DfE tools

Green design typically involves more than a cursory attention to environmental impact. Quality design teams will always have a set of environmental metrics for evaluating their concepts or detailed design. Assessment of these metrics is one way of understanding the choices being made in a particular design and is also a way to chose among competing designs. Assessments are also well suited for product re-design projects where the new version can be compared directly to the existing product to see how well the design team did.

There are several design tools that teams can use to guide the design process. Tools vary in their complexity, quality of information provided, and ease of use. Simple tools include a short check list of questions. Mid-range tool include matrix methods that enable an "impact score" for the product to be calculated. (Think green cost here.) Two examples of mid-range complexity are AT&T's Product Assessment and the European Eco-indicator 95. The most complex tool is the Life Cycle Analysis (LCA) that involves detailed numerical analysis of environmental impact throughout the full product life and is generally only useful for those high volume products where environmental impact is the number one concern. LCA was a perfect place to start, as it gives a whole world picture of green design.

The Minnesota Office of Environmental Assistance has created a "Tools for Design Teams" document that overviews a variety of methods teams can use to assess their products. It is available on-line as part of the MNOEA DfE Guide that assists businesses in implementing green design, and should be read by all design teams.

For students in capstone design projects, we recommend that one or both of the two design tools described below be used to evaluate the environmental impact of the product. The first tool is a set of closed and open-ended questions in the form of a checklist. The second is a matrix method that results in an environmental impact score. Your team should determine which method makes the most sense for your design, apply it, and document the method and results in your design report. The tool should be applied as early as you can in the design process so that the results can impact the design before it is too late. The tools exist to help you do a better design, and are should not simply be a means for doing a post design analysis of what you did. The team might consider using the tool twice. Once applied to the one-of prototype built for the purposes of demonstration, and again for what is proposed as the production-ready design.

Documentation is critical as it demonstrates to all stakeholders that environment issues were important design criteria. Note that the tools can also be used to critique and benchmark competing products. Remember that the main benefit of using the tool is that it forces the design team to consider the total environmental impact of the new product in a structured fashion. Thus, use the tool as a vehicle for discussion, but don't let the design team (or your bosses) get hung up over small details in the answers.

DfE Questionnaires

The simplest green design tool is a short set of questions that the team answers (with supporting documentation) for each design. This is the minimum bar and serves not only as a means for including environmental impact as a design criteria, but also exists as documentation that the product development team at least considered green design issues when developing the product. Thus, documenting the questions and their answers in the design report is essential.

A simple DfE questionnaire has been developed for student and professional design teams. Some entries require a simple yes/no check while others are open-ended needing anywhere from a phrase to a detailed paragraph or two to answer. Leave no blanks. Answer "Don't know" for questions where the team does not know the answer as a reminder that additional research is required. Use the glossary for terms you don't understand. The questionnaire is not rigid and your design team should feel free to modify so that the information is communicated effectively. As the design progresses and additional information is gathered, the "don't know" answers should be replaced with substantive responses.

Some simple DfE techniques

Here are some relatively simple things your design team can do for your own product or for benchmarking existing products:

Calculate the joules needed to power your product over its lifetime.
Estimate the number and total weight of batteries needed to power your product over its lifetime.
Calculate the the weight of the packaging that will be thrown away. What is the ratio of packaging weight to product weight?
Estimate the total weight of each material used in the product, e.g. steel, aluminum, polymer, glass,...
Estimate the volume or weight of what will end up in the incinerator or landfill at the end of the product life.

For some more simple DfE methods, see the grabbag.