Saturday, 9 November 2013

SUSTAINABLE DESIGN GUIDE (Part V)





The previous sections have laid out the context of sustainability and described how to know it when you see it. However, all of that information is irrelevant if it doesn't enable action—the point of assessing and reporting environmental impacts is to give you information on how design choices affect the relative sustainability of one product compared with other options. This section and the ones that follow show how to put all of that information into action.



5. INTERPRETING THE RESULTS

The first step is to determine what the results of the environmental impact assessments mean. No matter which tools or techniques you used, you should have some impact information about your product. As was noted earlier, sustainable design is a relative concept, so you should also have impact information against which to compare it. Common comparisons include:
  1. Standards: These may be certain thresholds or impact profiles that have been accepted as industry, or maybe even just company, standards.
  2. Previous Designs: The goal may be to make each generation of a product more sustainable than the previous one.
  3. Competitive Products: Whether for market positioning or internal purposes, it is sometimes helpful to compare to other companies’ solutions.
  4. Alternative Designs: One of the most common is to compare variations on a given design to each other to narrow down development to the best, most sustainable design options.

The comparison set should have been identified early in the process so that relevant impact information about the alternative designs could be gathered as a part of the overall process.

As you conduct the comparisons, it’s important to know what differences are meaningful. The significance of any differences identified will depend on the products and the measurement approach used. For even the more data-driven techniques used, not all incremental improvements are worth investigating. As a simple rule of thumb:
  • A +/- 10% difference on one or several environmental indicators gives an indication that the changes between the options can be considered “directionally” correct. Chances are, you’re moving on the right path.
  • For a relatively simple product—like Priscilla’s cup—a difference of +/- 30% on the indicator(s) is generally a meaningfully greener product.
  • For a more complex product, the decrease in impact that you should look to see to identify a greener product are higher, perhaps +/- 40-50%, because the chances of overlooking process steps or incorrectly modelling some assumptions increase with the complexity of the product.

These may seem like large percentages, but they can serve as a helpful reminder not to get caught up in trying to tweak less relevant aspects of a product and instead to focus on the major contributors to its impacts. This is particularly true given the need for the designer to simultaneously balance the environmental impacts of a product with its cost, durability, and other design criteria, along with how it fits in with the overall product strategy.

“Wow, that’s not as accurate as I thought given all of the calculations behind our LCA data,” said Tom reflectively.

“Actually, I think it’s pretty accurate,” responded Priscilla. “Keep in mind that measuring a single product’s impact on a global environmental metric like climate change is like trying to predict the weather in Boston a thousand years from today.” 

Once you have a sense for which impact areas are worth looking at, whether because of the significance of their differences from alternatives or other reasons (e.g., a corporate focus on carbon footprint), it is time to look for ways to reduce those impacts as effectively as possible. In many cases, there are certain elements of the design or product life cycle that generate most of the impact. It’s often a classic example of the 80/20 rule, with 20% of the design contributing 80% of the impact. For instance, in decreasing the impact of an electric coffee-maker the temptation might be to remould the plastic housing, since plastic is generally considered a less-than-sustainable material. However, simply shortening the electric cord decreases its overall impact many times what is saved by replacing the handle; and decreasing its energy usage may even dwarf that impact. 

“Ok, enough preparation, Tom! I think we know enough now to responsibly dig into our products. Can I go first?”

To be continued...

Sources: Dassault Systèmes - SolidWorks Corp, EPA.



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