Entry Type ID Date Applicable Rating System Primary Credit Inquiry (LIs) Ruling (LIs) Related Addenda/LIs Related Resources Campus Applicable Internationally Applicable Country Applicability Reference Guide (Addenda) Page (Addenda) Location (Addenda) Description of Change (Addenda) "LEED Interpretation" "1656" "2007-01-16" "New Construction, Commercial Interiors, Core and Shell" "EQc1 - Outdoor air delivery monitoring" "Residential projects without directly ducted makeup air typically get makeup air either from operable windows alone, from operable windows plus pressurized corridors, or from either or both of those sources, plus negative pressure created by bathroom fans and kitchen exhaust hoods (which may or may not be always on). For LEED NC 2.1 projects, it was asked whether CO2 monitors must be provided for low density residences. In the CIR ruling from 9/20/2004, it was confirmed that CO2 monitors for these residential spaces are not necessary to meet the intent of the credit. For LEED NC 2.2 projects, does this ruling from 9/20/2004 apply? Do residential units without ducted makeup air now require CO2 monitoring? If the ruling varies depending on the strategy by which the units receive makeup air (operable windows, pressurized corridors, bathroom and kitchen fans alone or in combination), can you indicate which scenarios require CO2 monitoring and which do not?" "The applicant is requesting clarification on the applicability of a LEED NC 2.1 CIR ruling for LEED-NC 2.2. Under LEED-NC v2.2, EQc1 has been modified to include two methods of compliance: 1. For densely occupied areas (25 persons/ 1000 SF) use CO2 monitoring 2. For systems serving all other spaces employ outdoor air delivery monitoring Based on the information provided in this inquiry, the first option described above does not apply to individual residential units. Therefore, the second option should be followed. If the outside air (OA) supply is through a pressurized corridor, the implementation of this credit is straight forward. If OA is introduced directly to a conditioning unit (for example- a heat pump or a fan-coil unit) it may be possible to monitor OA delivery to the unit individually. For all other modes of OA supply, this credit may not be applicable. If the residential project has any densely occupied spaces such as meeting rooms, CO2 monitoring should be provided for those specific spaces." "None" "None" "LEED Interpretation" "1701" "2007-03-15" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Carbon dioxide (CO2) monitoring " "USGBC allows projects registered under LEED-NC v2.1 to use LEED-NC v2.2 credits. USGBC also decided after this initial decision that certain credits must be a group because they were logically linked together. In this case EQ Prerequisite 1, Credit 1 and Credit 2 are a linked group. Some LEED-NC v2.1 projects pursuing EQ Credit 1 that completed design before the credits were grouped together by the USGBC. This means that CO2 sensors were designed into the system and construction was completed before the credit grouping occurred. If CO2 sensors were installed for every mechanical ventilation system that monitor non-densely occupied spaces, and those sensors provide monitoring in the breathing zone as defined by LEED-NC v2.2 (3 feet to 6 feet above the floor), can the sensors be used to obtain credit under v2.2 in lieu of the required direct outdoor airflow measurement devices? In essence, can CO2 monitoring be used non-densely occupied spaces, so long as the sensors meet the requirements for densely occupied spaces? Approving an approach as described above would help prevent v2.1 projects, which determined long ago that they meet the requirements of v2.2 for EQ Prerequisite 1 and Credit 2 more effectively than the v2.1 requirements, from ripping out properly placed and operational CO2 sensors to install OA sensors simply because a grouping of credits occurred after a project was designed and constructed." "EQc1 in LEED-NCv2.2 requires air flow measurement devices in each mechanical ventilation system serving non-densely occupied areas. This requirement is to meet the intent of sustaining occupant comfort and well-being through ventilation system monitoring. Use of CO2 sensors in non-densely occupied spaces that meet the requirements for densely occupied spaces under LEED-NCv2.2, in lieu of direct outdoor airflow measurement, meet the intent of EQc1.\n\n **Update October 1, 2013: Applicable credits were updated. " "None" "None" "X" "LEED Interpretation" "1716" "2007-06-06" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Carbon dioxide (CO2) monitoring " "Our project is a laboratory building with several different occupancies. We intend to meet the requirements of this credit (LEED 2.1) as follows: System 1) Office Area. This area consists of one conference room and two floors of private offices and open office areas. We will provide three CO2 sensors: one in the conference room and one at breathing level near a return grille in one of the open office areas on each floor to provide a representative reading for all the offices on that floor. The AHU will have a direct outdoor airflow measurement device and the outdoor air will be kept constant during occupied hours. (This conference room would not be considered a densely occupied space per LEED 2.2). System 2) Laboratory Spaces. These rooms will be provided with 100% outside air and 100% exhaust. The CIR ruling of 8/4/2003 stated that a lab space ""would require some instrumentation to report on the resulting IAQ conditions to capture the point. CO2 sensors per se may not be required, but a monitoring system for the lab spaces should provide feedback in a form that affords operational adjustments."" We propose using the thermostats as a means to monitor the lab IAQ. Thermostats located in the breathing zone would only be satisfied if the supply air (100% OA) was reaching the breathing zone. Operational adjustments to the air distribution system would be made as a result of low occupant comfort should the ventilation effectiveness be low. System 3) Electron Microscope Imaging spaces. These four rooms will be provided with minimal outside air due to the low occupant load relative to the equipment cooling load. We will provide a CO2 sensor in one of the four rooms at breathing level to provide a representative reading for these rooms. The AHU will have a direct outdoor airflow measurement device and the outdoor air will be kept constant during occupied hours. System 4) Clean Rooms. This large room is served by one large AHU, capable of providing 100% OA, and eight smaller recirculating AHUs. The clean room function requires that the outside air and exhaust air be maintained to keep the space positive at 0.02 inches. We will provide a CO2 sensor near the return at one of the circulating AHUs to provide a representative reading for this area. The large AHU will have a direct outdoor airflow measurement device. Do the quantities and locations of the CO2 sensors satisfy this credit for Systems 1, 3 and 4? Will the room thermostats suffice as a monitoring system as discussed for System 2?" "The applicant is requesting confirmation on the use of different strategies in order to comply with EQc1 requirements. System 1 - The approach presented is not acceptable. The numbers of sensors proposed do not cover the areas appropriately. For example, if there are more people in one office and other offices are empty, the CO2 sensor will still sense the same CO2 concentrations, in essence under-ventilating the occupied office and over-ventilating the unoccupied ones. System 2 - The proposed method is not acceptable. Satisfying a thermostat is not the same as meeting IAQ requirements. CO2 is used as an indicator of issues with IAQ for the purposes of this credit. Typically, projects with 100% Outside Air (OA) requirements have some form of differential pressure sensors to monitor IAQ. System 3 - One CO2 monitor will be required in each room to meet the requirements of this credit. System 4 - This approach seems reasonable. Locate the CO2 sensor at the return grille of the recirculating air-handler farthest away from the air-handler providing outside air. In your submission, include a drawing of the air-handlers with the OA AHU and the CO2 sensor location clearly marked. The information provided in the CIR indicates that this project could utilize strategies from NCv2.2 to earn this credit. Please refer here for additional information about substituting NCv2.2 credits in NCv2.1 projects: http://www.usgbc.org/ShowFile.aspx?DocumentID=1704 Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1741" "2007-03-27" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Outdoor air delivery monitoring" "Our facility\'s HVAC system consists of high-efficiency, packaged, direct-fired \'Cambridge\' Unit heaters, passive intake louvers and powered exhaust fans. There is no ducted air distribution system. We propose to install airflow devices at each of the exhaust fans, instead of the intakes. We feel that this makes sense because the exhaust fans will always be \'on\', whereas the \'Cambridge\' Unit heaters will not, when heat is not required. Furthermore, it follows that measuring air being discharged from the building would be equivalent to measuring fresh air being induced into the building, since fresh air will necessarily replace exhaust air in an equal amount. Considering that this building type can be somewhat porous (when the loading dock doors are open) and, per industry norms, always under negative pressurization, it is most logical to measure air where it is being exhausted (since this necessarily will happen in a controlled way at specific locations), rather than where it is being brought in (which would be variable and would happen throughout the building). In accordance with the requirements of this credit, the airflow metering devices will be tied to alarms to alert building occupants if the prescribed airflow pattern ever fails. Finally, the minimum outside air rate (OAR) will be considerably higher than the minimum prescribed by ASHRAE 62.1-2004. The standard prescribes a minimum OAR of 0.06 cfm/sf for this building type. The specified design OAR of 3 complete air changes per 8 hour interval exceeds this minimum by a factor of 3.66. This will also allow us to achieve EQc2 - Increased Ventilation. Is this allowed?" "The applicant is requesting an interpretation of EQc1 and proposing to monitor exhaust air-flow rather than incoming air flow. Based on the project description and conditions, it appears that this credit is not applicable. The credit is specifically intended to address issues with ventilation in environments where a fixed amount of minimum outside air is provided through a specific incoming path. Since the path of incoming air in this project can vary significantly, it would be nearly impossible to trouble-shoot any problems in the ventilation system through the proposed monitoring system. Based on the project narrative, it appears that this project would be best served by a CO2/ CO monitoring system that has alarm triggers." "None" "None" "LEED Interpretation" "1830" "2007-08-09" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell" "EQc1 - Outdoor air delivery monitoring" "We request clarification on the circumstances under which CO2 monitoring in non-densely occupied spaces can be employed in lieu of direct outdoor airflow measurement devices. The project is a hotel facility registered for NCv2.2. Common areas such as the lobby, corridors and meetings rooms are ventilated by roof top units, and guest rooms are served by individual VPAC systems installed in the perimeter wall. The project team is considering how the credit criteria can be applied to the guest rooms. Per the credit requirements, these spaces would qualify as non-densely occupied and therefore be subject to the requirement for a direct outdoor airflow measurement device. A 1/16/2007 NCv2.2 ruling addresses a similar situation in a residential project, and suggests that two design scenarios might allow for meeting the requirements in these spaces: 1) Make up air could be supplied via a pressurized corridor in a manner conducive to monitoring at the large AHU serving the space. 2) It may be possible to monitor OA that is introduced directly through a conditioning unit. The first scenario is not possible because of fire safety codes that prohibit use of the egress corridor to supply make-up air for the guest rooms. A review of available air flow monitoring products for these small HVAC systems indicates that the second scenario is also not possible due to a lack of commercially available options. The project team is willing to install CO2 monitors in each guest unit to ensure that adequate ventilation is maintained for occupant comfort and well-being. Another recent CIR filed under NCv2.1 seems to support this methodology and states that ""use of CO2 sensors in non-densely occupied spaces that meet the requirements for densely occupied spaces under LEED-NCv2.2, in lieu of direct outdoor airflow measurement, meet the intent of EQc1."" However, it is unclear if this ruling is specific to projects registered under NCv2.1 that are seeking to employ v2.2 credit criteria, or if this compliance path is available to all NC projects. Can an NCv2.2 project utilize CO2 monitoring in non-densely occupied spaces as well as densely occupied spaces to meet the intent of the credit? If not, would monitoring the volume of air traveling through the exhaust system in each guest room or continuously monitoring the damper position of each VPAC system be appropriate?" "The project is requesting the use of CO2 monitoring in non-densely occupied spaces as well as densely occupied spaces to meet the intent of EQc1. The CIR Ruling dated 3/15/2007 adequately addresses this question. This project will meet the intent of EQc1 based on their proposed approach as long as the requirements for CO2 sensors in densely occupied spaces per LEED NCv2.2 EQc1 are met for the non-densely occupied spaces as well. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1840" "2007-08-13" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Outdoor air delivery monitoring" "To monitor outside air intake we propose to utilize the DDC controls to measure temperatures for the outside air, return air, mixed air, and supply air. The DDC calculations will result in the total CFM of outside air delivered well within the 15% accuracy required. Additionally, the controls configuration will provide alarms whenever the delivered amount of outside air is below the minimum threshold. As a secondary measure, CO2 sensors will be required for ALL building tenants per the LEED CI credit EQ 1. This project exceeds the minimum ventilation requirements of ASHRAE Standard 62.1-2004 by well over 30%. These three parameters will ensure that the minimum outside air will be delivered, monitored, and alarmed per the requirements of LEED CS EQ credit 1. Will our proposal meet the intent of this credit?" "The applicant is proposing an alternative outside air delivering monitoring device which monitors temperatures of outside air. The EQc1 credit requirement states for mechanically ventilated spaces: ""For each mechanical ventilation system, provide a direct outdoor airflow measurement device capable of measuring the minimum outdoor airflow rate with an accuracy of plus or minus 15% of the design minimum outdoor air rate, as defined by ASHRAE 62.1-2004."" The system proposed does not directly measure outdoor airflow rates, as flow rate cannot be measured by temperatures; therefore this strategy would not meet the credit requirements. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2099" "2008-04-24" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc1 - Outdoor air delivery monitoring" "Our office has two projects that have been struggling with the requirements of EQ Credit 1. Although very different in type, they have taken similar approaches to ensuring outdoor air delivery to occupants. 1) The first project is a historic renovation of a low-rise residential building with seven units. Fresh air is delivered to the building via an Energy Recovery Unit (ERU) that exchanges exhaust air from the kitchens and washrooms of the units for 100% outside air, which is delivered to fan powered boxes in each unit. The ERU does not have an economizer or an air damper. 2) The second is the renovation of an existing doubled loaded corridor school building, which does not have a central air conditioning system, but instead uses perimeter unit ventilators to provide and heat outside air. The dampers on these units are controlled by CO2 sensors located at the thermostat, and will meet the intent of the credit. However, a few non-perimeter classrooms and offices cannot accommodate these perimeter unit ventilators, and thus has a centrally located unit ventilator that provides fresh air to these particular rooms. This ventilator also uses 100% outside air, and also has no dampers. Our suggested approach to both of these projects is to use a current transducer to monitor the performance and status of the ERU and unit ventilators, instead of using an airflow monitor as the credit requirements call for. The current of the fan varies proportionally to the load so that if the unit is malfunctioning (decreased or no airflow) it will be clearly indicated by the power being consumed by the fan. The CT monitor would then report immediately to building management who would field verify the problem and determine if maintenance is needed. We feel this approach complies with the intent of this credit for the following reasons: 1. The units are designed to run at a fixed airflow rate at all times, never to be affected by damper positions, and thus the only instance where air is not being delivered at the appropriate flow is if there is a malfunction with the unit. 2. Monitoring the outdoor airflow of units that are equipped with outdoor air dampers is useful because the dampers can be adjusted based on outdoor airflow readings. Our systems, however, do not have an outdoor air damper because they use only outdoor air. If we directly measure the outdoor airflow, the unit has no way to respond or be recalibrated to address excess CO2 in the space. Outdoor air flow monitoring could be performed, but the results would be of little use. 100% outside air systems are an important tool in providing fresh and healthy interior environments. We believe that the CT monitoring approach is the best method by which 100% outdoor air units can be measured, and also addresses the intent underlying tenets of the credit. It can be argued that outdoor airflow monitors could also provide this level of measurement (on or off), but it provides no more value or functionality than the CT monitor suggested here in the case of 100% outside air units. Please comment on whether this strategy can be used in achieving EQ credit 1." "The CIR 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. Note that the CT device does not relieve the project of the requirement to monitor room CO2 levels in all densely occupied spaces. -NCv2.2 Requirements state clearly that densely occupied spaces (such as classrooms - mentioned in the CIR) must have CO2 concentrations monitored. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2142" "2008-07-02" "New Construction, Schools - New Construction, Core and Shell" "EQc1 - Outdoor air delivery monitoring" "A roof-mounted fan delivers 100% outdoor air into a dedicated shaft duct. The fan operates using a variable frequency drive motor to maintain a constant static pressure within the shaft duct. A variable-air-volume (VAV) terminal unit located in the mechanical room on each floor of the building controls the delivery of the outdoor air from this shaft duct to the mechanical room. This VAV terminal unit is ducted on its intake side to the dedicated outdoor air shaft duct. Only outdoor air passes through this VAV terminal unit. The mechanical room acts as a mixing plenum for the outdoor air and the return air from the floor before that mixed air is drawn into the air handling unit located in the mechanical room. The air handling system is a floor-by-floor design with a single air handling unit located on each floor and serving only that floor. This VAV terminal unit contains a pressure independent primary air volume controller that controls the supply air quantity to within 5% of the airflow setpoint regardless of changes in system static pressure. This VAV terminal unit measures airflow with a pitot-tube assembly. The independent controller converts the measured velocity pressure using the known cross-sectional area to calculate the actual airflow rate. This measurement and calculation is within 5% of the airflow rate setpoint. In the ""occupied"" mode, each VAV terminal unit controls to the design outdoor air flow setpoint for its respective air handling system. In the ""unoccupied"" mode, the control damper in each VAV terminal unit is closed. The VAV terminal units controlling outdoor air to each air handling system operate based on the following sequence of operation for the control, monitoring and alarming of the outdoor airflow provided to each floor\'s air handling system: - Outdoor air fan energizes when the Energy Management System (EMS) indicates the building is in ""occupied"" mode. - Each VAV terminal unit in the outdoor air delivery system opens upon energizing of the outdoor air fan. - A temperature sensor at each VAV terminal unit controls the electric heater to maintain a minimum of 50 degrees F in the mechanical room. - A VAV terminal unit fails closed in the event of power loss. - The VAV terminal unit controller shall monitor and trend the outdoor air delivered to each air handling system. - Each VAV terminal unit graphic displays the measured airflow and the airflow setpoint. - If the measured airflow at a VAV terminal unit varies by more than 10% of its setpoint, an alarm message is sent to the Central Control Panel (CCP) and a notification alarm is generated to alert the building operator of this condition. With respect to carbon dioxide (CO2) monitoring, a CO2 sensor is located in the return air transfer duct at each floor\'s mechanical room. This sensor has an accuracy of +/-3% over a range of 0-2000 ppm. Each floor\'s CO2 sensor is monitored and trended by the EMS. The EMS has no less than fifty (50) points available for future tenant use as inputs for CO2 sensors installed in densely occupied areas. Does the system as outlined herein meet the requirements of LEED-CS v2 EQ Credit 1 - Outdoor Air Delivery Monitoring?" "The approach described above will satisfy the requirements of this credit. However, the project team should make sure that the VAV setpoint is established based on the minimum outdoor air requirements of ASHRAE Standard 62.1-2004, for each floor to comply with EQp1. Additionally, the roof-mounted fan which is stated to be maintaining static pressure in the shaft duct, should provide at least the minimum outdoor air requirement of ASHRAE Standard 62.1-2004, for the building to comply with EQp1. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2192" "2008-06-27" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc1 - Outdoor air delivery monitoring" "This CIR is in reference to the ventilation design for a two tower high-rise office building. The project in question uses several Air Handling Units (AHUs) which all use 100% Outdoor Air (OA). Those AHUs are equipped with heat recover units (run-around-coils) but don\'t have any economizers or air dampers. Unlike to a similar posted CIR, our systems utilize Variable Frequency Drives (VFD) to deliver a variable amount of the 100% OA to the space. The total volume flow between its minimum and maximum for each unit is dependent on the occupancy in the rooms and areas being served. The minimum requirements for fresh air according to ASHRAE 62.1-2004 are always met. Since we have only 100% OA systems, we intend using the frequency readout from the VFD as a measurement for the OA being delivered to the space. The VFD and its frequency readout will be calibrated to achieve an accuracy of plus or minus 15%. We would use the frequency of the VFD equal to the minimum air, which must be delivered to the space, as set-point for the minimum outdoor airflow rate as required by LEED for New Construction Version 2.2 EQc1. In case conditions vary by 10% or more from the set-point the building operator will be alarmed via the building automation system. Would this measurement method qualify for earning this credit? For the same system as described above we are planning to install CO2 sensors for densely occupied spaces to obtain the credit. The installation location of those sensors will be in the return duct of every densely occupied room and not in the breathing zone between 3 ft and 6 ft. This installation location makes sure no averaging of measurements from several rooms takes place. According to ASHRAE 62.1-2004 User\'s Manual page 6-27, 3rd column, this would be appropriate. Is the designed installation location in conjunction with the EQc1 requirements to qualify for this credit?" "The project is requesting guidance to determine if the project\'s Air Handling Units (AHUs) Variable Frequency Drives (VFDs) are a valid alternative to meeting the credit requirements (in lieu of installing a direct outdoor air measurement device), and if the installation of CO2 sensors in the return ducts also meets the credit requirements. Based on the description of the systems, fan speed can be calibrated to airflow and used to meet the EQc1 requirement for a ""direct outdoor airflow measurement device."" In this case, using the VFDs to determine the outdoor air intake flow in 100% outdoor air supply systems is a reasonable outdoor air delivery monitoring strategy. As for CO2 monitoring, the credit requires CO2 sensors to be installed in the breathable zone (3 to 6 feet above the floor) in densely occupied spaces. Even though ASHRAE 62.1-2004 may allow return duct CO2 sensors, the CO2 monitoring requirements for this credit are not specifically associated with ASHRAE 62.1-2004. Therefore, CO2 sensors are required in the breathable zone. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2435" "2009-01-23" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Outdoor air delivery monitoring" "Our project is designed with a 4 pipe fan coil system supplied by a central plant which thermally conditions the following type spaces; dormitories, active and passive common rooms (study/ recreation lounge), classrooms, conference rooms, and administration offices. We propose to meet the credit intent by incorporating the following strategies. The dormitories are designed for natural ventilation through operable windows sized to exceed EQ p2 requirements and will have a CO2 sensor that sends an alarm to the BAS when levels exceed 900 ppm. All other space types will receive outside air through a constant volume 100% OSA AHU located on the roof with airflow measuring stations that sends an alarm to the BAS if the design outside air monitors a change of +/- 15%. The active and passive common areas, classrooms, and conference rooms are considered densely occupied and will have a CO2 sensor that sends a signal to the BAS when CO2 level exceed 900 ppm. Our credit interpretation request is to confirm that for densely occupied spaces with our above system types that sending an alarm signal to the BAS meets the credits intent. It is unclear if an active means of bringing increased outside air to the densely occupied spaces is required." "The applicant is requesting confirmation on the strategy of using CO2 sensors connected to the BAS system for densely occupied spaces for EQc1. These strategies described above appear to meet the intent of the credit; an active means of bringing increased outside air to the densely occupied spaces is not necessary to meet the credit requirements. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "431" "2002-12-04" "New Construction, Commercial Interiors, Core and Shell" "EQc1 - Carbon dioxide (CO2) monitoring " "A previous Credit Ruling stated: ""The Committee agreed that monitoring CO in a residential application was an appropriate step to address indoor air quality in this occupancy."" We have thus chosen to use this approach for another multi-family rental apartment project. This project has no assembly spaces of any kind, so our strategy relies solely on the CO monitoring of each individual dwelling unit. We propose to install battery-powered CO monitors with requirement placed on tenants not to tamper with these units, while providing tenants information on testing CO monitor functionality and providing building-wide testing and battery replacement for the CO monitors as part of annual unit inspections and maintenance. Please confirm whether this approach constitutes an acceptable approach to CO monitoring of the dwelling units, or whether hard-wiring will be required." "The approach to equivalency for this credit described above is not adequate to meet the intent of the credit. Although CO monitoring may be an integral part of an indoor air quality monitoring program in residential projects, the system described does not effectively address indoor air quality by itself. To achieve an equivalency to this credit, an indoor air quality monitoring program must be robust and on-going. The credit requires that the data collected from air quality monitoring be used to inform building operating procedures, by generating data which can be used to improve building operation. In the 1/18/2002 credit inquiry cited, the CO monitors were part of a wider IAQ monitoring protocol which was implemented throughout the building by building management. This protocol was designed to test for a variety of indoor air contaminants, supported by the use of CO monitors at key locations near combustion devices to support achievement of the credit. The proposed interpretation request suggests that the IAQ program consists only of CO monitors. The program does not address a range of possible contaminants, does not describe how residents can be required not to tamper with the monitors, and does not indicate that high CO readings will be addressed by building management in any way which would improve indoor air quality. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "5073" "2007-09-11" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell, Existing Buildings" "EQc1 - Outdoor air delivery monitoring" "Our project is an engineering educational facility with extensive laboratory and research spaces. Our building is mechanically ventilated, and for densely occupied spaces (occupant density above 25 persons/1000 SF), we are able to provide calculations demonstrating that the outside air rates never drop below those required by ASHRAE 62.1-2004. In addition, based on the outside air rates, the CO2 concentrations never exceed the limits as set by ASHRAE 62.1-2004, Appendix C. In this case, if calculations are included with our LEED submittal, can we be exempted from the requirement for CO2 monitors in densely occupied areas? Below is the calculation for the building. 4 Supply Units at 42,500 CFM each = 170,000 CFM 1 Return Unit at 40,000 CFM 1 Exhaust Unit at 126,000 CFM Max OA = 130,000 CFM = 76% Below are minimum values based on minimum exhaust requirements and 30% turndown on VAV spaces. These values are based on minimum everything for a conservative calculation, and the assumption is that in reality, not all spaces will be minimal at once. Supply = 72,000 CFM Return = 16,000 CFM Exhaust = 53,000 CFM OA = 56,000 CFM = 78% Below is then the calculation for one example 1,400 square foot laboratory space. Min Supply = 1,100 CFM Min OA = 856 CFM (78% of Supply) ASHRAE 62.1-2004 OA = 672 CFM" "No, densely occupied areas cannot be exempted from the CO2 monitor requirement to earn EQ credit 1. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "908" "2004-12-21" "New Construction, Existing Buildings, Commercial Interiors, Core and Shell, Schools - New Construction" "EQc1 - Carbon dioxide (CO2) monitoring " "The intent of the credit is to ""Provide capacity for indoor air quality (IAQ) monitoring to help sustain long-term occupant comfort and well-being"". The requirements are ""Install a permanent carbon dioxide (CO2) monitoring system that provides feedback on space ventilation performance in a form that affords operational adjustments"". The requirements portion of the credit language then refers to complying with ASHRAE 62-2001 Appendix C. The reference manual Design Approach section of EQc1 provides a suggested approach to obtaining the credit and in our opinion incorrectly states that ""Indoor CO2 concentrations must be compared to outdoor CO2 concentrations to determine the differential point at which ventilation rates should be adjusted"". Our understanding is that credits are awarded based on the Credit Intent and the stated Requirements contained in the credit language. The reference guide plays a valuable role in helping practitioners apply the principles but does not override the specific credit language. Previous credit interpretations have maintained the requirement for outside CO2 sensor based on the Design Approach contained in the reference guide but not the specific requirements of the credit. The specific requirements of the credit are ""Install a permanent carbon dioxide (CO2) monitoring system that provides feedback on space ventilation performance in a form that affords operational adjustments"". An outside sensor is not required to accomplish this requirement. The second requirement is to meet ASHRAE 62-2001 Appendix C. Appendix C provides guidance and recommendations on CO2 concentrations including concentration levels above outside conditions to maintain satisfactory conditions for bioeffluents (body odor) dilution, typical range of outdoor CO2 concentrations, and fresh air flow rates required as a function of physical activity, none of which require the installation of an outside CO2 sensor. Outside CO2 concentrations in the area of the project have fluctuated less than 75 PPM over the last 10 years based on several hundred indoor quality studies performed by members of our firm during this period. The fluctuations observed can be attributed to proximity to carbon dioxide production activities such as vehicle traffic, electrical generation, or other forms of combustion or contaminate sources. While outdoor ambient CO2 fluctuations exist, they are generally minor and represent negligible impact on the volume of fresh air introduced into the building. Buildings are designed for a maximum ventilation rate based on occupant load. The ventilation system fresh air volume can be fluctuated based on CO2 concentrations in the building. This is our understanding of the intent of EQc1. The designer established the ventilation rate on the requirements in ASHRAE 62 based on the type of occupant activities. These rates are related to CO2 levels based on assumptions of outdoor CO2 levels in ASHRAE 62 allowing energy savings from reduced ventilation rates when building occupant population is less than peak design. As such the standard does not require outdoor CO2 sensing because the design ventilation maximum is fixed and cannot be changed by an outdoor CO2 sensor. The reference to ""above outdoor levels"" contained in the standard is to alert the designer to consider ambient CO2 levels in establishing the maximum ventilation rate, not as a requirement for an outside CO2 sensor. The population of occupants in the building can be monitored and controlled through the building automation system by a CO2 monitoring system measuring only interior conditions. We are requesting the USGBC clarify that the EQc1 Intent and Requirements contained in the credit language are the standard that must be met for this credit and, based on the specific requirements of the credit language including ASHRAE 62 Appendix C, acknowledge that an outside sensor is not required thus correct the 9/8/2004 CIR." "The project is requesting clarification on whether an outdoor CO2 sensor is required for achievement of this credit. The approach outlined in your request is reasonable. USGBC will allow projects to determine setpoints based on an ambient CO2 concentration at a conservative fixed value based on reliable measurement data. In most areas ambient CO2 concentrations are stable, and therefore this approach is reliable. Alternatively, the project can simply use 400 ppm for the assumed constant outdoor CO2 value as it is a conservative assumption and supported as such by its use in California\'s Title 24 energy code. Note: This ruling overturns part of the EQc1 ruling dated 3/25/03. Applicable Internationally" "None" "None" "X"