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" "10133" "2011-11-01" "Commercial Interiors" "EAc1.3 - Optimize energy performance - HVAC" "How much HVAC equipment must be installed within a LEED for Commercial Interiors project scope of work in order to meet the intent of CI 2.0 EA credit 1.3, Option A, Equipment Efficiency?" "The project is eligible to earn the credit if the project scope of work includes one of the following:\n\n1. Air handlers with Variable Speed Controls complying with the requirements of E-Benchmark Section 2.6 that supply at least 60% of the total supply air volume used within the project scope \n\nOR\n\n2. Mechanical equipment that complies with the prescriptive efficiency requirements of E-Benchmark Section 2.5, and provides at least 60% of the cooling or heating capacity for the project scope\n\nNote that requiring 60% correlates to the LEED CI MPR #2 requirement that there must be tenant improvements made for 60% of the project scope in order to pursue a LEED for Commercial Interiors or LEED for Retail: CI rating.\n\nOR\n\n3. The project can comply with the requirements of the credit if the project team can show that the relevant criteria have been met for all HVAC systems serving the area within the project scope, whether or not the HVAC systems are installed as part of the tenant scope of work. Applicable internationally.\n" "None" "None" "X" "LEED Interpretation" "10135" "2011-11-01" "Commercial Interiors, Retail - New Construction" "EAc1.3 - Optimize energy performance - HVAC" "In the LEED for Commercial Interiors and LEED for Retail: Commercial Interiors rating systems, EA credit 1.3, Option A (for 2.0) or Option 1 (for 2009), Appropriate Zoning and Controls, the credit language states, ""Zone tenant fit-out of space to meet the following requirements ... Private offices and specialty occupancies (conference rooms, kitchens, etc.) must have active controls capable of sensing space use and modulating HVAC system in response to space demand"". The Interior Design and Construction Reference Guide states that, ""requirements need only apply to the extent of the project scope"". Does ""project scope"" refer to all spaces that are within the LEED project boundary, regardless of whether they are included in the scope of work for the project? Must each private office have its own controls, or can private offices be grouped together?" "Yes, ""project scope"" refers to all spaces within the LEED project boundary, regardless of whether or not they are included in the project\'s scope of work. The project can comply with the requirements of the credit as long as all spaces within the ""project scope"" satisfy the requirements.\n\nEach private office must have its own active controls. Grouping of offices using a single control does not meet the intent of the requirements. \n\n" "None" "None" "LEED Interpretation" "10158" "2012-04-01" "New Construction, Core and Shell, Schools - New Construction, Retail - New Construction, Healthcare, Data centers - New Construction, Hospitality - New Construction, Commercial Interiors, Retail - Commercial Interiors, Neighborhood Development" "EAc1 - Optimize energy performance" "Can we take credit for a demand ventilation system for an automotive service area?\n\nEssentially we propose to model the service area in the Baseline Cases at 100% outside air at 1.5 CFM/sq.ft. during occupied periods to meet ASHRAE 62.1. We plan to model the service area in the Proposed Case with typical storage ventilation rate. See rationale below to validate our assumptions.\n\nWe further propose to model this energy efficiency measure in the standard credit energy models (not as an exceptional calculation) as part of the Baseline and Proposed Cases in order to accurately account for the differences in ventilation load. The differences are based on outside air conditions which change throughout the year and they also impact the supply air unit and fan sizes. The simulation program must size the equipment for the Baseline Case at the peak load and model it use 8760 hours in the year. \n\nASHRAE 62.1 lists a specific minimum ventilation rate for automotive service areas at 1.5 CFM/sq. ft. Ventilation reduction controls are not stated in Ashrae 62.1, nor are they mandated in ASHRAE 90.1-2007. The governing Mechanical Code (International Mechanical Code) optionally permits the use of approved automatic detection devices to control the required ventilation fans and/or make-up air systems. Large make-up air systems providing 100% outside air are still readily available and utilized in order to meet the mandated code. \n\nWe have utilized the following assumptions for modeling energy usage:\n\nBaseline Case - The exhaust ventilation system is modeled to operate at 1.5 CFM/sq.ft. during occupied hours per occupancy schedule. The modeling software automatically sizes the air conditioning system to operate as a 100% outside air system as the total CFM requirement exceeds the design load amount. The unoccupied fan cycle does not include the ventilation and only operates to maintain unoccupied thermostat set point.\n\nProposed Case - The exhaust ventilation system is modeled to be non-operational at any time. We make this assumption based on calculation and witnessed operation at like facilities with the identical control system in place. We have calculated carbon monoxide production based upon maximum estimated daily vehicle round trips through the service area. Eighteen service stalls with an average of 3 vehicles per day and 1 minute round trip drive time yields an estimated total vehicle drive time in the service area to be 54 minutes. The average modern vehicle with catalytic converter produces approximately 150 CFM of exhaust airflow at idle to slow speed containing approximately 1,000 PPM of carbon monoxide. 150 CFM X (0.1%) = 0.15 CFM of carbon monoxide production. The requirement to engage the exhaust ventilation system is 50 PPM of carbon monoxide. The volume of the space is 236,900 cu.ft. and would require 11.845 cu.ft. of carbon monoxide to engage the system. This would require 78.97 minutes of continuous operation without any dilution in a facility this size which exceeds the estimated maximum vehicle operation time of 54 minutes by 30%. The air conditioning equipment serving the area provides 800 CFM outside air and is equivalent to a complete air change twice a day and therefore doubling the daily total required operation time to 157.94 minutes. Operation of vehicles for diagnostic testing is excluded as there is a separate tailpipe extraction system in place to remove all exhaust during testing. \n\nCalculations are no substitute for actual conditions. We have interviewed service managers as to the operations of the emergency exhaust system controlled with a CO monitor system. The feed back is overwhelming that the emergency system is never engaged during normal operation. The technicians in these facilities have been trained in the control systems operations and do not desire to have their ""conditioned"" air purged from the building due to excessive operation of the vehicles within the space." "A project team cannot be awarded credit for demand controlled ventilation in an automotive service area, due to concerns over contaminants, and possible effects on indoor evironmental quality. As there is no current accepted methodology, the potential human health risks outweigh the energy savings." "None" "None" "LEED Interpretation" "10242" "2012-10-01" "Commercial Interiors, Retail - New Construction" "EAc1.3 - Optimize energy performance - HVAC" "We are seeking clarification on the definition of active controls for non-VAV systems. The response from USGBC to CIR 5273 states that thermal control is not sufficient alone if it does not include for variable central plant such as VAV AHU. In some versions of VAV, thermal control can be achieved without modulating the central plant and this delivers no energy savings. These systems deal with low flow situations by allowing the excess air to discharge back to the ceiling void or similar whilst keeping the AHU at a constant speed, which does not result in any energy savings. Thus for the case proposed by the design team on CIR 5273, it is possible to achieve an equipment configuration which does not realize any energy savings from thermal controls.\n\nThis inquiry refers to a Variable Refrigerant Flow (VRF) system. The VRF system operates by delivering refrigerant to the room device/terminal to deliver heating or cooling to the space. Each space has thermal control. The thermal control operates by varying the amount of refrigerant delivered to the room device/terminal and as such varying or modulating the central plant. This ability to vary the heating or cooling delivered to the space allows the central plant to modulate and match the instantaneous load in the space at any given time. This delivers energy savings in the central plant. Furthermore the VRF system also has heat recovery, which allows for heat taken from a space which is in cooling mode to be used in a space in heating mode and vice versa.\n\nNote that because of the closed-loop nature of the VRF system, it is not possible to operate the system in a mode, which does not save energy, as it is not possible to ""vent"" any excess refrigerant in low load situations. The variability of the system comes not from changing the amount of air into the space, but by varying the amount of refrigerant from the central system to the project space. \n\nThe requirement by the reviewers to provide demand controlled ventilation as part of the response to CIR 5273 is inappropriate for a VRF system, which - by definition - ramps up and down based on temperature readings, not air flow measurements. Since the trigger for a VRF system to ramp up and down is related to temperature, we believe that the thermal controls in each room are sufficient active controls for a VRF system, as they provide both individual control in the meeting rooms and private offices and realise energy savings resulting from individual controls.\n\nWith this system, we are still able to meet the requirements of ASHRAE 62.1 for the highest design occupancy and provide adequate ventilation to the project space.\nWe do not believe that the argument that the thermostat will not pick up on when a person leaves the room, as this may not be the major load in the space, is relevant. While this is correct, with a thermostat, the system will modulate to control the space regardless of what is generating the load, e.g. solar, people, equipment. The fact that the people load is not the significant load means that the control of the other loads is the more important element, therefore the system will respond to whatever changes the load, whether it is people, equipment, lighting or something else. \n\nIt was suggested that the proposed design also does not meet the intent of the credit, because of the lack of ability to vary the amount of fresh air into the space. However, feedback seems to suggest that occupancy and CO2 sensors would help achieve this credit, although it is unclear whether installing these in the system would achieve the credit or if this is only in the context of VAV systems.\n" "The definition of active controls that meet the requirements in LEED-CI 2009 EA credit 1.3, and clarifications on what non-VAV systems are eligible for active controls are listed below. Active control is the control capable of sensing space occupancy and adjusting the HVAC system demand based on the changes in space occupancy, which does not equal a thermostat or a separate thermal zone for each space. For VAV systems and non-VAV systems, active controls typically regulate the required outdoor air flow for ventilation, such as using demand controlled ventilation with CO2 sensors in each private office and specialty occupancy space, or regulate temperature set point based on occupancy by adjusting the HVAC system to operate under the unoccupied set back when occupant sensors indicate that the space is unoccupied.\n\nAlternatively, VAV systems meeting all the requirements in LEED Interpretation 5273 are also eligible. However, those systems which do not modulate the system level supply air flow but only redirect the excess air back to the ceiling void or return air duct under low demand conditions are not eligible for this alternative compliance path. \n\nFor a VRF system or another constant volume system with separate thermal zones for each specialty occupancy or private office, the following active controls would be considered sufficient to meet the credit criteria:\n\nPRIVATE OFFICES: Occupant sensor controls or CO2 sensors in each private office sense space occupancy, and modulate the HVAC temperature set points when the space is detected as unoccupied. Additionally, the fan coil serving the room has the fans set to cycle on and off with loads or to operate on the lowest multi-speed setting for multi-speed fans when the space is detected as unoccupied.\n\nSPECIALTY USE SPACES: Conference rooms and other specialty use spaces have CO2 sensors or occupant sensor controls, which modulate the HVAC temperature set points when the space is detected as unoccupied. Additionally, demand control ventilation is used to limit the outdoor air supplied to the space based on CO2 levels or space occupancy. \n\nPlease note, although the VRF system as described can vary the amount of refrigerant supply to the project spaces and save energy, the thermostat controls described are not considered active controls due to the following two reasons: \n1. The system is controlled based only on thermostats. For private offices and specialty occupancies where the occupancy varies during the occupied period, thermostat control is not sensitive to the change of occupancy and therefore is not capable adjusting the VRF system to respond to the change, because occupant load is not a major load of the perimeter zones, and is also likely not very significant compared to the cooling load from lighting and equipment in the internal zones. When the occupants are absent or reduced, the HVAC system cannot effectively respond to the change and reduce heating and cooling supply, and/or the ventilation rate. \n2. The VRF system is a constant volume system. It cannot reduce airflow to respond to the load change. Please note that the alternative compliance path in LEED Interpretation 5273 requires the system achieve significant supply flow reduction at both the system and zone levels. To achieve this, the system must have fan static pressure reset, and especially, for the spaces where the minimum outdoor air exceeds the required minimum supply volumes, some form of occupant sensing or demand controlled ventilation must be employed to allow the minimum supply volumes to be met. This requires projects to use either CO2 sensors or occupancy sensors in conference rooms or other specialty occupancies, because the room airflow in these spaces cannot typically be reduced to the required percentage of the peak supply volumes while still maintaining the ASHRAE 62.1 ventilation requirements associated with peak occupancy. With variable refrigerant flow and heat recovery which essentially allows for heat exchange between spaces under cooling mode and spaces under heating mode, the VRF system has high cooling and heating efficiency and can achieve high part-load energy performance. This may qualify the project for Option 1 - Equipment Efficiency. Please consider attempting this option in lieu of the option for active zoning and controls, if active controls will not be used with the VRF system." "None" "None" "LEED Interpretation" "10263" "2013-01-01" "Commercial Interiors, Retail - New Construction" "EAc1.3 - Optimize energy performance - HVAC" "Many space types will not function as regularly-occupied private/individual or multi-occupant spaces, nor will those spaces be utilized for extended periods of time (such as kitchen/break room, meeting room, or conference room). Some unique and smaller (less than 200 SF) programmed space types are infrequently occupied (less than 1 hour) and by only one or a few people at a time. One exception to the credit requirement that ""private offices"" must have active controls is granted in LEED Interpretation #1645 and clarified in the IDC Reference Guide 2009 Edition, which states that ""small private spaces intended for single, temporary occupancy (e.g. for making confidential telephone calls) may be included as part of a larger thermal zone, since changes in occupancy will not cause large swings in the heating and cooling loads."" Given the credit intent to reduce energy in occupied spaces and the ruling of LEED Interpretation #1645, we propose to expand the definition for small, temporarily-occupied spaces in two ways: 1. For laboratory buildings/spaces, where loads are typically based on equipment loads, we propose a more specific addition to the definition of Special Occupancy to include spaces that are less than or equal to 200 SF and occupied by two or fewer people for short periods of time. 2. For all project types, we propose an expanded definition of Special Occupancy to include spaces with equal or less than 300 cfm, per ASHRAE 90.1-2007 definition of small zones. ASHRAE 90.1-2007 defines small zones as those with less than 300 cfm, as referenced in Sections 6.3.2.n Criteria, 6.4.3.4.3 Shutoff Damper Controls, and 6.5.2.1.a.4 Simultaneous Heating and Cooling Limitation - Zone Controls. In both of these cases, we propose the space types described above be considered Special Occupancy spaces that may be included as part of a larger thermal zone. Are these definitions acceptable?" "No, these spaces cannot be considered Special Occupancy. The credit requirements state that private offices and specialty use spaces must have their own active controls capable of sensing space use and modulating the HVAC system in response to changes in space demand.\nSpecialty use spaces are considered to be conference rooms, break rooms, classrooms, gymnasiums with variable use patterns, cafeterias, hotel guest rooms, residential dwelling units, and other occupied spaces where energy savings can be achieved by adjusting the temperature setpoints and/or air volume supplied to the space when the space is unoccupied, or densely occupied space where energy savings can be achieved by adjusting the ventilation air supplied to the space when the space is partially occupied. Laboratory spaces would be considered to be specialty use spaces, since these spaces generally have 100% outside air, where setting back the temperatures and/or the fume hood ventilation when the space is unoccupied or the fume hood(s) are not actively in use would lead to significant energy savings. Laboratory prep and laboratory support spaces, and resource rooms would also be expected to achieve energy savings by adjusting the temperature setpoints and/or air volume supplied to the space when the space is unoccupied, since these spaces are frequently unoccupied throughout each day; therefore, these rooms would be considered to be specialty use spaces. \nException: Spaces that would otherwise be considered specialty use spaces but are smaller than 75 square feet, such as the phone rooms referenced in LEED Interpretation #1645, or a lactation room smaller than 75 square feet are not required to have individual active controls capable of sensing space use and modulating in response to changes in space demand.\nSpaces not considered to be specialty use spaces: Open offices, reception areas, warehouse or storage spaces, merchandising spaces, lobbies, nursing stations, manufacturing spaces, auto service bays, library stacks, library multi-occupant reading areas, bank teller areas, hallways, and similar spaces are not considered to be specialty use spaces since these spaces would be expected to be at least partially occupied for the majority of the time the HVAC system is operational, and would not be expected to achieve energy savings by adjusting the temperature setpoints and/or air volume supplied to the space when the space is unoccupied. \nControls capable of sensing space use and modulating the HVAC system in response to changes in space demand include the following:\nInterior private offices or interior non-densely occupied specialty use spaces - a separate thermal control for each space. This would be considered sufficient because the space demand is related to internal loads (lighting, occupants, and plug loads). When the occupant leaves the space, particularly if the space has lighting occupant sensors and Energy Star computing equipment, the thermostat will be able to sense a change in space demand, and modulate the HVAC system in response to the change in space demand.\nPerimeter offices or perimeter non-densely occupied specialty use spaces - a separate thermal control for each space paired with an occupant-sensing or CO2 sensing device, which is used to set back the temperature setpoint and airflow to the space when the space is unoccupied. In many cases, the occupant sensors used for lighting can be integrated with the HVAC controls. This is necessary in perimeter spaces because the space has both envelope loads and internal loads, and the HVAC system would respond minimally to changes in space occupancy if additional occupant-based setback controls were not in place. For a VRF system, fan coils, or packaged single-zone system, the fan coil serving the room must have the fans set to cycle on and off with loads or to operate on the lowest multi-speed setting for multi-speed fans when the space is detected as unoccupied. \nVAV systems with supply air diffusers and room thermostats: Per LEED Interpretation #5273, VAV systems having supply air diffusers equipped with room thermostats for each private office or non-densely occupied specialty use space may be used in lieu of a separate thermal zone per private office or non-densely occupied specialty use space. If this compliance path is followed, the following additional requirements apply:\n1. The system must be capable of modulating AHU and zone minimum supply volume down below 0.30 cfm/sf of supply volume for standard VAV terminals, or below 22.5% of the peak design flow rate for fan-powered VAV boxes. For spaces where the minimum outdoor air exceeds the minimum supply volumes specified here, some form of occupant sensing or demand controlled ventilation must be employed to allow these minimum supply volumes to be met. \n2. The building control system must include controls for fan static pressure reset. \n3. The mandatory requirements of ASHRAE Standards 90.1-2007 and 62.1-2007 must be met. \nDensely Occupied specialty use spaces (such as a conference room) - a separate thermal control for each space paired with a CO2 or occupant sensing device, which is used for demand control ventilation and to set back the temperature setpoint to the space when the space is unoccupied. \nApplicable Internationally." "1645, 5273" "None" "X" "LEED Interpretation" "1645" "2006-12-14" "Commercial Interiors" "EAc1.3 - Optimize energy performance - HVAC" "The purpose of this project is to allow Bank of America employees an opportunity to work closer to home and reduce their commute to the office. One of the features for the plan on this project is the ""Focus"" Rooms. These rooms allow the people throughout the floor to conduct phone/conference calls confidentially. These spaces are approximately 35 square feet in area. Based on the point for Appropriate Zoning and Controls, it requires private offices, conference rooms and kitchens to have their own controls. Currently, there are 4 of these spaces zoned together on one side of the floor plan. On the other side of the plan, 2 focus rooms are zoned with a wellness room (approx. 62 sf). I am requesting that these focus rooms be excluded from this requirement due to their low airflow requirements and intermittent use. Please clarify if these rooms will be accepted as they are currently zoned." "The project team is requesting clarification regarding the occupancy-type classification of small spaces used exclusively for making confidential phone calls. These rooms are not intended for use as regularly occupied private office spaces. Also, since these rooms are intended for single occupancy, changes in occupancy will not result in large swings in the heating and cooling loads, as would be true for a break room or conference room. Accordingly, these spaces may be included as part of a larger thermal zone. Applicable Internationally." "10263" "None" "X" "LEED Interpretation" "2177" "2008-05-28" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell" "EAc1 - Optimize energy performance" "See below for treatment of District Thermal Energy systems in LEED-NCv2.2, LEED-CSv2.0, and LEED-CIv2.0." "USGBC has developed a document that clarifies how district or campus heating or cooling systems are to be treated in all Energy and Atmosphere prerequisites and credits for LEED-NC, LEED-CS, and SSc1, Options K & L under LEED-CI. That document is available for download from the LEED Reference Documents page, here: https://www.usgbc.org/ShowFile.aspx?DocumentID=4176. All LEED-NC, LEED-CS, and LEED-CI projects involving district or campus heating or cooling systems that registered for LEED after this posting date must follow that guidance, and such projects that registered before this date may optionally follow that guidance." "None" "None" "LEED Interpretation" "2305" "2008-08-26" "Commercial Interiors" "EAc1.3 - Optimize energy performance - HVAC" "The design of an 11,000 square foot library and offices in a new LEED NC building targeted low energy use and superior indoor air quality as two of its most important green building goals. From the beginning of design, our mechanical engineering team has prioritized efficient equipment to meet the E-Benchmark prescriptive criteria for efficiency requirements (EQc1.3 Option A point 1) and EQ credit 5 for high filtration media. We are limited by those requirements to a single proprietary mechanical system of water source heat pumps. As-built conditions in the space revealed that in order to fit our heat pump units in the available head heights, two units serving the Entry Lobby/Children\'s Room and Auditorium needed to be changed to split units. This split effectively reduces the EER and COP standards to slightly lower than the E-Benchmark standards. The total average of system efficiency by capacity remains well above the EER and COP E-Benchmark threshold requirements. These HP-2 split units are sized for a maximum occupancy load that will only occur several times a year in the Lobby and occasionally in the Children\'s Room and Auditorium. As it is not required for LEED-CI, we do not have an energy model to show annual expected use. However, since these split units are sized for a maximum capacity that does not occur regularly, we conclude that the actual average of system efficiency by usage will be much higher than the average by capacity which already meets the threshold. Unit AC-1/ Quantity 1 / Capacity 3 tons / EER=14.0/COP=5.0 Unit AC-2/ Quantity 1 / Capacity 2 tons / EER=18.1/COP=5.7 Unit HP-1/ Quantity 4 / Capacity 10 tons/ EER=16.0/COP=5.0 Unit HP-2/ Quantity 2 / Capacity 8 tons / EER=13.1/COP=4.5 Unit HP-3/ Quantity 1 / Capacity 2 tons / EER=16.5/COP=5.6 Average by capacity: EER=15.25/COP=4.91 E-Benchmark Standard: EER=14.00/COP=4.60 * * 2005 New Building Institute E-Benchmark Standard, Table 2.5.2 Unitary & Applied Heat Pumps, Electrically Operated, p. 69 We propose that we meet the intent of the credit to provide highly efficient HVAC units which meet a high standard, increase our level of energy conservation, and associated environmental impacts." "The project team is inquiring as to whether or not they can deviate from one of the prescriptive requirements of the Advanced Buildings Energy Benchmark Standard. Per LEED NC EAc1 CIR ruling dated 4/23/2008; prescriptive compliance paths and the standards they reference must be met exactly as specified in order to ensure credit compliance. Option 1 - Whole Building Simulation, offers the flexibility that the project team requires. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "2550" "2009-04-14" "New Construction, Schools - New Construction, Commercial Interiors, Core and Shell" "EAc1 - Optimize energy performance" "Background: Our project is a 3 story, 16,500-sq.ft. addition to an existing 3 story, 84,000 sq.ft. building. The existing building is predominately laboratory space with some office space. The addition will be of similar use. The heating and cooling of the existing building is served by a central utility plant which provides chilled water and hot water via a steam boiler and heat exchanger. It is proposed that the addition also be served by the central plant. The central plant serves several other buildings on the site as well. In order to make a decision on whether we would like to obtain LEED registration on just the new addition or on the entire building with the new addition, a preliminary building simulation is being modeled. For the ASHRAE baseline, the system is modeled as a ""System 3 - PSZ-AC"" (packaged rooftop, constant volume, direct expansion, and fossil fuel furnace) per table G3.1.1A of ASHRAE 90.1-2004. Though the combined building size would categorize building with addition as a ""System 5 - Packaged VAV w/ Reheat."", section G3.1.1(c) mandates conforming to the requirements of System 3 as an exception due to the special pressurization relationship/ cross-contamination requirement of the laboratory. Interpretation Request: Little is stated in ASHRAE 90.1 2004 on the most appropriate way to model a system that has chilled water and hot water heat supplied from a central plant. However, there are a few CIRs concerning similar circumstance that allude to it such as the 1/27/2004-2/24/2004 EA1.1 CIR. In it, it is stated that ""While the situation described is not using purchased chilled water or steam, this HVAC description for the budget building is the closest to the proposed design and should be used for the energy modeling purposes."" This approach for the budget building model is quite workable since the building owner has costs available for both chilled water and heating hot water. However, the baseline is modeled as a DX cooling and gas fired furnace. Is it appropriate to model the budget building with chilled water and heating hot water, when the baseline model is using neither of these? If not, how should the baseline and budget building be modeled?" "The applicant is requesting clarification regarding modeling methodologies for projects which include a central utility plant. Note that the USGBC published a document titled ""Required Treatment of District Thermal Energy in LEED-NC version 2.2 and LEED for Schools"" in May of 2008 located at the following website: http://www.usgbc.org/ShowFile.aspx?DocumentID=4176 Please refer to this guidance document, which is also referenced in a CIR dated 5/28/2008. Also note that the exception in ASHRAE 90.1-2004 Section G3.1.1 Exception (c) is only applicable for zones that have special pressurization requirements. All zones of the building or addition that do not meet the exception requirements must be modeled using System 5 - Packaged VAV w/ Reheat in the baseline. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5273" "2007-09-24" "Commercial Interiors" "EAc1.3 - Optimize energy performance - HVAC" "The project wishes to use Therma-Fusers in private offices to satisfy the intent of LEED CI Eac1.3. Therma-Fusers are supply air diffusers, which are each equipped with an individual thermostat, meaning they have ""active controls capable of sensing space demand."" However, although the Therma-Fusers do not specifically ""modulate the HVAC system in response to space demand,"" they do satisfy the intent of the credit which is to ""achieve increasing levels of energy conservation beyond the prerequisite standard to reduce environmental impacts associated with excessive energy use."" Therma-Fusers function at low pressure, which can reduce the horsepower (and therefore reduce the energy demand) necessary to run the fan motor. This fan energy is further reduced because the VAV system serving this particular space incorporates variable speed drives, which allow the system to turn down even further to save more energy. Also, because a typical pressure independent VAV terminal unit can only turn down to 30%, Therma-Fusers save even more fan energy because they can turn down to less than 10% and maintain individual temperature control. Also, because each Therma-Fuser is a zone of control providing individual room control, heating and cooling energy are reduced because no portion of the building is ever over-cooled or over-heated. An independent study has shown 40% energy savings for interior zones and 29% energy savings for perimeter zones when individual room control was compared to multi-room control. Although Therma-Fusers may not save HVAC energy precisely in the manner specified by the credit, we believe, given the energy saving capabilities of incorporating Therma-Fusers within the space mentioned above, their use satisfies the intent of LEED CI EA credit 1.3." "The applicant has requested confirmation that supply air diffusers equipped with room thermostats"" meet the requirements of EAc1.3 Option A: Appropriate Zoning and Controls to provide ""active controls capable of sensing space use and modulating HVAC system in response to space demand."" The supply air diffusers with room thermostats do not meet this requirement alone. In order to meet this requirements, the following criteria need to be met: 1. The system must be capable of modulating AHU and zone minimum supply volume down below 0.30 cfm/sf of supply volume for standard VAV terminals, or below 22.5% of the peak design flow rate for fan-powered VAV boxes. For spaces where the minimum outdoor air exceeds the minimum supply volumes specified here, some form of occupant sensing or demand controlled ventilation must be employed to allow these minimum supply volumes to be met. 2. The building control system must include controls for fan static pressure reset. 3. The mandatory requirements of ASHRAE Standards 90.1-2004 and 62.1-2004 must be met. These criteria apply only when there is not a separate method employed for modulating the HVAC system in response to space demand such as Demand Controlled Ventilation, or modulation of the HVAC system tied to occupant sensor controls. Applicable Internationally. " "10263" "None" "X"