Ventilated Buildings


  • All occupied spaces in naturally ventilated buildings require the installation of at least one CO2 sensor. The number of CO2 sensors depends on the project’s design and should be calculated by the mechanical engineer. Projects can use one CO2 sensor for multiple spaces only if the project is ventilated by an approved “engineered natural ventilation system” according to ASHRAE 62.1-2007 requirements and if it does not require occupant intervention. This type of ventilation system connects adjacent spaces via air pathways that utilize the stack effect, or passive air movement from openings at a lower level than the point of exhaust. A single CO2 sensor can be used in these connected spaces. To meet the credit requirement, an engineer must demonstrate that the natural ventilation system can maintain adequate ventilation rates.


  • Mechanically Ventilated Buildings


  • All densely occupied spaces in mechanically ventilated buildings require the installation of at least one CO2 sensor per space. Non-densely occupied spaces require an outdoor airflow (OA) monitoring device. For mechanically ventilated spaces, the CO2 sensor has to be installed for the zone being served by one ventilation system. The credit requires only one sensor per space, but installing multiple sensors within a large space helps measure varying concentrations of CO2.  For example, if the sensor is located in one location, while people are congregating in another corner of the same space, the sensor will not recognize the high CO2 concentrations. Spread the sensors out to accommodate for more uses of the space. Also, use at least one sensor per ventilated zone, for a large space being served by multiple zones. Consult the mechanical engineer on the quantity and placement of CO2 sensors.


  • For mechanical ventilated spaces that are installing a BAS or BMS, the system should be capable of integrating with the CO2 sensor and outdoor air flow monitors for immediate response with increased fresh air, such as demand-control ventilation.


  • Airflow measurement devices are installed as part of the air duct system and are designed to measure airflow and transmit a signal when airflow deviates from established set points. Two common types of these devices are those that measure intake volume directly by measuring air velocity (advanced thermal dispersion) and those that measure differential pressure across a fixed opening (pitot arrays and flow-rings). Both can provide the accuracy required for the credit. Advanced thermal diffusion is more accurate and requires less maintenance, but is more expensive.


  • CO2 monitors installed in return-air ducts (in the ceiling or floor) will not meet the credit requirements, as monitors are required to be placed 3–6 feet above the floor in all densely occupied spaces.


  • In laboratory and health care facilities, consider continuously measuring additional air quality factors such as TVOCs, carbon monoxide, and other small airborne particulates to reduce ventilation rates down to two air changes per hour (ACH), as conditions permit, in order to save energy.


  • Integrating an ERV or HRV into a system that meets the Outdoor Air Delivery Monitoring credit can be particularly cost-effective with large centralized systems.


  • Demand-control ventilation can help reduce peak load allow you to select smaller mechanical systems, minimizing upfront costs.


  • Not all conference rooms are densely occupied spaces! Densely occupied spaces are defined as having 25 people per 1,000 square feet of space.

Construction Documents

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  • Include CO2 sensors and outdoor air delivery monitoring devices on the project plans and Equipment Schedule. Also highlight the interface between monitors and BMS or alarm on project plans.


  • Review drawings to ensure that all densely occupied spaces contain CO2 sensors.


  • Detailed construction instructions with locations of monitoring devices help to ensure that these devices are installed correctly.


  • Outdoor airflow monitors may be integrated within AHUs and ventilation equipment specifications.


  • The monitoring and alarm systems need to be included in the commissioning plan for EAp1: Fundamental Commissioning with the appropriate sampling rate.


  • The outside air delivery monitoring device should be specified along with the Air Handling Unit (AHU) equipment package.


  • Ensure that monitoring devices are included in budget estimates from the beginning to avoid any surprises.


  • Document credit compliance on LEED Online. This credit has an LPE path for Professional Engineers where project plans, drawings, and other information is not necessary for upload. For the full documentation path you will need to complete the following:

    • Mechanical ventilation
      • Provide the completed ASHRAE 62.1-2007 calculator.
      • Provide controls drawings showing outdoor airflow measurement devices serving non-densely occupied spaces.
      • Provide detailed information on outdoor air ventilation rates (including required air flow rate, accuracy of devices and setpoints).
      • The controls designer will need to sign the LEED Online credit form stating that the monitoring devices meet the credit requirements.
      • Proivde drawings showing the location of CO2 sensors for densely occupied spaces.
      • Provide a list of densely occupied spaces
      • The controls designer will need to sign the LEED Online credit form stating the CO2 sensors are programmed to generate an alarm.
    • Natural Ventilation
      • Provide a drawing showing the zones, windows and location of CO2 sensors.
      • The controls designer must sign the LEED Online credit form stating that CO2 sensors are installed in all naturally ventilated spaces, are located in the breathing zone, and will generate an alarm.

Construction

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  • Contractor installs the monitoring devices as recommended by product manufacturer and mechanical engineer. Verify that all alarms have set points complying with ASHRAE 62.1-2007.


  • Verify that CO2 sensors are 3–6 feet off the floor.


  • The commissioning plan should include HVAC, monitoring, and alarm systems, with the appropriate sampling rate.


  • Integrating an automated BMS requires a highly skilled construction team. The BMS is a complex tool requiring skilled personnel who understand the controls and settings as applicable to the project.


  • Ensure that CO2 sensors and outdoor air monitors, and installation costs are incorporated into the detailed budget from the bid documents through final contracts. CO2 sensors are not common, and although the mechanical engineer is responsible for accounting for them on drawings, they could be a forgotten detail.


  • During the buyout phase, ensure CO2 sensors are included in the mechanical or controls contractor’s scope of work.

Operations & Maintenance

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  • Monitor and recalibrate the monitoring and alarm systems as specified by the product manufacturer.


  • Occupant behavior is likely to evolve over the first few months of occupancy. If the building has a BMS, the control sequence, timers, thermal setpoints and other parameters might need to be tweaked for some time. Use the outdoor air monitoring and CO2 sensors to maintain good indoor air quality as well as efficiency.


  • Train facilities personnel to use systems as intended. Facilities personnel should be given all appropriate product data.


  • When alarms are activated by CO2 monitoring devices, facilities personnel and building occupants, if appropriate, need to be aware of the needed corrective measures, such as opening windows or changing AHU settings. The alarm should be visible enough to be noticed.


  • Include the alarm system in the occupant survey for IEQc7.2: Thermal Comfort—Verification to determine its effectiveness.


  • CO2 sensors and outdoor air flow monitors will need recalibration and maintenance, which will bring a minimal additional cost. If they are not recalibrated, there is potential for overventilation or underventilation, and consequently, unnecessary energy consumption or reduced indoor air quality.

  • USGBC

    Excerpted from LEED 2009 for Commercial Interiors

    IEQ Credit 1: Outdoor air delivery monitoring

    1 Point

    Intent

    To provide capacity for ventilation system monitoring to help sustain occupant comfort and well-being.

    Requirements

    Install permanent monitoring systems to ensure that ventilation systems maintain design minimum requirements. Configure all monitoring equipment to generate an alarm when the airflow values or carbon dioxide (CO2) levels vary by 10% or more from the design values via either a building automation system alarm to the building operator or a visual or audible alert to the building occupants.

    AND

    Case 1. Mechanically ventilated spaces

    Monitor CO2 concentrations within all densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). i.e., those with a design occupant density of 25 people or more per 1,000 square feet (95 square meters). CO2 monitors must be between 3 and 6 feet (between 1 and 2 meters) above the floor.

    Provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor air intake flow with an accuracy of plus or minus 15% of the design minimum outdoor air rate, based on the value determined in IEQ Prerequisite 1: Minimum Indoor Air Quality Performance, for mechanical ventilation systems where 20% or more of the design supply airflow serves non-densely occupied spacesNon-densely occupied spaces are areas with a design occupant density of less than 25 people per 1,000 square feet (40 square feet or more per person).".

    Case 2. Naturally ventilated spaces

    Monitor CO2 concentrations within all naturally ventilated spaces. CO2 monitors must be between 3 and 6 feet feet (between 1 and 2 meters) above the floor. One CO2 sensor may be used to monitor multiple nondensely occupied spaces if the natural ventilation design uses passive stack(s) or other means to induce airflow through those spaces equally and simultaneously without intervention by building occupants.

    Potential Technologies & Strategies

    Install CO2Carbon dioxide and airflow measurement equipment and feed the information to the heating, ventilation and air conditioning (HVAC) system and/or Building Automation System (BAS)A building automation system (BAS) uses computer-based monitoring to coordinate, organize, and optimize building control subsystems, including lighting, equipment scheduling, and alarm reporting. to trigger corrective action, if applicable. If such automatic controls are not feasible with the building systems, use the measurement equipment to trigger alarms that inform building operators or occupants of a possible deficiency in outdoor air delivery.

    FOOTNOTES

    1 Project teams wishing to use ASHRAE approved addenda for the purposes of this credit may do so at their discretion. Addenda must be applied consistently across all LEED credits.

Technical Guides

IEQ Space Matrix - 2nd Edition

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: Outdoor Airflow Monitoring Devices.

ASHRAE 62.1-2007 should be referenced when designing outdoor airflow monitoring devices.


Indoor Air Quality Building Education and Assessment Model (I-BEAM)

I-BEAM is a comprehensive tool for building professionals and others responsible for indoor air quality in commercial buildings; it provides state-of-the-art guidance for managing Indoor Air Quality in commercial buildings.


IEQ Space Matrix - 1st Ed.

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.

Publications

Building Air Quality: A Guide For Building Owners and Facility Managers

This guide is for preventing, identifying and resolving 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. problems in existing commercial and public buildings.


Energy Cost and IAQ Performance of Ventilation Systems and Controls Study

A study on the compatibilities and tradeoffs between energy and ventilation, which gives an idea of strategies that best meet both objectives.


Indoor Air: International Journal of Indoor Environment and Health

This journal presents research to help designers, owners and operators provide healthy buildings.

Organizations

Database of State Incentives for Renewables and Efficiency (DSIRE)

This database shows state-by-state incentives for energy efficiency, renewable energy, and other green building measures. Included in this database are incentives on demand control ventilation, ERVs, and HRVs.


Low Impact Hydropower Institute

The Low Impact Hydropower Institute is a non-profit organization and certification body that establishes criteria against which to judge the environmental impacts of hydropower projects in the United States.

Design Narrative

All Options

Use a narrative to describe how your project meets the requirements for outside air monitors and carbon dioxide monitors.

Compliant Products

Use manufacturer cut sheets to find credit-compliant products and to document compliance when necessary.

LEED Online Forms: CI-2009 IEQ

Sample LEED Online forms for all rating systems and versions are available on the USGBC website.

Design Submittal

PencilDocumentation for this credit can be part of a Design Phase submittal.

45 Comments

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Agata Mozer GO4IT SP Z OO SP K
Apr 19 2017
LEEDuser Member
1183 Thumbs Up

Locker rooms

Project Location: Poland

Are CO2Carbon dioxide sensors required in locker rooms? Loker rooms are non-regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. but they are also densely-occupied spaces. I assume that since this kind of space is not included in ASHRAE table with minimal ventilation rates (loker rooms are only included in the table with minimum exhaust requirements) then we don't have to install CO2 sensors there even though it's a densely-occupied space. Is this correct?

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Ronald Dean Sumac Inc.
May 05 2016
LEEDuser Member
1940 Thumbs Up

Outdoor Air Delivery Monitoring System for LEED CS building

Project Location: Peru

We have a leased office in a LEED C&S project. As a part of the C&S scope, the building has two centrifugal fan boxes that supply 100% outdoor air to the offices through a masonry duct, this system has an airflow device at the outdoor air intake to ensure that the building ventilation system maintain design minimum requirements.

For the office, we have to extend the metal duct provided by the building ventilation system and install ventilation grilles for each space. This metal duct has a damper and has been dimensioned to provide the required ventilation rate according to ASHRAE 62.1.

Is it necessary to install an additional airflow monitoring device to meet the IEQc1 credit requirements for a LEED CI office?

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Jan 18 2017 LEEDuser Moderator

Ronald, I don't think so. It sounds like the requirement is met by the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, and materials and products installed in the project (e.g., flooring, casework, wall coverings)..

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CT G
Feb 18 2016
LEEDuser Member
728 Thumbs Up

CO2 in small space / private offices

Dear all,

Once I saw 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. stating that small spaces, or private offices, could be exempt of installing CO2Carbon dioxide sensors to comply with this credit, for CI only, not to NC.
I can't find the LI now. Can someone help me with the number of the LI? And is there a similar interpretation exempting us to install CO2 sensor in private offices for NC?

Regards,
Anderson

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Michelle Halle Stern LEED Fellow, The Green Facilitator Feb 19 2016 LEEDuser Expert 1502 Thumbs Up

I'm not aware of an LI, but you only need sensors in densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). of 25 people within 1000 s.f. For a 100 s.f. office to need a sensor it would have to accommodate 3 people. Is that your situation?

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CT G Feb 19 2016 LEEDuser Member 728 Thumbs Up

Thank you for your reply Michelle.

Yes, our situation is similar to what you described. We have a 25 s.f. space with one person.

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Michelle Halle Stern LEED Fellow, The Green Facilitator Feb 19 2016 LEEDuser Expert 1502 Thumbs Up

I did a little digging and the only thing I found was a post in LEEDUser saying that there is not exception for CO2Carbon dioxide monitors is rooms with fewer than 10 people. (Vamshi Gooje Nov 21 2011 in response to a question from Dylan)
Though I'm not sure what the source of this information is.

I think your situation is worth submitting a 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. It seems a little overkill to provide a CO2 sensor for such a small space serving one person. However also consider how long this person is in this 5'x5' space. Is it really regularly occupied or just used intermittently? If I was stuck in a 25 sf space all day I'd feel better knowing that fresh air was being brought in if the CO2 levels were elevated.

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Christie Rimes
Sep 07 2015
LEEDuser Member
69 Thumbs Up

100% OA VAV Base Building system

Project Location: Australia

Hi, the CI project I am working on uses only the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, and materials and products installed in the project (e.g., flooring, casework, wall coverings). system supply for meeting rooms with between 2 and 8 people. These rooms are all located internally and only use a temperature sensor to modulate the 100% OA 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. base building system. As the system is 100% OA there is ample ventilation being provided to the space. Also the VAV damper is connected to a temperature sensor that will modulate with the occupant density.

I would like to confirm that our system meets the intent of the credit and that CO2Carbon dioxide sensors are obsolete in this senario.

Any meeting rooms with more than 8 people are provided with a supplementary system with temeprature and CO2 sensors.

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Roger Chang Principal, Energy and Engineering Leader, DLR Group | Westlake Reed Leskosky Jan 05 2016 LEEDuser Expert 4586 Thumbs Up

There is no exception for a case like this, because there is still the potential that 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 could fully close or not open sufficiently, resulting in an indoor environmental issue. An issue could also develop at the air-handling unit itself where having carbon dioxide sensing would provide another layer of feedback. I do agree with the direction you're headed in conceptually, as this type of system has a greater chance of providing sufficient ventilation under all conditions versus a VAV system with a lower system level ventilation fraction.

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Christie Rimes Jan 10 2016 LEEDuser Member 69 Thumbs Up

Any system has the potential to not work resulting in an indoor environmental issue. The credit asks that a damper is connected to a CO2Carbon dioxide sensor in the room. This has the same potential to not work as 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.
If there is a problem at the air-handling unit itself this would be picked up due to the temperature sensors as the rooms wouldn't be conditioned correctly.

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Michelle Halle Stern LEED Fellow The Green Facilitator
Jun 11 2015
LEEDuser Expert
1502 Thumbs Up

CO2 Monitors in Waiting Room Without 4 Walls

Project Location: United States

I'm working on a HC interiors project with waiting rooms and nurse stations that have density of 25 people/1000sf, however they do not have 4 walls enclosing the spaces. The nurse stations have large counters open to the corridor, and the waiting rooms are part of larger open spaces that lead to corridors, also not separated by doors. Are CO2Carbon dioxide monitors required in these spaces?

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Dylan Connelly Mechanical Engineer, Integral Group Sep 08 2015 LEEDuser Expert 9645 Thumbs Up

Recommend a 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 if you're unclear. Or submit how you think makes sense and see if you are questioned. My feeling is that the nurse stations are more office than densely occupied. And a waiting room probably has a wall somewhere you can put a CO2Carbon dioxide sensor on. Typically the rooms in this credit are enclosed but if they are mostly enclosed I can see it being a requirement.

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Kristopher Baker Syska Hennessy
Jun 10 2015
Guest
21 Thumbs Up

Alternative to OA airflow measurement device at Building AHU

Project Location: United States

So like many on this thread, i have a LEED CI project that is 1/3 of 1 floor and is served by the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, and materials and products installed in the project (e.g., flooring, casework, wall coverings). 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. that is outside the scope and LEED boundary of the project. The base building AHU is a single massive unit that serves the entire building (15 floors) and does not have any airflow measurement device on the outside air intake. At this scale, installing an OA measurement device for the non-dense space criteria is not financially feasible for our small CI project. I would like to propose an alternative and see if y'all have any feedback.

We know that the design outside airflow for the base building AHU is 15%; this is primarily based on the interviews with the facility operator since there are no as-built drawings. We based our design and subsequent ASHRAE 62 calculations on this premise. Essentially, as long as the outside air ratio is at least 15% for the supply air, our project's indoor air quality is sufficient.

So what i propose is the use of 3 CO2Carbon dioxide sensors to measure the %OA for the supply air. If it is below the 15% value then an alarm kicks in for the occupants of the space. The CO2 sensors would need to be installed such that one is located in the collective return, one is located anywhere outside or at the OA intake, and one is located in any supply air location. The %OA would then be calculated similar to how we were all taught to determine mixed air temperatures.

I believe this follows the intent of the credit that we are measuring actual conditions to identify if we are meeting the design assumptions used within the ASHRAE 62 calculation that shows we have sufficient ventilation.

So here are the questions to you all: Does this make sense? Has anyone had success with this strategy in the past? Am i missing a simpler way to achieve the same thing (i do have a tendency to complicate things)?

Thanks for you time...

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Dylan Connelly Mechanical Engineer, Integral Group Sep 08 2015 LEEDuser Expert 9645 Thumbs Up

Interesting idea. Not sure what kind of accuracy you'll get but it's worth a shot. Perhaps go for a 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. Or submit with this as an alternative compliance and see if you pass.
Btw. I'd recommend you pay for a test and balancer to take an actual measurement on the outside air intake. Taking the building operators word for it isn't accurate enough IMO.

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James Keohane, PE LEED BD+C CxA CPMP Sustainability and Commissioning Consultant Sustainable Engineering Concepts, LLC
Jul 09 2014
LEEDuser Member
1067 Thumbs Up

Non Regularly Occupied Spaces

RE: CO2Carbon dioxide Sensors for Densely Occupied SpacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person).

Are spaces designated as Non-regularly Occupied Spaces excluded from consideration as Densely Occupied Spaces?? Examples spaces: Focus and Collaboration areas intended for use by small groups for meetings lasting less than 1 hour.

Recall the definition of Non-regularly occupied spaces is as follows:

Non-regularly occupied spaces are spaces that occupants pass through, or spaces used in pursuit of focused activities for less than one hour per person per day (on average).

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Dylan Connelly Mechanical Engineer, Integral Group Sep 08 2015 LEEDuser Expert 9645 Thumbs Up

Focus rooms maybe. But conference rooms are regularly occupied. I'd recommend a 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.

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Michelle Halle Stern LEED Fellow, The Green Facilitator Sep 09 2015 LEEDuser Expert 1502 Thumbs Up

Generally "regularly occupied" is determined by the activity in the space and not the time spent in the space. Please make a strong argument in your 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 for why focus rooms shouldn't follow the requirements of regularly occupied. Look at the space matrix for guidance. http://www.usgbc.org/resources/eq-space-type-matrix

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Jon Clifford LEED-AP BD+C, GREENSQUARE Sep 09 2015 LEEDuser Expert 6929 Thumbs Up

James – I think that you are confusing the term “Non-Regularly Occupied Space” with the term “Nonoccupied Space.”

According to the IEQ Space Matrix, IEQc1 applies to both kinds of occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. (regularly and non-regularly occupied), but excludes NONOCCUPIED spacesNonoccupied spaces are defined as spaces designed for equipment and machinery or storage with no human occupancy except for maintenance, repairs, and equipment retrieval., which are “spaces designed for equipment and machinery or storage with no human occupancy except for maintenance and repairs, and equipment retrieval” (supply, warehouse, storage, inactive bookstacks, mechanical/electrical rooms, data floors, closets, etc.), “for areas with equipment retrieval, the space is only nonoccupied if the retrieval is occasional.”

Therefore, if a Focus/Collaboration space is “densely occupied” when in use, it should have CO2Carbon dioxide sensors. In fact, such a space, which may be vacant much of the time, may be the textbook use of such sensors to send increased fresh air only when needed.

“Non-regularly Occupied Spaces” appear only to be excluded from IEQc6 Controllability and IEQc8 Daylight & Views Credits. Even then, this definition includes the proviso, “The one hour timeframe is continuous and should be based on the time a typical occupant uses the space. For spaces that are not used daily, the one hour timeframe should be based on the time a typical occupant spends in the space when it is in use.” Examples include lobbies, pantries, linen closets, active bookstacks, locker rooms, bathrooms, restrooms, fitting rooms, copy rooms, break rooms, waiting rooms, stairways, and corridors.

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MM K
Jun 12 2013
Guest
2658 Thumbs Up

Other routes for airflow measurment devices

Are there any other ways of achieving the credit for non-densely occupied spacesNon-densely occupied spaces are areas with a design occupant density of less than 25 people per 1,000 square feet (40 square feet or more per person)." using another route than airflow measurement devices ?

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Dylan Connelly Mechanical Engineer, Integral Group Jul 01 2013 LEEDuser Expert 9645 Thumbs Up

If you have a constant volume system or 100% OA see 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. #2099. Otherwise you need to have airflow measurement.

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MM K
Jun 12 2013
Guest
2658 Thumbs Up

Non-densely occupied spaces without airflow measurement device

Do all the spaces come into account for this credit? Or are we only looking at the regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space. and deciding which is densley occupeid and which is non-densely occupied?

Also, if there are only few non-densely occupied spacesNon-densely occupied spaces are areas with a design occupant density of less than 25 people per 1,000 square feet (40 square feet or more per person).", can we go without airflow measurement devices? How many are we allowed to have without any measurement devices?

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Dylan Connelly Mechanical Engineer, Integral Group Jul 01 2013 LEEDuser Expert 9645 Thumbs Up

There is no mention of "regularly occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space." in this credit. I doubt you can exclude those spaces. For example, if you have an auditorium that seldom used the system serving it would still need to comply.

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Jeremy Kuhre Sustainable Buildings & Operations Manager Sustainable Solutions Corporation
Jun 03 2013
Guest
1081 Thumbs Up

100% OA VAVs

We are remodeling two floors of a high-rise office tower. A 100% OA 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. introduces OA into the mechanical room for each floor where it is mixed with return air. An 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. in each mechanical room distributes the mixed air to the floor using a VAV system.

With this arrangement, I want to confirm that installing an air flow monitor on the two OA VAVs (or simply showing that the fan is "on" per LIR #2099) and installing CO2Carbon dioxide sensors in all densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). fulfill the monitoring requirements of this credit.

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Ante Vulin Sustainability Manager, YR&G Jun 03 2013 LEEDuser Member 1737 Thumbs Up

The system you describe is not a 100% OA CV system as specified in 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 #2099, so a "fan on" sensor or transducer is not appropriate. For the configuration you describe, the ventilation rate can potentially be determined through monitoring of return, outdoor and mixed air temperatures (before the coil) as well as supply air flow.

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Rubén M. R. Codirector CIVITA
Dec 11 2012
LEEDuser Member
1069 Thumbs Up

Too many densely occupied spaces

Hello everyone, I am working on a three-level commercial office project. The project includes, in total, 223 densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). consisting of meeting rooms of different sizes (4, 8,10 and 14 people) as well as phone booths and some training rooms and cafeterias. As you can tell, this many densely occupied spaces make the credit very expensive for the client, as the number of CO2Carbon dioxide sensors needed is very high.

Do you know any Alternative Compliance Path that we can use to comply with this credit without installing CO2 sensors on each space?

As additional information, we can't install CO2 sensors on the return air ducts, per HVAC design.

Thanks in advance,

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Dylan Connelly Mechanical Engineer, Integral Group Dec 11 2012 LEEDuser Expert 9645 Thumbs Up

Ruben,

Not all credits are good credits for every project. The credit language states "All densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person)." and I don't know how you could alternatively comply.

Personally, I don't agree that small meeting rooms of 4 people or less & less than 150 sf should be included. The energy savings is so minimal it's not worth it. Vamshi Gooje had a good idea (his comment is below) for an argument in favor of excluding such spaces. However, you'd be taking a risk if you didn't include them.

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Wayne Mason Chief Engineer Lincoln Property Company
Aug 22 2012
Guest
83 Thumbs Up

Multiple AHU from shared OA

I have a situation where a mechanical room (4 actually) has two SCU units and one OA inlet. The room acts as a mixing chamber for the return air and outside air but I'm being told I have to have be able to measure the OA going to each SCU individually.

Anyone run into similar situation?

Thanks

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Dylan Connelly Mechanical Engineer, Integral Group Sep 04 2012 LEEDuser Expert 9645 Thumbs Up

Wayne,
Your situation isn't entirely uncommon on older existing systems. We've run into similar cases with mixing chambers associate with large existing units.
Unfortunately, you do need to be able to measure each SCU's outside air intake individually. If you have a common return and OA mixing chamber that both units share you're unlikely to achieve this credit without a system retrofit.
You could submit an "alternative compliance" narrative stating you are meeting the intent of the credit but have an existing system that only allows you to measure the sum of both SCU's OA quantities. I wouldn't hold out on this credit, not all projects are suitable.

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Wayne Mason Chief Engineer, Lincoln Property Company Sep 04 2012 Guest 83 Thumbs Up

Dylan
Thanks for the reply.
I had actually meant to post this under IEQp1. Here is what we have come up with to determine quantities to meet IEQp1 so hopefully the same methodology will apply.

Outside air fraction per unit equation:

Determine the fraction at 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: (AHU-1 CFM) / ((AHU-1 CFM) + (AHU-2 CFM))
For AHU-2 the fraction is the remaining percentage [1 - (Solved Fraction above)]

Once you know that, take the fraction and multiply it by the known measured Outside airflow of the mech room.
Seems pretty straight forward.

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John Kitsalis Principal New England Engineering, Inc.
Aug 16 2012
Guest
227 Thumbs Up

IEQc1 Language

Hello,

I understand the part of the credit involving CO2Carbon dioxide sensors but do not understand the language involving the outdoor airflow measurement device:

"Complete Table IEQc1-2 for all mechanical ventilation systems where 20% or more of the design supply airflow serves nondensely-
occupied spacesEnclosed space intended for human activities, excluding those spaces that are intended primarily for other purposes, such as storage rooms and equipment rooms, and that are only occupied occasionally and for short periods of time. Occupied spaces are further classified as regularly occupied or nonregularly occupied spaces based on the duration of the occupancy, individual or multioccupant based on the quantity of occupants, and densely or nondensely occupied spaces based on the concentration of occupants in the space.."

In my design, all spaces are non-densely and I have multiple indoor units. I have one monstrous unit that provides direct OA to all of the indoor units. How would the phrase above be applied to my design?

Thanks,
Resmey

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David Hubka Director of Operations, Transwestern Sustainability Services Aug 16 2012 LEEDuser Expert 5321 Thumbs Up

All indoor units, served by the montrous unit, must be input into Table IEQc1-2. I assume the indoor units are fan coils or heat pumps; they are considered the system level and therefore each indoor unit must include a OA measurement device with an accuracy of +/- 15% of the design minimum outdoor air rate. Additionally an alarm must be triggered when conditions vary by 10%.

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John Kitsalis Principal, New England Engineering, Inc. Aug 17 2012 Guest 227 Thumbs Up

Thank you! That makes much more sense. Although, how does the 20% come into play? I am thinking that the OA provided to each individual indoor unit must be 20% or more of the supply of the "monstrous" unit.

Additional Info: (The "monstrous" unit is actually an ERV UNIT that provides 100% OA)

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David Hubka Director of Operations, Transwestern Sustainability Services Aug 22 2012 LEEDuser Expert 5321 Thumbs Up

If the project building contains an 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. in which at least 20% of it's design supply airflow is being provided to a non-densely occupied space; then an OA measurement device must be installed at the AHU. Your building does not include densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). therefore every AHU must include an OA measurement device. If your project contained an AHU that exclusively served a densely occupied space; this AHU would not need to be included in table IEQc1-2 of the credit template.

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Michelle Ruda
Sep 20 2011
Guest
158 Thumbs Up

Non-Densely Occupied Spaces Served by Existing AHU

If you have non-densely occupied spacesNon-densely occupied spaces are areas with a design occupant density of less than 25 people per 1,000 square feet (40 square feet or more per person)." served by an existing 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., how should the outdoor airflow measurement be handled?

There is no baseline for when an alarm should occur on the ventilation air since not all spaces are within the LEED scope and no minimum ventilation rate has been calculated via 62.1.

On our specific project, there are 10 floors served by multiple 100% outside air units. We are doing work on a very small portion of multiple floors. The units are not within our scope of work. Short of adding an alarm to each valve providing airflow to each renovated space, which would get very costly very quickly, what would qualify for this credit?

We have no problem meeting the CO2Carbon dioxide sensor portion of this credit.

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Dylan Connelly Mechanical Engineer, Integral Group Sep 22 2011 LEEDuser Expert 9645 Thumbs Up

What you have going for you is that the units are providing 100% outside air. That is much easier to monitor than minimum OSA fans. However, you would likely need an airflow station and alarm (or control wiring to a BMS) at each OSA entrance in order to satisfy the credit.

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Dylan Connelly Mechanical Engineer Integral Group
Jun 27 2011
LEEDuser Expert
9645 Thumbs Up

Demand Control Ventilation

I have a small TI project with 14 small rooms (<100sf, 4 or less people per room) and it seems ridiculous to have to buy expensive C02 stats that will save minimal energy and won't affect the OSA to the space. I have CO2Carbon dioxide stats and DCV in the larger conference rooms.

Title-24 (containing the Mechanical Code in California) has exceptions to the need to have C02 sensors in small rooms with a design occupancy higher than 25 people/ 1000 SF (Spaces with an area less than 150 SF, or a design occupancy of less than 10 people are exempt).

Why doesn't LEED allow this type of exception. Do they?

Quote from the Non-Res Compliance Manual code:

"The fourth exception recognizes the fact that DCV devices may not be cost effective in small spaces such as a 15 ft X 10 ft conference room or space with only a few occupants at design conditions."

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Vamshi Gooje Associate, Thornton Tomasetti | Fore Solutions Nov 21 2011 Guest 301 Thumbs Up

Your argument is reasonable, though LEED has no exception for densely occupied spacesAreas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). with less than 10 people. You can attempt the credit selecting alternative compliance path on the LEED credit form. Acceptance of this approach depends on the GBCIThe Green Building Certification Institute (GBCI) manages Leadership in Energy and Environmental Design (LEED) building certification and professional accreditation processes. It was established in 2008 with support from the U.S. Green Building Council (USGBC). reviewer's discretion and how strong a case you make. Alternatively, you can submit a project 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 but note that the GBCI website states, "... the credit language nor the minimum achievement thresholds can be changed through the Project CIR process." It is hard to say whether you will have success with either of these approaches.

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Max Calabro
Apr 30 2011
Guest
351 Thumbs Up

Automated control

I notice the credit language here requires an alarm when CO2Carbon dioxide levels are more than 10% above desired. We're installed our system to be automated, immediately kicking up air intake when the level increases. I believe this fulfills the intent of the credit, but may not match the language exactly. Has anyone experienced this before, or have an idea what we should expect from the reviewers? Thanks very much!

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Nov 20 2011 LEEDuser Moderator

Max, I believe this would qualify—"alarm" doesn't have to mean bells and whistles going off.

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Suraj Shah Owner Green Footprints
Dec 21 2010
Guest
166 Thumbs Up

Outdoor Air delivery monitoring with increased ventilation rate

How does the alarming system work if the project is attempting IEQ credit 2, wherein 30% extra fresh air is provided? Does the set point then change to the designed fresh air quantity & then trigger alarm if the quantity deflects by +/- 15%?

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Dec 28 2010 LEEDuser Moderator

The credit language ccalls for the set point to be the "Design values." So if your design has higher ventilation rates, that would be the relevant threshold.

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Kathy Buck Senior Project Manager Neumann/Smith Architecture
Aug 23 2010
LEEDuser Member
1821 Thumbs Up

Outdoor Air Delivery Monitoring System installed post-occupancy

Our building owner is having a building-wide outdoor air delivery monitoring system installed throughout the building (not just in the LEED-tenant area of our project) but it won't be installed in our tenant spaceTenant space is the area within the LEED project boundary. For more information on what can and must be in the LEED project boundary see the Minimum Program Requirements (MPRs) and LEED 2009 MPR Supplemental Guidance. Note: tenant space is the same as project space. until about 3-months post occupancy.

Can this still count?

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Tristan Roberts LEED AP BD+C, Executive Editor – LEEDuser, BuildingGreen, Inc. Aug 29 2010 LEEDuser Moderator

I think you would have to submit as an alternative compliance path and hope for a positive response from the reviewer. Seems to me like it meets the intent.

Not sure if this is practical, but could you delay your final application until three months post-occupancy and document it in the regular fashion?

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Michael Smithing Director - Green Building Advisory, Colliers International Jul 19 2011 LEEDuser Member 4584 Thumbs Up

Do I understand correctly that if we have outdoor air delivery monitoring on each of 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. in the building then there is no need to separately monitor the air flow to the CI space we are fitting out?

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Dylan Connelly Mechanical Engineer, Integral Group Sep 22 2011 LEEDuser Expert 9645 Thumbs Up

If the base buildingThe base building includes elements such as the structure, envelope, and building-level mechanical systems, such as central HVAC, and materials and products installed in the project (e.g., flooring, casework, wall coverings). AHU1.Air-handling units (AHUs) are mechanical indirect heating, ventilating, or air-conditioning systems in which the air is treated or handled by equipment located outside the rooms served, usually at a central location, and conveyed to and from the rooms by a fan and a system of distributing ducts. (NEEB, 1997 edition) 2.A type of heating and/or cooling distribution equipment that channels warm or cool air to different parts of a building. This process of channeling the conditioned air often involves drawing air over heating or cooling coils and forcing it from a central location through ducts or air-handling units. Air-handling units are hidden in the walls or ceilings, where they use steam or hot water to heat, or chilled water to cool the air inside the ductwork. is monitored and you know for example it has 15% outside air. Then you can assume the amount of air delivered to your CI space also has 15% outside air. You may want to monitor or at least balance the airflow to your space to ensure that it is adequate.

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