Step 4. Design a building to meet the requirements of the applicable energy code
Designing a building to meet the requirements of the energy code can impact the look, feel, and function of the building.
Energy codes also affect the design of all building systems separately and collectively. It is very important that the professionals responsible for designing the building envelope, lighting, and HVAC work together to consider interactions to best control overall building energy use. Integrated design, although not a requirement of the model codes and standards, is critical to minimizing initial project cost and being as effective as possible.
WBDG.org, a web-based portal from the National Institute of Building Sciences that provides information on whole-building design, defines the integrated design approach as an approach that …asks all the members of the building stakeholder community and of the technical planning, design, and construction team to look at the project objectives, and building materials, systems, and assemblies from many different perspectives. This approach is a deviation from the typical planning and process of relying on the expertise of specialists who work in their respective specialties somewhat isolated from each other. Whole-building design in practice also requires an integrated team process in which the design team and all affected stakeholders work together throughout the project phases and to evaluate the design for cost, quality-of-life, future flexibility, efficiency; overall environmental impact, productivity, creativity; and how the occupants will be enlivened.
DOE's Building America Program has for many years promoted an integrated design approach to optimize energy efficiency in residential buildings. "The U.S. Department of Energy's Building America Program strives to develop integrated energy systems that dramatically reduce annual energy use and peak energy loads in existing and new homes while also improving overall building quality, comfort, safety, and durability."
Building energy modeling is a key tool used by designers to guide design and construction decisions. Energy modeling is most often used to (1) comply with code requirements, particularly for performance paths in the IECC or ASHRAE Standards; and (2) comply with program requirements for desired outcomes (e.g., LEED certification, qualification for tax incentives, and qualification for utility incentives). Using energy modeling early and iteratively throughout the design process, the architect maintains control over the design while meeting building energy thresholds set by minimum codes or client values.
Table 1 under "Know the requirements of the applicable energy code" indicates that designing an energy code-compliant building can be a complex task requiring a knowledgeable set of practitioners, particularly for larger commercial buildings. Two specific approaches to building design may make that task easier: integrated design teams and building information modeling (BIM; Resource 1).
Integrated Design Teams
Looking at Table 1 under "Know the requirement of the applicable energy code" again, it is clear that commercial building energy codes impact a large number of aspects of building design, and that those codes touch on a wide variety of disciplines. It would require a very well-educated practitioner to master all the necessary disciplines and code requirements associated with a large commercial building. Rather than have a single "super practitioner," most projects involve a design team of complementary practitioners. However, Table 1 also shows that there are many areas that require cooperation among practitioners.
- An architect’s decisions on the location, orientation, and performance of windows may impact the lighting designer's approach to lighting due to the influence of daylighting.
- The control engineer needs to know if there will be a change in how lights are controlled due to daylighting.
- A landscaping designer may need to know about outdoor lighting specifications from the lighting designer as well.
All of this interaction implies a need for an integrated design team that works together to design the whole building. The concept of integrated design teams has been around for many years, but effective integration does not always happen. Resource 2 is a good video discussing their importance. Integrated design teams are especially important in federal construction, as current executive orders require the use of integrated design teams and new federal requirements are focused solely on whole-building energy or whole-building fossil fuel-based energy consumption. While most energy codes are still written as stand-alone prescriptive sections for different disciplines, the future of commercial building energy codes is likely to be whole-building approaches.
Use of an integrated design approach requires an integrated design team, and an integrated design team requires well-drafted contracts, subcontracts, and consultant agreements that will help project participants clearly define the roles and responsibilities necessary for code compliance and successful project completion. The American Institute of Architects (AIA) publishes a variety of standard form agreements that define the critical roles and responsibilities involved in the design and construction of projects across a variety of delivery models (see Resource 3 for more information on AIA contract documents). DOE has also prepared a Commercial Buildings for Architects Resource Guide that covers integrated design and many other topics (Resource 4).
The Whole-Building Design Guide offers a free online class on integrated design (Resource 5). Residential buildings are generally simpler than commercial buildings and therefore the “integrated design team” may include fewer members, but the principles of integrated design still apply.
Building Information Modeling
Table 1 also provides a reminder that someone on the building team needs to be responsible for documentation of the design. Three separate sections of this toolkit focus on documenting the original design, documenting the building "as built," and providing that documentation to the code official for approval. With the ever increasing complexity and volume of documentation, the concept of BIM becomes increasingly attractive.
The Commercial Buildings for Architects Resource Guide (Resource 4) has this to say about BIM: Building information modeling (BIM) software allows essentially all project-related data to be placed in an electronic library for the entire project team to see. While traditional paper-based materials can provide the same information, the ability to "see and apply" such paper-based information is very limited, even if only two people try to do it at the same time. An electronic format can provide a virtual building where designs can be evaluated for cost, schedule, conflicts of systems space, visual atmosphere, energy use, and code compliance, to name a few.
DOE provides an excellent tool for documenting energy code compliance in the COMcheck software, but this is a stand-alone tool that requires someone to manually enter data from plans and specifications. DOE and others provide a number of whole-building energy simulation tools that can be used to predict whole-building energy usage of a proposed design. But again, these tend to be stand-alone tools that require someone to manually enter data. The “Holy Grail” of the building design community is (and should be) a tool that allows practitioners to follow an integrated design approach and that provides any necessary energy simulation and code compliance documentation automatically. BIM tools may soon provide that “Holy Grail.”