• Fixed formatting issues in the Performance Outputs tab
• Corrected calculation within the Service Water Heating tab.
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Frequently asked questionsSee all forum discussions about this credit »
ASHRAE Interpretation “ASHRAE/IES IC 90.1-2007-14” states that the baseline pump power cited in Section G18.104.22.168 was developed as 22 W/gpm total for all baseline chilled water pumps. Is this applicable for LEED projects?
ASHRAE Interpretations are considered applicable for all LEED projects using the referenced ASHRAE Standard, regardless of LEED registrations date, since ASHRAE Interpretations are considered to be clarifications of the ASHRAE standards only. However, in consideration of the long-standing GBCI review approach that allowed 22 W/gpm for each Baseline chilled water pump, this ASHRAE Interpretation which states that “the baseline pump power in Section G22.214.171.124 was developed as 22 W/gpm, and is the total wattage allowed for all cooling system pumps,” shall be mandatory only for projects registered after the publication date of this LEED Interpretation.
For projects registered after the date of this LEED Interpretation, the total Baseline chilled water system pump power shall be 22 W/gpm per ASHRAE 90.1-2007 Section G126.96.36.199; and the Baseline pump power shall be evenly distributed between the Baseline primary and secondary chilled water pumps. Alternatively, if the proposed case has primary/secondary chilled water pumps, the Baseline pump power may be distributed between the Baseline primary and secondary pumps consistent with the proposed design.
As 90.1-2007 is essentially a compilation of addenda, we assume it may be treated in the way outlined in the footnote to EA prerequisite 2, "Project teams wishing to use ASHRAE approved addenda for the purposes of this credit may do so at their discretion. Addenda must be applied consistently across all LEED credits." However, between 2004 and 2007 Appendix G was modified in some ways without addenda being published or approved, and these modifications were made official only by inclusion in the 2007 version. We further assume that we can use these modifications, as long as we use ALL the modifications in the 2007 Appendix G and referenced sections of 90.1, similar to the guidance on addenda noted above. Is this correct?
For LEED v2.x Rating Systems, where ASHRAE 90.1-2004 is the referenced standard, it is acceptable to use ASHRAE 90.1-2007 Appendix G in place of ASHRAE 90.1-2004 Appendix G if the energy simulation follows the language of 2007 Appendix G in its entirety, though the project must only meet the prescriptive requirements listed in 2004. Projects that want to use 90.1-2007 in its entirety may do so as well. Applicable internationally.
We are working on a multi use facility with a full kitchen for restaurant style serving of the employees. There is nothing in the ASHRAE 90.1-2004 standard that defines the baseline energy for a restaurant and kitchen equipment. The owner is investing significant funds in highly efficient kitchen equipment and would like to take credit for the energy savings related to the kitchen. How do we define the baseline energy and calculate the ASHRAE savings to be incorporated in our energy calculations?
The project team is requesting guidance on defining a baseline for restaurant and kitchen equipment as well as instruction on how to take credit for using efficient equipment in the proposed design. The LEED-NCv2.2 Reference Guide states that project teams may follow the Exceptional Calculation Method (ECM) (ASHRAE 90.1-2004 G2.5) to document measures that reduce process loads. Please refer to the Standard for more information on the ECM methodology. The CIR dated 8/07/2007 also offers guidance on ECMs for process loads. An appropriate baseline for restaurant and kitchen equipment may be created using the energy rates for various equipment found in the 2005 ASHRAE Handbook - Fundamentals, Chapter 30, Table 5 in conjunction with an appropriate equipment schedule. Please comply with the documentation requirements laid out in ASHRAE 90.1-2004 G2.5 for the Exceptional Calculation Method. Another resource for determining the appropriate baseline for restaurant and kitchen equipment is the LEED for Retail Rating Systems. These can be found on the USGBC website. An informed determination can only be provided during LEED certification review if the requirements ASHRAE 90.1 Section G2.5 guidance are satisfied (i.e., provide theoretical and empirical information verifying accuracy). Applicable Internationally.
Can a project team demonstrate compliance with EA Credits 1.1 through 1.4 by the use of a tenant-level energy simulation?
Project teams may demonstrate compliance with the Minimum Energy Performance Prerequisite, and EA Credits 1.1 through 1.4 by a tenant-level energy simulation. If this path is selected, this compliance path must be used in its entirety to replace EA Prerequisite 2: Minimum Energy Performance, and EA Credit 1.1 through 1.4: Optimize Energy Performance.
Demonstrate an improvement in the proposed performance rating compared with the baseline performance rating for portions of the building within the LEED project boundary. Calculate the baseline according to ANSI/ASHRAE/IESNA Standard 90.1–2007, Appendix G, with errata (or a USGBC-approved equivalent standard for projects outside the U.S.), using a simulation model for all tenant project energy use.
The proposed design must meet the following criteria:
- compliance with the mandatory provisions of ANSI/ASHRAE/IESNA Standard 90.1–2007, with errata, (or a USGBC-approved equivalent standard for projects outside the U.S.);
- inclusion of all energy consumption and costs within and associated with the tenant project; and
- comparison against a baseline tenant project that complies with Standard 90.1–2007, Appendix G, with errata but without addenda (or a USGBC-approved equivalent standard for projects outside the U.S.).
Percentage Improvements Required to Achieve EA Prerequisite 2: Minimum Energy Performance, and points under EA Credit 1.1 through 1.4: Optimize Energy Performance are as shown in the Related Resource "ASHRAE 90.1-2007 Point Scale for LEED-CI v2009 Tenant-Level Energy Models".
Document the energy modeling input assumptions for unregulated loads. Unregulated loads should be modeled accurately to reflect the actual expected energy consumption of the tenant project.
If unregulated loads are not identical for both the baseline and the proposed performance ratings, and the simulation program cannot accurately model the savings, follow the exceptional calculation method (ANSI/ASHRAE/IESNA Standard 90.1–2007, G2.5). Alternatively, the following exceptional calculation methods are approved for unregulated loads:
- use the COMNET modeling guidelines and procedures to document measures that reduce unregulated loads;
- for equipment that is classified as eligible by ENERGY STAR, complete the appropriate ENERGY STAR savings calculator. The baseline design energy consumption for ENERGY STAR-eligible equipment shall be the average annual power consumption for the equivalent Conventional equipment as determined by the ENERGY STAR savings calculator. The proposed design energy consumption may be either the average annual power consumption for ENERGY STAR equipment as determined by the ENERGY STAR savings calculator, or manufacturer reported average annual power consumption that has been calculated in accordance with the appropriate ENERGY STAR product specification.
Modeling the Baseline Case:
The baseline HVAC system type must be based on the building’s area and number of floors (not the project’s area and number of floors).
Existing conditions for lighting and HVAC systems must be modeled as new construction in the baseline case, following Appendix G, for all components and systems.
If appropriate, apply Section G3.1.1 exceptions (a–f) to the model. More specifically, if the building heating source (fossil fuel or hybrid versus electric) or building type (nonresidential versus residential) varies from the predominant conditions of the building for an area exceeding 20,000 square feet, an alternative system type should be modeled for the space where exception (a) applies. Additional systems should be modeled in any portions of the space where exceptions (b) through (d) apply.
Allocation of Central HVAC and DHW systems to the project space:
In many projects, a portion of a base building HVAC or service water heating system serves the project’s tenant space. To allocate a percentage of that HVAC or service water heating system to the tenant area, use whichever of the following two methods is more appropriate. (Note: for air handling units, this method should be consistent with the method used for IEQ Prerequisite 1: Minimum Indoor Air Quality).
Method 1 is applicable when the additional spaces served by the HVAC or service water heating system have similar occupancies to the project space, provided the resulting unmet load hours for the proposed design do not exceed the amount allowed by ASHRAE 90.1.
- Determine the total square footage (square meters) served by the HVAC or service water-heating system.
- Determine the project floor area served by the HVAC or service water-heating system.
- For air-handling units, determine the design supply airflow, design fan power, design heating capacity, design cooling capacity, and outdoor airflow. For central service water heaters or thermal energy plants (e.g., steam, hot water, or chilled water) located in the building, determine the chiller or boiler quantities and capacities, storage tank volumes as applicable, pump design supply volume for each pump as applicable, heat rejection fan power, and any other pertinent parameters relative to HVAC system capacities.
- Determine the relative contribution of the HVAC or service water-heating system to the project floor space by applying the project floor space ratio to each design parameter (design supply airflow, design fan power, design heating capacity, design cooling capacity, outdoor airflow, chiller capacity, service water heating storage volume, or pump capacity):
Adjusted parameter = Parameter x Project area served by system / Total area served by system
- Model the HVAC or service water-heating system based on the actual design conditions and sequence of operations, but use the adjusted parameters as calculated above.
- For chilled water, hot water, or steam central plants, the District Energy Guidance may be used in lieu of the method above to determine average efficiencies for the central plant equipment.
Method 2 is applicable when the other spaces served by the air-handling unit have dissimilar occupancies to the project space.
- For air-handling units, determine the design supply airflow, design fan power, design heating capacity, design cooling capacity, and outdoor airflow. For central thermal energy plants or service water heaters located in the building, determine the chiller or boiler quantities and capacities, storage tank volumes as applicable, pump design supply volume for each pump as applicable, heat rejection fan power, and any other pertinent parameters relative to HVAC system capacities.
- Determine the percentage allocation of HVAC or service water heating capacity to the project space, using the following equations:
% allocation = Airflow allocated to project space / Total design supply airflow
% allocation = Chilled water capacity allocated to project space / Total chilled water capacity
Example: A dedicated outside air system supplies the entire building, and VAV boxes distribute the outside air to each tenant space. The team makes the calculation as follows:
% allocation = [AHU design supply flow] / [Sum of all VAV box peak design flows] x [VAV box peak design flow for project space]
- Provide documentation from the base building’s owner identifying the airflow and/or thermal capacity allocated to the project space versus the total design supply airflow and/or thermal capacity. Justify this percentage allocation in a narrative.
- Identify the different occupancies, by type and square footage (square meters), served by the air-handling unit or thermal energy system.
- In ASHRAE 90.1 User’s Manual or ASHRAE 62.1, look up default assumptions for the other occupancies’ lighting loads, ventilation, occupancy, etc. Use these values to determine (per square foot or square meter) the peak heating and cooling loads, design supply air volume, and design outside air volume for the other occupancies:
Total load = Sum [(Design load/ft2) x (Area)]
Adjusted parameter = Parameter x Total project area served by AHU or thermal system / Total area served by AHU or thermal system
- Model the air-handling unit or thermal energy system based on the actual design conditions, but use the adjusted parameters as calculated above.
- For chilled water, hot water, or steam central plants, the District Energy Guidance may be used in lieu of the method above to determine average efficiencies for the central plant equipment.
We request a ruling regarding building ventilation and its impact on EAp2/EAc1. The question is two-fold: (1) Will USGBC/GBCI allow credit for a design that increases ventilation effectiveness other than Displacement Ventilation (a noted exception for PDV now exists in ASHRAE 62.1-2010), and, (2) will USGBC/GBCI allow credit for reduced ventilation by decoupling the outdoor air from the multi-zone VAV system, which requires increased ventilation rates to ensure the appropriate airflow is reaching all of the zones? Project Design Information:The project is a multi-story office space undergoing a major renovation. In accordance with ASHRAE Standard 90.1-2007 Appendix G, the baseline system is System 8. Ventilation is handled by VAV air handling units, thus requiring multi-zone calculations. Due to elevated terminal heating temperature, zone air distribution effectiveness (Ez) is 0.8.Similarly, the proposed system will employ a VAV system, but with decoupled constant-volume ventilation, thus foregoing multi-zone calculations and reducing outdoor air. Ventilation is room neutral resulting in an Ez of 1.0.Referenced Standards/Guidelines/Research:Ez factors and ventilation rates are determined from ASHRAE Standard 62.1-2007 Tables 6-2 and 6-1, respectively.ASHRAE Standard 90.1-2007 Appendix G Section G.188.8.131.52 Design Airflow Rates states:(D)esign supply airflow rates for the baseline building design shall be based on supply-air-to-room-air temperature difference of 20°F
This exceeds the 15°F limit from Table 6-2. ASHRAE 62.1-2007 User’s Manual (page 6-27) instructs to use the worst case factor, which is the heating Ez of 0.8.
ASHRAE Standard 90.1-2007 Appendix G Section G.184.108.40.206 Ventilation states:
(V)ventilation rates shall be the same for the proposed and baseline building designs.
Reviewing the User’s Manual for this section adds:
(V)ventilation can be a major contributor to building energy consumption, but it is not considered an opportunity for energy savings... (V)ventilation is energy neutral as far as tradeoffs are concerned.
Spare a recent exemption for using PDV to reduce outdoor air rates via an allowable manipulation of Ez, no other exemptions exist. Yet, ASHRAE research recognizes the advantages of decoupling ventilation in its ability to reduce ventilation volume and therefore energy costs. From Jeong, J.W., et. al, ASHRAE Transactions 2003, Volume 109, Part 2:
“All-air [VAV] systems are widely used in many types of buildings, [even though] these common systems have several significant deficiencies. …(T)he multiple spaces method must be used to increase the [OA fraction... This increase… may add significantly to energy consumption and operating cost…
“The challenge of conforming to [ASHRAE Standard 62] in an energy efficient manner can be met with a dedicated outdoor air system (DOAS)… The DOAS provides 100% of the required ventilation air at constant volume”
In addition, EPA’s Technical Report PNNL-18774 (Strategies for 50% Energy Savings in Medium Office Buildings) recognized DOAS as a primary energy savings strategy using the previous research by ASHRAE noted above as support and justification.
It is clear that, as written, the ventilation volumes should be the same in both models. But we respectfully ask the LEED® Reviewer to provide us feedback on whether this makes sense for the current LEED® Rating Systems. It appears the rules are evolving (ex. Displacement Ventilation) as technologies and techniques evolve. And yet full credit for decoupled ventilation systems doesn’t currently exist and therefore may discourage designers and owner from investing in a system that often has higher first cost. We recommend and endorse this investment because of the excellent returns both in terms of dollars saved and carbon emissions reduced. We ask for your ruling to create an exception that allows credit for increased ventilation effectiveness and reduced ventilation rates (compared to multi-zone VAV systems) using a DOAS.
Credit cannot be taken for ventilation effectiveness in systems other than displacement ventilation, such as a dedicated outdoor air unit, using an Ez of 1.0 in the proposed case, with an Ez of 0.8 for the baseline case (VAV system).Addendum bj to ASHRAE 90.1-2007 states that the Baseline Case ventilation airflow rates can be calculated using an Ez value of 1.0 only if the Proposed Case Ez value is greater than 1.0. The project team may not take credit unless the Proposed Case Ez value is greater than 1.0, because 90.1 does not set a Baseline Case standard for that scenario. Equivalent to ASHRAE 90.1 may be used.
We would like clarification as to whether EA p2 can be demonstrated and EA credit 1 points achieved based on centrally managed lighting wattage limits. Specifically, we would like to know if the wattage limits set by the DALI (Digital Addressable Lighting Interface) system, which allows maximum wattage limits to be programmed into all fixtures, can be used to show credit compliance. Our project, the fit-out of an office space, would like to utilize these controls in order to provide exceptional energy efficiency, individual occupant control including individual fixture dimming in the open office space, as well as to control these lamps with IR occupancy sensors, photo sensors, and programmable time clocks for additional energy savings. The system also includes facility maintenance reporting of lamp and ballast status and energy usage monitoring and trend logging and could include demand response interface with BMS if desired, though not part of this project. While setting the maximum allowable wattage on the DALI system absolutely limits the amount of wattage able to be drawn by the fixtures and this limit is not something that can be over-ridden by building occupants, it is not clear if computer based controls are allowed by ASHRAE 90.1 or the LEED Rating System. It is standard practice for LEED projects to utilize reduced ballast factors or physical wattage limiters as a means to claim energy efficiency from a fixture. The dimmable DALI system and efficient T-5 linear fluorescent lamps proposed by our project cannot utilize fluorescent ballasts with a reduced ballast factor, but the equivalent energy savings can be seen by capping the fixture wattage when setting up the space\'s lighting controls. The alternative to this approach would be to utilize fewer fixtures and produce more light from each, but then the individual workstation controllability provided by the DALI system is negated because individual fixtures are shared by multiple workstations. We would like verification that it is OK to use the maximum allowable wattage set in the DALI system to compare to the AHSRAE lighting power density. The building owner will provide a signed note stating that the wattage limits will not be altered (and won\'t need to be as the lighting levels are designed to be completely sufficient with the 70% wattage limits proposed). This is consistent with the LEED Core and Shell energy modeling requirements that allow reduced lighting power densities if included in the lease agreement (a written confirmation that these levels will be met). Consistent with ASHRAE and the LEED Reference Guides, we will assume the highest wattage lamps acceptable in the fixtures and follow all other ASHRAE guidelines.
The applicant is requesting verification regarding the applicability of electronically controlled lighting wattage limits by using a Digital Addressable Lighting Interface (DALI) system. The proposed approach is an acceptable means of lighting power reduction provided the overall maximum Lighting Power Density is maintained at or below ASHRAE 90.1 specifications. The commissioning authority (CxA) must confirm that the wattage limits used to document credit achievement for EAc1 are programmed correctly as part of the fundamental commissioning activities performed to achieve EAp1. Additionally, the project team should provide documentation to verify the wattage limits (e.g., cutsheets, specifications, etc.) when documenting compliance for EAc1. Applicable Internationally.
For a project located in China, where there is limited availability of Energy Star equipment, is it acceptable to use products that meet the same criteria as Energy Star products, or to use the "China Energy Label" standards for determining product equivalency?
The project should pursue the prerequisite using the standard approach, identifying all equipment that has actually achieved an Energy Star rating as such, and identifying all local Chinese products that meet the Energy Star criteria as Energy Star equipment. Backup must be provided showing that these Chinese products meet the Energy Star criteria. Applicable internationally.
The ENERGY STAR program is continuously releasing new and updated standards for products. Project teams may be unaware that a product they are purchasing is subject to an ENERGY STAR standard. Can a project team exclude equipment covered by recently developed ENERGY STAR product specifications from the prerequisite and credit calculations? If all equipment must be included, are teams required to use the rated power or can teams “discount” the rated power to reflect average consumption or actual operating power demand? And how should international projects apply this to new ENERGY STAR product specifications or other equipment or appliances where an ENERGY STAR option is not available locally?
As required in LEED Interpretation 10044, all equipment classified as eligible by ENERGY STAR must be included in the calculations. Equipment that is procured within two years of the effective date of the first (i.e. Version 1.0) ENERGY STAR product specification for that equipment category may be included or excluded at the discretion of the project team; however, all equipment within that category must be included or excluded consistently. Refer to the ENERGY STAR product specification(s) for the effective date.
Calculations may be completed using either the rated power OR the average annual power consumption, but the metric selected must be consistent for all equipment included in the calculations. For the purposes of demonstrating equivalency to the ENERGY STAR product specification by average annual power consumption, equipment purchased may use no more than the average annual energy consumption of the equivalent ENERGY STAR-qualified product as determined by the appropriate ENERGY STAR savings calculator. The average annual power consumption for purchased equipment may be demonstrated by manufacturer documentation or calculated from actual equipment operating data and anticipated use profiles.
For Uninterruptible Power Supply (UPS) equipment:
If using the rated power methodology, the UPS “rated power” for the LEED Calculation may optionally be derated to 35% of the UPS Rated Output Power to more accurately reflect the relative energy usage associated with UPS equipment compared to other Energy Star equipment.
If using the average annual power consumption methodology, the UPS average annual power consumption (in units of kWh/year) shall be calculated as:
UPS Annual Power Consumption = 6,600 x Power x (1-EffAVGMIN)
Power is the UPS Rated Output Power in units of kW.
EffAVGMIN is determined consistently with the ENERGY STAR® Program Requirements, or 93.7% if unknown.
For projects located outside of the United States, the following approved standards may be used in place of ENERGY STAR for equipment categories covered by these standards: EU ENERGY STAR, TCO, Blue Angel. Additionally, equipment classified as eligible by ENERGY STAR but not ENERGY STAR-qualified may be deemed equivalent if the equipment has been labeled by a local energy label and has been rated by the labeling program to use no more than the average annual energy consumption of the equivalent ENERGY STAR-qualified product as determined by the appropriate ENERGY STAR savings calculator.
Updated 01/05/18 for rating system version applicability and to provide additional calculation options for Uninterruptible Power Supply equipment.
There are two main components to this CIR with regards to the prerequisite (envelope / simplified approach with HVAC) detailed as follows: Maximum U-factor and SGHF requirements for the building envelope The majority of the building is naturally ventilated and only the three following areas are being air conditioned:- a) Room 1: Room 1 is air conditioned via an air cooled split package unit system consisting of an outdoor condensing/compressor unit coupled to an indoor air handling unit with a direct expansion cooling coil. The cooled air is distributed to the room via a network of insulated galvanized steel ductwork with ceiling mounted diffusers. b) Room 2: Room 2 is air conditioned via an air cooled variable refrigerant package unit system consisting of an outdoor inverter condensing/compressor unit coupled to a few indoor concealed ducted fan coil units. The cooled air is distributed to the room via a network of insulated galvanized steel ductwork with ceiling mounted diffusers. c) Area 3: The office and meeting rooms are air conditioned via an air cooled variable refrigerant package unit system consisting of an outdoor inverter condensing/compressor unit coupled to a few indoor concealed ducted fan coil units. The cooled air is distributed to the room via a network of insulated galvanized steel ductwork with ceiling mounted diffusers. With regards to the maximum U-factor and SGHF requirements on the building envelope it is suggested we apply only to parts of the envelope separating the air conditioned space with the outdoor space. We also understand there are some requirements for the envelope elements that are adjacent to the \'unconditioned space\' in the Semi-heated column of ASHRAE 90.1-2004 section 5.5.2 and figure 5-5 that we will need to be in compliance with. Simplified Approach Option for HVAC System Instead of complying with the mandatory provision of Section 6.4 of ASHRAE Std 90.1 - 2004, we propose the above mentioned approach based on Section 6.3 of the same standard. The standard allows building with gross floor area less than 2,300 m2 to follow this approach. Although the proposed building gross floor area is approximately 8,300 m2, the air conditioned area in this building is only approximately 1,230 m2. In addition, the proposed air conditioning system as described in Issue 1 (a), (b) and (c) is fairly simple system. Will this suggested building envelope and simplified HVAC System approach be acceptable?
To demonstrate compliance with ASHRAE 90.1-2004 using the prescriptive or trade-off approach, only those areas that are heated or cooled per section 2.2.(a) of the standard must comply with the envelope requirements. As for compliance with the HVAC section 6, the gross floor area of your project is greater than the 25,000 ft2 maximum required by section 6.3.1(b). Gross floor area represents the entire building floor area, not just the gross conditioned floor area. The HVAC systems must comply with the mandatory requirements in section 6.4. Note that the building systems must also meet the requirements of section 7, 8 and 9.
Background: This project is using underfloor air distribution (UFAD) as the main HVAC system. Passive floor-mounted swirl-type diffusers (manually operated by the occupants for interior "cooling-only" zones. They will not be controlled via thermostats. The perimeter zones will be served by UFAD fan powered units (with electric heat for heating) and will be controlled via space mounted thermostats. The prerequisite requires compliance with ASHRAE 90.1-2004, section 6.4. Section 220.127.116.11.1 states: "The supply of heating and cooling energy to each zone shall be individually controlled by thermostatic controls responding to temperature within the zone". Question: Does the use of passive floor mounted diffusers in the UFAD system and controlled as described above meet the requirements of ASHRAE 90.1-2004, section 18.104.22.168.1 and this prerequisite?
The project team is requesting clarification regarding the requirement for zone-specific thermostat controls in order to meet the requirements of section 22.214.171.124.1 of ASHRAE 90.1-2004 for EAp2. The interior spaces of the project receive cooling air through in-floor swirl-diffusers that are occupant controlled, but there is no zone-specific thermostat control. In this case, the design meets the intent of the ASHRAE 90.1 requirement. Ultimately the temperatures in these spaces are maintained in a similar approach to a VAV box, by regulating air flow. The occupants control this airflow based on personal comfort levels, and are effectively the controls system (similar to operable windows in a naturally ventilated and cooled space). Provided that the system meets the rest of the requirements of section 6.4 (especially 126.96.36.199.1-Automatic shut-down), and thus does not supply unneeded cold air during unoccupied hours, the design appears to meet the intent of ASHRAE 90.1 and LEED-NC 2.2- EAp2. Applicable Internationally.
In consideration of EAp2, are plug-in type occupancy sensors acceptable to control task lights?
The proposed task lighting controls are acceptable. Although ASHRAE 90.1-2004 Section 188.8.131.52 does not list an exemption for task lighting, the context of this section implies that the requirement applies only to general lighting. Applicable Internationally.
Our project is subject to ASHRAE Standard 90.1-2013 for code compliance. To pursue Option 1: Whole Building Simulation, is there a methodology for documenting additional energy performance for LEED v4 projects regulated by ASHRAE Standard 90.1-2013?
Yes, projects applying Option 1: Whole Building Simulation, and regulated by ASHRAE Standard 90.1-2013 may document additional energy performance improvement under LEED v4 EA credit Optimize Energy Performance as described below. The Appendix G modeling method must be used for the LEED submission, even if the Energy Cost Budget method is used to document local code compliance.
Projects may calculate the Equivalent ASHRAE 90.1-2010 Performance improvement as:
Equivalent performance Improvement = % better than ASHRAE 90.1-2013 + Additional Percent Savings
Where Additional Percent Savings is shown in Table 1:
Table 1: Additional Percent Savings for ASHRAE 90.1-2013
Project Type1 Additional Percent Savings
NC-Retail (except restaurant/grocery) 5%
NC-Health Care 3%
NC-Restaurant / Grocery 3%
NC-All Other 2%
CS-Retail (except restaurant/grocery) 3%
CS-Health Care 1%
CS-Restaurant / Grocery 2%
CS-All Other 1%
CI-Retail (except restaurant/grocery) 4%
CI-Health Care 2%
CI-Restaurant / Grocery 3%
CI-All Other 2%
1 Mixed use buildings shall use the weighted average Additional Percent Savings based on the gross enclosed floor area associated with each building type. Unfinished spaces not submitted in the CS rating system shall use the CS values. Data center space must always be considered “All Other”.
We are in the process of submitting a Laboratory for LEED certification. The building contains a two-story, 6650 square foot Electromagnetic Compatibility (EMC) Laboratory which houses several shielded enclosures. Experiments are performed in and around the shielded enclosures that are very sensitive to electromagnetic interference (EMF). To minimize EMF issues, a two-tiered lighting scheme was developed. Tier 1 consists of thirty-one (31) industrial high bay luminaires, containing 1000 watt incandescent lamps, which are to be operated when experiments are running because they are EMF neutral. Tier 2 consists of thirty (30) industrial high bay luminaires containing 400 watt metal halide lamps (455 watts with ballast) which are to be operated for maintenance and general illumination when experiments are not running for higher efficiency. The space also contains 1200 watts of accent lighting. The lighting power density (LPD) of Tier 1 is 4.7 watts per square foot. The LPD of Tier 2 is 2.1 watts per square foot. Even if we take into account the Exception to 9.2.4 in ASHRAE 90.1-1999: "if two or more independently operated lighting systems in a space are capable of being controlled to prevent simultaneous user operation, the installed interior power shall be based solely on the lighting system with the highest wattage", the 4.7 watts per square foot in this space still far exceeds the 1.8 watts per square foot prescribed in the space-by-space method for laboratories. Because of the highly specialized nature of the EMC Laboratory and the fact that incandescent lamps sources had to be deployed, we feel that the LPD requirements stipulated in ASHRAE 90.1-1999 cannot be achieved. Therefore, we are asking to exclude the EMC Laboratory from our lighting power allowance calculations.
The applicant is seeking a waiver to exclude the EMC Laboratory from their lighting power allowance calculations. Based on the narrative, it would be appropriate to consider the lighting systems that are required only during the experiments as a process load. The lighting that is used for maintenance and general illumination and when experiments are not running needs to be accounted for. However, even this LPD is higher than stipulated. Please note that if the project is targeting EAc1, the applicant must include the larger lighting power density on the appropriate schedule to generate accurate equipment sizing scenarios.
Our project is a commercial office tenant improvement which occupies the 10th floor of an existing 12 story building in New York City. Our scope of work will consist primarily of an interior cosmetic refurbishing of a previously occupied space. According to LEED CI v2.0 EA Prerequisite 2 - Minimum Energy Performance, the portions of the project covered by the tenant\'s scope of work have to comply with ASHRAE 90.1-2004 or the local energy code, whichever is more stringent. It is our understanding that the base building mechanical system does not meet these requirements. Consistent with CIR\'s dated 04/23/2007 and 02/18/2008 and Rulings dated 05/16/2007 and 03/13/2008, respectively, we are seeking clarification that we are responsible only for those portions of the systems that we are modifying in our physical space and that previously installed base building systems supplying our space are exempted from the requirements of this prerequisite.
The applicant is requesting confirmation that existing base building systems, which are not included in the tenant scope of work, are exempted from consideration under the prerequisite. Yes, only portions of the building as covered by the tenant\'s scope of work are considered under this prerequisite. Applicable Internationally.
For a restaurant project located overseas, how should particular equipment for which an Energy Star certified version cannot be found be accounted for in the Energy Star Rated Equipment Table?
Equipment that is not classified by Energy Star does not need to be included in the calculation; however, equipment that is classified by Energy Star, but an Energy Star certified version was not chosen, should be included in the calculation as non-Energy Star. Applicable internationally.
Where the local code does not require vestibules or allows alternatives, can the project team take a penalty for not including vestibules in the design model?
Yes, in locations where the local code does not require vestibules or revolving doors the project team may choose one of the two options below. Additionally, all projects using this method must provide a narrative explaining how infiltration and exfiltration of air through building entries is addressed in the design.
1. Manual subtraction of the energy cost savings associated with vestibules as conservatively estimated by PNNL-20026 “Energy Saving Impact of ASHRAE 90.1 Vestibule Requirements: Modeling of Air Infiltration through Door Openings”. Refer to the Related Resource “Default Deduction for Vestibules” for the specific percentage subtraction required based on project type and climate zone.
2. Provide detailed exceptional calculation method calculations with each step of the calculation clearly described and in alignment with the analysis performed in PNNL-20026, but specific to the project building. Document the additional energy consumption of the project building associated with removing the vestibules from the project. No credit will be given for the use of air curtains when using this approach. A sensitivity analysis related to the number of occupants entering on an hourly basis would need to be justified. The narrative would also need to justify that the simulation software is capable of addressing the conditions required for the calculation. (Software with a well-mixed air assumption would not be able to apply this modeling approach).
***Update 11/9/20: This ruling is now applicable to LEED v4.1 BD+C and ID+C projects.
The SRA Arlington Consolidation design development phase started in February of 2005. The owner asked that the project be designed per the LEED-CI criteria and an early analysis of the project checklist indicated a possible Silver Certification. The LEED-CI checklist was discussed at our weekly project meetings from February 2005 until May 2005, when our CD\'s were Issued for Bid on 5/13/2005. In February 2005, the current LEED-CI checklist was Version 2, which referenced the ASHRAE 90.1-2001 criteria. We continued to review the LEED-CI criteria, and completed our CD\'s as stated above utilizing the 2001 criteria. Up unitl this time, we anticipated a paper submittal to USGBC. The LEED Online website was introduced at GreenBuild in Atlanta in November 2005, however USGBC wrestled with numerous technical challenges and did not go live until the Spring of 2006. (We know this because we attempted several times to access the website to begin entering our data the early part of 2006.) The project was bid and then sat dormant until the base building progressed to a point when the interiors portion of the work could start, per the lease, in January 2006. Also, in late summer/early fall 2005 there was significant concern on the part of the interiors team that the base building was not hitting critical milestone dates, thus providing the tenant an escape clause included in the lease - effectively cancelling the construction of interiors portion of the project. Due to these delays and uncertainty, the project was not registered with USGBC until 1/26/2006. We are asking for relief or a variance from the USGBC regarding the ASHRAE 90.1 standard, specifically that due to the timing of our design phase and CD\'s (5/13/05) versus the release of LEED-CI Version 2 on 5/25/05 that we be allowed to use ASHRAE 90.1 - 2001 criteria and not ASHRAE 90.1 - 2004. Obviously, without this prerequisite we will not be able to continue completing the submittal for this project.
Projects must adhere to the requirements of the version in effect at the time of the project\'s registration. No exceptions can be made. Applicable Internationally.
Is there an adjusted point scale and minimum point threshold where applicable for LEED v2009 projects using ASHRAE 90.1-2010?
**July 1, 2016 update:This ruling has been revised to address the LEED 2009 minimum point requirement released 4/8/2016.**
Yes, LEED v2009 projects that demonstrate compliance using ASHRAE 90.1-2010 may utilize the adjusted point scale as shown in the Related Resource "ASHRAE 90.1-2010 Adjusted Point Scale for LEED v2009 Projects", subject to the following limitations:
• All mandatory provisions associated with ASHRAE 90.1-2010 (or an approved alternative standard) must be met in order for the project to use this compliance path.
• The ID+C thresholds shown are only relevant for projects using the Alternative Compliance Path described in LEED Interpretation 10412 that replaces the LEED 2009 requirements for EAp2, EAc1.1, EAc1.2, EAc1.3, and EAc1.4 with a Performance compliance path. All other ID&C projects would use the standard points available from EAc1.1 through EAc1.4 to comply with the 4-point minimum requirements.
• The CS 2009 EAp2-c1 ACP (http://www.usgbc.org/resources/cs-2009-eap2-c1-acp) may not be used in conjunction with this ASHRAE 90.1-2010 ACP. The project team must either use ASHRAE 90.1-2007 Appendix G with the CS 2009 EAp2-c1 ACP or use ASHRAE 90.1-2010 Appendix G without the CS 2009 EAp2-c1 ACP.
For projects that register on or after April 8th, 2016 and are subject to the mandatory Optimize Energy Performance point minimum:
If the project complies with all LEED v4 Minimum Energy Performance requirements for the relevant LEED v4 rating system, the project shall be considered to satisfy the LEED 2009 EA Prerequisite: Minimum Energy Performance mandatory minimum EAc1 points requirements (applicable for projects registered on or after April 8th, 2016), regardless of number of points achieved when applying this LEED Interpretation. The points documented under EAc1: Optimize Energy Performance shall be as shown in the ASHRAE 90.1-2010 Adjusted Points Scale for LEED v2009 for projects following the Performance Path, and zero for projects following a Prescriptive path.
Table G3.1.1A lists two possible categories for the building heating source: (1) Fossil fuel, fossil/electric hybrid, & purchased heat; (2) Electric and other. In cases where the proposed building design includes both a natural gas heating source and an electric heating source, when should the heat source in Table G3.1.1A be identified as "Fossil/Electric Hybrid" versus "Electric"?
Clarification is requested regarding when a building heat source in Table G3.1.1A should be identified as "Fossil/Electric Hybrid" versus "Electric". The ASHRAE 90.1-2007 User\'s Manual states that a fossil/electric hybrid source "refers to a system with any combination of fossil and electric heat, and the baseline system for this is a fossil fuel system". Therefore, the heating source for the proposed building would be considered "Fossil Fuel" or "Fossil/Electric Hybrid" if the building uses any fossil fuel source for space heating (including backup heating or preheating), and the baseline building heat source would be fossil fuel.Exception: ASHRAE 90.1 Section G3.1.1 Exception (a) stipulates additional system type(s) for non-predominant conditions (i.e. residential/non-residential or heating source) if those conditions apply to more than 20,000 square feet of conditioned floor area. EXAMPLES OF BASELINE HEATING SOURCE DETERMINATION: The Baseline heat source from Table G3.1.1A for the following Proposed Case system types would be fossil fuel since the proposed system design includes a combination of fossil and electric heat: 1. Variable air volume system with gas furnace preheat and electric reheat2. Packaged terminal heat pumps with outside air tempered by fossil fuel furnace3. Water source heat pumps with fossil fuel boiler4. Ground source heat pumps with backup fossil fuel boiler5. 90,000 square feet is conditioned by a variable air volume system with electric reheat, and 10,000 square feet is conditioned with fossil fuel furnacesThe following buildings would be modeled with an additional system type with a different Baseline heating source in accordance with Section G3.1.1 Exception (a):1. 90,000 square feet is conditioned by a variable air volume system with electric reheat, and 20,000 square feet is conditioned with Packaged DX systems with fossil fuel furnaces. In this case, the 90,000 square feet of area would be modeled with an electric heat source in the Baseline Case (System Type #6 - Packaged VAV with Electric PFP Boxes), and the 20,000 square feet of area would be modeled with a fossil fuel heat source in the Baseline Case (System Type #3 - Packaged Single Zone AC with fossil fuel furnace).2. 50,000 square feet is conditioned by water source heat pumps with a fossil fuel boiler, and 25,000 square feet is conditioned by electric heat pumps. In this case, the 50,000 square feet of area would be modeled with a fossil fuel heat source in the Baseline Case (System Type #5 - Packaged VAV with hot water reheat), and the 25,000 square feet of area would be modeled with an electric heat source in the Baseline Case (System Type #4 - Packaged Single Zone Heat Pump). Applicable internationally.
This project consists of the rehabilitation of a one-story brick warehouse in downtown Phoenix, Arizona, built by the Arizona Hardware Supply Company in 1930. It has been determined to be eligible for listing on the National Register of Historic Places, and formal listing is anticipated following review and approval by the National Park Service (NPS). The building will be rehabilitated in accordance with the Secretary of the Interior\'s Standards for Historic Preservation. Plans are being reviewed by the Arizona State Historic Preservation Office (SHPO). The warehouse will be converted into a commercial office housing about 40 people, and may be the first project in Phoenix to combine LEED-NC certification with the Federal Rehabilitation Tax Credits. Existing brick walls are of double wythe construction, 8 inches in nominal thickness, with original bricks set in a common bond pattern. Consistent with the Secretary of the Interior\'s Standards for Rehabilitation, changes to the building that would alter the historic character, both inside and outside, are not recommended by the SHPO and NPS. Therefore, the addition of insulation to the interior or exterior walls is prohibited since it would alter one of the main "character-defining features" of this building. The ground floor level and surface of the concrete floor are also subject to the constraints of the SHPO/NPS requirements. The only proposed alterations to the building envelope are the addition of storm windows, with insulated glass placed on the interior of the window opening to provide thermal efficiency, and providing insulation to a value of R-30 for a roof that has never been insulated. EAp2 requires this renovation project to comply with ASHRAE 90.1 2004 Sections 5-10 and EAc1 requires that the project secure 2 points, or a 7% improvement over the same ASHRAE standards. While we anticipate meeting the mandatory and prescriptive requirements listed in Sections 6-10, we are unable to meet the requirements in Section 5: Building Envelope. ASHRAE 90.1-2004 Section 184.108.40.206 lists exceptions to compliance with Sections 5-10 for "a building that has been specifically designated as historically significant by the adopting authority or is listed in \'The National Register of Historic Places,\' or has been determined to be eligible for listing by the US Secretary of the Interior need not comply with these requirements." In a Credit Interpretation Ruling dated 5/27/2008, a brick warehouse project similar to this one, also being renovated to meet the Secretary of the Interior\'s standards, and reviewed by the applicable SHPO, and the NPS, was granted permission "to exclude those components that cannot be upgraded to meet the mandatory and prescriptive requirements due to the standards of the Secretary of the Interior and of the National Park Service from demonstrating compliance" in order to comply with LEED Energy and Atmosphere requirements. With this in mind, will this project be allowed to meet EA Prerequisite 2 without securing two points under EAc1, considering that ASHRAE 90.1-2004 exempts the project from meeting the requirements, owing to its historical significance?
The project team is requesting a variance from meeting the mandatory and prescriptive requirements of ASHRAE 90.1-2004 under EAp2, specifically Section 5-10. The project team is also requesting a variance from meeting the mandatory achievement of 2 points under EAc1 (achieving a 7% energy cost savings for an existing building renovation). For EAp2, the cited exemption for meeting the requirements of Section 5-10 of ASHRAE 90.1-2004 applies to this project, provided that the project receives the designation, listing, or eligibility that is required by the exception. For EAc1, there are other efficiency measures that can and should be pursued to meet the minimum target of 7% in energy cost savings for existing building renovations. As the opportunity to pursue other energy saving measures exists for this project, the request for variance is denied.
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.
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.
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.
Updated 8/7/17 for rating system applicability.
The project consists of a consumer products manufacturing facility.The energy intensive manufacturing process exceeds an estimated 90% of the facility\'s total energy load. The Project Client has developed a new manufacturing process which consumes approximately 15% less energy per produced than the previous generation process.The new proprietary process has recently been installed at a similar facility and energy reduction has been demonstrated. Since industrial energy for manufacturing is not covered by ASHRAE 90.1-2007 and the building cannot be accurately modeled using the Appendix G method, project team is seeking to establish and obtain approval of an alternative compliance path.Following the Appendix G procedure would be very challenging because there are so many interacting process and non-process systems. Artificially segregating the systems in the model would not reflect energy consumption patterns accurately. Focusing on non-process components that represent less than 10% of the total energy consumption would not demonstrate the majority of the facility\'s energy savings. Manufacturing process improvements targeted at the other 90% of energy usage have a much greater impact on the entire facility\'s energy consumption. Instead of creating an energy model, baseline and proposed energy consumption will be compared by utilizing an Energy Consumption Index (ECI), which is recognized by the Association of Energy Engineers as an accepted methodology for calculating energy consumption in a manufacturing facility. The Project Client has tabulated historical overall site energy data and production at an existing facility which uses only the previous generation manufacturing platform and is also tabulating data from a site with new generation equipment. The energy data from both of these plants is not sub-metered between process and building loads because there is little economic benefit to meter the small building-only loads. An alternative compliance path will be established using the overall site ECI. Please verify that the following method may be used for determining the entire facility\'s energy cost savings.PROPOSED COMPLIANCE PATH:1. Baseline Building:The existing baseline site
Using the Energy Consumption Index instead of ASHRAE 90.1-2007 Appendix G to determine the annual cost savings of the building is not acceptable. The manufacturing process(es) should be calculated using the Exceptional Calculation methodology. A narrative should describe all Baseline and Proposed case assumptions included for this measure, and the calculation methodology used to determine the project savings. The narrative and energy savings should be reported separately from efficiency measures in the template Section 1.7. Additionally, documentation should be provided to verify that the manufacturing process is not standard practice for a similar newly constructed facility by including a recently published document, a utility incentive program that incentivizes the new process, or by documenting the systems used to perform the same function in other newly constructed facilities. While it is acceptable to use monitored data from a similar facility (constructed within the last five years) to document these exceptional calculation savings using a per product or per pound metric, sufficient information must be provided to document the nature of the efficiency improvements made, and to confirm that the data has been normalized appropriately. Specific product names are not required, and the specific details of the manufacturing process are not required; however, the description of the efficiency improvements to the manufacturing process must be adequate to allow the reviewer to confirm that improvements in energy consumption are tied to improved equipment or controls efficiency, and are not associated with decreases in building square footage, differing project locations, local climate data, quantity of shifts operating per day, etc. Any process energy differences related to local climate or weather (such as refrigeration energy, boiler energy, etc.) should be accounted for in the data normalization process, and the method used for normalizing must be clearly indicated. Ensure the same utility rate is used for the proposed case, baseline case, and exceptional calculation. Additionally, all mandatory requirements of ASHRAE 90.1-2007 must be met."
We have 108 heat pump PTAC\'s that meet the efficiency requirements of EA prerequisite 2 credit. Due to application requirements, we need to also have 2 vertical heat pump PTAC units. The 2 vertical heat pump PTAC units do not meet the efficiency requirements of EA prerequisite 2 credit. Efficiencies are below: 108 units at EER of 12.8, EA prerequisite 2 requires 11.3 2 units at EER of 9.6, EA prerequisite 2 requires 11.3 The 2 units that don\'t meet the efficiency requirement are similar in capacity to the other 108 units. These units need to be ducted however and they do not offer a ducted unit with the high efficiency option. These units were added to meet building code needs. With only 2 out of 110 total units not meeting efficiency requirements, the average efficiency of the 110 units (all similar in capacity) easily exceeds the minimum requirements. Is it okay to have these 2 units out of 110 total?
The project team has furnished further details explaining that in trying to meet building code requirements to provide heating and cooling to the corridors with outside air, and due to the peculiar configuration of the building, it was unable to use minimum efficiency ducted PTACs for 2% of the building\'s cooling capacity for two corridors of the building. It also states that ducted PTACs were not available in a higher efficiency option. Per LEED-CI Reference Guide, all equipment components must meet the mandatory, minimum efficiency requirements as listed in ASHRAE Standard 90.1-2004 Tables 6.8.1A-G. Utilizing the mean efficiency of all equipment in a system is not listed as an acceptable method of satisfying this requirement in ASHRAE Standard 90.1-2004. The PTACs (even those that are ducted) must be rated at the rating conditions specified in ARI 310/380 and 95
Please confirm that the tenant\'s scope of work does not need to include the upgrade of the existing base building HVAC equipment (that is remaining in place and not being altered) that may not meet ASHRAE 90.1 - 2007 requirements under EAp2.
The existing HVAC does not need to be upgraded; however, all new and replacement ductwork must meet the requirements of section 220.127.116.11.4 of ASHRAE 90.1-2004. Applicable internationally.
What is considered “hybrid” heating?
**Update 1.11.2019: LI is applicable to LEED v4 projects.
Clarification is requested regarding when a building heat source in Table G3.1.1A should be identified as "Fossil/Electric Hybrid" versus "Electric".
The ASHRAE 90.1-2007 User's Manual states that a fossil/electric hybrid source "refers to a system with any combination of fossil and electric heat, and the baseline system for this is a fossil fuel system". Therefore, the predominant heating type for the building shall be determined based on the percentage of building area served by Electric-only heating versus “Fossil Fuel” and/or “Fossil/Electric Hybrid” heating. The heating source for any building space would be considered “Fossil Fuel/Electric Hybrid” if the space is heated by any combination of fossil fuel and electricity. This includes backup heating, heating of ventilation air serving the space, or preheating, But does not include emergency backup heat sources. The predominant heating type for the building shall be determined based on the percentage of building area served by Electric-only heating versus “Fossil Fuel” and/or “Fossil/Electric Hybrid” heating. (Note: Emergency back-up heating refers to heating that runs when the primary system fails or needs to be shut off in an emergency, and does not refer to a backup system which may be used to provide additional capacity as needed.)
Exception: ASHRAE 90.1 Section G3.1.1 Exception (a) stipulates additional system type(s) for non-predominant conditions (i.e. residential/non-residential or heating source) if those conditions apply to more than 20,000 square feet of conditioned floor area.
EXAMPLES OF BASELINE HEATING SOURCE DETERMINATION:
The Baseline heat source from Table G3.1.1A for the following Proposed Case system types would be fossil fuel since the proposed system design includes a combination of fossil and electric heat serving the same space for the majority of the building:
1. Variable air volume system with gas furnace preheat and electric reheat
2. Packaged terminal heat pumps with outside air tempered by fossil fuel furnace
3. Water source heat pumps with fossil fuel boiler
4. Ground source heat pumps with backup fossil fuel boiler
5. Residential condominium units with packaged terminal heat pumps, that have any amount of ventilation air provided to the space from air handling unit(s) where the supply air is tempered with fossil fuel.
The following buildings would be modeled with an electric heat source for the Baseline Case since the heating source serving the majority of spaces is electric-only:
1. 90,000 square feet is conditioned by a variable air volume system with electric reheat, and 10,000 square feet is conditioned with fossil fuel furnaces
2. 50,000 square feet is conditioned by electric heat pump systems. 15,000 square feet is conditioned with fossil fuel radiant heaters.
The following buildings would be modeled with an additional system type with a different Baseline heating source in accordance with Section G3.1.1 Exception (a):
1. 90,000 square feet is conditioned by a variable air volume system with electric reheat, and 20,000 square feet is conditioned with Packaged DX systems with fossil fuel furnaces. In this case, the 90,000 square feet of area would be modeled with an electric heat source in the Baseline Case (System Type #6 - Packaged VAV with Electric PFP Boxes), and the 20,000 square feet of area would be modeled with a fossil fuel heat source in the Baseline Case (System Type #3 - Packaged Single Zone AC with fossil fuel furnace).
2. 50,000 square feet is conditioned by water source heat pumps with a fossil fuel boiler, and 25,000 square feet is conditioned by electric heat pumps. In this case, the 50,000 square feet of area would be modeled with a fossil fuel heat source in the Baseline Case (System Type #5 - Packaged VAV with hot water reheat), and the 25,000 square feet of area would be modeled with an electric heat source in the Baseline Case (System Type #4 - Packaged Single Zone Heat Pump).
Pacific Lutheran University is doing a major interior remodel of its University Center Building. The mechanical scope for this job is limited to moving diffusers and adding three direct expansion air conditioning coils in the existing ductwork. No work is being done to the existing air handlers or other mechanical systems. The LEED-CI Reference Guide states that the requirement of the credit is to "Design portions of the building as covered by the tenant\'s scope of work to comply with ASHRAE Standard 90.1-2004 or the local energy code, whichever is more stringent." As the tenant\'s scope of work is limited to the new air conditioning coils, they are the only pieces of equipment that will comply with ASHRAE 90.1. We feel that this interpretation is consistent with the intent of the prerequisite by bringing the new tenant mechanical systems into code compliance. We are also following the assumption that punishing the tenant for pre-existing equipment is not the goal of this credit. We would like confirmation that we are interpreting the \'tenant\'s scope of work\' correctly. Please confirm that we have interpreted the \'tenant\'s scope of work\' correctly and are meeting the intent of this Prerequisite?
The project team is requesting clarification regarding the applicability of ASHRAE 90.1-2004 HVAC requirements to existing HVAC systems. Per the ASHRAE 90.1-2004 standard, alterations to HVAC Systems in Existing Buildings shall follow all the requirements listed in ASHRAE 90.1-2004 Section 18.104.22.168. If no ductwork is being added or replaced, then ductwork does not need to comply with Sections 22.214.171.124 & 126.96.36.199. Based on the information provided in this CIR, the project team is correct in stating that the new air conditioning coils are the only pieces of mechanical equipment that need to comply with ASHRAE 90.1-2004. Any alterations to the envelope, service water heating, power, and / or lighting systems are also required to comply with the requirements of ASHRAE 90.1-2004. Applicable Internationally.
The tenant\'s fitout design complies with most of the requirements of EA P2 however due to local design standards and the clients operational process requirements there are 2 clauses that we are not able to achieve and as such will require a waiver for : ASHRAE 90-1 2004 Clause 6.5.4 Hydronic System Design and Control As part of the Client\'s global network the fitout for the above project includes a data centre/ main communications room (MCR). The cooling load associated with the MCR is served by a number of chilled water units connected to 2no tenant packaged air cooled chiller. Due to the constant nature of the process load associated with the MCR room it is not proposed to install Variable speed drives to the pumps. The heat load associated with the servers contained within the MCR room is maintained at close to 100% due to the international nature of the network that the system serves and as such it is operated 24/7. The introduction of Variable Speed pumping to this system (as required to comply with ASHRAE 90.1 -2004 clause (188.8.131.52 Hydronic Variable Flow Systems) would therefore not achieve any energy saving and as such is not proposed to be installed. The client is willing to install them if necessary however does not understand how the procurement, manufacture, installation and maintenance issues associated with the additional equipment increases the sustainability of the project, given the very limited scope for VSDs to reduce energy use. Furthermore the additional complexity of Variable Speed Drives within such a critical process system adds further risk to the client business. ASHRAE 90.1-2004 allows exemption to clause 184.108.40.206 where a reduced "flow is less than the minimum flow required by the equipment manufacturer for the proper operation of the equipment served by the system" we believe that we qualify for this exemption as the client\'s critical system would be affected by any reduction in chilled water flow. As such it is proposed to install the pumps as a constant volume system albeit fitted with high efficiency motors which when combined with high efficiency air cooled chillers which exceed the minimum set out in ASHRAE 90.1-2004 (table 6.8.1C) produce an energy efficient solution which does not compromise the clients operational requirements. Further to this the application of temperature reset on the chilled water system (clause 220.127.116.11) would also be detrimental to the clients critical systems as such we believe that the system is exempt under the relevant exemption clause within the standard. ASHRAE 90-1 2004 Clause 8.4.1 Voltage Drop The local design standards require the voltage drop across the system to be sized as a maximum of 4% with 3.5% being from the feeder conductors and 0.5% from the branch circuits. The ASHRAE standard calls for a maximum voltage drop at design of 5% with 2% being from the feeder conductors and 3% from the branch circuits. As such the local design standard calls for a smaller voltage drop across the system, relative to the ASHRAE standard, but with a different split between sections. The project is therefore looking for a credit interpretation regarding this issue on the basis of the local design standards being lower on a total system basis, albeit with a different percentage split across the system.
The applicant is requesting a waiver from the provisions of ASHRAE 90.1-2004 Mandatory Requirements as they pertain to the data-center portion of the project. As per section 2.3, sub-section (C), requirements of ASHRAE 90.1-2004 do not apply to process requirements provided it meets the following criteria: 1. Equipment is primarily dedicated to process loads (50% or more of the flow is supplying process loads). 2. Exemption applies only to EAp2 and not EAc1 Regarding the issue of voltage drop, the project team should use the requirements of the local governing code. Applicable Internationally.
Can servers installed for a data center project that are not Energy Star rated, but meet the requirements of Energy Star rated equipment, verified by the Electric Power Research Institute, meet the requirements of EAp2?
The reported values for the servers in the project fall in the range of typical efficiencies for Energy Star rated servers so they are acceptable as Energy Star equivalent equipment, provided that the confirming documentation is submitted. Applicable internationally.
Our project is located in California. To pursue Option 1: Whole Building Simulation, is there a methodology for documenting additional energy performance for LEED v4 projects regulated by Title 24-2016?
Additional Percent Savings
NC-Retail (except restaurant/grocery)
CS-Retail (except restaurant/grocery)
CI-Retail (except restaurant/grocery)
The project is a 3,000 square foot 1-story new office building. The requirements of this prerequisite are to comply with the mandatory provisions (sections 5.4, 6.4, 7.4, 8.4, 9.4, and 10.4) of ASHRAE/IESNA Standard 90.1-2004 and the prescriptive requirements (sections 5.5, 6.5, 7.5, and 9.5) of ASHRAE/IESNA Standard 90.1-2004. ASHRAE/IESNA Standard 90.1 2004 Section 18.104.22.168 states "Feeder conductors shall be sized for a maximum voltage drop of 2% at design load." The exception we would like to take is as follows: We meet all the other requirements of this prerequisite for minimum energy efficiency requirements. Our design is approximately a 2.9% voltage drop, which meets the latest edition of the National Electric Code 215-2(A)(2) FPN#2 which allows between 3-5% voltage drop. The cable size is parallel 500 MCM. To meet the 2% requirement, the cable size would be increased to parallel 750 MCM. This is a significant cost increase to the project without gaining any energy savings. Will the 2.9% voltage drop be acceptable to use?
The project is requesting a relaxed voltage drop requirement for feeder conductors. ASHRAE/IESNA Standard 90.1-2004 is the referenced standard for EAp2 for LEED. The purpose of this standard is to provide minimum requirements for the energy-efficient design of buildings except low-rise residential buildings. This Standard is explicit in the requirement as stated in Section 22.214.171.124: "Feeder conductors shall be sized for a maximum voltage drop of 2% at design load." The fundamental purpose of the National Electrical Code (Section 90.1(A) and (B)) is to provide for practical safeguarding of persons and property, and contains provisions that are necessary for safety. In keeping with the purpose of the ASHRAE/IESNA Standard 90.1-2004, its requirements are more stringent than the allowances in the National Electrical Code. Therefore, the project must meet the requirement per Section 126.96.36.199 of the Standard in order to comply with this prerequisite. Applicable Internationally.
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