Implementing Performance-Based Design

Once an organization or project team has decided to incorporate a PBD approach, initiating the process can be relatively simple, but it requires a thoughtful review of the current methods and design tools used. The critical milestones in the PBD process includes: setting relevant performance goals for a project, performing an analysis of those goals, and evaluating the results. At each of these milestones, it is important the design team be able to easily communicate with all the key players in the process and then “course correct” as needed to achieve project goals.

Setting Goals

Let’s look at the first step: setting measurable project goals. Goals are critical to the process because they do three key things. First, they let the team link client values to measurable performance metrics. If a client is interested in achieving net-zero energy in a project, for example, an obvious and measurable goal would be optimizing energy use and energy generation such that the net energy use of the building is zero. Second, setting goals focuses the team on asking relevant questions for the project. Again, this links to the goals and to the client requests, and the questions help narrow the focus to a measurable metric. For example, a client may wish to emphasize annual energy efficiency in the building design, but is unable to pinpoint what specific level of energy performance he or she is seeking. With precise, measurable goals, the team can work through iterative analysis to achieve the desired level. Finally, setting project goals is useful for clear communication both within the design team and with the client. When the team sets up a clear structure for its goal setting and has a clear plan for iterative analysis, it can present its findings and progress very clearly to the client over the course of the project.

As an example, consider a common goal in modern design—the request for “good daylighting.” The design team might translate this into a daylight autonomy target based on best practices or specific guidelines, such as LEED daylight credits. Clearly established project goals set the design limitations and needs for the entire project. This “eye on the prize” approach helps focus the entire design and construction team on achieving measurable performance criteria and requires that every part of the building process be aligned with these criteria.

Analysis

Once these goals are set, a PBD approach implements a phase of iterative analysis. This phase links directly to the project goals, and can help the team identify its design direction. The iterations may include performance comparisons across a variety of alternative options or optimized performance for a single design, and they can be done very early in the design process. After the initial performance goals are set, the design team should plan to:

• Ask specific questions about the design.
• Undertake a lot of small analyses.
• Focus on the deliverable and the output.

By asking questions about the design—both internally and with the client—the design team can better narrow down its own analyses and perhaps think differently about ways to approach design problems in the project.

Traditional design is a more isolated and independent approach that separates architects from engineers and specialists until specific questions need to be addressed. PBD, on the other hand, requires ongoing collaboration, where each design decision is evaluated for its impact on the overall goals of the project. Fortunately, new tools have been developed to enable PBD and the collaboration it requires.

The Power of Advanced Software

Analysis of the building as a whole can be done almost instantaneously and in an open and collaborative context thanks to new software applications.

These 3-D drawing tools enable the three-dimensional modeling of every design element of a project, from the building space to the interior design. The iterative element of the tools means that designers can quickly explore the implications of their design choices. Moreover, these tools can easily turn designs into 2-D construction documents. Advanced 3-D modeling software is a critical, if not necessary, part of the modern PBD process.

Image courtesy of SketchUp

Modeling software that incorporates performance analysis supports architects' pursuit of high-performance design solutions.

Kerger Truesdell, product manager at Sefaira, a developer of cloud-based software for the design of sustainable and high-performance buildings, believes that leveraging modern technology with PBD helps architects define, quantify, and optimize the energy, water, carbon, and financial benefits of relevant design strategies. This combination of PBD with intuitive software tools helps architects become more competitive.

“High-performance buildings are becoming increasingly common, with demand coming from both owners and tenants. Performance includes not just lower energy use and good daylighting, but also lower operating costs,” says Truesdell. “Architects that can consistently deliver these design outcomes in their projects are winning more work and developing a positive reputation as leaders in the market.”

One of the key benefits to using a advanced software to facilitate PBD is the ease and speed of obtaining performance feedback and analysis.

“Modern computer software can now directly import the architect’s model into the application platform, and then—by simply inputting the site location and HVAC system—the software can deliver information on sizing and peak loads within minutes,” notes Sterner. This near-instant feedback on performance expectations is a significant improvement over the traditional evaluation approach, which would require architects to wait for analysis results compiled by engineers.

In addition, performance-based design helps architects reduce rework later by addressing potential challenges early in the process. Also, for projects that have specific green building certification requirements, like meeting the 2030 Commitment or attaining LEED certification, architects can reduce the risk of missing those targets because they can align the project early on with those performance goals.

It is important that architects choose the right design tools to implement and achieve performance-based design goals. Software that integrates with other platforms and allows a whole-building approach tends to be the most versatile. Architects and designers benefit most from a nimble system that can track and maintain building performance goals throughout the project life cycle. The platform should also be able to provide comparative massing studies and to analyze potential design solutions as early in the project as possible.

A successful collaborative software application includes these key attributes:

• Flexible design parameters and easy data entry
• Iterative design
• Multiple stakeholder input
• Design tracking and reporting
• Intuitive use

Performance-based design software can benefit architects and their firms by helping them set clear performance goals, carefully iterate on and analyze their designs, and clearly report their design decisions both for their own records and for their clients. Software that easily facilitates this process can shift architects to a more accountable, data-driven practice.