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" "1580" "2006-10-03" "New Construction" "Our project is registered under LEED version 2.1 and is located in California. Its energy simulation for code compliance demonstrates energy savings relative to Title 24 2005. LEED 2.1 Energy and Atmosphere Credit 1 Table 8c Point Interpolation Table converts Title 24 2001 savings to EAc1 points, but there is no equivalent table for Title 24 2005. Several studies have shown that Title 24 2005 is significantly more stringent than Title 24 2001 (See, for example, 2005 Title 24 Savings by Design Impact Study, Energy Soft LLC, which shows that project savings calculated relative to Title 24 2005 are 10-20% less than when calculated relative to Title 24 2001. This study is available at http://www.californiaenergyefficiency.com/efficiency/SCGWorkpapers/NonPartnershipPrograms/SavingsByDesign/SavingsByDesignWorkpapers.doc.). Using the cited study above, can we assume that the Title 24 2005 version is 10% more stringent than Title 24 2001, add 10% to our project\'s savings calculated relative to Title 24 2005 and assign EAc1 points based on Table 8c? As a fall back, acknowledging that Title 24 2005 is at least as stringent as Title 24 2001, may we use Interpolation Table 8c with our simulated savings (as is) relative to Title 24 2005 so that we may avoid re-modeling the project for Title 24-2001?" "California Title 24-2005 code can be used in lieu of California Title 24-2001 code in the form of direct equivalence; no extra savings can be assumed in LEED. You may apply your Title 24 modeling results as-is to Table 8c in the point interpolation document found on www.usgbc.org/leed/nc. Please note another option: the USGBC allows the application of California Title 24-2005 for LEED-NC v2.1 projects if the NCv2.2 compliance path is adopted as a suite of credits including EAp2, EAc2 and EAc6. Please refer to www.usgbc.org/leed/nc, Version 2.1 section, for the document ""Submitting v2.2 credit paths"" for more information. ""California Title 24-2005 Equivalency,"" within the Version 2.2 Rating System section of that Web page, may also be useful." "None" "None" "LEED Interpretation" "1693" "2007-02-26" "New Construction, Core and Shell, Schools - New Construction" "We request the USGBC confirm our understanding that the 90.1-1999 ECBM and LEED modeling protocol allows us to receive credit for EAc1 energy cost savings for desuperheaters recovering heat from water source heat pump compressors, and using this heat to preheat service water heating, and that this can be done without an Exceptional Calculation, with the supporting discussion below. We understand that the heat recovery method would qualify as site-recovered energy as discussed under section 11.2.3 and its Exception, and is not included in the design energy cost, and the equivalent usage is met in the budget model by the backup energy source, which is electricity. Therefore, the measure is eligible for savings credit and to be modeled differently in the design model from the budget model. The desuperheaters and their heat recovery to service water heating can be readily modeled within eQuest and its computational engine, DOE-2.2, and therefore do not become an exceptional calculation for that reason. Therefore, the measure appears eligible for savings credit, and does not seem to require an exceptional calculation. Is this approach considered acceptable?" "The applicant is requesting clarification regarding whether desuperheaters must be modeled using the exceptional calculation methodology when the energy software program used for EAc1 compliance is capable of modeling heat recovery. The exceptional calculation methodology is only required when one of the following conditions are met: 1. The simulation program being used for the LEED EAc1 calculations cannot adequately model a design material or device 2. Input parameters that ASHRAE 90.1 requires to be modeled identically in the budget and proposed case must be modified to show the impact of the efficiency measure (e.g. schedule changes must be used to demonstrate improved efficiency, such as for demand control ventilation). 3. Previous LEED CIRs have mandated the use of the exceptional calculation methodology (e.g. - eQUEST is capable of modeling demand controlled ventilation, but since eQUEST accomplishes this by internally editing schedule values, the exceptional calculation methodology is still required for LEED v2.1 projects). In the case of desuperheaters, ASHRAE 90.1-1999 specifically requires condenser heat recovery to preheat service hot water under certain conditions (Section 6.3.6.2). Since heat recovery is prescriptively required under certain conditions, and since the software is capable of modeling desuperheaters without the use of supplemental spreadsheet calculations, the measure may be modeled without using the exceptional calculation method. The applicant should be sure to include all input assumptions regarding the desuperheaters in the input comparison table, and should provide sufficient information to confirm that condenser heat recovery does not have to be modeled in the budget case under the requirements of section 6.3.6.2. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "1763" "2007-05-14" "New Construction" "Per ASHRAE 90.1-1999 and 2004 mandatory requirements, hotel guestrooms must include a master control device at the main room entry that controls all permanently installed luminaires and switched receptacles. We are considering automating this lighting control with the use of a key card-activated master switch. The control would turn off all permanently installed and switched receptacle lighting after the guestroom is unoccupied for more than 30 minutes. The controls may also be configured to allow the interior window shades to be closed automatically when the guestroom is unoccupied. Monitored data for hotel lighting usage patterns is provided in a 1999 Research study by Erik Page and Michael Siminovitch entitled ""Lighting Energy Savings in Hotel Guestrooms."" This study indicates an average daily usage of nearly 8 hours for the bathroom light, 2 hours for the desk table lamp, 5 hours for the bedside lamp, and 3 hours for a floor lamp. The study also showed that the high use fixtures (the bathroom fixture and bed lamp) did not experience a significant drop during typically unoccupied periods. Instead, these lights were 20% - 25% on during these periods; and the lighting energy consumed during these periods accounted for about 60% of the total guestroom lighting energy consumption. Another study for ACEEE entitled the ""Emerging Energy-Savings Technologies and Practices for the Building Sector as of 2004"" projects an energy savings for key card lighting controls of 30%. Based on the information provided in these two studies, it seems reasonable to credit hotel guestroom lighting fixtures with a 30% energy savings for automated control based on room occupancy. We propose to model the energy savings achieved through automated control of lighting and interior window shades as an exceptional calculation measure. The lighting savings would be calculated by adjusting the proposed case lighting schedules for all permanently installed and switched receptacle fixtures to 50% lower than the budget case for the percentage of guestrooms modeled as unoccupied. Lighting during all occupied periods will be modeled identically to the budget case. The guestroom lighting energy savings achieved through this measure for the affected lighting fixtures would be 30%. Automated control of the blinds is intended to limit solar heat gains, since the building is in a hot dry climate. The blinds will be modeled identically during the occupied periods as 50% open during daylit hours, and 25% open during evening hours. During unoccupied periods, the shades will be modeled as 25% open. As with all exceptional calculation measures, the savings for this automated control measure will include a narrative documenting the lighting and interior shading schedules and assumptions, and the calculation methodology, and will include a separate line item on the ECB report documenting the savings achieved from this measure. We would like confirmation whether the proposed modeling methodology is acceptable, or direction regarding any modifications that would need to be made to the proposed modeling methodology in order to comply with LEED ECB modeling requirements." "The applicant is requesting confirmation on the proposed strategy for two exceptional calculations. Based on the description of the lighting assumptions, the proposed approach is acceptable. In the LEED submittal please include a narrative documenting the lighting schedules and assumptions and the calculation methodology. Also include a separate line item on the ECB report documenting the savings achieved from this measure. Please provide enough detail in the documentation to allow the review team to ascertain the amount of credit claimed. Based on the description of the automated blinds, the assumptions concerning blind control are insufficient to model the proposed building." "None" "None" "LEED Interpretation" "1849" "2007-08-13" "New Construction, Core and Shell, Schools - New Construction" "Our LEED project consists of two office buildings of approximately 160,000 sf each plus a central refrigeration plant and parking deck. All buildings will be submitted as one LEED project. The project is currently under construction. The energy model for the project was constructed using Trace700 and is a comprehensive model of all three structures. In addition to the 20% energy savings already being reflected in the model, substantial energy savings will be realized by the investments the Owner has made in advanced energy efficiency measures such as daylighting through a central atrium and interior glazing, raised floor thermodynamics and a hybrid HVAC system. Due to limitations of the Trace700 modeling software, the contributions of these sophisticated energy efficiency measures are not currently reflected in the modeled energy savings. To support the ongoing operations of the building, the Owner has invested in a measurement and verification system, which per EA Credit 5, will include measurement of all electrical power panels, lighting panels broken into interior and exterior lighting, and all hvac equipment. The M&V system will measure and trend demand and consumption of electricity, water and natural gas on an hourly basis for all hours of the year. The project cannot bear the added expense that would be required to perform extensive hand calculations, daylight models or to use more sophisticated energy modeling software, but we would like the Owner to be recognized with LEED points for the contribution that their investment in energy efficient design strategies represents. We would like to incorporate the actual measured performance of the lighting, power, and HVAC systems into the Trace700 model. We propose to delay our LEED application at the end of construction and with all buildings in operation, to measure the building systems performance for 3 to 6 months through the M&V devices. We would then substitute values from the measured performance into the design case energy model. The data would be input on a watt/sqft, kw/cfm, btu/hr, cfh, or gal/min basis. We believe that using measured performance data in the creation of the final design case model would be a cost-effective, accurate means of accounting for the contributions of sophisticated energy efficiency measures, and request permission to use this approach on our project." "The CIR is asking if actual logged energy use data being collected for EAc5 can be used to more accurately represent the proposed building energy use for EAc1, with the caveat that the project certification will be held up until this data has been collected and the energy model has been calibrated. It should be noted that incorporating measured data into an energy model is a strategy fraught with many technical challenges. USGBC encourages project teams to use energy models as a design tool. That said, the proposed technique is acceptable, provided the following conditions are met: [1] One full year\'s worth of energy use data must be included to account for seasonal effects. Additionally, this gives time for the commissioning of the facility to be completed and the ""bugs"" worked out of the system. [2] The collected energy data cannot be directly compared to the baseline modeled energy data. Instead the collected data should be used to populate the inputs to the energy modeling program (ie- plug loads, lighting densities, etc). This is because modeling programs inherently contain assumptions and methodologies that do not directly correspond to actual building energy use. By still running a simulation for the baseline and proposed cases, these discrepancies effectively cancel each other out. [3] The applicant must be able to show that the occupancy schedules, building set points, and intended use of the facility are the same in the baseline and proposed case. [4 The baseline energy simulation must utilize a weather file that represents the same metrological conditions that occurred during collection of the energy use data. [5] Submit all documentation required for an Exceptional Calculation Methodology, as described in ASHRAE 90.1-2004 Appendix G. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1876" "2007-09-10" "New Construction" "Our project team requests clarification of the applicability of ASHRAE 90.1-1999 section 9.3.1.2 Additional Interior Lighting Power (b) in determining the baseline space by space lighting power densities. In determining energy code compliance, the referenced section allows the values in Table 9.3.1.2 to be increased by up to 0.35 W/ft2 for those spaces where visual display terminals are the primary viewing task and fixtures are installed that meet the detailed luminance at angle criteria. Please confirm that for any space type where visual display terminals are the primary viewing task and the proposed fixtures meet the detailed luminance at angle criteria, the baseline lighting power density shall be the value from Table 9.3.1.2 plus an additional allowance of 0.35 W/ft2 from 9.3.1.2 Additional Interior Lighting Power (b), regardless of the proposed lighting power density." "Per ASHRAE 90.1-1999, section 9.3.1.2 Additional Interior Lighting Power (b), the budget lighting power density is the value from Table 9.3.1.2 plus 0.35 W/sf where visual display terminals are used. The additional 0.35 W/sf only applies to those areas with visual display terminals; spaces without the visual display terminals do not qualify for the additional wattage. The spaces with visual display terminals must also meet the maximum average luminance requirements of this section. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1890" "2007-09-26" "New Construction" "This is a LEED NC v2.1 higher education, 240,000-sf student union building located in Washington State. We have provided Radiant Panels to service the heating and cooling loads of general office space. The radiant panels rely on a secondary water loop that supplies either hot or chilled water depending on the demand of the system. Outside air is being provided through operable windows or a dedicated 100% outside air handling unit. After doing some research on several energy modeling programs, we have not been able to find one that can model this approach. Instead, we used a four pipe fan coil unit and zeroed out the fan energy to try and mimic the water loads, but take away the fan motor loads. When we compare the proposed case with the base case for ASHRAE 90.1-1999, the proposed case in the energy model will call for a four pipe fan coil unit (system type 7), which in turn will designate the base case to be a four pipe fan coil system as well. It is our opinion that the base case does not need to be this. For a conventional office space in Washington, the industry standard is to provide a standard rooftop VAV unit and provide each zone with a fan powered terminal with reheat. Also, by using the Budget System Type flow chart in ASHRAE Standard 90.1-1999 and inserting data specific to our project (e.g. water cooled, fossil fuel heating, and non-residential space), we get System Type 2, which is a standard VAV with reheat system. Given this approach, can we use the standard VAV system as a base case for the radiant panels since we are not really using Fan Coils in this system?" "The project team is seeking clarification regarding the appropriate Budget case system type selection for a non-residential building with radiant cooling and heating as its primary source of conditioning. Four pipe fan coils (System type 2) are the appropriate selection for a building with water-cooled chillers and fossil-fuel fired hot water boilers serving radiant panels. Radiant panel systems are generally considered to be single zone systems, since both the heating and cooling panels are located in each zone, and are separately controlled in each zone. Accordingly, the Budget system type would map to Water-cooled ? Single Zone Non-Residential ? Fossil Fuel. Per ASHRAE 90.1-1999 modeling requirements, the fans must be modeled with the same bhp/cfm in both the budget and proposed case (with the exception of savings allowed for premium efficiency motors). Therefore, if the fans from fan coils are modeled with zero power in the budget case, they must be modeled the same in the proposed case. Also, per ASHRAE 90.1-1999 requirements, the dedicated outside air unit providing ventilation to the building must include energy recovery in the budget case if required by Section 6.3.6.1. The project does have the option of pursuing credit for EAc1 using the LEED v2.2 requirements (as long as any submittals for EAp2, EAc2, and EAc6 are also submitted using the LEED v2.2 requirements). This would allow the project to reflect the fan energy savings associated with radiant heating / cooling systems, and to model the Baseline system as a VAV system with hot water reheat as requested in this CIR. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "1911" "2007-10-05" "New Construction" "Our project has a city zoning requirement for artwork to be installed on our site. The artist that the owner has selected is creating sculptural artwork that incorporates computerized lighting that creates art with lighting. The artwork lighting is programmed to create patterns, colors and movements on site that are not related in any way to pedestrian security lighting or required site lighting. The artwork lighting is also motion controlled to create different patterns depending on how many pedestrians are present on site. Can this artwork lighting be excluded from the EA Credit 1 (Optimize Energy Performance) calculations?" "The CIR is inquiring as to whether the energy use from the lighting for on-site artwork needs to be included in the EAc1 calculation. This energy use falls under the ""process load"" classification, and needs to be included in the energy model if it generates internal heat gains or interacts with other energy systems, as per the LEED-NC v2.1 Reference Guide. In this particular case, the CIR wording implies that the artwork is outside and thus the lighting should not contribute to HVAC equipment loads. Also the lighting is specifically intended for artistic effect and therefore can be excluded from the exterior site lighting requirements based on ASHRAE 90.1-1999 Section 9.3.2 Exception (b). Assuming there are no additional interactions with building energy systems, this energy usage can be excluded from the EAc1 calculations. Please note, this lighting would still need to comply with the requirements of Sustainable Sites Credit 8, if attempted." "None" "None" "LEED Interpretation" "2485" "2009-02-23" "New Construction" "Our project is a new 135,000 sf office and classroom building on the University of Iowa campus. The building is served by the University\'s combined heat and power plant. (UI-CHP) The project requires that we follow the LEED NC 2.2 CHP methodology Case 3. The CHP methodology document requires certain qualifications for the combined heat and power plants. Specifically, Qualification 2 requests a narrative addressing emissions and demonstrating that the environmental impact of the system is lower than if the building heating requirements are met with an 80% efficient gas boiler and cooling requirements are met with baseline cooling systems using electricity provided from the local grid. In this case, the University of Iowa measures the emissions and is required to file an annual emissions report every year with the Iowa DNR. This report details emissions for SOx, NOx, CO2, and particulates. These same emissions are available from the local utility that would otherwise provide power to the building. On-site gas firing emission data from The Climate Registry General Reporting Protocol Version 1.1. We propose to use the report required by the Iowa DNR that documents the emissions from the University plant as well as the emissions data provided by the Utility to evaluate the project with respect to LEED NC 2.2 CHP methodology Case 3, Qualification 2. UI-CHP emissions for the building will be calculated as: Cooling energy use BTUs from Proposed Model x UI-CHP emissions per BTU + Heating energy use BTUs from Proposed Model x UI-CHP emissions per BTU Utility and on-site heating and cooling related emissions will be calculated as: Cooling energy use BTUs from Proposed Model with baseline cooling system x Utility emissions per BTU of electricity at site + Heating energy use BTUs from Proposed Model with 80% efficient gas boilers x Emissions per BTU of gas firing We will compare the UI-CHP emissions with the Utility and on-site heating and cooling related emissions for each metric (SOx, NOx, CO2 and particulates) to determine that UI-CHP has a lower environmental impact. Is this approach acceptable?" "The applicant wants verification for the process of calculating GHG Emissions. The process is based on mandatory reporting required by the Iowa DNR and therefore is acceptable. The applicant must provide the referenced emissions reports as part of the submittal. Please include a brief narrative to explain the process and cross reference this CIR ruling." "None" "None" "LEED Interpretation" "282" "2001-09-05" "New Construction, Schools - New Construction, Core and Shell" "For the Blanchard College Center project, we are asking the USGBC to clarify the criteria for declaring whether a building is New or Existing in relation to the available points for this credit. In the specific case of the Blanchard College Center, the project is primarily a gut renovation of an existing historical facility, to which two new additions will be added. The area of the existing facility is approximately 33,403 s.f. The area of the two additions totals approximately 13, 885 s.f. The additions therefore represent approximately 29.4% of the total building area. From a systems standpoint, approximately 95% of the existing shell will be reused, however, there will be new furring/insulation for the walls and roof, new lighting, and new mechanical systems. We are assuming that this facility qualifies as an existing building, primarily because the existing facility represents the majority of the overall square footage of the project. In addition, the efforts to preserve the form and shell of the existing building has restricted the designer opportunities to pursue more aggressive energy reduction strategies (e.g., building orientation, daylighting/ventilation strategies, high performance envelope, etc.). Please clarify that this is the correct assumption for this project." "THIS LEED INTERPRETATION HAS BEEN REVISED AS OF 9/21/06 TO PROVIDE A CALCULATION THAT IS MORE WIDELY APPLICABLE (AND IS EQUIVALENT FOR THIS SCENARIO). To calculate the optimization point table for a project that has both existing and new construction, use the following formula for each line of the table: target percent = (existing SF / total SF) * (existing percent) + (new SF / total SF) * (new percent) *This equation applies to LEED NC v2.0, v2.1, and v2.2 and LEED CS v2.0 ORIGINAL LEED INTERPRETATION 9/5/01: To calculate the optimization point table for a project that has both existing and new construction, use the following formula for each line of the table: existing percent + ((new SF / total SF) * 10) = target percent. Applicable Internationally." "None" "None" "X" "LEED Interpretation" "3300" "2003-03-11" "New Construction, Core and Shell, Schools - New Construction" "ASHRAE 90.1 does not allow credit for air leakage reduction. However, it does indicate that windows are allowed to have 1 cfm per square foot air leakage (at 0.30"" water.) The windows we are using in this project are very high performance, with significantly lower air leakage rates. The manufacturer has supplied test results indicating the tested air leakage rate. Further, we are using a blower door and infra-red camera simultaneously to locate and seal any air leaks in the window system that result from installation. We propose to take credit for this air leakage reduction, with the following methodology:\n\nThe tested air leakage rate at 0.30"" can be established for the windows as installed, based on manufacturer\'s data, and for the base case windows based on ASHRAE 90.1. Both these values will be extrapolated to expected winter heating season air leakage rate, using the LBL correlation for blower door test data. We have run two blower door tests, and will use the most recent (during which most of the air leakage has been taken care of) test data to establish the relationship between the air leakage rate at 0.30"" static pressure (75 Pa) and the average heating season air leakage rate, which is calculated at the building pressure established by the LBL correlation, which is based, in part, on the exposure of the building to wind. In this case exposure is significant, as the building is fully exposed on the west side of the building to windows ranging from south to west to north.\n\n We then propose to run the base case building, in the energy modeling, using TRACE, with the air leakage rate for the windows established in the above manner. The building as built would be modeled with zero air leakage rate. Preliminary estimates indicate that the difference in overall extrapolate natural air leakage rates in 0.04 air changes per hour, at typical heating season winter conditions.\n\n Blower door guided air leakage reduction: A significant effort at air sealing is part of the energy saving strategy for this building. With the location noted above, air leakage reduction is particularly important. Two blower door tests with simultaneous infrared scanning, have been completed. The first identified a number of areas that were not complete as designed. Most of these were completed by the time of the second test, and a number of areas were identified during the second test that, in my opinion, would not have subsequently been air sealed had this procedure not been in place. A list of further items was developed from this second air leakage test, and this list has been circulated by the GC to responsible parties, who will sign off when they have completed the items. When those items are complete, a third, and hopefully final, blower test will be conducted.\n\nWe propose to take credit in our energy calculations for the air leakage reduction between the second and third blower door tests, using the LBL correlation to extrapolate to typical heating and cooling season air leakage rates, as described in number 2 above. The extrapolated seasonal air leakage rate reduction would be applied to the base case building. For example, if the extrapolated air leakage reduction were 0.1 heating season air changes per hour from blower door test #2 to test #3, we would assign 0.1 ACH to the base case building and zero air leakage to the building as built.\n\nWe feel that this third round of testing and air leakage reduction is well beyond typical attention paid to air leakage, that air leakage control is particularly important in this very cold (7700 degree-day) climate and at this exposed site, and that we have demonstrated a method using accepted principals to quantify the savings. Blower door test results and LBL correlation spreadsheets for each test would be provided as part of the submission. We would also submit the list of items to be air sealed as part of the final air leakage reduction package.\n\n Windows and air leakage reduction together: We propose to add the two air leakage reductions - from window improvements and blower-door-guided air leakage reduction. For example, if the blower-door-guided heating season air leakage rate reduction were 0.1 ACH and the window air leakage reduction were 0.04 ACH, the base case building would be modeled at 0.14 ACH and the building as built at 0.0 ACH.)" "Advanced air sealing is a strategy that can lead to measurable energy savings, particularly in cold climates. Although this measure is outside the scope of ASHRAE 90.1 modeling protocol, you may be able to make a case for the significance of this strategy in improving energy performance. However, this will require clear and thorough documentation in order to be considered under the requirements of this credit.\n\n The following guidelines are provided to help strengthen your approach:\n\n(1) Provide manufacturer\'s air leakage test results that use the same testing protocol as that by which ASHRAE identified the baseline for window air leakage.\n\n(2) Use a typical infiltration rate as a baseline, and reduce it by the amount of improvement you can document or estimate from the air sealing strategies employed. Do not use zero infiltration in the model, as this is not a realistic assumption. A zero infiltration strategy would over-emphasize the percentage of overall energy use reduction represented by infiltration improvements.\n\n(3) Include required fresh air ventilation rates (per ASHRAE 62) in both the proposed and baseline model results.\n\n(4) Provide clear documentation of air sealing strategies and blower door test results, corrected for wind and temperature effects, to clarify anticipated air sealing performance.\n\n(5) Provide documentation which clarifies the percentage of energy savings attributed to the air sealing strategy, as opposed to other energy performance measures incorporated into the building.\n Applicable Internationally. \n\n **Updated January 1, 2014\n Advanced air sealing is a strategy that can lead to measurable energy savings, particularly in cold climates, though its effectiveness is especially dependent on the quality of construction and cannot easily be predicted during the design phase. Recognizing this, the ASHRAE 90.1 committee developed Addendum ag to Standard 90.1-2010, which establishes guidelines for claiming energy savings that result from reduced infiltration in Appendix G. The approved change allows credit only for buildings that complete envelope pressurization testing in accordance with ASTM E779. The appendix establishes a baseline air leakage rate of 0.40 cfm/ft2 (2.03 L/s•m2) at 0.3 in. wc (75 Pa) pressure differential compared to the measured leakage results in the proposed building.\n\n Projects wishing to claim energy savings from advanced air sealing may do so given they meet the following requirements:\n\n 1. Utilize Addendum ag to Standard 90.1-2010 to document savings.\n\n 2. Provide clear documentation of air sealing strategies and air leakage results from ASTM E779-10 Standard Test Method for Determining Air Leakage Rate by Fan Pressurization, including confirmation that all testing criteria defined in the standard have been met.\n\n 3. Provide documentation that clarifies how energy savings from reduced air leakage has been estimated from the ASTM E779 test results and identifies the percentage of energy savings attributed to the air sealing strategy, as opposed to other energy performance measures incorporated into the building. " "5060, 5691, 5456" "None" "X" "LEED Interpretation" "5017" "2006-07-05" "New Construction" "Harvard Cowperthwaite Residence Hall, located in Cambridge, MA, is a six story, graduate student dormitory with 201 beds in 142 living units. The new building will include three levels of below grade parking, which has vehicle access at the grade level of the first floor of the residence hall. The above-grade portion is 102,036 SF and the below-grade portion is 106,307 SF, for a total of 208,343 SF. This new building is being constructed on the site of a grade level flat paved parking lot. The footprint of the garage is actually larger than the footprint of the residence hall to accommodate the college\'s parking needs. We intend to keep all of the garage within the scope of the LEED project, along with the residence hall. There will also be a 3-story wood frame residential building built above the footprint of the garage that is detached from the main 5-story residence hall. The three-story wood frame building is an additional 4,168 SF, with five additional beds in three apartments. This 3-story building will be supplied with heating hot water and chilled water from the plant in the 6-story building. The project team would like to exclude the 3-story wood frame building from the LEED project scope. The three story wood frame building is not covered by ASHRAE 90.1 - 1999, while the 6-story residence hall is covered by ASHRAE 90.1. The wood frame building is also covered by a different section of the Massachusetts Building and Energy Code than the 6-story residence hall. Therefore, we propose to make the LEED boundary include the underground parking garage but exclude the 3-story wood frame building by drawing the boundary horizontally below the wood frame and above the garage. We would propose to keep this LEED project scope of work boundary consistent through all the credits we are pursing. Please confirm that this approach is acceptable." "The project team proposes to draw a horizontal LEED boundary that will exclude a 3-story residential building from the LEED project scope, even though the buildings have a shared central plant. The residence hall qualifies as a stand-alone structure, and does not contribute towards the overall function of the parking garage or the 6-story residence hall which will be included in the project scope. Therefore, the LEED boundary may exclude the 3-story residential building from the project scope. The central plant for the project is shared between the 6-story residence hall and the 3-story residential building. For EAc1, the central plant should be modeled with identical efficiencies to those required by ASHRAE 90.1-1999, but the plant capacities (including chiller, boiler and cooling tower capacities, and circulation loop flow) should be scaled to represent the portion of peak thermal loads contributed by the 6-story structure. For example, if the peak chilled water loads are 200 tons for the 6-story structure and 100 tons for the 3-story structure, the capacity modeled for the 6-story structure would be two thirds multiplied by the installed chiller capacity." "None" "None" "LEED Interpretation" "5025" "2007-01-27" "New Construction" "Our project is a 41,000 sqft museum building with exhibit, studio, classroom, retail, office space, and an auditorium. Because of the tight humidity control, the museum requires a constant volume air handling system for the museum spaces in the building. The constant volume system designed is permissible under the ASHRAE 90.1-1999 Chapter 6 prescriptive path. Specifically, two critical requirements of the prescriptive path are satisfied by the design: - The design\'s fan power limits are within those prescribed in section 6.3.3.1 for constant volume systems. - Reheating of the supply air is allowed per exception 6.3.2.3, as this is a museum building with a specific dehumidification system. According to the ECB method, systems with water cooled condensers and fossil fuel heating that serve multi-zone non-residential spaces shall be compared to ""System 2."" System 2 is a VAV system with chilled water and a fossil fuel boiler. Because the space-use dictates a constant volume system, and given that the proposed system is allowable per the Chapter 6 prescriptive path, we are asking the USGBC to allow us to compare the constant volume systems of the proposed design to constant volume systems in the budget building." "(Revised 2/7/07) The project is requesting a waiver from the Energy Cost Budget requirements of comparing their proposed system type to a variable volume system. Yes, the project team may model the budget building as constant volume. The project has met the requirements of table 11.4.3A note 4. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5060" "2007-07-09" "New Construction, Schools - New Construction, Core and Shell" "ASHRAE 90.1 sets specific requirements for the building envelope, including meeting all requirements of Section 5.4. Air Leakage, Section 5.4.3, requires sealing, caulking, gaskets and weather stripping of the building envelop to minimize air leakage. For the Barkesdale Dormitory, additional methods were used to minimize air infiltration. Additional barriers, taping, and low leakage panels per ASTM E283-84 (0.06 cfm per square foot of fixed wall at 63.3 mph wind and 1.92 iwg.) were used. Additionally, the building was pressurized to prevent infiltration. A baseline building model is neutral with average construction. With the value added benefit of additional barriers, taping and low leakage panels and pressurization, the Barkesdale Dormitory can be considered a ""tight-pressurized construction"". These differences could effect the energy calculations. Is this a logical conclusion?" "This CIR seeks to use reduced infiltration rates from a superior building envelope as a variable in the energy cost budget calculation for optimizing energy efficiency. The ASHRAE modeling protocol does not allow the infiltration rate to be changed between the budget and the design case. The CIR ruling of 3/11/2003 for EAc1.2 provides some guidelines on how a case might be made for advanced air sealing. The methodology proposed for this project does not address all the issues raised in that ruling and would be insufficient to grant an exception to the modeling protocol. Applicable Internationally. " "3300" "None" "X" "LEED Interpretation" "5139" "2008-08-26" "New Construction, Core and Shell" "Our project is being considered for re-registration from LEED-CS v2.0 to LEED-NC v2.2. The building is 65,762 GSF with 48,664 SF of total leasable space. 25,997 SF (53%) of the building has been leased, designed, and under construction. However, the remaining 22,667 SF (47%) is unleased shell space. The unleased shell space is outside of the project scope and there is no design currently underway for this to complete work in this area. In order to pursue EA Credit 1 (Optimize Energy Performance), our engineers would like guidance on how to create their energy model based on our building situation of 53%-to-47% leased vs. shell spaces. It is their intention to model the unleased shell space as if the space were ""upfit"" to the same standard as the leased portion of the building. This standard would be described in a tenant improvement guidelines provided to future tenants. Please verify this method is acceptable or provide an alternate method for energy modeling." "The applicant is requesting clarification regarding energy modeling of shell spaces that do not yet include tenant fitouts. This topic has been extensively addressed in the published erratum for LEED-CSv2.0 (http://www.usgbc.org/ShowFile.aspx?DocumentID=3334), as well as previous CIR rulings (CSv2.0 Rulings dated 05/27/2008, 04/25/2008, 04/23/2008, 04/24/2008, 02/11/2008, 11/28/2007, 12/5/2007, 11/14/2007, and 05/30/2007). For LEED-CS, tenant guidelines alone are not sufficient to verify energy efficiency measures incorporated into future leased space. The published erratum indicates that documentation should be provided including lease or sales agreements verifying that 100% of the leased square footage complies with the credit requirement, and a statement signed by the owner / developer verifying that all leases and/or sales agreements will comply with the credit requirements. For future leased spaces, the letter from the owner / developer is only required if efficiency measure improvements beyond ASHRAE 90.1-2004 are reflected in the future leased spaces (e.g. improved lighting power density, improved HVAC efficiency, etc.). Applicable Internationally." "None" "None" "X" "LEED Interpretation" "5297" "2008-03-13" "New Construction, Schools - New Construction, Core and Shell" "Our project is a science and technology lab building on the University of Nevada Las Vegas Campus of approximately 181,000 sf, with a 1200 sf greenhouse for experiments. The greenhouse has four cells which will mimic the exact environmental conditions of the Nevada (nuclear) Test Site as they occur in the open desert. Thus the greenhouse cells will be conditioned to match the exact temperature and humidity conditions at the test site; lighting will also match the conditions at the test site. This is being accomplished with a system separate from the rest of the lab building. Since the greenhouse conditioning and lighting is for the purpose of carrying out experiments, it is similar to a lab hood or other lab process equipment. We will treat the energy use from lighting and conditioning the greenhouse as a process load in the Energy Cost Budget Method model and subtract it for calculating the percent energy savings. Please confirm that this approach is acceptable." "Based on the description above, it appears that the energy use would most likely be considered process related and therefore could be excluded from the Energy Cost Budget (ECB) Method model. ASHRAE 90.1-1999 defines process energy as ""energy consumed in support of manufacturing, industrial, or commercial process other than conditioning spaces and maintaining comfort and amenities for the occupants of a building."" Please note that if any of the energy use in the greenhouse is deemed as necessary for the comfort of occupants (lighting, auxiliary heating, etc.) and is not associated with the lab related experiments, then it would need to be included in the ECB calculations as a regulated energy use. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5416" "2001-06-07" "New Construction" "As we understand, ASHRAE 90.1" "The reference standard does not allow variations in schedules to generate energy savings. All basic simulations used to satisfy Credit 1, Optimize Energy Efficiency, must use the same schedules for the Budget and Proposed cases. This approach simplifies inspection of the basic modeling results by the USGBC. To document savings for this scheme, follow the ECB Exceptional Calculation Method. See Section 11.5 of the ASHRAE 90.1 User\'s Manual. Under the ECM, schedule variations may be used as a basis of engineering calculations for discrete measures that are precluded by the reference standard or the LEEDTM EMP. The savings should be modeled as a discrete measure, and the resulting energy savings deducted from the DEC\'. This handles the ""exceptional"" savings in the same fashion as renewable energy. An engineering narrative must provide a theoretical basis and describe the expected interactive modes the measure will have with other systems of the basic simulation, and it shall describe all of the assumptions in the analog system model used to predict the savings. Advanced approval (prior to Application) of the proposed analog model and the predicted savings through this Credit Interpretation Request process is suggested. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5417" "2001-06-25" "New Construction" "The LEED Resource Guide 2.0 explains in the Calculations and the LEED Energy Modeling Protocol (p. 92-93 of the unformatted review draft) that on site renewable energy (photovoltaics in our case) is deducted from the Proposed Building Energy Cost. Is this ""double-dipping""? Please verify that this is possible as we see no cross-referencing anywhere else in the guide for this strategy." "The contribution of the renewable energy sources is in fact deducted from the Design Energy Cost to arrive at a net energy cost. The calculation is straight forward but requires several steps to complete. Please see the June 2001 Reference Guide for details of the calculation. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5456" "2003-03-11" "New Construction" "2. Optimize Energy Performance -- Credit EA1 - Credit Interpretation Request - Air leakage reduction Windows: ASHRAE 90.1 does not allow credit for air leakage reduction. However, it does indicate that windows are allowed to have 1 cfm per square foot air leakage (at 0.30"" water.) The windows we are using in this project are very high performance, with significantly lower air leakage rates. The manufacturer has supplied test results indicating the tested air leakage rate. Further, we are using a blower door and infra-red camera simultaneously to locate and seal any air leaks in the window system that result from installation. We propose to take credit for this air leakage reduction, with the following methodology: The tested air leakage rate at 0.30"" can be established for the windows as installed, based on manufacturer\'s data, and for the base case windows based on ASHRAE 90.1. Both these values will be extrapolated to expected winter heating season air leakage rate, using the LBL correlation for blower door test data. We have run two blower door tests, and will use the most recent (during which most of the air leakage has been taken care of) test data to establish the relationship between the air leakage rate at 0.30"" static pressure (75 Pa) and the average heating season air leakage rate, which is calculated at the building pressure established by the LBL correlation, which is based, in part, on the exposure of the building to wind. In this case exposure is significant, as the building is on the shore of Lake Champlain, fully exposed on the west side of the building to windows ranging from south to west to north. We then propose to run the base case building, in the energy modeling, using TRACE, with the air leakage rate for the windows established in the above manner. The building as built would be modeled with zero air leakage rate. Preliminary estimates indicate that the difference in overall extrapolate natural air leakage rates in 0.04 air changes per hour, at typical heating season winter conditions. Blower door guided air leakage reduction: A significant effort at air sealing is part of the energy saving strategy for this building. With the location noted above, air leakage reduction is particularly important. Two blower door tests with simultaneous infrared scanning, have been completed. The first identified a number of areas that were not complete as designed. Most of these were completed by the time of the second test, and a number of areas were identified during the second test that, in my opinion, would not have subsequently been air sealed had this procedure not been in place. A list of further items was developed from this second air leakage test, and this list has been circulated by the GC to responsible parties, who will sign off when they have completed the items. When those items are complete, a third, and hopefully final, blower test will be conducted. We propose to take credit in our energy calculations for the air leakage reduction between the second and third blower door tests, using the LBL correlation to extrapolate to typical heating and cooling season air leakage rates, as described in number 2 above. The extrapolated seasonal air leakage rate reduction would be applied to the base case building. For example, if the extrapolated air leakage reduction were 0.1 heating season air changes per hour from blower door test #2 to test #3, we would assign 0.1 ACH to the base case building and zero air leakage to the building as built. We feel that this third round of testing and air leakage reduction is well beyond typical attention paid to air leakage, that air leakage control is particularly important in this very cold (7700 degree-day) climate and at this exposed site, and that we have demonstrated a method using accepted principals to quantify the savings. Blower door test results and LBL correlation spreadsheets for each test would be provided as part of the submission. We would also submit the list of items to be air sealed as part of the final air leakage reduction package. Windows and air leakage reduction together: We propose to add the two air leakage reductions - from window improvements and blower-door-guided air leakage reduction. For example, if the blower-door-guided heating season air leakage rate reduction were 0.1 ACH and the window air leakage reduction were 0.04 ACH, the base case building would be modeled at 0.14 ACH and the building as built at 0.0 ACH.) " "Advanced air sealing is a strategy that can lead to measurable energy savings, particularly in cold climates. Although this measure is outside the scope of ASHRAE 90.1 modeling protocol, you may be able to make a case for the significance of this strategy in improving energy performance. However, this will require clear and thorough documentation in order to be considered under the requirements of this credit. The following guidelines are provided to help strengthen your approach: (1) Provide manufacturer\'s air leakage test results that use the same testing protocol as that by which ASHRAE identified the baseline for window air leakage. (2) Use a typical infiltration rate as a baseline, and reduce it by the amount of improvement you can document or estimate from the air sealing strategies employed. Do not use zero infiltration in the model, as this is not a realistic assumption. A zero infiltration strategy would over-emphasize the percentage of overall energy use reduction represented by infiltration improvements. (3) Include required fresh air ventilation rates (per ASHRAE 62) in both the proposed and baseline model results. (4) Provide clear documentation of air sealing strategies and blower door test results, corrected for wind and temperature effects, to clarify anticipated air sealing performance. (5) Provide documentation which clarifies the percentage of energy savings attributed to the air sealing strategy, as opposed to other energy performance measures incorporated into the building. Applicable Internationally. " "3300" "None" "X" "LEED Interpretation" "5495" "2003-11-03" "New Construction" "Background: The 307 Westlake S&C will house laboratories facilities for two biomedical research institutions in Seattle. It will contain some limited office and retail space as well. Our project is pursuing LEED Certification and planning to participate in the upcoming S&C Pilot Program. The design incorporates several energy-savings measures, and so our target credits include Energy Optimization Credit EA1. Our initial model runs used the LEED NC Rating System, using various assumptions for TI systems, and results indicated a minimum 20% savings. At that point, we decided to put the energy modeling effort on hold until we learned more about how modeling would be handled for Shell & Core projects. The project is now under construction, and we would like to complete our energy modeling effort. Since last summer, we have completed lease arrangements and have the interior layout and mechanical and electrical designs of the TI spaces. We have also had the opportunity to review the draft S&C Rating System. Based on our review of the latest S&C draft, we understand that the approach for EA1 will be to model S&C systems only. The question then becomes how to establish the boundary between S&C and the TI portion. For some S&C projects, it might be straightforward to establish the boundary between S&C and the TI portion. In our case, it is not, so we would like to propose an alternate approach for our project. In addition, we have several questions that relate to adapting the LEED guidelines to our laboratory facility and its innovative HVAC system design. Proposed Modeling Approach: We to perform and document an energy model of the entire building, not just shell and core. We believe this is a sound approach and a conservative one. We know what the interior is going to be" "The LEED Core & Shell pilot program is not yet ready, but this inquiry can be addressed in the context of LEED for New Construction (LEED-NC). As the energy modeling protocol now stands in LEED-NC, energy models should be prepared with all applicable loads and equipment included in the modeling results, as you have proposed. The modeling results are then subject to post-processing as explained in the LEED V2.1 Reference Guide on pages 145 to 148. The post-processing simply factors out the non-regulated components from the modeling results. In this manner the HVAC loads associated with the non-regulated equipment are taken into account. Regarding the additional questions as they apply to LEED-NC: 1. Laboratory systems meeting 6.3.7.2 are exempt from the exhaust air energy recovery requirements in 90.1. As such heat recovery in this area would be considered a valid energy saving strategy applied to a regulated component. Follow the ECB Exceptional Calculation Methods in section 11.5. See numerous previous CIRs (EAc1.1 dated 7/22/03, 1/20/02, 7/10/01, 11/9/01, 6/27/01 (several), and 6/7/01) for guidance on applying this method. 2. The design building should be modeled with the actual HVAC equipment, which has been designed for the project. If following the ASHRAE 90.1 HVAC Systems Map (Figure 11.4.3) results in the selection of a chilled water system and the size of the system dictates two equal sized chillers (see Table 11.4.3A, Note 5), then this becomes the requirement for the budget building. Comparisons are made between the design and budget buildings. This is a valid potential energy optimization strategy. 3. Regarding plug load capacities the energy models should include a level appropriate to the building type. Specific guidance on selecting the appropriate level is contained in the LEED V2.1 Reference Guide on page 143 under the ""Process energy"" section. 4. Garage ventilation is indeed non-regulated as stated on page 145 of the LEED V2.1 Reference Guide. Energy saving measures applied to non-regulated components can obtain credit for savings as an innovation credit. To achieve a point for this strategy, the applicant must demonstrate that energy savings represent a significant fraction of building energy use (at least 5%); comparable to the level of achievement required by EAc1. Follow the procedures outlined in numerous, previous CIRs (EAc1.1 dated 8/15/03, IDc1.1 dated 4/17/03, 8/16/02, 6/21/02). " "None" "None" "LEED Interpretation" "5498" "2002-01-20" "New Construction" "Based on the LEED Energy Modeling Protocol (EMP), and our results using the LEED Calculator.xls, the use of CO2 monitoring systems provides one (1) point under the \'Indoor Environmental Quality\' Credit 1. Demand controlled outdoor air based on CO2 levels is incorporated on this project and this credit interpretation, is to obtain approval for the resulting energy saving, under the \'Energy and Atmosphere Credit 1 - Optimize Energy Performance Category\'. We believe that a similar Credit Inquiry request was submitted under Inquiry ID Number 0050-EAc11-071001 which ruled ""An engineering narrative must provide a theoretical basis and describe the expected interactive modes the measure will have with other systems of the basic simulation, and it shall describe all of the assumptions in the analog system model used to predict the savings. Advanced approval (prior to Application) of the proposed analog model and the predicted savings through this Credit Interpretation Request process is suggested."" This response was not explicit and thus we are following through with the following request for credit interpretation. In support of this application we have computed energy savings using the LEED EMP. The air handling systems for the West Chevron Expansion at the Vancouver International Airport must be capable of providing substantial quantities of outdoor/ventilation air for the many passengers and staff during peak occupancy periods. Throughout most of the year and for many hours during every day, the occupancy levels will be only a fraction of the peak volume. It is proposed that multiple CO2 sensors will be installed throughout the airports public spaces. Feed back from these sensors will vary the volume of outdoor air supplied by the modular air handling units through the Building Management Controls system to maintain air quality as per ASHRAE Std 62.1999 regardless of the number of people in the terminal. This methodology will reduce energy consumption substantially particularly during the winter, and prolong the life of both particulate and gaseous absorption filters installed in each unit. Airline scheduling of the gate operations will also be factored into the Building Management Systems controls sequence to permit reinstating higher ventilation rates just prior to increased occupancy levels. Using the LEED EMP guidelines, the Design Energy Cost (DEC) for the proposed building with CO2 based demand controlled outdoor air is $281,701 equating to an energy savings of 6.6% over the ASHRAE 90.1. When CO2 based demand control outdoor air is not considered in the ASHRAE 90.1 model, the energy savings achieved for the proposed building model is 20.7% better than ASHRAE 90.1. Given the wide fluctuations in airport terminal building occupancy, a situation which is quite unlike that of most other facilities, we believe that the energy savings resulting from the use of CO2 based demand control outdoor air should be accounted for in the comparison of the \'LEED\' proposed building with a base building which utilizes a minimum outdoor air setting based on peak occupancy. The ruling based on this principle will provide 2 Credits under the \'Energy and Atmosphere Credit 1 - Optimize Energy Performance Category\'." "Savings due to demand management, including CO2-based demand controlled outside air, can be included in the energy savings. The distinction being made is that the savings predictions cannot be based on schedule manipulations embedded in the energy simulation, where the baseline and proposed use different schedules to simulate the technology. Rather, a stand alone calculation must be presented for inspection and approval by the LEED review, and then it is deducted from the total energy use. Please refer to inquiries 0111-EAc11-062701 and 0050-EAc11-071001 for previous interpretation of this issue. To document savings for this scheme, follow the ECB Exceptional Calculation Method. See Section 11.5 of the ASHRAE 90.1 User\'s Manual. The savings should be modeled as a discrete measure, and the resulting energy savings deducted from the DEC. This handles the \'exceptional\' savings in the same fashion as renewable energy. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5535" "2002-07-19" "New Construction" "Early in the design process, Valley View School District 365U had discussions of HVAC system selections. While a choice for direct expansion roof top units is typical in our area and for the school district, knowing that they wanted to design a school that was environmentally friendly and energy efficient, enabled them to steer quickly away from that choice to a much more efficient variable air volume with reheat, water cooled chillers, and hot water boilers. In previous experience with LEED, we would compare the base compliant ASHRAE 90.1 system - a roof top unit, with our choice of compliant ASHRAE 90.1 HVAC systems. The way the LEED resource guide is written, referencing the use of the Energy Cost Budget, does not allow us to compare our very efficient VAV system to the direct expansion roof top units discussed early on. One of your previous rulings states, ""the reference standard was changed to limit gaming and inflated claims of energy savings."" We think that the choice our client made to invest premium dollars for a more efficient system early on to reap energy savings qualifies for credit recognition. Do you agree? Are we permitted to compare the energy benefits of a direct expansion roof top unit to the system of choice described above?" "The use of the Energy Cost Budget accounting method allows the LEED process to be more consistent in comparing energy performance between projects. ASHRAE 90.1 is nationally recognized as the basic comparison standard for identifying building energy performance, and there are significant advantages to the LEED program to using this standard consistently. An exception to this protocol will not be allowed for your project, so you may not use packaged roof-top equipment for your baseline. However, LEED recognizes some of the limits of the ASHRAE baseline protocol, and has adopted one exception to ASHRAE standard that you may be able to use to capture more of the energy credits for your design. (See below) It is true that the ASHRAE methodology limits the recognition of some good design measures that improve building performance. Your decision to steer the client away from packaged roof-top equipment will save cost in the long run, and this represents a good design strategy for the client\'s interests. However, to achieve LEED points for optimizing energy efficiency, you must follow the procedures described in ASHRAE 90.1 for comparing the proposed and baseline buildings. There is one exception listed in the Reference Manual which will allow you to capture some additional credit for your mechanical design strategy. On page 126, the LEED Reference Guide lists an exception to the ASHRAE protocol which allows a project to use an air cooled chiller as a baseline for water-cooled chiller designs if chiller capacity is less than 150 tons. If applicable in your case, this exception may allow you to capture additional energy performance credits. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "5541" "2001-10-25" "New Construction" "Energy and Atmosphere. EA Credit 1: CAEEC Block 225 intends to use Californi?s Title 24 Energy Standards as the metric for the Energy Credit 1, as previously approved by the LEED interpretation committee. However, the design of CAEEC includes several innovative energy savings ideas for which credit is not allowed to be taken according to the Energy Budget Method rules of Title 24, including: " "There are two options for dealing with California Title 24 Energy Standards. Option 1: Calculate energy use according to Title 24 Rules. Then calculate the percent savings compared to Title 24. The LEED interpretation committee has approved the following equivalency table: ASHRAE TITLE 24 20% 10% 30% 20% 40% 30% 50% 40% 60% 50% Option 2 addresses projects that include strategies that are disallowed by Title 24 but that are allowed under The LEED Energy Modeling Protocol. To determine percent savings for EA Credit 1, calculate both proposed and baseline energy costs with the LEED modeling rules. The comparison is made and the points are earned using the standard LEED point table. For this option, the project must still meet Title 24 Standards, the local energy code, for the EA Prerequisite 2." "None" "None" "LEED Interpretation" "5632" "2004-02-24" "New Construction" "Intent: To properly calculate the energy points available in EA credit 1.1 through 1.10 for connection to an innovative district cooling system in lieu of constructing an independent building cooling system. Background: Cornell University designed and built an innovative campus cooling system called Lake Source Cooling to replace an existing chiller-based central cooling system. Lake Source Cooling\'s pumping system cools the campus chilled water loop using a closed loop heat exchanger system with water withdrawn from the depths of Cayuga Lake, without refrigerants. The overall energy efficiency of this system is extremely high, requiring less than 10% of the electrical energy of a conventional cooling system. This system has won numerous awards for innovation and energy efficiency, including the following: " "Centralized utility plants can offer energy savings over dedicated single building systems. However, credit for this strategy cannot be awarded under EAc1 due to limitations in the energy modeling protocol. When selecting the HVAC system for the budget building using Table 11.4.3A, note 5 indicates that when using purchased chilled water is used, the chillers are not explicitly modeled. While the situation described is not using ""purchased"" chilled water, this HVAC description for the budget building is the closest to the proposed design and should be used for energy modeling purposes. The issue raised by this CIR is not explicitly addressed in either ASHRAE 90.1 or the LEED Energy Modeling Protocol. As such, action in this area may be eligible for an innovation credit to projects that are able to document source energy efficiency realized through connection of a new building to an existing centralized distribution system. This would require the development of a modeling protocol applicable to all projects. The selection of a proper baseline for comparison needs to be consistent and fair. The USGBC will examine this issue and prepare a subsequent ruling to identify a proper methodology for comparison. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5649" "2003-05-05" "New Construction" "Kelley Engineering Center is in design as a 144,000 s.f. university research and teaching building. This project includes a 2200 s.f. data center with racks of servers, and a uninterruptible power supply room. This area has dedicated cooling equipment to extract the heat produced by all of the electronics. Given the nature of the space, and the purpose of the cooling equipment, it appears to meet the definition of a process load, and can be excluded under ASHRAE 90.1 from the energy cost budget for this credit. Do you agree with this interpretation?" "Yes, as described the dedicated server room air conditioning equipment fits the ASHRAE 90.1-1999 definition of ""process load."" As such it can be excluded from the project\'s Energy Cost Budget. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5728" "2003-06-27" "New Construction" "Our project is a golf clubhouse with a kitchen. When we did the energy modeling, we included kitchen loads--refrigerator plug loads, dishwasher loads, icemaker, etc. in both the baseline and the design building. Now, based on some credit interpretations we\'ve seen on the LEED site, we\'re realizing that perhaps we should not have included any of what seem to be ""process"" loads in the models. This would increase our energy efficiency results significantly. This issue also bears on the water reduction credit. We can achieve a 20% reduction by adding lower flow showerheads and toilets if we don\'t include kitchen uses like sinks, ice makers, dishwashers. These too have been called ""process loads"" in previous credit interpretations. (Rightfully so--we don\'t want to make less ice in a restaurant, or fill a sink less quickly...) Our question is: can we exclude kitchen energy and water uses from building modeling: we would still included loads from stove hoods, for example, since that is part of the HVAC system, but we would exclude energy and water use from dishwashers, refrigerators, ice machines, disposals. " "Only one credit can be interpreted per CIR; therefore, the question pertaining to the EA credit will be addressed. It is correct to consider kitchen equipment as process loads which result in non-regulated process energy consumption; but energy consumed by kitchen exhaust hoods and make-up air systems that serve the kitchen must still be considered part of the regulated building\'s energy consumption, since it results from HVAC systems that maintain comfort (and indoor air quality) for occupants. As a result, ventilation-related kitchen equipment loads should be included in both the Proposed Design and Energy Cost Budget simulation models; but their direct process energy, as non-regulated components, should be deducted from the total energy use of both the Energy Cost Budget and the Proposed Design, following the procedure described in the LEED Reference Guide. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5733" "2004-10-04" "New Construction" "Our project is a new 8,700 square foot building to house pets awaiting adoption. Space for administrative functions and animal treatment is included in the new facility. Additional floor space was provided in the building for future use. A nominal 45-ton closed loop geothermal heat pump (GHP) system was installed to provide space heating and cooling capacity. This system consists of two water-to-water heat pumps connected to a vertical ground loop heat exchanger. These heat pumps supply either hot or chilled water to dual temperature coils in four air handling units. The two air handling units serving the animal wings are variable air volume. Manual switches have been provided to electrically open and close zone dampers in the animal housing area depending on space occupancy. Both air handling units are equipped with variable speed drives to vary supply and exhaust air flow in response to a duct static pressure control. These units also include plate type heat exchangers to pre-heat or pre-cool 100% outdoor air before it is conditioned by the hot or chilled water supplied by the heat pumps. Constant volume units serve the lobby and administration area. When outside weather conditions permit, two large sliding doors in the lobby can be opened to provide natural ventilation. These doors are interlocked through a control system to shut down the lobby air handling unit when either door is open. Gas duct heaters are installed upstream of all four air handling units to temper outdoor air (to about 40" "Utility and municipal efficiency programs/protocols, including ASHRAE 90.1, do not allow a comparison between a baseline water-source system and an air source system. Due to different system characteristics and performance efficiencies, there is potential for the estimated energy savings to become skewed and overstated. This is also the case when trying to compare an electric resistant heat to gas fired heat sources. Again, the differential cost between these fuel sources can artificially inflate the Energy Cost Budget (ECB), dependant on which fuel source is modeled. Since ASHRAE 90.1-1999 is the credit\'s reference standard, then its modeling guidelines and protocols should be followed unless the local code is more stringent. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5773" "2003-02-25" "New Construction" "Our question pertains to a residential highrise project. It has been observed by our energy modeler that no baseline exists either within ASHRAE or the local energy code for residential lighting power density. In fact, in ASHRAE 90.1 Section 9.1 ""General"", lighting within living units is explicitly not included (Exception b.). The 1.0 w/sf allowance under 9.3.1.1 is for common areas only. These comprise a small percentage of a typical residential highrise building. Similarly, our state (Oregon) Energy Code Section 1316.1 Exception 4 provides 1.2 w/sf for apartment buildings, which would be the applicable code for the common areas of the building, including mechanical rooms, stairs, lobbies, and hallways, but excludes living areas. Because the residential lighting will comprise a relatively significant component of the total energy load of a residential highrise project, we propose that a baseline must be established against which energy efficient design strategies can be measured and rewarded. We retained Benya Lighting Design (BLD), a nationally-recognized consultant, to propose a baseline for us. James Benya, BLD Principal, is a member of the ASHRAE 90.1 committee. BLD" "NOTE: this credit ruling was amended on 3/29/05, regarding maximum W/sf. Assumptions used as a baseline for residential lighting will need to be supported by specific study results if you propose to include residential lighting savings in the energy performance calculations. These studies will need to address both light density AND daily duty cycle. The maximum allowable baseline for such residential lighting is restricted to 2 W/sf. Also note the following in response to details in your inquiry: (1) Although residential lighting density is higher than offices, the duty cycle of these lights is much lower than in offices. Some studies suggest figures near 2 hours a day or less for hard-wired residential fixtures. This reduces the significance of residential lighting in the energy model. (2) Baseline lighting assumptions should not include \'portable\' light fixtures, nor should the baseline calculations assume use of hard-wired fixtures in rooms where the studies cited indicate portable lights are the norm. Therefore applying a factor of 3 w/sf to the entire residential floor area, even though only three rooms would be anticipated to have hard-wired fixtures, would be inappropriate. (3) In residential units which are heating-load driven, there is an energy offset penalty of approximately 40% (according to numerous Pacific Northwest studies) for reductions to residential lighting load. That is, 4 of every 10 watts saved by reduced lighting loads must be made up for by increased heating energy. This offset must be accounted by your model. (4) Use of residential lighting energy savings to achieve LEED credit represents an exceptional calculation methodology outside of the LEED modeling protocol. As such it will be carefully scrutinized with respect to baseline and performance claims, and clear and concise documentation will be expected." "None" "None" "LEED Interpretation" "5823" "2005-02-25" "New Construction" "The ""Greening of Dana"" project is a renovation of an historic building at the University of Michigan. The project retained some pre-existing mechanical systems and also installed new ones. This CIR seeks help applying the ASHRAE 90.1 rules for establishing the budget building systems in this context. The total Dana area is roughly 107,800 SF. Air handling unit 1 (AH-1) is a 100 % outdoor-air (OA) ventilation-only unit that was installed when 23,800 SF were added to the building two years before the current 84,000 SF project. AH-1 was designed to provide OA for both the addition and the rest of the building. The revised HVAC system for the Greening of Dana project uses pre-existing perimeter radiators for heating and a new radiant panel system for cooling. AH-1 was incorporated into the new system as it was originally intended, to provide OA throughout the building. Re-using AH-1 was both economically practical and logical for the design. The question that this context raises is, ""What is the proper system configuration for the budget building energy model?"" Specifically, ""Should the budget building model include an economizer?"" For existing buildings, ASHRAE 90.1 has conflicting requirements. In 11.1.3 Trade-Offs Limited to Building Permit it states that ""[w]hen the building permit being sought applies to less than the whole building, only the calculation parameters related to the system to which the permit applies shall be allowed to vary. Parameters relating to unmodified existing conditions . shall be identical for both the energy cost budget and design energy cost calculations."" By this logic, since AH-1 is existing, it makes sense that this system be modeled in both the budget and proposed simulations. However, in section 11.4.3 HVAC Systems, it states that the HVAC system type and design parameters for the budget building shall be determined by the system map and requires that budget systems shall have economizers in accordance with the requirements of section 6.3.1 Economizers. Section 6.3.1 states that for this climate (1% Twb of 73F and 640 hrs from 8am and 4pm where the Tdb is between 55F and 69F) economizers are required for all systems greater than 11 tons. (Note that the Twb and the Tdb hours in this climate barely require an economizer.) Due to this requirement, the budget building system should ostensibly be modeled with an economizer. However, due to the 11-ton limit, a fan-coil system serving the budget building with individual fan-coils of less than 11 tons each would be exempted from the economizer requirement. This is the situation we found at the start of the Dana project - multiple small fan-coils and no economizer. Further, if section 11.4.3 were to be followed, it is not clear how the requirements of section 11.1.3 would also be followed. The OA-only ventilation system was an existing to remain condition and we were directed by this section to model it the same in the budget and design case buildings. If we follow this rule, how could we then also simulate an economizer? The two systems are mutually exclusive. Finally, a number of factors preclude the use of a water-side economizer, including the historic nature of the building and campus location. To summarize, AH-1 was existing equipment before the Dana renovation project. Section 11.1.3 of ASHRAE 90.1 prescribes requirements to be followed in existing buildings. ASHRAE 90.1 includes many other requirements for all building types, most of which are new construction. The Dana team believes that section 11.1.3 requirements in ASHRAE 90.1, written specifically for existing buildings, take precedence over other more general conflicting requirements. We ask USGBC to rule that it is appropriate to model the budget systems without an economizer because this approach is a realistic and fair way to evaluate the energy performance of the project and because this approach is consistent with the intent of ASHRAE 90.1 when applied to existing buildings. " "Since air handling unit 1 (AH-1) was an existing system and remained unmodified, it should be modeled identically in both the budget building design and the proposed building design as it exists without the economizer in accordance with ASHRAE 90.1-1999 Section 11.1.3. " "None" "None" "LEED Interpretation" "5850" "2003-03-25" "New Construction" "The energy efficiency implications of radiant floor heating is relatively well documented, but neither LEED nor the ASHRAE 90.1-1999 Standard appear to define how credit is provided within the energy performance simulation. In the July 2002 issue of the ASHRAE Journal, Bjarne W. Olesen provides research information on the effectiveness of radiant floor heating systems in his article ""Radiant Floor Heating in Theory and Practice."" In his work, Dr. Olesen indicates that a ""5 K (9" "Under certain circumstances, radiant floor heating systems may lead to system performance efficiencies. However, this is not always the case, nor is it always true that the performance benefits are substantial. The article cited does not indicate building type and operation, and the projected savings may not translate to your building type. In particular, the ventilation rate used in the study will affect it\'s applicability to other building types. Although it is implied that the project will adopt lower air temperatures if a radiant system is installed, there are significant control capability implications to this which may negate the effectiveness of this strategy. Furthermore, cooling and ventilation performance are integrally affected by this system. Finally, the usefulness of the air temperature strategy described will be limited to parts of the heating season, depending on indoor and outdoor conditions, ventilation rates, internal gains and solar loading, occupant densities, and a host of other factors. Due to the complexity of these issues, the strategy proposed to demonstrate \'energy performance\' by correlating it to indoor air temperature is over-simplified, and would not be acceptable as proposed. If the project could demonstrate that the ventilation rate used in the study was the same as the ventilation rate of the proposed building, some limited adjustment to indoor air temperatures might be acceptable. The project would need to demonstrate that the control system is specifically configured to achieve this goal, and that seasonal variations are accounted for. The performance improvements would need to be specifically evaluated in a building energy use model that complies with the ASHRAE 90.1 energy modeling protocol. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5877" "2001-09-28" "New Construction" "The McGowan Center is a research facility that includes office space (40%) and labs, animal procedure rooms, MRI\'s, animal holding, animal surgery, and support spaces (60%). Because the functions within the building are not manufacturing, commercial or industrial, we are assuming that no energy use in the facility should be considered process load. Additionally, all heating, cooling, auxiliaries (pumps, fans, etc), water heating and interior lighting needed for the building should be considered in determining percent energy savings. Some of the requirements of the labs and procedure rooms include 100% outside air, high air change rates and HEPA filtration. We assume that the fan energy, cooling energy and heating energy needed to support these requirements should be considered in determining the percent energy savings, as they are not considered to be process energy. We wish to know if the above assumptions are correct. As background for our assumptions, the LEED June 2001 Reference Guide states ""only energy regulated by Standard 90.1-1999 is considered in determining the percent energy savings. The \'regulated energy components\' are heating, cooling, auxiliaries, water heating and interior lighting. \'Non-regulated components\' are plug loads, process energy (including special filtering requirements for clean rooms, etc), garage ventilation, exterior lighting, elevators, and any other miscellaneous energy uses in the building"" Standard 90.1-1999 defines process energy on page 10 as energy consumed in support of a manufacturing, industrial or commercial process other than conditioning spaces and maintaining comfort and amenities for the occupants of a building""" "Specialized lab equipment plug loads are considered non-regulated loads and are not included in the energy savings calculations for the this credit. LEED only compares regulated loads. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5878" "2003-07-22" "New Construction" "The MITRE Center is a new 96,000 SF Employee Amenity building encompassing MITREÆs executive offices, meeting/presentation rooms, a full-service kitchen, servery and dining rooms. The facility will be located within MITREÆs existing campus and will replace the existing kitchen/cafeteria building, which will be demolished. The new building will serve as the primary campus dining facility. With the exception of the lobby, the entire first floor (approx. 30,000 SF) of the building is kitchen, servery and dining area use. Thus, 1/3 of the building is dedicated to food service making food service a primary (rather than ancillary) use within the building. The MITRE Campus is in a suburban office park setting, away from town center and commercial area restaurants and food shops. The MITRE Campus daily population is 1600 employees and 50 to 200 visitors to the new building conference and meeting rooms. Due to the large number of employees on-site, and the nature and business of the visitors, MITRE maintains a large kitchen and dining area as an amenity for the employees and visitors. The cooking equipment in MITREÆs existing kitchen is electric, and most was scheduled for re-use. As an energy saving measure the design team convinced MITRE to replace the electric equipment (ranges, skillets, charbroilers and convection ovens) with new gas-fired kitchen equipment. To support our position, we offer the following: EA Credit 1 looks to reduce design energy cost for regulated building components as compared to a baseline ASHRAE 90.1-1999 compliant building. Regulated building energy components include HVAC systems, building envelope, service hot water, building lighting, and other regulated systems as defined by ASHRAE 90.1-1999. /n Process energy for non-regulated systems must be excluded from the Design Energy Cost (DEC) and the Energy Cost Budget (ECB). Process energy is defined by ASHRAE 90.1-1999 as Energy consumed in support of a commercial process other than conditioning spaces and maintaining comfort and amenities for the occupants of the building. Previous CIR û EAp20, dated 9/18/02: a planting area (conservatory) inside a residential community is defined as an amenity, being provided for use by the residents of the project. As such, the conservatory HVAC systems must be included in the energy simulation and savings calculations. /n Previous CIR EAc11 page 3, dated 6/27/01: The energy cost savings for utilizing premium efficient cooling equipment for a kitchen can be documented using the ECB Exceptional Calculation Method from Section 11.5 of ASHRAE 90.1-1999. The savings should be modeled as a discrete measure, and the resulting energy savings deducted from the DEC. The kitchen make-up air (taken from the house air system), kitchen hood exhaust fan, and water heating can be modeled using procedures outlined in ASHRAE 90.1-1999 to demonstrate energy savings. However, whereas ASHRAE 90.1-1999 defines process energy as noted above, to ""maintain amenities for the occupants"", and the new MITRE Center kitchen is clearly an amenity for the occupants, and the intent is to replace all the existing electric cooking equipment with new gas-fired cooking equipment, which will reduce the energy cost of the kitchen, we propose that the kitchen cooking equipment be included in the model to demonstrate additional energy cost savings. Therefore, we propose to utilize Section 11.5 of ASHRAE 90.1-1999, the Exceptional Calculation Method, to demonstrate that the new gas-fired cooking equipment will reduce energy cost over a similar kitchen utilizing electrical equipment. The savings will be modeled as a discrete measure, and the resulting energy savings deducted from the DEC. We will include documentation of all assumptions and calculation methods, and will utilize the same input parameters for both the gas-fired and the electrical equipment cases. /n Please confirm that this approach is acceptable. " "The approach as presented seems to be acceptable. Kitchen equipment energy use is considered process energy and as such is exempt from the requirements of ASHRAE 90.1-1999. However, kitchen exhaust hoods and make-up air systems that serve the kitchen must be included in the energy model as regulated loads (see the Credit Ruling for EAc1.5 dated 6/27/03). The fuel in the design and budget cases must be the same. Energy cost savings in this area are to be determined using the ECB Exceptional Calculation Method. See Section 11.5 of the ASHRAE 90.1 User\'s Manual. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5947" "2002-06-28" "New Construction" "This inquiry is regarding the envelope criteria for energy modeling of a new building (ASHRAE 90.1-1999, Section 11.4.2). Based on LEED Energy Modeling Protocol and ASHRAE 90.1, ""the budget building design shall have identical conditioned floor area and exterior dimensions and orientations as the proposed design"" The proposed new Barrel Aging Room (5805 s.f.) was initially designed by a local architect as a standard above ground facility, similar to other structures in the region. The winery\'s interest in sustainability drove the decision to pursue burying the building as an energy conservation measure. The current architectural firm was asked to redesign the project and completed the design as an earth-covered building. The intent of burying the building was to save energy by eliminating most of the building\'s cooling load.(see note below) In modeling the PowerDOE proposed building (underground), standard procedure requires that the first foot of the walls be calculated as ""underground-wall type"" in order to estimate the associated edge loss to the first foot of soil, the remainder of the wall is modeled as an ""interior-wall type."" When changing the proposed model to the budget building, the ""exterior wall type"" was used to model the walls, as is typical of an above ground building. The dimensions of the building have not changed, only the dimensions attributed to each required wall type designation. This credit interpretation is being submitted to obtain approval for comparing the proposed walls that are modeled as ""below-grade"" to the baseline walls modeled as ""exterior."" The conditioned floor area between the two models remains unchanged. The exterior dimensions and orientation on the site between the two models remains unchanged. Summary We believe our proposed modeling method meets the spirit and intent of EA Credit 1 to optimize energy. If our modeling method is accepted, the project will pursue 8 points under Energy & Atmosphere Credit 1: Optimize Energy Performance. (Note) The average ground temperature in Oregon is about 53" "The measure you are proposing is, in effect, additional insulation in the wall system, and a reduction of the delta t across that wall system. Using this interpretation, the budget building design does have identical conditioned floor area, exterior dimensions and orientations as the proposed design. This approach is reasonable provided that the top of the wall is modeled accurately. The accuracy of this modeling approach depends upon several specific details of the wall system. As you point out, the \'deep\' ground temperature is almost ideal for your purposes. However, as you get closer to the surface, air temperature will affect the heat loss rate of the system. Soil has an approximate R-value of R-2.5/foot, so near the surface, this will have a substantial effect on the heat loss of the wall system. Likewise, concrete, at R-1/ft. will transmit heat from lower in the wall to the cold upper part of the wall. As you suggest, modeling the near-surface wall as \'exterior\' will help to identify this effect. However, if your wall is totally uninsulated, heat will move from at least the top several feet of the wall surface toward the \'cold spot\' at the top. (This is why some energy codes require at least 2 ft. of perimeter insulation at slab edges.) The accuracy of your modeling strategy therefore depends on the minimum depth below grade (minimum soil thickness) , AND the insulating strategy used (and modeled) at the top of the wall. If you clearly make the case that you have accurately characterized the performance of the near surface wall area, this modeling strategy seems reasonable. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5952" "2003-02-25" "New Construction" "This inquiry pertains to Energy and Atmosphere Credit 1. The project is a 3 storied speculative office building in McKinney Texas, 60,000 sf, aiming for a Platinum certification. The mechanical cooling system under consideration is a 100 ton Single Effect Absorption Chiller served by a rooftop array of hot water parabolic collectors with a back up gas boiler. Combined with a hot water storage tank in the building, this system has a solar fraction of 89% for cooling and 93% for heating. The air delivery system will be under floor with a VAV system. There are 2 parts to this inquiry. (1) Since this is an atypical system and not covered by the ASHRAE ECB method for selecting a base HVAC system, we would like to use a rooftop air cooled direct expansion gas fired VAV system (this is the typical system for a 3 storied speculative office building of our size). Is that the correct system for our base system? (2) The energy model has been built in DOE2.1E. This program does not have the capability to model solar assisted absorption chillers. As a result, in DOE2 we model this system using a single effect absorption chiller and backup boiler along with our envelope and lighting measures. We then extract hourly loads on the chiller and boiler, outdoor temperatures and solar insolation (rate of delivery of direct solar radiation per unit of horizontal surface)out of DOE2. Then we post process these numbers in an hour-by-hour spreadsheet model that uses the insolation and outdoor temperatures to calculate the solar panel efficiency based on the manufacturer\'\'s efficiency equations. Thus an hour-by-hour output from the solar panel is added to a hot water storage tank that is depleted by the hour-by-hour heating and cooling loads from the building. We use this thermal balance calculation at the storage tank to size the tank and the solar array. The annual summation of the thermal balance calculation gives us the solar fraction as well as annual reduction in utilities. We would like to submit the DOE2 results (from the BEPS report) as result of the envelope, lighting, daylighting, and mechanical system (absorption chiller) compared to the energy cost budget model (the air cooled DX system), as shown in Table 7 (page 132) of the LEED Reference Guide (June 2001). We will then add energy savings as a result of the solar panels (arrived at from our hour-by-hour spreadsheet model) similar to the way renewable energy savings are added in that table. The building also has a significant photovoltaic array and the energy from this array will be added as another line item. Does this method of calculation and documentation seem plausible?" "(1) The LEED energy modeling protocol (EMP) defines the baseline for equipment under 150 tons of cooling capacity to be \'air-cooled\'. See page 126 of the Reference Guide. (2) The calculation methodology seems reasonable, as long as the storage tank temperatures assumed by the DOE-2 model do not incorporate solar effects that are also then counted under the solar energy line item. You will need to clarify how the baseline is modeled without solar contribution. As explained, it seems that the DOE-2 model will assume that heating and absorption chillers are driven by a gas boiler. Outside of the model, the calculated solar thermal contribution will offset boiler heat based on the hourly contribution calculated from the solar panels. Be sure to clearly identify and describe any exceptions employed to standard modeling protocol when submitting calculations and supporting documentation. Applicable internationally." "None" "None" "X" "LEED Interpretation" "5967" "2002-06-14" "New Construction" "This project is a new approximately 4000 square foot Emergency Medical Services (EMS) station in Austin, which will be occupied 24/7. This question pertains to EA Credit 1 (Optimize Energy Performance) and relates to the determination of the baseline HVAC system. The two systems proposed by the mechanical engineer are: Option 1: One ductless split system heat pump per zone. Outside air will be provided to the zones by one central outside air unit with DX cooling and gas heating. (Single zone AC, multi-zone ventilation) Option 2: Ducted DX split systems serving multiple zones with gas heating. Outside air same as in #1 above. (Multi-zone AC, multi-zone ventilation) In our current baseline modeling, we selected the baseline system in accordance with ASHRAE 90.1-1999 section 11.4.3. This section offers three possible system type categories. The applicable category for baseline modeling is based on the type of system proposed in the actual design. The possible system categories are \'Single Zone Residential\', \'Single Zone Non-Residential\', and \'All Other\'. Given that ventilation outside air for either of the two proposed systems above is multi-zone, we categorized the proposed system as \'All Other\'. According to ASHRAE 90.1-1999 Figure 11.4.3 the baseline system is a Packaged VAV with parallel fan-powered boxes and VAV fan control. Question #1: Is this baseline system correct? Question #2: Does this system qualify for the exception (b) of ASHRAE 90.1-1999 6.3.2.1? ASHRAE 90.1-1999 allows for the baseline modeling of a constant-volume packaged unit with parallel fan-powered boxes in place of the packaged VAV system with parallel fan-powered boxes if a VAV system would be considered impractical for the subject project. Question #3: Since system #1 is single-zone, we would like to know if we can base our modeling of the baseline system chosen by the \'Single Zone Non-Residential\' category. Using this category will require a baseline system that is significantly different than the baseline system currently required under the \'All Other\' system category. In short, in our use of ASHRAE 90.1-1999 11.4.3, do we have flexiblity to treat the HVAC system as single-zone, although ventilation air is provided with a multi-zone system?" "This is a complicated question, and only some of the information needed to evaluate your project\'s ASHRAE baseline is provided. The basic answer to your question 1 is that you have not identified the correct baseline according to ASHRAE 90.1. See discussion below. Likewise, for question 2, you do not need to apply exception (b) of ASHRAE 90.1-6.3.2.1 because neither VAV nor fan-powered boxes accurately describe your system configuration. In question 3, you are on the right track, because for purposes of this discussion, your system(s) are each single zone, not multi-zone systems, as described more specifically below. For Option 1 Your system utilizes two separate system types and two separate heating fuel types. In this case, ASHRAE requires you to model the two systems separately (See section 11.4.3 (k)). The ductless heat pumps must use the efficiencies in Table 6.2.1A, B, or D (depending on configuration) as the baseline, using the values for small individual equipment. This equipment is not considered multi-zone, because each heat pump serves only one zone. (System type 9) The packaged rooftop equipment (ventilation) should be modeled as a System type 11, and meet the appropriate efficiency requirements for use of gas heat with AC. Both systems should be present in the baseline, based on their respective capacities. Option 2 As we understand your system, you are using split system heat pumps with zone dampers. This equipment probably does not include fan boxes, nor does it include the capacity to vary fan speed based on zone demands. Therefore, it is effectively acting as a single zone system, and should be modeled as such. There is no reason to model this system against a VAV baseline, nor can we see how this would be advantageous to your energy performance, since VAV systems account for adjustable fan power in the baseline energy use, and your system cannot. In this option, all equipment in the baseline should meet the efficiency requirements for each piece of equipment (zone HP\'s, ventilation HP) based on the capacity of the individual equipment. These questions have been answered based on limited information about your system configuration and control strategies. It will be important to confirm the assumptions here about system configuration with your mechanical designer." "None" "None" "LEED Interpretation" "6028" "2003-03-25" "New Construction" "We are submitting the following appeal to the USGBC Project Manager\'\'s Ruling of a CIR in the Energy and Atmosphere category, Credit EA-1. The Credit Interpretation Request was submitted on 7/17/2002 for the Valley View School District 365U. The issue raised was whether exceptions are allowed in the ASHRAE 90.1 Energy Cost Budget (ECB) methodology to allow for comparisons of different HVAC system types - specifically when a higher performing system has been selected over a less efficient system that would typically be used for a particular building type. The Project Manager\'\'s Ruling states that the answer is no, although one exception is allowed for equipment with less than 150 tons of cooling capacity. While we are not appealing the specific scenario of this CIR (i.e., whether packaged rooftop units can be compared to water-cooled chillers for a school) we are appealing the broader reasoning that allows only one exception to the ASHRAE ECB methodology. As the Project Manager\'s ruling states, the LEED program allows the following exception to the ASHRAE ECB methodology: air-cooled chillers can be used in the baseline for water cooled chiller designs if chiller capacity is less than 150 tons. This exception clearly rewards projects for choosing a more efficient system type, as opposed to more efficient equipment within the same system type. The LEED 2.0 Reference Guide notes that this exception ""encourages the switch to more efficient water based cooling over air cooling in smaller equipment sizes."" We applaud this reasoning, as it supports the overall LEED program goals of transforming market practices and encouraging investment in high-performance buildings. However, we feel the logic of the one exception should be extended to recognize other similar situations where different HVAC system types are involved. For our building type (a high-rise residential building), it is by far the norm to use through-the-wall direct expansion (DX) air conditioning units as the means of cooling individual apartments (the individual units are normally 1 ton or less in capacity, with one or more units installed per apartment, depending on size). In our project, a deliberate decision was made to use a much more expensive central cooling system, using gas-fired double-effect absorption chillers (one 420 ton unit and one 380 ton unit) with cooling towers. From an ASHRAE 90.1 ECB standpoint, we are required to compare the double-effect absorption chillers to an equivalent system, which is, in fact, double-effect absorption chillers. This gives the project practically no savings for the chillers, as all double-effect absorption chillers operate within the same efficiency range. With the current ruling in place, we therefore have the following paradoxical situation: if a multi-family residence has a typical through-the-wall DX system, but specifies more efficient units, LEED acknowledges the energy savings. However, if the multi-family residence has an absorption chiller plant, which is more energy efficient than any through-the-wall DX system, LEED acknowledges no energy savings for the plant. This situation contravenes the USGBC\'s mission and, we submit, is a very high price to pay for the sake of consistency. Because of this situation, we are making the case that, for high-rise multi-family residential buildings, the basis of comparison for HVAC should be the predominant standard of through-the-wall DX units. A ruling by the USGBC in favor of this request will support efforts to transform the market for multi-family residences away from inefficient, air-cooled DX systems. In addition to increased energy-efficiency in cooling the building, such a move will have the following additional benefits: " "The USGBC will not change the standard by which this credit is evaluated. Because the USGBC does not have the resources to develop and maintain in-house standards for complex and controversial technical issues like energy modeling protocols, the USGBC relies on guidelines and standards developed by national organizations of experts whose purpose is to provide national consistency on issues like this. In this case, the USGBC relies on ASHRAE, and specifically on the ASHRAE 90.1-1999 energy modeling protocol to provide a basis for comparison of energy performance in LEED projects. Although this protocol does not recognize all of the energy performance advantages which may be available to a project, it is able to provide a consistent protocol which can be evaluated and enforced. This feature is critical to the acceptance of LEED as a national standard, and is also critical to the USGBC to provide a level playing field for disparate projects. Recognizing the limitations of the ASHRAE 90.1 energy modeling protocol, the ASHRAE 90.1 committee has proposed revisions to this standard to focus more on overall building energy performance, and less on minimum energy performance. If these standards are adopted by ASHRAE, and subsequently by the USGBC, this standard could represent a substantial improvement in the energy modeling protocol used by LEED. In the meantime, rather than abandon or relax the current protocol, the USGBC will continue to maintain project review consistency by using the existing standard without the type of exception proposed by this project." "None" "None" "LEED Interpretation" "6057" "2004-03-24" "New Construction" "We have used the LEED"" Energy Modeling Protocol, including a central plant model and applicable time-of-use utility rates, to determine the percent energy cost savings achieved by our proposed building with reference to the budget (reference) case. Our local energy standard is California Title 24-2001. We calculate 56% energy cost savings, which would appear to qualify for the maximum 10 EA1 credits per Amendment #LEED 2.0-EAc1-133. Our proposed building and plant emphasizes design features that provide efficiency during periods of summer peak electricity demand (e.g. lighting systems, cooling systems). These periods have the highest electricity costs under the applicable time-of-use rate schedule. Our proposed plant includes chilled water thermal energy storage which shifts electricity used for cooling to off-peak periods with lower electricity costs. Thus, the time-dependent value of the electricity accounts for a significant portion of the energy cost difference between the budget (reference) and proposed cases. The corresponding calculation for source energy savings (performed for the California ""Saving-by-Design"" utility incentive program) indicates a 37% savings from California Title 24-2001 for the proposed building. The time-dependent energy cost savings is a proxy for substantial environmental benefits which are captured off of the proposed building site. There is reduced need for expansion of power plant and electric transmission facilities. Use of environmentally undesirable power plants ( including both old plants or peaking plants) is also avoided with further reduction in emissions and further reduction in use of energy resources. Transition to renewable resources may also be facilitated by minimizing peak power demand. Please note that the DRAFT 2005 revision to California Title 24 (currently close to adoption by the State of California) includes the use of time-dependent electricity valuation as the basis for savings calculations. This implies that future Title 24-based calculations will inherently recognize the value of the energy cost based calculation for proposed buildings like ours. The environmental benefits associated with the time-dependent energy cost savings for our proposed building appear to meet both the letter and the spirit of the credit intent. We would like to confirm that our use of the protocol and our high credit count will be considered valid if some of the savings are derived from the time-dependent energy cost savings. " "The LEED Energy Modeling Protocol requires that both budget and design energy simulations use the same energy rate schedule (see LEED v2.1 Reference Guide, page 143). Both the proposed and budget buildings will need to use the same time-of-use rate. Applying this rate to the budget building systems will result in any off-peak usage being calculated at the off-peak rate. A previous CIR (EAc1.1 - 6/27/01) indicates that ice storage may be eligible for an innovation credit. The same ruling could be applied to chilled water storage. The actual environmental benefits of thermal storage systems are dependant upon numerous factors. Any attempt to demonstrate the environmental benefits must be comprehensive and quantifiable. " "None" "None" "LEED Interpretation" "6244" "2001-05-01" "New Construction" "2. ASHRAE 90.1-1999 base building model. The rules for the energy cost budget method remove any incentive to optimize the shape and orientation of the proposed design because the base building is to have the same shape and orientation for comparison using the energy cost budget method. This is one change from ASHRAE 90.1-1989 which, I believe, is regressive. In the 1989 Standard, the base building was a ""prototypical"" building with a fixed shape and orientation with the same number of stories and overall area. The prototype building was selected as an example of the least efficient design with the idea that design teams would optimize their proposed design shape and orientation to make it more efficient than the base case. While the LEED program encourages an optimized shape and orientation (see ""Harvesting free energy"" in the Reference Guide), LEED gives no credit for this effort because the base building ends up having the same shape and orientation. Can you comment as to why LEED mandates that the base building must have the same shape and orientation as the proposed design when using the Energy Cost Budget method." "The reference standard was changed to limit gaming and inflated claims of energy savings. LEED has been designed to minimize excursions from the standards that it references. Reducing spurious claims of energy savings is aimed at protecting the value of a LEED Certification in the market. Applicable internationally." "None" "None" "X" "LEED Interpretation" "6245" "2001-05-01" "New Construction" "5. ASHRAE 90.1-1999 vs. local energy code. We are required to show compliance with the Model National Energy Building Code (MNECB) as part of the application process for the Commercial Building Incentive Program (CBIP). This program is offered by Natural Resources Canada to promote energy efficient design in new and renovated existing buildings. We have to use the Performance Path Method, which is similar to the Energy Cost Budget method in that simulations of both the proposed design and a Reference building are performed to compare energy results. Our goal is to better the MNECB Reference model by 25% to qualify for a CBIP funding. At first glance, both codes would appear to be as demanding. There are differences in the codes but where one is stricter in an area, the other is stricter in other areas. A model of both base buildings would be required to accurately determine which is stricter. What is your recommendation?" "The LEED Energy Modeling Protocol allows for and engineering inspection of two energy standards and the drawing of conclusions as to their equivalency. A detailed report would be required to argue the case before the Rating Body. The more certain and faster route would be to revise the simulation model to reflect the ASHRAE requirements. Applicable internationally." "None" "None" "X" "LEED Interpretation" "6246" "2001-05-01" "New Construction" "The project is an existing building that is being converted from a hospital to an office complex. A project goal is to ""reuse"" by keeping the structure and some of the HVAC systems, but to completely upgrade the shell, lighting, and most of the HVAC systems to achieve a ""green"" building. Does the building qualify as a New or Existing building when applying Energy Credit 1: Optimize Energy Performance." "As the only part of the building fabric that is being retained is the structure, and most (>50%) of the HVAC system is being replaced, this project would need to meet the requirements for a new building. Applicable internationally." "None" "None" "X" "LEED Interpretation" "873" "2004-11-01" "New Construction" "Our team has a unique opportunity to utilize the project\'s roof snowmelt system during non-snowmelt sunny days to preheat domestic hot water. This heat recovery system would operate similar to a conventional solar thermal panel system minimizing consumption of fossil fuels. The copper roof, when not covered in snow, would absorb the solar energy, heating the coils, which we\'d then use to pre-heat domestic water. We are not aware of this being done before. In addition, we anticipate running calculations after construction to calculate energy savings data. Will the USGBC grant an Innovation and Design credit for this unique system? Also, will the USGBC grant Optimize Energy Performance and Renewable Energy credits if the system satisfies the credit requirements?" "NOTE: This ruling has been overturned by an administrative EAc2.1 ruling dated 7/7/2006 which updates the definition of qualifying renewable energy. The use of solar thermal technology is a strategy that qualifies for energy savings under EAc1: Optimize Energy Performance. Innovation credits are not awarded if the strategy contributes to an existing credit, such as with this case. EAc2 (Renewable Energy) is based on renewable strategies which generate electricity. The LEED-NC v2.1 Reference Guide specifically states on page 155 that solar hot water heating is not applicable to EAc2. Applicable Internationally. " "None" "None" "X" "LEED Interpretation" "10286" "2013-10-01" "New Construction, Core and Shell, Schools - New Construction, Retail - New Construction, Healthcare" "A centrifugal chiller, manufactured in Brazil, is specified for the project. The chiller is not AHRI certified and there is no laboratory in Brazil that can do this test. Since there is no laboratory in Brazil that can do this test, to comply with section 6.4.1.4 Verification of Equipment Efficiencies of ASHRAE 90.1-2007 Standard, would the equipment fall under option d (if no certification program exists for a covered product, the equipment efficiency ratings shall be supported by data furnished by the manufacturer)? Can this equipment be used in the project?" "A supplier’s claims regarding energy efficiency would not be considered sufficient to document compliance with EA Prerequisite 2 (Minimum Energy Performance) and EA Credit 1 (Optimize Energy Performance) for a centrifugal HVAC unit that has not been tested and certified by a 3rd party in accordance with AHRI Standard 550-590. However, if the project team can provide documentation that the efficiency has been tested by a third party using an equivalent standard for HVAC efficiency, this testing would be sufficient in lieu of the AHRI Standard 550-990 testing. Any differences in test conditions and the resulting adjustments to the efficiency values claimed in the energy model would need to be described in the project submittal documentation. Alternatively, the project team may use the supplier’s claims regarding energy efficiency if the commissioning scope of work includes field testing of the equipment efficiency for the range of full- and part-load design conditions under which the building will operate; any adjustments related to altitude, etc. must be accounted for in the commissioning testing. In this case, the energy modeling documentation must include details about the commissioning functional testing method to confirm the performance of the chiller at full and part load operation. If the LEED submittal is provided as a split design / construction phase submittal, and the commissioning agent determines that the equipment efficiency does not meet or exceed the efficiency values claimed by the supplier, the energy documentation must be resubmitted at the construction phase with the values measured by the commissioning agent." "None" "None" "X" "Brazil" "LEED Interpretation" "10390" "2014-07-01" "New Construction, Core and Shell, Schools - New Construction, Retail - New Construction, Healthcare, Commercial Interiors, Retail - Commercial Interiors" "There is significant confusion, and seemingly contradictory LEED Interpretations on the required methodology for addressing “purchased” on-site renewable energy, and/or purchased biofuel that is not considered on-site renewable energy within the LEED energy model. For renewable fuels meeting the requirements of Addendum 100001081 (November 1, 2011) or other purchased renewable fuels, how should purchased on-site renewable energy be treated in the LEED energy model? How should purchased bio-fuels (meaning it I not fossil fuel but is used in a similar manner to bio-fuel) be treated in the energy model?" "For any on-site renewable fuel source that is purchased (such as qualifying wood pellets, etc.), or for biofuels not qualifying as on-site renewable fuel sources that are purchased, the actual energy costs associated with the purchased energy must be modeled in EA Prerequisite 2: Minimum Energy Performance and EA Credit 1: Optimize Energy Performance, and the renewable fuel source may not be modeled as ""free"", since it is a purchased energy source.\n\n For non-traditional fuel sources (such as wood pellets) that are unregulated within ASHRAE 90.1, use the actual cost of the fuel, and provide documentation to substantiate the cost for the non-traditional fuel source. The same rates are to be used for the baseline and proposed buildings, with the following exception: If the fuel source is available at a discounted cost because it would otherwise be sent to the landfill or similarly disposed of, the project team may use local rates for the fuel for the baseline case and actual rates for the proposed case, as long as documentation is provided substantiating the difference in rates, and substantiating that the fuel source would otherwise be disposed of.\n\n When these non-traditional fuel sources are used for heating the building, the proposed case heating source must be the same as the baseline case for systems using the non-traditional fuel source, and the project team must use fossil fuel efficiencies for the Baseline systems, or provide evidence justifying that the baseline efficiencies represent standard practice for a similar, newly constructed project with the same fuel source." "100001081" "None" "X" "X"