© 2009 Autodesk Autodesk Sustainable Design Curriculum Lesson Seven: Modeling Sustainable Building Construction  Sustainable Construction Management  Modeling Green Construction  Net Present Valuation  Life Cycle Assessment  Embodied Energy versus Operating Energy  Prefabrication  BIM Tools and Sustainable Construction

© 2009 Autodesk Sustainable Construction Management For the sake of completeness, and to keep this curriculum firmly grounded in reality, a list of the construction trades, as compiled by the U.S. Department of Labor, is included below. Without the involvement of these construction professionals, no sustainable design project would ever be built. The building construction trades include: Boilermakers Brickmasons, blockmasons, and stonemasons Carpenters Carpet, floor, and tile installers and finishers Cement masons, concrete finishers, segmental pavers, and terrazzo workers Construction and building inspectors Construction equipment operators Construction laborers Drywall installers, ceiling tile installers, and tapers Electricians Elevator installers and repairers Glaziers Hazardous materials removal workers Insulation workers Painters and paperhangers Pipelayers, plumbers, pipefitters, and steamfitters Plasterers and stucco masons Roofers Sheet metal workers Structural and reinforcing iron and metal workers

© 2009 Autodesk Sustainable Construction Management There are four main areas that the USGBC LEED standard recognizes that construction operations can align with to contribute to the sustainability of a building project: Construction waste management Erosion and sedimentation control Limiting the footprint of construction operations Construction indoor air quality Additional opportunities for greening of a construction operation include: Recycling of site materials such as topsoil, lime rock, asphalt, and concrete into the new building project. Paying attention to moisture control in all aspects of construction to prevent future mold problems. Minimizing the impact of construction operations, such as compaction and unnecessary destruction of trees on the site. The ability to model these aspects of construction enables construction managers to plan in advance to perform what-if scenarios, and to easily adjust their operations as environmental, social, and economic conditions change.

© 2009 Autodesk Sustainable Construction Management Construction costs related to the initial establishment of the facility include: Land acquisition, including assembly, holding, and improvement Planning and feasibility studies Architectural and engineering design Construction, including materials, equipment, and labor Field supervision of construction Construction financing Insurance and taxes during construction Owner's general office overhead Equipment and furnishings not included in construction Inspection and testing Operation and maintenance costs that arise in subsequent years over the project life cycle include the following expenses: Land rent, if applicable Operating staff Labor and material for maintenance and repairs Periodic renovations Insurance and taxes Financing costs Utilities Owner's other expenses Source, Chris Hendrickson, 2009, "Project Management for Construction", Dept. of Civil and Environmental Engineering, Green Design Institute at Carnegie Mellon University.

© 2009 Autodesk Modeling Sustainable Construction Management Illustration of a concrete-placing simulation model. Source, Chris Hendrickson, 2009, "Project Management for Construction", Chapter 4, "Labor, Material and Equipment Utilization.“ Dept. of Civil and Environmental Engineering, Green Design Institute at Carnegie Mellon University.

© 2009 Autodesk Modeling Sustainable Construction Management Top: Formula for unit cost method of estimation, based on labor, material, and equipment. From Chapter 5, “Cost Estimation.“ Bottom: Illustration of planned versus actual expenditures on a project. From Chapter 12, "Cost Control, Monitoring and Accounting." Source, Chris Hendrickson, 2009, "Project Management for Construction", Dept. of Civil and Environmental Engineering, Green Design Institute at Carnegie Mellon University.

© 2009 Autodesk Net Present Valuation Building information modeling (BIM) tools lend themselves well to the financial appraisal of long- term projects and cost estimation during design and construction. The primary tools for calculating and communicating this type of financial information are spreadsheets and graphs that use financial equations. BIM makes it possible to accurately estimate the “first” capital costs of construction, as well as the total operating expenses, also referred to as life cycle costs, associated with a variety of sustainable design and construction scenarios. The standard method for long-term financial appraisal used for capital budgeting is called Net Present Valuation (NPV). “NPV compares the value of a dollar today to the value of that same dollar in the future, taking inflation and returns into account. If the NPV of a prospective project is positive, it should be accepted. However, if NPV is negative, the project should probably be rejected because cash flows will also be negative. “ (“Net Present Value “ Investopedia, Using financial modeling techniques such as NPV, developers, designers, engineers, and builders can use BIM to more accurately describe how the practice of sustainable design can potentially reduce the costs of constructing and operating a building, and generate a solid return of the investment of precious financial capital.

© 2009 Autodesk Net Present Valuation Where: t = Time of the cash flow n = Total project time r = Discount rate C t = Net cash flow at time t C 0 = Capital outlay when t=0 NPV Example An investment with an initial cash outflow of $100,000 pays back $34,432 in the first year, $39,530 in the second year, $39,359 in the third year, and $32,219 in the fourth year. If the rate of return is 12%, find the Net Present Value (NPV).

© 2009 Autodesk Life Cycle Assessment (LCA) According to the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO), LCA is a “compilation and evaluation of the inputs, outputs, and the potential environmental impacts of a product system throughout its life cycle” (ANSI / ISO 1997). ISO’s LCA standards state that a LCA incorporates a goal and scope definition, life cycle inventory (LCI), and life cycle impact assessment (LCIA). “A well performed LCA is a systematically inclusive inventory and impact assessment for each life cycle stage of a given product. The phases for which impacts are determined often include resource extraction, material production, manufacturing, assembly, use, and disposal (reuse, recycling, incineration, or landfill).” Aurora Luscher Sharrard, 2007 "Greening Construction Processes Using an Input- Output-Based Hybrid Life Cycle Assessment Model" Dept. of Civil and Environmental Engineering, Green Design Institute at Carnegie Mellon University

© 2009 Autodesk Life Cycle Assessment (LCA) According to the American National Standards Institute (ANSI) and the International Organization for Standardization (ISO) LCA is a “compilation and evaluation of the inputs, outputs, and the potential environmental impacts of a product system throughout its life cycle” (ANSI / ISO 1997). ISO’s LCA standards state that a LCA incorporates a goal and scope definition, life cycle inventory (LCI), and life cycle impact assessment (LCIA). Aurora Luscher Sharrard, 2007 "Greening Construction Processes Using an Input-Output-Based Hybrid Life Cycle Assessment Model" Dept. of Civil and Environmental Engineering, Green Design Institute at Carnegie Mellon University

© 2009 Autodesk Embodied Energy versus Operating Energy Embodied energy is defined as the sum total of available energy that was used in the work of making a product, and that is necessary for its entire product life cycle. Some embodied energy units that have gained some acceptance are MJ/kg (megajoules of energy needed to make a kilogram of product) and CO 2 (tons of carbon dioxide created by the energy needed to make a kilogram of product). The “operating energy” of a building design is a fairly straightforward concept; it can be measured by means of reviewing the fuel and utility bills, and all of the individual energy- consuming components of an existing building of a similar construction type and end use. This serves as a “baseline” for modeling alternative designs.

© 2009 Autodesk Embodied Energy versus Operating Energy The most well known and widely adopted method for estimating a baseline operating energy cost of a building that has not yet been built is the 90.1 standard developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) and the Illuminating Engineering Society of North America (IESNA). This standard has been in use for over 30 years and continues to be updated. Some research indicates that the operating energy usage of a building is at least an order of magnitude greater than the initial embodied energy of the materials used. This depends to a large degree on the lifespan of the building. In the U.K., the average lifespan of a building is 132 years. In the U.S., the median office building lifespan is 73 years. The average lifespan of a building in Tokyo is 25 years. In China it is less than 10 years. The shorter the lifespan of the building, the more relevant an embodied energy analysis becomes. The longer the building lifespan, the more relevant the operating energy usage becomes. See

© 2009 Autodesk Prefabrication Although it has recently gained attention as a “greener” way of building, the prefabrication of building components and of whole buildings is not a new concept. Prefabricated homes and other building types were produced during the 1840s and 1850s Gold Rush in the United States, when kits were produced in order to enable Californian prospectors to quickly and effectively construct living accommodations and public buildings. Today, building component manufacturers, using techniques developed by the automobile and airframe industry and other manufacturing industry segments, can offer sophisticated aluminum-framed, face-sealed, water-managed, and pressure-equalized rainscreen curtain walls, containing in-fills of glass, metal panels, or thin stone, all at a very high quality and a relatively low price. Entire steel-frame buildings covering thousands of square feet are now being efficiently prefabricated. Manufacturers have been steadily improving their ability to control quality and reduce waste by pre-engineering and automating many aspects of construction in a controlled factory environment. The most notable examples come from the transportation sector, where entire bridges are being successfully prefabricated and quickly installed.

© 2009 Autodesk Prefabrication Left: A 771-metric ton (850-ton) prefabricated steel truss span being set in place over rail lines in New Haven, CT, in one operation at midnight to avoid impacts on a vital railroad corridor. Source: Connecticut Department of Transportation, Public Roads Magazine, United States Department of Transportation, Federal Highway Administration. Right: Diagram of a portion of the Baldorioty de Castro Avenue overpasses in San Juan, PR, showing some of the elements of a concrete bridge that were built offsite, transported to the construction site, and then put in place. Source: Precast/Prestressed Concrete Institute, Public Roads Magazine, United States Department of Transportation, Federal Highway Administration.

© 2009 Autodesk BIM Tools and Sustainable Construction Although BIM tools and processes are relatively new to the construction industry, some forward- looking firms have already adopted the technology and are making strides in applying it to the process of sustainable design. Using BIM technology, designers and builders can produce and share a range of vital information, including: Display: Planning information, site history, soil conditions, survey, utility availability, weather conditions (prevailing winds, velocity, rainfall, snow load, degree days, sun angles), seismic conditions, zoning, key public officials (city/town council, congressional district), planning commission members, zoning board members, inspectors, public meeting dates, and points of contact. Collaboration: Ability to share information between members of the design team and public officials. Software interoperability with various design packages. Development of master production schedules, work in place, requests for information, change orders, estimates and actual costs, materials testing results. Data Capture: Tools to extract information necessary for the facility owner and operator. Includes extracting information from invoices related to model and serial number, and date purchased and installed. Collection of cautions and maintenance schedules, identification of hazardous materials, and any off-gassing issues.

© 2009 Autodesk Summary Without active engagement of the construction team, early in the design process, sustainable design goals will never be achieved. Construction managers and the design team need to collaborate at the outset of the project, to share their knowledge and insights. Information modeling techniques and tools can be used to powerfully bridge disciplinary and professional boundaries, and to perform simulations and contingency analyses that enable the entire project team to collaborate at very high levels of performance and accountability, regarding financial, social, and environmental risks and rewards, costs and benefits.

© 2009 Autodesk Autodesk, Green Building Studio and Revit are registered trademarks or trademarks of Autodesk, Inc. and/or its subsidiaries and/or affiliates, in the USA and/or other countries. All other brand names, product names, or trademarks belong to their respective holders. Autodesk reserves the right to alter product offerings and specifications at any time without notice, and is not responsible for typographical or graphical errors that may appear in this document. © 2009 Autodesk, Inc. All rights reserved.