NC-2009 IEQc1: Outdoor Air Delivery Monitoring

  • Outdoor Air Delivery Monitoring requirements diagram for NC, CS, Schools, and CI
  • 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 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.


  • 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 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.


  • 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.


  • 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.


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


  • 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.

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 New Construction and Major Renovations

    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 spacesDensely occupied spaces are areas 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, ventilating 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.


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.


ASHRAE 62.1-2007: Outdoor Airflow Monitoring Devices.

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


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.

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: NC-2009 IEQ

The following links take you to the public, informational versions of the dynamic LEED Online forms for each NC-2009 IEQ credit. You'll need to fill out the live versions of these forms on LEED Online for each credit you hope to earn.

Version 4 forms (newest):

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."

Design Submittal

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

240 Comments

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Lyle Axelarris Civil/Structural Engineer, LEED AP BD+C, O+M Design Alaska
Aug 19 2014
LEEDuser Member
737 Thumbs Up

Please update checklist above

The "Document credit compliance on LEED Online" portion of the checklist provided above needs to be corrected to avoid further confusion.
1. References to ASHRAE 62.1 and OA ventilation rates are not relevant to this credit (or at least to LOL version 4 template)
2. There is no signatory for the ventilation or controls designer for this credit
3. There is no LPE for this credit.
If I am mistaken, please let me know.

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LEED Consultant Green Building and Alternative Energy
Aug 02 2014
LEEDuser Member
1552 Thumbs Up

Outdoor air monitoring through BMS

Hello all,

We want to achieve this credit for a manufacturing facility. The air supplied to the production area is delivered through 26 propeller hooded roof fans and each one supplies 20,000 CFM to the ventilation zone. The ventilation rates supplied to the space are much higher than the ventilation rates stated by ASHRAE 62.1-2007, due the low occupancy. Therefore we would like to justify the credit monitoring the ventilation performance through the BMS to verify the correct performance without having the airflow measurement devices. If an equipment fails, an alarm will be send to the central monitoring and the maintenance department will be notified.

This is because the purpose of the credit is to avoid the CO2Carbon dioxide concentrations in the spaces, but evaluating the proportion of the space, the quantity of occupants in the area and the ventilation rates in the ventilation design this condition will not happen, and also the ventilation system will operate continuously during the occupation hours, this way we can corroborate that the outdoor air flow is according the project. Could this be acceptable for reaching this credit?

Thank you in advance.

Regards,

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LEED Consultant Green Building and Alternative Energy
Jul 02 2014
LEEDuser Member
1552 Thumbs Up

Airflow measurement devices in manufacturing facility

Hello,

We are working on a project which is an industrial plant, the building will be mechanically ventilated. The manufacturing area is about 142,800 sf and this space will only have about 60 workers and it counts with 25 ceiling exhaust fans in the area, my question is, do we have to install one airflow measurement device for each one of the ceiling fans even though it is an open floor plant? or can we install only in half of them and connect the devices to the central system that can control all the ceiling fans and activate them if necessary?

Thank you in advance.

Regards!

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LEED Consultant Green Building and Alternative Energy Jul 02 2014 LEEDuser Member 1552 Thumbs Up

I´m sorry, i meant supply filtered fans, no exhaust fans.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jul 07 2014 LEEDuser Expert 2639 Thumbs Up

Since they are constant volume you are allowed to monitor fan status only.

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LEED Consultant Green Building and Alternative Energy Aug 02 2014 LEEDuser Member 1552 Thumbs Up

Thank you Andrew, we will apply considering only the fan status monitoring.

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Charles Daze Project Engineer Burns & McDonnell
Jun 24 2014
Guest
19 Thumbs Up

Special Circumstance - Ventilation Air Not Required

We have a building with a large area of lockers/toilets. According to ASHRAE 62.1 these spaces do not require ventilation air. These spaces do require exhaust air.

Due to the large area of these spaces and minimal conditioning requirements, these spaces are being served by a dedicated 100% OA unit that heats and/or ventilates only.

Since these spaces are not required by ASHRAE 62.1 to be provided ventilation air, do these units need air flow monitoring? (The rest of the facility will have airflow monitoring as required). Yes, these serve 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)." only.

If yes, CT's on the fans meet the requirements per 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 ID #2099, right?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jul 07 2014 LEEDuser Expert 2639 Thumbs Up

If it is only for make-up air for the required exhaust, then it is not required.

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CT G
Jun 16 2014
LEEDuser Member
154 Thumbs Up

Not enclosed meeting room

Dear all,

We are working with a project that have a densely occupied meeting room. The walls of this room do not go from floor to ceiling and the room is located in a not densely occupied open office.

Do we need to install CO2Carbon dioxide sensors?

Thanks in advance,
Anderson Letti

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jun 17 2014 LEEDuser Expert 2639 Thumbs Up

How tall are the walls and what is the ceiling height?

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CT G Aug 28 2014 LEEDuser Member 154 Thumbs Up

1.8 m / 6 ft

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David Hahn CBHF ENGINEERS, PLLC
Jun 10 2014
Guest
8 Thumbs Up

CO2 Sensors in Firehouse

In the service bayA bay is a component of a standard, rectilinear building design. It is the open area defined by a building element such as columns or a window. Typically, there are multiple identical bays in succession. area (Non-densely occupied space garage) we have a Vehicle Exhaust Removal system AIRVAC911 to maintain air quality and radiant slab heating to condition the space during the winter. The space is naturally ventilated, requiring the occupants to open bay doors as needed to provide ventilation. My questions are:
Is providing a CO2Carbon dioxide Sensor enough for this type application since we have a Vehicle Exhaust Removal system? Do we need to provide some other means of ventilation such as a Fan/Louver combo providing x amount of air changes per hour in addition to the CO2 sensor?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jun 10 2014 LEEDuser Expert 2639 Thumbs Up

Your first question really depends on your design. If you meet all natural ventilation requirements then you are fine for LEED purposes of ventilation. As for this credit, you only need to add CO2Carbon dioxide sensors for any naturally ventilated space. Mechanically ventilated spaces are different.

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Rodrigo Vazquez DYPRO
May 26 2014
Guest
9 Thumbs Up

Outdoor air delivery monitoring

If the project is a core & shell design and the distribution of the area is not know (tenants space) yet, is it correct to specify only a CO2Carbon dioxide sensor on the return duct 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.?

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John McFarland Director of Operations, WorkingBuildings, LLC May 26 2014 LEEDuser Expert 879 Thumbs Up

Hi Rodrigo,
No, a CO2Carbon dioxide sensor in the return duct won't do you anything good either for earning the credit or for knowing whether you have properly ventilated the space.
For core & shell projects, you have to provide a building automation system that has the capacity for future tenants to add CO2 sensors in their densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person).. You also have to provide the direct outdoor airflow measurement and corresponding controls to monitor and alarm in the core & shell design (assuming that you are installing an HVAC system in the core & shell package).
Hope this helps,
John

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Agata Jarzynska Ove Arup & Partners Int. Ltd Sp. z o.o. Oddzial w Polsce
Apr 10 2014
LEEDuser Member
50 Thumbs Up

Classification of a room as "densly occupied"

Hi,
We have a project, where there are large directors' offices. In general, only one person will be working there, but there will be tables with 6 chairs, so let's say additional 6 people can be in this office for some time during the day, from time to time. The office is private office, it is not a meeting room.
If we divide 7 people over the area of the room - we come into "densly occupied space".
We have CAV system there and the amount of fresh air is calculated based on the 7 people in the room, so even if we have only 1 director in the office, there is a lot of fresh air provided.
The system is 100% OA.
Should we provide the CO2Carbon dioxide sensors there and treat the space as "densly occupied"?

Many thanks !

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Apr 11 2014 LEEDuser Expert 2639 Thumbs Up

Agata, since the zone population is defined in AHRAE 62.1-2007 addendum as the number of people expected to occupy the space under normal circumstances, I would say that the population is 1 and non-densely occupied. You may want to use a reset strategy to save energy on unnecessary OA (sized for 7 people) but that is not applicable to this credit.

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Agata Jarzynska Ove Arup & Partners Int. Ltd Sp. z o.o. Oddzial w Polsce Apr 23 2014 LEEDuser Member 50 Thumbs Up

Thanks Andrew!

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Seung Jae Lee
Mar 14 2014
Guest
6 Thumbs Up

Device's capability of measuring the airflow rate

I have a question relating to NC IEQ C 1. Outdoor Air Delivery Monitoring.

According to the “Intent” and “Requirements” of this credit, checking whether ventilation systems supply minimum outdoor airflow rate at all expected system operating conditions is the key function of an outdoor airflow measurement device, not measuring the outdoor airflow rate at all expected system operating conditions.

However, the ‘LEED Reference Guide for Green Building Design and Construction, 2009 Edition’ says, “The direct outdoor airflow measurement device must be capable of measuring the outdoor airflow rate at all expected system operating conditions, within an accuracy of plus or minus 15% of the design minimum outdoor air rate.” (page 439, line 2 to 5)

Is it means that outdoor airflow measurement device should have a capability of measuring the airflow rate of which amount is equal to the amount of maximum supply airflow rate if a VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system have 100% outdoor air operating mode?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Mar 17 2014 LEEDuser Expert 2639 Thumbs Up

You need to determine the OA flow rate that you need to satisfy your system in every condition. It is up to you whether you decide to use the most critical flow as a constant volume flow or to use a setback strategy to determine a variable setpoint. Regardless of which one you choose, your flow station should measure the air and sound an alarm if it is outside of the acceptable variance from the flow setpoint.

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Magda Aghababyan CEO Co-Energi (Pvt) Ltd.
Mar 12 2014
LEEDuser Member
570 Thumbs Up

Air flow measurement for non densely occupied zones

Dear Sir/ Madam,

I have a project that is a hotel with 200 guest rooms that are non-densely occupied. Each guest room floor (20 rooms per floor) is supplied with 3 AHUs. Therefore 100% of the OA suppled by these AHU are served in to the 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).". However if I calculate based on the total OA requirement of the building there is no single guest room that takes 20% or more OA from that total OA requirement, but add up 200 guest rooms and then altogether they take more than 20% OA.

Based on that I have the following questions.

IEQc1 requires direct air flow measurement devices mechanical ventilation systems where 20% or more of the design supply airflow serves non-densely occupied spaces. But I'm not sure whether I should define "space" as a single guest room unit or all guest rooms together (because one AHU supplies air to multiple guest rooms).

Secondly I'm also not sure whether 20% OA requirement is based on the total OA requirement of the building or the outdoor air supplied by each AHU.

I appreciate clarification on this.

Thank you very much.

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John McFarland Director of Operations, WorkingBuildings, LLC Mar 12 2014 LEEDuser Expert 879 Thumbs Up

Hi Magda,
The air handling units each need to have direct airflow measurement. You add up all the airflow going to the 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).". If that is greater than 20% of the total then the requirement applies. Don't forget that all densely occupied spaces still need CO2Carbon dioxide sensors in order to earn the credit.
Good luck,
John

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Magda Aghababyan CEO, Co-Energi (Pvt) Ltd. Mar 12 2014 LEEDuser Member 570 Thumbs Up

Thanx John. So according to your explanation since the total amount of OA supplied to guest rooms is more than 20% of the total OA supplied to building, I have to have direct air flow measurement.

Now next question is at which point the measurement should be taken? Is it at 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. (one measurement per AHU) or is it at each diffuser point (one measurement per guest room)? It makes more sense to measure at each diffuser point because that is the only way to ensure that in each guest room the air flow is maintained within the required limits. But this is a costly exercise.

Will LEED accept if I have air flow measurement devices at AHU level?

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John McFarland Director of Operations, WorkingBuildings, LLC Mar 12 2014 LEEDuser Expert 879 Thumbs Up

Hi Magda,
You measure at the outdoor air intake or better downstream of the filters but before any recirculation of return air (if applicable). I say downstream of the filters because some airflow measuring devices get clogged by particulates so it's better to filter those out. I'm guessing your system is constant volume. If that's the case once each room is balanced to receive the proper amount of outdoor air, the flow rate won't vary. That's why you don't need to measure at each room. If you have a variable flow system, then we may need to talk further.
All the best,
John

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Magda Aghababyan CEO, Co-Energi (Pvt) Ltd. Mar 12 2014 LEEDuser Member 570 Thumbs Up

Hi John. It is a VAVVariable Air Volume (VAV) is an HVAC conservation feature that supplies varying quantities of conditioned (heated or cooled) air to different parts of a building according to the heating and cooling needs of those specific areas. system. What do you think is the appropriate strategy then?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Mar 13 2014 LEEDuser Expert 2639 Thumbs Up

Magda, to clarify what John was saying; the 20% is of the total supply, air not the OA. If you have a 5000 cfm 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 and more than 1000 cfm serves non densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). then an air flow measuring station would suffice in the OA duct. The OA setpoint should be determined using the 62mz calculator for vav systems.

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Magda Aghababyan CEO, Co-Energi (Pvt) Ltd. Mar 13 2014 LEEDuser Member 570 Thumbs Up

Thank you very much Andrew.

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Ian McCall Environmental Engineer Le Sommer Environnement
Feb 18 2014
LEEDuser Member
471 Thumbs Up

CO2 sensors in return air duct instead of within the room

Hello,

As per the CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide # 2142 (http://www.usgbc.org/leed-interpretations?keys=2142), it seems that USGBC allowed CO2Carbon dioxide sensors in return air duct, but as the CIR concerned also others topics (i.e. 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. monitoring), I'm not sure if it is really allowed.
Has anyone tried this solution and been awarded (or refused) the IEQ credit 1 by USGBC ?

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Lauren Wallace LEED Project Reviewer, LEED AP BD+C, Senior LEED Specialist, Certifications Department Manager, Epsten Group, Inc. Feb 18 2014 LEEDuser Member 1295 Thumbs Up

Ian,
CO2Carbon dioxide sensors for densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). must be within the vertical 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 62.1–2007), which is 3-6 feet above the finished floor. In the referenced 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., the project is a Core and Shell project that is a) not required to provide CO2 sensors for densely occupied spaces, and b) is installing an EMS system that allows for future tenants to connect CO2 sensors installed in densely occupied spaces (which is a requirement for LEED-CS projects). A LEED-NC project has different requirements, which is likely why it seems as though USGBC has "allowed" this approach. Measuring the CO2 levels within the return air duct may not be as accurate as measuring the air within the vertical breathing zone, and therefore, locating CO2 sensors in the return air duct within densely occupied spaces is not a valid strategy for EQc1 for LEED-NC projects. Hope this helps.

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Farah A.
Feb 17 2014
Guest
471 Thumbs Up

Increased Ventilation

I am stuck on this LEED BD+C question.

The future building tenant decides to increase the outdoor air ventilation rates by 30% compared to the ASHRAE 62.1-2007 standard in a mechanically ventilated building. Which of the following statements are true? (Choose 3)

-The requirements of the Increased Ventilation credit are met
-The Air Handling Unit flow measurement alarms need to be recalibrated to the new design rates
-The total green energy purchase required for the Green Power credit must be recalculated
-MERVMinimum efficiency reporting value.-13 filters must be installed
-The minimum distance between smoking areas and air intakes has to be 30% higher
-The breathing zones need to be redefined to comply with the Increased Ventilation credit

Apparently the green power is one of the answers- is that an error? I don't understand why it would be an answer.

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Sylvain laporte GASD-Co Feb 17 2014 LEEDuser Member 143 Thumbs Up

Increase the ventilation will increase total energy consumption thus impacting green power amount needed.

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Magda Aghababyan CEO Co-Energi (Pvt) Ltd.
Jan 29 2014
LEEDuser Member
570 Thumbs Up

Automatically adjust dampers

Dear all,

If the system can automatically adjust the dampers when the CO2Carbon dioxide levels vary by +/-10% (instead of the alarm) will it be acceptable for the credit?

Thank you.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jan 29 2014 LEEDuser Expert 2639 Thumbs Up

It would not explicitly comply with the credit requirements but you could submit 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. The problem is that even with dampers, the actuator may fail or the space may be overloaded so, when the system tries to compensate it may not succeed and no one would know.

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Ilana Judah Director of Sustainability FXFOWLE
Jan 14 2014
LEEDuser Member
340 Thumbs Up

CO2 sensors in Residential Project

We have a large residential project that has natural ventilation being used. Are CO2Carbon dioxide sensors required in every room/bedroom of the apartments? Or can we only have one or two in each apartment unit? Thank you.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Jan 14 2014 LEEDuser Expert 2639 Thumbs Up

It would be required in each occupiable space. Do not include bathrooms or closets.

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Kent Liu Mar 13 2014 Guest 40 Thumbs Up

What about the kitchen and the study?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Mar 13 2014 LEEDuser Expert 2639 Thumbs Up

Yes. Those are occupiable spaces.

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Mike Oliva
Dec 06 2013
Guest
49 Thumbs Up

DOAS units

I need some clarification on what definition of a "ventilation system" would be with respect to design that uses a DOAS unit that provides outdoor air to each space. If the OA from the DOAS is ducted to heat pumps distributed throughout the building would you need OA flow stations at each OA duct to each heat pump or just at the DOAS unit OA intake assuming the system is constant volume and balanced to the correct airflow for the space? Thanks!

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John McFarland Director of Operations, WorkingBuildings, LLC Dec 06 2013 LEEDuser Expert 879 Thumbs Up

Hi Mike,
If the DOAS is constant volume, then the airflow measuring device just needs to be at the outdoor air intake for the DOAS equipment. This assumes fixed-position (i.e., non-modulating) balancing dampers at each heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source..
If the DOAS is variable volume where the OA flow to each heat pump could vary based on the OA requirements for each ventilation zone, then an airflow measuring device is needed at each heat pump since the flow could now vary from setpoint.
Hope this helps clarify things.
Good luck,
John

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Lauren Wallace LEED Project Reviewer, LEED AP BD+C, Senior LEED Specialist, Certifications Department Manager, Epsten Group, Inc. Dec 06 2013 LEEDuser Member 1295 Thumbs Up

Hey, John!

I'm not sure your comment about outdoor airflow measurement devices being located at each heat pumpA type of heating and/or cooling equipment that draws heat into a building from outside and, during the cooling season, ejects heat from the building to the outside. Heat pumps are vapor-compression refrigeration systems whose indoor/outdoor coils are used reversibly as condensers or evaporators, depending on the need for heating or cooling. In the 2003 CBECS, specific information was collected on whether the heat pump system was a packaged unit, residential-type split system, or individual room heat pump, and whether the heat pump was air source, ground source, or water source. on a variable volume DOAS is accurate. The intent behind providing outdoor airflow measurement devices is to measure the outdoor air intake flow to ensure that the design minimum outdoor air rate prescribed by ASHRAE Standard 62.1 is being provided at the system level, not at the zone level. In a similar design where the DOAS was variable volume without heat pumps, the outdoor airflow measurement device would still be located at the DOAS. Is there something I'm missing here?

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Mike Oliva Dec 06 2013 Guest 49 Thumbs Up

Lauren, this definition of system and zone were a bit of my issue to begin with... Seems like with a variable volume DOAS as you describe there would be no way to ensure the airflow to each zone is maintained. One zone may require less but the other zones would require the same. If this system is hard balanced and the DOAS modulates down all the zones would be receiving less OA.

therefore it seems you would need the airflow station at each zone AND a modulating damper that would satisfy each zone OA requirement as the DOAS unit modulates airflow?

John, thank you for the response. I hope that is indeed the case.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Dec 06 2013 LEEDuser Expert 2639 Thumbs Up

Mike, the answer to your question is dependant on your design intentA written document that details the ideas, concepts, and criteria that are determined by the owner to be important to the success of the project.. If you just want to comply with the credit requirements then all you would actually need is a CT at the DOAS motor to provide system status. You can look this up in the interpretations library. If you are looking at this from a practical design standpoint then John's answer is 100% correct.

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Valentin Grimaud Thermal Engineer TERAO Green Building Engineering
Dec 02 2013
LEEDuser Member
1038 Thumbs Up

Zero 'densely occupied space'

The project we are working on as no 'densely occupied space' at all. Can we still apply to this credit? In this case I guess we fall 100% in the 'type 2' category isn't it?
Or asked differently: is there a minimum surface area that must be densely occupied in order to be eligible for this credit?
Thanks for your feedback.

Edit: I actually found a densely occupied space, sorry about that. I'm still interested in knowing the answer to this question.

Additional question: Are toilets included in this credit?

Edit again: found my answer, toilets are not included. sorry about the multiple edits.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Dec 03 2013 LEEDuser Expert 2639 Thumbs Up

The answer is no. If you do not have any densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). then there are two possible requirements:

1. Natural ventilation - install CO2Carbon dioxide sensors in every occupied space.
2. Mechanical ventilation - install an outside air flow meter for the OA serving occupied spaces.

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Lauren Wallace LEED Project Reviewer, LEED AP BD+C, Senior LEED Specialist, Certifications Department Manager, Epsten Group, Inc. Dec 03 2013 LEEDuser Member 1295 Thumbs Up

Valentin,

I wanted to piggy-back on Andrew's answer (which is 100% accurate) to point out that you may want to crosscheck what you are submitting under IEQp1: 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. ASHRAE 62.1 will classify spaces as "densely occupied" simply based on the occupant density rates given in Table 6-1 of the Standard. If you are using these rates verbatim in your calculations, the review team may question whether or not there are densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person). within the project. Just know that you are able to calculate your ventilation requirements not using the default values in ASHRAE 62.1 if the spaces should not be seen as densely occupied. Hope this helps!

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Valentin Grimaud Thermal Engineer, TERAO Green Building Engineering Dec 03 2013 LEEDuser Member 1038 Thumbs Up

Lauren and Andrew,

thanks for your reply, that was really helpful!

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John Covello LEED AP BD+C, EBOM, LEED and Sustainability Manager Development Management Group
Nov 11 2013
LEEDuser Member
407 Thumbs Up

Hotel Guest Villas Need OA measurement device?

Hello,

I am with a hotel project that will have 80 odd guest villas. Most will be between 90 M2 (968 sq ft) and 130 M2 (1400 sq ft) in size. There will be three main rooms (bedroom, dressing room, and living room) with fan coil units in each varying in capacity from 570 to 680 cfm. We expect 50 to 60% occupancy with an average of two guests per villa. The villas seem to fall under the definition 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).".So my interpretation of the credit and diagram above is the units will require OA measurement devices. Does this sound correct?

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Rudolph Carneiro HVAC consultant, Sustentech Nov 11 2013 Guest 605 Thumbs Up

Yes, it definitely falls under the requirement of OA measurement. There is a doubt I had with this particular configuration. If the system is variable, i.e., you have variable outside air to the building with ducted outside air to each room with a main OA supply on the Roof. (Which would save you a whole lot on your utility bills). Will you have to vary the setpoint of measurement automatically? In other words, if half of your rooms are occupied in the morning, and in the afternoon you have 25% occupancy, and you plan on shutting off outside air to those unoccupied rooms to save on energy costs, will you have to vary the minimum measurement to set off the visual or audible alert automatically?

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David Eldridge Project Manager, Grumman/Butkus Associates Nov 11 2013 LEEDuser Member 488 Thumbs Up

Are you submitting the villas for ASHRAE 62.1 compliance as mechanically ventilated or as naturally ventilated?

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Susan Clark Technical Specialist NCC Teknik
Oct 01 2013
LEEDuser Member
32 Thumbs Up

CO2 Monitoring in Telephone Rooms

I am working on a project with a number of small quiet rooms. These rooms are approximately 35sf and their purpose is to provide privacy for individuals during phone calls. While they are equipped with a single chair and a small worksurface, the quiet rooms are distributed through an open office landscape where staff have their normal work spaces, and it is not anticipated or intended that they will be used for extended periods.

Because these rooms will be sporadically used by single individuals for short periods of time, the design team does not feel that CO2Carbon dioxide monitoring in each quiet room is practical. Is it reasonable to exclude these rooms from the requirement to install CO2 sensors, even though they technically fall below the 40sf/person threshold defining densely-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.?

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Ahmed Younis Instrumentation and Control Engineer / LEED AP BD+C, Dar Al Handasah Oct 01 2013 Guest 201 Thumbs Up

I think you are right, it is reasonable to exclude these rooms as they not classified as densely occupied spacesDensely occupied spaces are areas with a design occupant density of 25 people or more per 1,000 square feet (40 square feet or less per person)..

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Susan Clark Technical Specialist, NCC Teknik Oct 01 2013 LEEDuser Member 32 Thumbs Up

Actually, they do technically qualify as densely-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.: if the density is 25 people per 1000sf (40sf per person) then it is densely-occupied. The quiet rooms have only 35sf for one person. But it does not seem practical to equip each of these small rooms with a CO2Carbon dioxide monitor.

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Ahmed Younis Instrumentation and Control Engineer / LEED AP BD+C, Dar Al Handasah Oct 01 2013 Guest 201 Thumbs Up

ooops, you right
I will try to find you an answer.

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Ahmed Younis Instrumentation and Control Engineer / LEED AP BD+C, Dar Al Handasah Oct 01 2013 Guest 201 Thumbs Up

Densely occupied space is defined as an area with a design occupant density greater than or equal to 25 people per 1,000 square feet (40 square feet per person). If the total square footage of all dense space is less than 5% of total occupied square footage, the project is exempt from the requirements of this section. Rooms smaller than 150 square feet are also exempt.
I have downloaded PDF from USGBC, I will try to send it to u

http://www.usgbc.org/credits/eq12

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Oct 01 2013 Guest 3686 Thumbs Up

can you post a link to the PDF? or direct us to it? This is a common issue.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Oct 01 2013 LEEDuser Expert 2639 Thumbs Up

Ahmed, your verbiage and link are for LEED EBOMEBOM is an acronym for Existing Buildings: Operations & Maintenance, one of the LEED 2009 rating sytems.. This forum is for NC-2009. There is no 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 this credit that allows for the use of those exceptions. Another user has reported that they achieved this credit simply by omitting the small rooms from the template. They were never questioned about them, which seems reasonable.

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Ahmed Younis Instrumentation and Control Engineer / LEED AP BD+C, Dar Al Handasah Oct 02 2013 Guest 201 Thumbs Up

thanks Andrew
execuse me all for my mistake :)

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Maria Porter Environmental Certification Engineer, Skanska Sweden Oct 02 2013 LEEDuser Member 2455 Thumbs Up

I have gotten this credit denied because we didn’t want CO2Carbon dioxide monitors in this type of tiny chat rooms. I have also questioned why this credit allows exemptions in some systems but not other for the exact same credit.
http://www.leeduser.com/credit/CS-v4/EQc1
and below under Jan 21st 2013.

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John McFarland Director of Operations, WorkingBuildings, LLC Oct 02 2013 LEEDuser Expert 879 Thumbs Up

Maria is correct. There is no exemption in LEED NC for very small but still densely occupied rooms. The spaces require a CO2Carbon dioxide sensor regardless. It may not make sense (and I would say requiring an occupancy sensor that alerts the BAS to the room's occupancy would be a better solution especially for a demand controlled ventilation strategy), but that's the rule and we have to follow it to comply with the credit requirements. As to the project team that omitted the small rooms and were never questioned, shame on them. GBCI should investigate and revoke the credit if that's true. We can't pick and chose which requirements to follow and still say that we are earning the credit.

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BR+A LEED Oct 02 2013 LEEDuser Member 104 Thumbs Up

To follow up on John's comment, there is no language saying that having a CO2Carbon dioxide sensor in the room means it has to have demand control ventilation. The CO2 sensor, for the credit, only needs to alert the occupants when the CO2 levels go 10% above the setpoint.

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Oct 02 2013 Guest 3686 Thumbs Up

weird question- what if a small room had a louvered door like this http://www.jeld-wen.com/catalog/interior-doors/louver could it possibly mitigate CO2Carbon dioxide buildup issues? I'd imagine that if people are in a room for a very long time it would not be helpful ... I guess this would be a question 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.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Oct 10 2013 LEEDuser Expert 2639 Thumbs Up

I think if you had louvered doors then you could consider the small space as part of the larger space (if it exists in that configuration) and be able to take credit for the low density area in the larger space.

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Muhammad Faisal Azizullah Jaffar Sustainability Consultant Ramboll
Sep 19 2013
Guest
124 Thumbs Up

Constant volume system in some areas, VAV in others

Hello,
my project is a campus golf course community project in Qatar. One of the buildings in the master site, the clubhouse, is mixed-use: part hotel, part retail, part restaurants etc. In all areas of this building, except the banquet hall, a constant volume system is used. There will, most probably, be sensors to measure the status of the fans and pressure. Is this sufficient for compliance, at least, in those areas of the building? In the banquet hall, variable air volume is being supplied. Therefore, CO2Carbon dioxide sensors will also be installed. Also there will be 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. boxes with a flow grid that measures both the fresh air intake and recirculated air. Is this approach acceptable?

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Sep 19 2013 LEEDuser Expert 2639 Thumbs Up

Under LEED 2009, there is no provision to monitor only fan status for this credit for CV systems. OA flow needs to be measured on its own.

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Oct 01 2013 Guest 3686 Thumbs Up

Have you looked at 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? The CIRCredit Interpretation Ruling. Used by design team members experiencing difficulties in the application of a LEED prerequisite or credit to a project. Typically, difficulties arise when specific issues are not directly addressed by LEED information/guide is asking if current transducer (CT) monitors are adequate devices to monitor outside air delivery. For a constant volume 100% outside air system similar to the one described by the proponent, the CT approach may satisfy the credit requirement for a direct outdoor airflow measurement device, provided the CT device has been properly calibrated during the installation and commissioning process. Properly calibrated, the CT device would alert the BAS to a change in the fan status, which would indicate a change to the amount of outside air being delivered. In order to satisfy the credit requirements the submittal must show how the CT has been calibrated, and must outline the monitoring sequence. If the system is not 100% outside air, or not constant volume, the CT device would not be adequate.

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Andrew Mitchell, P.E. Mechanical Engineer / LEED Coordination Manager, Moses & Associates Oct 01 2013 LEEDuser Expert 2639 Thumbs Up

Kathryn, I am aware of that interpretation and I have used it to achieve this point on projects in my office. The original comment did not mention the use of 100% OA units, but does mention recirculated air. The CIR will not apply to CV mixed air units. If there is a 100% OA unit then Mr. Jaffar should clarify. Thanks for adding this though.

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Aaron Doherty
Sep 13 2013
Guest
9 Thumbs Up

C02 Monitoring Project

Hi all,

I am doing an undergraduate senior project for my major requirement in my University. My partner and I are planning to monitor the levels of C02 in dorm rooms on campus. More specifically, there are dorms that do not have central air and these dorm rooms tend to get "stuffy" in the heating season. We are out to discover if there is possibly a build up of unhealthy C02 levels in these rooms. As you can imagine, I have many questions as to how to go about this in the right way. Where in these rooms should we place the sensors? Should we also measure outdoor levels? Any tips are greatly appreciated. Thanks!

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Kathryn West LEED AP BD+C, O+M, Green Globes Professional, Guiding Principles Compliance Professional, Energy Ace Oct 01 2013 Guest 3686 Thumbs Up

It'd be helpful to read ASHRAE 62.1

LEED says to measure in the 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 62.1–2007) 3'-6' above the floor (around where light switches are located is ~48") I think ASHRAE 62.1 says the breathing zone is 3" - 6' above the floor. The best measurement location may depend on the type of air distribution system (ceiling supply vs under floor air distribution) I am not sure, I'm not a mechanical engineer, maybe someone can chime in.

Yes it would be a good idea to measure outside CO2Carbon dioxide concentrations. It will give you a better understanding of what's going on, especially if you're near any industrial area or highway.

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Marian Keeler Senior Associate Thornton Tomasetti / Sustainability
Aug 23 2013
LEEDuser Member
3556 Thumbs Up

High Rise Residential - smoke detector/CO2 mon. combined device?

Hi All -- I see my question might already be partially answered in the conversation from May 28, 2013. Here's the question: Because the 250 residential units in our project are non-densely occupied, is the solution as simple as installing CO2Carbon dioxide monitor/detectors in each unit? Design engineers are proposing a combined CO2 / smoke in each unit. If this is allowed by LEED, I assume they must be hardwired, not plug ins? Thanks.

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John McFarland Director of Operations, WorkingBuildings, LLC Aug 24 2013 LEEDuser Expert 879 Thumbs Up

Hi Marian,
I think you need to go back to your design engineers and ask them to show you this combo CO2Carbon dioxide/smoke detector they propose. I have yet to see such a device available. I have a feeling that they are confused between CO and CO2. There are many CO/smoke detectors out there, but CO is not a surrogate for CO2. That said if you measured and alarmed based on CO2 in EVERY space (not just the residential unit as a whole) perhaps you could meet the credit requirement via an alternative compliance path. Your rationale would be that by ensuring CO2 levels are acceptable in EVERY space then the OA ventilation rate must be at least the rate required by 62.1. To reiterate though, first make sure your design engineer is up to speed on their high school chemistry. :-)
Good luck,
John

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Nov 23 2014
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