U.S. Department of Energy - Energy Efficiency and Renewable Energy
Building Technologies Office
Commercial Building Energy Asset Score Frequently Asked Questions
The U.S. Department of Energy's (DOE) Commercial Building Energy Asset Score program has received numerous questions from building owners and operators, state and local governments, realtors, and other stakeholders interested in learning more about the Commercial Building Energy Asset Score. Responses to some of the most frequently asked questions can be found below within the following categories:
Q: What is the Commercial Building Energy Asset Score?
A: DOE established a Commercial Building Energy Asset Score to help building owners, managers, and operators understand and compare the energy efficiency of various buildings. Facility managers, energy auditors, and building engineers can use a free, web-based Asset Scoring Tool to evaluate the physical characteristics of the building and its overall energy efficiency independent of occupancy and operational usage. The Asset Scoring Tool, which uses the Energy Plus simulation model, takes into account key factors and variables that affect a building's energy usage including the building envelope, mechanical and electrical systems, and other major energy-reliant equipment. The Asset Scoring Tool identifies potential opportunities for energy efficiency upgrades and assesses what impact the recommended upgrades will have on the building's Asset Score.
Q: What types of buildings can be scored using the Asset Scoring Tool?
A: A variety of commercial building types — both new and existing buildings — can be scored in the 2013 Pilot (see Development Schedule and Pilot Testing), including office, retail, multifamily (four stories and higher), K-12 schools, hospitality/lodging, unrefrigerated warehouses, courthouses, libraries, and buildings with a combination of aforementioned use types. The 2013 Pilot cannot accommodate buildings that require significant commercial refrigeration or commercial kitchens (e.g., refrigerated warehouses, grocery stores, restaurants). Future versions of the Asset Scoring Tool will accommodate more complex systems or those for which we currently have a limited body of information, such as data centers, laboratories, refrigerated warehouses, food service, food sales, health-care facilities, public assemblies, and so on.
Single family homes, attached homes, and low-rise multifamily (three stories and below) can be scored using DOE's Home Energy Scoring Tool. Information on the Home Energy Score can be found at www.homeenergyscore.gov or by emailing email@example.com.
Q: What is DOE's objective in creating an Asset Score for commercial buildings?
A: DOE's goal in developing a national Asset Score is to facilitate and encourage cost-effective investment and energy efficiency in commercial buildings. As part of the effort, DOE provides a free Asset Scoring Tool that allows building owners, managers, and operators to understand the relative efficiency of different buildings in a way that is distinct from building operations and occupancy. The Asset Scoring Tool applies a consistent method for evaluating the efficiency of buildings and serves as a less costly means of getting useful information about potential efficiency upgrades. However, the Asset Score is not intended to be a replacement for a full energy audit of a building.
Q: Do you anticipate the Asset Score becoming mandatory?
A: DOE created the Asset Score to give building owners, operators and others a low-cost and consistent means for assessing the energy performance of buildings and for identifying short- and long-term opportunities for cost-effective energy efficiency upgrades. Interested parties can voluntarily choose to use it but it is not mandatory.
Q: How is the Asset Score different from ENERGY STAR® Portfolio Manager?
A: The Asset Score is intended to be complementary to Portfolio Manager. An ENERGY STAR® Portfolio Manager score is based on one year of utility bills and provides a benchmark for building owners or operators to see how their actual energy consumption compares to that of other buildings with similar operating characteristics. The Portfolio Manager score reflects both the building's overall energy systems, and operation and maintenance.
In contrast, a building's Asset Score reflects how energy efficient the building is in terms of its design, construction, and energy systems. The Asset Score is calculated using standard assumptions about how buildings are operated, depending on the building type. Consequently, the Asset Score helps isolate issues related to the building's structure and systems, independent of operation and maintenance. It allows users to compare the expected efficiency of different buildings, by eliminating the wide variation due to differences in operation and maintenance, plug loads, and occupant behavior. The Asset Scoring Tool also provides more granular information, enabling building owners to target limited resources toward those areas that will produce the greatest results.
In any given building, a number of factors influence energy use and the outcomes measured by the energy bill. The ability to see these factors in isolation can help building owners and operators better understand whether higher-than-expected energy use is due to inefficient physical infrastructure and specific building systems or occupancy, operations, or other factors.
Q: Is there a cost to score a building?
A: The Asset Scoring Tool and Asset Score Report generated by the tool are free to all users. The only cost associated with scoring a building is the time required for the user to collect and enter the building data into the Asset Scoring Tool. In the future, DOE may consider giving users the option to obtain a verified score which would require some type of verification of the data submitted as well as potential eligibility requirements for the individual submitting the data. In such cases, stakeholders interested in obtaining a verified score may need to pay a qualified individual to collect, verify, and/or submit the data. The requirements for a verified score will be further evaluated in FY2014.
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Development Schedule and Pilot Testing
Q: When will the Asset Scoring Tool be available?
A: The Asset Score program is currently in the pilot phase. The first round of pilot testing was conducted in 2012. A second round of pilot testing is scheduled for 2013. The Asset Scoring Tool will be updated in 2014 based on the findings from the 2013 Pilot and may include additional capabilities, including new building use types, renewable energy data fields, expanded HVAC and controls options, a customized user interface based on climate and use type, and the ability to hand pick upgrade opportunities to determine how they impact the building Asset Score. DOE anticipates that a new version of the Asset Scoring Tool will be launched publically in 2014.
Q: Will education and training be incorporated as part of the rollout?
A: Yes. DOE will provide education and training materials for data collection, use of the Asset Scoring Tool, and interpretation of the Asset Score Report. During the 2013 Pilot, DOE will also provide direct user support to Pilot Participants and encourage two-way communication between users and DOE.
Q: When will the 2013 Pilot take place?
A: The pilot is running from July through September 2013.
Q: Why should I participate in the pilot?
A: Commercial building owners, operators, and managers will have the opportunity to use the latest version of the Asset Scoring Tool to score their buildings and thereby gain a better understanding of their buildings' energy efficiency and potential for upgrades. The tool will also provide recommendations for cost-effective energy efficiency upgrades as well as a qualitative assessment of the building's individual energy systems. Pilot Participants will have the opportunity to help inform future direction of the program by providing their feedback on the Asset Scoring Tool, data collection process, and information provided in the Asset Score Report.
Q: How can I participate in the pilot?
A: Interested parties should email firstname.lastname@example.org with "Interested Pilot" in the subject line. DOE is continuing to accept new participants. Please include the number of buildings you'd like to score during the pilot, as well as building type, square footage, and location. If you have not yet identified specific buildings, please include your best guess of the buildings that are under consideration.
Q: What is the purpose of the 2013 Pilot? How is it different from the 2012 Pilot?
A: The 2013 Pilot will enable DOE to analyze data for a variety of commercial building types across a range of climate zones, as well as obtain qualitative feedback from Pilot Participants. This information will help DOE assess the performance of the Asset Scoring Tool and inform potential improvements or refinements to the tool and program overall. The 2013 Pilot includes more building types and Pilot Participants are using an updated version of the Asset Scoring Tool and new user interface.
Q: Is there a limit to the number of users that can participate in the 2013 Pilot or the number of buildings that can be included?
A: No. There is no limit to the number of users that can participate or buildings that can be scored. The more buildings assessed and scored during the 2013 Pilot, the more data and feedback DOE will have to fine tune the Asset Scoring Tool and overall program.
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Understanding the Asset Score Report and Using the Asset Scoring Tool
Q: What's the difference between a simple and an advanced score?
A: A simple score is based on a minimum set of required building data. For any non-required inputs, users can rely on inferred values generated by the Asset Scoring Tool. If an Asset Score Report is noted as advanced, this means the user provided one or more data points beyond the minimum requirements.
Q: Why does my building's Asset Score Report have a "Preliminary" watermark on it?
A: At this time, the Asset Scoring Tool only generates preliminary scores – whether data is provided at the simple or advanced level. DOE is currently evaluating options for offering a verified score, which would provide an Asset Score Report without the preliminary watermark. The data and quality assurance requirements for generating a verified score are still under development.
Q: Do you need to model different sub-types within a building?
A: Most buildings with regular geometry and one set of HVAC systems can be modeled as a single space. For example, it is unnecessary to separately model meeting rooms, lobbies, and offices within an office building. The Asset Scoring Tool can model more complex buildings that are made up of sections with distinctly different physical configurations or energy features. When a building has sections with different number of floors or served by different types of HVAC systems, users can create multiple blocks and define properties for each block.
Q: Is there a minimum size threshold for buildings that can be scored?
A: No. The goal is to make the Commercial Building Energy Asset Score system equally applicable to small and large commercial buildings.
Q: Can the Asset Score be used for both new and existing buildings?
A: The Asset Score is designed to provide building owners with information on the energy efficiency of their existing buildings along with general guidelines for improving their performance. However, the approach can also prove useful for considering the energy efficiency of new buildings in the planning and design stages. The determination of cost effectiveness would be slightly different for a new building; however, the general recommendations will still apply.
Q: What information will be available for the public and what will be kept confidential?
A: Sharing of the information is up to the discretion of the individuals submitting the data and scoring the buildings. DOE has no intention of disclosing any information entered into the Scoring Tool that can be used to identify a specific building without the consent of the owner of that information. However, DOE will likely use aggregated information about the buildings for statistical analysis. Individual building data will not be identifiable.
Q: Are there varied levels of user access to the Asset Scoring Tool?
A: At this time, anyone who wants to access the Asset Scoring Tool can receive a user name and password to generate a preliminary Asset Score Report. In the future, DOE may create other types of user access. For example, program administrators may be able to access multiple buildings in their service territories if individual users grant them access to the information. Or, an assessor who wants to provide a verified Asset Score may need different access credentials in order to generate such a report. The requirements for generating a verified Asset Score are still in development.
Q: Is there a demo available where I can learn more about how to use the Asset Scoring Tool?
A: Yes, a demo of the Asset Scoring Tool (WMV 90 MB) was presented during a webinar on June 18, 2013, which was recorded and available for download.
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Q: What metrics are used to determine the score?
A: The Asset Scoring Tool runs an energy simulation using the building data submitted by the building owner, operator or other tool user to generate a site-energy based estimate of energy use intensity (EUI) for the building. This site EUI is then converted to a source EUI. Source energy takes into account the building's energy use as well as losses that result from transmission and distribution. The Asset Scoring Tool then generates a score for the building based on its estimated source EUI. In order to allow equivalent comparisons of buildings across the U.S., the Asset Scoring Tool applies a weather adjustment to those energy uses that depend on climate (e.g., heating, cooling). For example, two buildings with different source EUIs in different parts of the country may actually have the same final Asset Score given that a building in a harsher climate will use more energy than one in a temperate climate. In addition to the Asset Score, the Asset Score Report provides other metrics including site and source energy use separated out by fuel types, and system-level performance indicators, among other information.
Q: What building components are considered in scoring the building?
A: The Asset Score takes into account the physical characteristics of the building as built and its overall energy efficiency, independent of occupancy and operational choices. The physical characteristics include the building envelope and the mechanical and electrical systems. The Asset Score also takes into account if a building has controls such as daylighting controls and occupancy sensors, and variable air volume terminal units. The Asset Score applies standard assumptions regarding how these controls are operated. The Asset Scoring Tool also applies standard assumptions concerning miscellaneous loads (e.g., office equipment, vending machines) based on building type.
Q: Are greenhouse gas emissions reflected in the score?
A: Greenhouse gas emissions are not used in the calculation of the score. In the future, projected greenhouse gas emissions may be included as optional content in the Asset Score Report.
Q: Are energy and operational costs reflected in the score?
A: Building specific energy and operational costs are not included in the calculation of the building score. The Asset Score Report contains estimated annual building energy usage as well as estimated cost savings associated with recommended energy upgrades. These estimates are based on average regional utility rates and standard assumptions about operational factors such as occupancy density, hours of operation, number of computers and other miscellaneous loads.
Q: Does the Asset Scoring Tool compute the Asset Score with or without on-site renewable energy systems?
A: Currently, the Asset Scoring Tool does not include on-site renewable energy generation in the EUI calculation. DOE is evaluating different means to address on-site renewable energy generation in the next version of the Asset Scoring Tool.
Q: Does the Asset Score include information on water use or other green building features?
A: Water use is not included in the calculation because energy is the focus of the Asset Score; however, the energy model includes a calculation of the energy used to heat domestic water assuming a fixed amount of water consumption per occupant.
Q: Is there an added distinction in the model to ensure accurate scoring for new construction and existing buildings? What about historic buildings?
A: All buildings are scored using the same method. If a newly constructed building is expected to use less energy, it will receive a higher score than an existing building. However, it is also possible for an older building to have a higher score than a newly constructed building, if the older building was efficiently designed with, for example, a small glazing area, appropriate orientation, effective shading, etc.
Q: Does the Asset Scoring Tool account for the year that equipment is installed and for performance degradation?
A: The Asset Scoring Tool accounts for the year that equipment is installed when estimating the equipment efficiency. Performance degradation is not considered because it is affected by maintenance and many other factors.
Q: Does the Asset Scoring Tool account for different occupancies, building additions, and renovations?
A: Occupancy is standardized across the model to allow apple-to-apple comparisons of buildings. It assumes the building is fully occupied with normal operating hours based on building type. Building additions and renovations are accounted for when scoring the building as long as the users include the relevant information.
Q: Does the Asset Scoring Tool use a standard set of operating conditions? What are those standard operating conditions?
A: Yes, buildings are modeled using a standard set of operating conditions. DOE uses recognized standards such as those defined by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). A complete description of these assumptions can be found in the Operational and Equipment Sizing Assumptions.
Q: How is building location assessed? Does the energy simulation tool normalize energy use for weather?
A: The Asset Scoring Tool uses Typical Meteorological Year 3 (TMY 3) data to model a building's projected energy use and account for climatic differences between specific locations. Each building is assigned a specific weather location based on its zip code.
Q: How does the Asset Score account for the effect of local climate on a building's energy use?
A: To account for climate variability and allow a fair comparison of buildings in different locations, the Asset Scoring Tool applies "adjustment coefficients" to energy loads that are sensitive to weather before calculating a building's score. These adjustment coefficients (sometimes referred to as "multipliers") were derived by comparing energy simulations of ASHRAE Standard 90.1-2004 compliant buildings in 1,008 U.S. weather station locations. The adjustment coefficients are unique for each of the 1,008 weather locations. Most use types, except for warehouse, use the same set of weather coefficients. To calculate a building's Asset Score, the tool runs an energy simulation of the building, estimates the site energy use intensity (EUI) associated with each of the building's HVAC loads (heating, cooling, and fans), and then applies weather coefficients to these EUIs based on a building's location. The adjusted EUIs, along with the other weather-independent EUIs (e.g. lighting) for the building, are then combined to determine the building's Asset Score. Buildings, regardless of their location, are scored using a 100 point scale that applies to the specific building type (e.g., office, retail, multifamily).
Compared to a heating/cooling degree-days-based approach for weather normalization, which often relies on regression analysis of a large amount of measured energy use data and focuses mainly on dry-bulb temperature, simulation-based coefficients can account for other climatic factors such as wind speed, humidity, insolation, etc. In addition, by using energy simulation, weather-sensitive end uses can be separately examined from base loads such as lighting and miscellaneous loads.
Q: What is the basis of the software that is being used to model the building's energy use? What simulation guidelines and procedures might be proposed for the Asset Score?
A: The Asset Scoring Tool uses EnergyPlus as its centralized energy modeling engine; however, tool users do not need to interact directly with EnergyPlus. Users enter a limited set of building data into a user-friendly interface and obtain the Asset Score Report through the web-based tool. Therefore, no specific modeling guidance is necessary. A Data Collection Form and on-line help within the Asset Scoring Tool are available to all users. DOE's modeling methodology is explained in the Program Overview and Technical Protocol.
Q: Does the web-based Asset Scoring Tool perform building simulations in real time, or does it look up pre-simulated values?
A: The web-based Asset Scoring Tool runs real-time simulations.
Q: What is the minimum amount of data necessary for the Asset Scoring Tool to be sufficiently robust?
A: DOE worked with the Pacific Northwest National Laboratory (PNNL) and the National Renewable Energy Laboratory (NREL) to conduct sensitivity analyses and better understand what level of data is necessary to provide meaningful results. DOE reduced the number of required data inputs based on this analysis but will continue to work to determine which data points are most critical depending on building use type, location, and other factors. To generate a simple version of the Asset Score and Report, the user is required to provide all data inputs identified as critical during the sensitivity analysis. If the user provides any additional data beyond the minimum requirements, the Asset Score Report is designated as advanced for the purposes of the 2013 Pilot.
Q: Is there a detailed list of required building data to be collected and inputs provided in the Web-based tool?
A: Yes. A Data Collection Form that lists all data fields is available on the website. Required data inputs are shaded green.
Q: How does the model deal with mixed-use properties?
A: To score a building with multiple use types, the Asset Scoring Tool first calculates a score for each portion of the building dedicated to a specific use type. Then, the Asset Scoring Tool generates an overall score for the building by prorating the scores associated with each use type according to that use type's square footage.
Q: Does the Asset Scoring Tool provide scores for individual systems in a building?
A: No, the Asset Score is intended to reflect the whole building. However, the Asset Score Report includes system-level evaluations for the building envelope, lighting, cooling and heating systems, and service hot water systems.
Q: Is there an offset for passive design elements?
A: Passive design elements are considered on their own merit rather than specifically as a "passive element." For example, window shading is a passive feature. When analyzed in the tool, if a building's shading reduces the total energy consumption of a building, it is reflected in a better building Asset Score.
Q: Can the EUI (kBtu/ft2) value provided by the Asset Scoring Tool be directly compared to the EUI number derived from ENERGY STAR® Portfolio Manager?
A: The EUI provided by the Asset Scoring Tool reflects modeled energy use under standard operating conditions; the EUI derived from Portfolio Manager is measured energy use under actual operating conditions. Therefore, these EUI values are not directly comparable.
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Q: What scale is used for the Asset Score?
A: After evaluating various ways to construct a scoring scale, DOE decided to use a technical scale that directly converts kBtu/ft2 into a score along a 100-point scale. DOE plans to use results from the 2013 Pilot to further refine the scale for each building type.
Q: What are the two extremes of the 100-point scale?
A: DOE has created preliminary 100-point scales for each building type. Based on the findings of the 2013 pilot, these scales may be refined. Currently, the "100" point on the scale is associated with a very low energy use intensity (EUI) needed to be able to reach net zero energy should the building be able to apply renewables. A score of 1 on the scale corresponds to a high EUI. Both ends of the scale vary depending on use type.
Q: Is there a need to create different 100-point scales for different building types? Won't most buildings essentially have the same types of assets?
A: To ensure a fair scoring and comparison, it is necessary to evaluate buildings by use type because the assumed standard operating conditions are different. For example, schools have operating schedules and miscellaneous plug loads that are very different from those of retail establishments.
Q: Is there a reference point or baseline building associated with some point on the scale?
A: No. A building's Asset Score is based only on the modeled EUI estimate generated by the Asset Scoring Tool. It is not dependent on a baseline building.
Q: Is the Commercial Buildings Energy Consumption Survey (CBECS) used as a baseline for the scoring scale?
A: A building's Asset Score is independent of the CBECS data because the Asset Scoring Tool evaluates a building on its own merits rather than against a population of other buildings. DOE uses CBECS and other building databases only to ensure that the 100-point scales developed for each building type can accommodate the wide range of buildings currently in the U.S. building stock.
Q: Will the scales adjust over time or with technological advances?
A: After DOE releases the next version of the Asset Scoring Tool (post Pilot 2013), it is expected that a building's score should remain constant for about 10 years. However, as DOE refines the Asset Scoring Tool, buildings that have already been scored can have their scores automatically recalculated to reflect the most recent version of the tool as well as any changes to the scale. If efficiency upgrades are made or other infrastructure changes implemented, users should re-score the building to reflect its new characteristics.
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Identified Opportunities for Energy Efficiency Upgrades
Q: How are the recommendations for energy efficient upgrades determined?
A: Potential upgrade opportunities are considered in a package using an optimization process based on life-cycle cost (LCC) analysis. Building LCC analysis algorithms provided by the National Institute of Standards and Technology are used in the optimization process to rank recommendations. Interactive effects between measures are considered. The economic assumptions used in the LCC analysis (0% discount rate and 25 years of study period) were selected to produce a diverse, comprehensive list of upgrade opportunities, and do not attempt to match a user's unique set of economic expectations. Building owners and managers need to consider local costs of upgrades and their own financial perspectives when deciding whether to pursue specific recommendations. The next version of the Asset Scoring Tool will likely allow users to test different upgrade opportunities and generate their own Asset Score with upgrades based on the upgrades they select rather than a predefined list.
Q: How does the Asset Scoring Tool ensure the recommendations provide useful guidance and keep up with technological advances?
A: The Asset Scoring Tool considers the limitations of the existing building construction, accounts for applicability of various HVAC systems, and performs life-cycle cost analysis. All these capabilities help ensure that the identified opportunities are practical. The modeling tool and upgrade opportunities library will be maintained to keep up with the technological advances. Updates to the upgrade opportunities library may affect the upgrade recommendations and a building's potential Asset Score, but will not change a building's current Asset Score.
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Q: How does DOE maintain quality control for the Asset Scoring Tool?
A: First, the energy modeling approach is a centralized real-time simulation using EnergyPlus. Although individual users gather and enter the data onto the web-based tool, the modeling itself is standardized. Second, the Asset Scoring Tool uses an established and standardized methodology for data collection to ensure consistency with other existing standards. Third, the user interface includes automated checks and provides a warning if entered data appears incorrect or incomplete. Users are also provided with online help, data input checklists, and other useful data collection tools. Finally, all of the documentation for the Asset Scoring Tool is available online, allowing for transparency.
Q: How are accuracy and consistency of the input and output ensured?
A: In terms of ensuring the quality of inputs, DOE is considering different approaches, such as requiring submissions from a qualified professional in order to receive a verified score. The output is generated through a centralized modeling tool, which ensures consistency and replicability of the results.
Q: How detailed are the input requirements?
A: DOE's objective is to find the level of detail that provides a reasonable balance between accuracy and data collection burden. Fewer required inputs minimize the effort required to collect data. However, using a larger number of inputs can increase the efficacy of the simulation and results. The program provides consistent definitions for data requirements and will continue to take steps to encourage consistent data collection and measurement. Ultimately, however, the Asset Scoring Tool is not intended to be a replacement for a full energy audit of a building, which can entail detailed calibration, complex analysis and onsite visits.
Q: What type of training or credentials will be required of the qualified professionals? Will third-party verification be used to issue an Asset Score?
A: DOE is still evaluating different options for what types of requirements may be needed to receive a verified score. Additional data beyond what is needed to generate a simple score will likely be required. Furthermore, the individual collecting and submitting the data for scoring will likely need to meet some type of qualification requirements.
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Q: Can the Asset Score be used with ENERGY STAR® Portfolio Manager?
A: ENERGY STAR® Portfolio Manager users can import their building information via a link in the Asset Scoring Tool to avoid repetitive data entry. This feature will be up and running in summer 2013 when the next version of Portfolio Manager is available.
Q: Will there be an ability to link the Asset Scoring Tool with third-party applications?
A: Yes. DOE is creating an application programming interface (API) to enable third parties to build applications that can exchange data with the Asset Scoring Tool. This will allow users of other software tools to seamlessly submit data and score their buildings without double entry of data.
Q: How will the Asset Scoring Tool respond to localized requirements and opportunities? Will there be features of the system to allow for state/local flexibility?
A: DOE recognizes that some users may wish to compare buildings to a specific population of peers or to incorporate the Asset Score into other programs. DOE is investigating if it will be possible to customize the system to meet this demand. Interested parties can also integrate the Asset Scoring Tool into their existing tools or build additional features via the API.
Q: Will the Asset Scoring Tool allow for comparisons to local code or other user-defined reference points?
A: The Asset Scoring Tool is being designed to allow for third-party applications to interface with the system. These third-party entities may develop applications that would allow comparisons to local codes or other user-defined reference points. The Asset Scoring Tool, however, does not do this independently.
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