Wednesday, 23 October 2013



Your Influence Is Critical

In the midst of the myriad sustainability tools, techniques, global and local activities, and corporate initiatives the product designer plays a key role. This person has an impact in the pivotal stage where decisions are made about what inputs are needed, how they must be processed, what the product’s lifecycle looks like, and what its end of life looks like. Engineering for sustainability early in the design process creates a trajectory that can lock in the benefits from the beginning, whereas leaving environmental impact considerations for later stages creates costly clean-up and accommodation efforts. For instance, a product designed for easy disassembly requires much less effort to convert into recyclable and reusable components than one designed as a single module requiring energy-intensive end-of-life processing. The following graph reflects the advantages of making sustainability a priority as early in the design process as possible.

There are obviously many decisions affecting sustainability over which design engineers have little or no influence. For instance, it’s usually not solely up to the designer where a component is manufactured, what transportation modes will be used to deliver it to customers, what materials suppliers use, and so on. Even so, what engineers can do to influence a product’s environmental impact has far-reaching implications. In his book The Total Beauty of Sustainable Products, Edwin Datschefski writes, “Design is the key intervention point for making radical improvements in the environmental performance of products. A 1999 survey by Arthur D. Little revealed that 55 per cent of senior executives in industry singled out design as the most important mechanism for their companies to tackle sustainability.” Along with influencing the product development process, it is often the designer’s identification of a more responsible choice that can cause changes in other areas towards creating a more sustainable company overall.

A Sustainable Design Challenge

Let’s start off with an example—something you can look at from all angles, at least virtually. We’ll also introduce a character to champion this example.

Our first protagonist is a producer of paper and plastic products for the public, whose name is Priscilla. Her story illustrates many of the concepts we’ll be up against.

Priscilla was tasked with a seemingly straightforward question:

"How can we make our disposable drinking cups greener?"

Priscilla’s first thought, especially given her background as a polymer engineer, was that this was going to be a game to find the least-impactful plastic polymer with the desired properties… but we’re getting ahead of ourselves.

First, here’s a picture of the cup in question that Priscilla was starting with:

Now, let’s get down into the details of what environmental impact assessment looks like. We’ll see that examining the environmental impacts of this cup was anything but simple.

Environmental Impact Assessment Tools & Techniques

Sustainable Design Is Relative
First, you’ll notice we said we wanted a greener drinking cup. There is no such thing as a “sustainable” or “green” product, only a more sustainable or greener one. In fact, a green product is one that’s never made -- the most sustainable solution is to avoid making unnecessary items altogether.

When Priscilla learned the “Sustainable design is relative” concept, she stopped to think about her product. Were disposable drinking cups really necessary? Shouldn’t Priscilla be encouraging her consumers to use reusable cups instead? That was fine in theory, but reusables were made in another division and in another country. So, thought Priscilla, let’s try to make the best disposable drinking cup we can, and revisit the deeper product redesign later. After all, even if Priscilla succeeded in encouraging her customers to buy reusables, they weren’t going to stop buying disposable cups overnight.

For those products that we’ve decided are necessary, everything has impacts of some sort. The basic purpose of sustainable design is to find ways to reduce those impacts, and by doing so find a more sustainable solution. This section describes ways to determine what “more sustainable” looked like for Priscilla.

What Am I Comparing?

Priscilla’s next thought was: “more sustainable than what?”

Designers who want to decrease a product’s environmental impact need to have some way of evaluating what difference their choices make. The only way to evaluate whether a design is more sustainable is to see how its impacts compare with other options, such as an alternative design, a previous version, a benchmark, or an impact goal.

Throughout this guide, the term product has been used to describe the object of the designer’s work. When it comes to determining environmental impact, it’s important to specify a unit of analysis. Relative comparisons only work if there is a common basis. In some cases this might be quite straightforward, such as when it’s two generations of the same design or when faced with a simple material substitution. However, in most redesign opportunities, it’s necessary to specify a common “product unit” for the analysis.

An often-used way of handling this is to identify a functional unit. Instead of looking at a product as an item, it can be seen as a way for a certain function to be performed. In order to compare two different product systems, it’s necessary to choose a measure of the function of the systems that is consistent between the two. For instance, for a coffee maker it might be cups brewed, for laundry detergent it could be washing cycles, for paint it could be surface protection over time. This way, it’s possible to assess the impact of various ways to perform a specific function, without being constrained by differences in the forms of the designs.

“Well, that’s easy,” thought Priscilla. “My cup’s purpose is to hold liquid.” But when she thought about all the products designed to hold liquid -- detergent bottles, soda cans, mop buckets -- Priscilla realized she had to narrow down this purpose to define the functional unit. She decided that her cup’s functional unit was sixteen ounces or about 500 mL of (cool) liquid that could be poured in or out—or even better, 1600 ounces, equaling the volume of a pack of 100 cups. Now she could compare her bag of cups with all the other products imaginable that could hold this amount of cool liquid (and pour it in and out) and find the most sustainable option.

What Am I Measuring? The Three Choices of Environmental Assessment

Product sustainability is not only relative, it’s multidimensional. There is no single, universal indicator of sustainability (no, not even carbon). The appropriate impact metrics and dimensions on which products are compared can differ significantly, depending on the purpose of the evaluation. Impact measurement creates the key dashboard for sustainable design, so it’s important to choose an assessment approach that will generate information consistent with its intended use.

The appropriate technique for evaluating the environmental impact of a design depends on the answers to the following three questions:
  1. What impacts do you care about? Does toxicity matter? Water use? Only CO2 equivalents?
  2. What is the scope of the assessment? How far up and down the supply chain does it go? How much of the product’s lifecycle should it reflect? What is the unit of analysis for the assessment? Is it for a component, an assembly, a product, a system?
  3. What types of metrics are appropriate for your purposes? What will the assessment information be used for, and by whom? Is rigorous detail necessary, or is a “rough idea” good enough?

The following figure lays out these choices graphically, using examples of some of the impacts, scope elements, and metrics that might be used. The sections that follow will explore each of these elements in more depth and give examples of the kinds of assessment techniques appropriate at each level.

“This is pretty intense,” thought Priscilla. “I’m going to call up my friend Tom and talk to him about sustainable engineering and my little cup. Maybe Tom has been through this process before.”

As luck would have it, Tom was going through an identical exercise with a product of his own. Tom is a tinkerer of tiny toys for tots and toddlers, and now he was toying with the idea of making a greener holiday gift for his wee customers.

Here’s the toy that Tom showed Priscilla:

“It’s a pretty simple toy,” Tom told Priscilla. “The child pushes it around, and at the push of the button, the lights flash and the siren sounds. They can also pull the fireman out of the truck.”

“I had to think for a while about the functional unit that I was using for environmental comparisons,” continued Tom.  After all, this toy is clearly more impactful than other toys—say, some simple plastic blocks of similar size. After all, my toy uses a battery. But I’ve noticed that my own kids will play with a toy a lot longer if it does something—like having flashing lights. So I decided that my functional unit was a children’s toy with interactive components, which can be played with on the floor. So my question is:

“How can I make a greener children’s toy?

“I’m at the stage now where I’m making my three measurement choices,” Tom finished. "Perfect," thought Priscilla.

Choice 1: Environmental Indicators

There are a wide range of environmental impacts that can be assessed. However, it's not always necessary to try to cover many, or even some, of these impacts if you're mainly interested in one impact measure, or environmental indicator. For instance, there's a lot of attention on greenhouse gas (GHG) emissions these days, due to their association with climate change. If the carbon footprint resulting from these emissions is the only impact your organization or your customers are focused on, it would be unnecessary to spend time assessing impacts on such things as air quality or human toxicity; measuring your product's carbon footprint would suffice. So, step one is to determine which impacts should be measured based on the purpose of the assessment and how its data will be used.

Five Categories of Impact
How to choose among the dozens of different types of environmental impacts? We'll start with grouping some commonly used environmental impact categories into five major domains:
  1. natural resource depletion,
  2. air impacts,
  3. terrestrial & aquatic impacts,
  4. climate effects, and
  5. human health.

Choice 2: Scope

The second major consideration in assessing the sustainability of a product is the scope of analysis. For products, the scope is usually described by how much of its lifecycle is included in its impact assessment. 

Lifecycle Stages:

As with impact categories, there is not a single standard set of lifecycle stages, although there are certainly some that are most commonly used. In general, the full lifecycle of a product can be measured in five to seven stages:

Raw Material Extraction
This includes the energy and other resources used to acquire the basic materials used in the product, whether through mining ore, harvesting timber, extracting oil, etc. This stage can include harvesting materials from recycled sources if they are in the form of raw materials.

“My cup is plastic, so it starts with oil extraction,” said Priscilla.

“A lot of my toy does, too,” replied Tom. “But it also has some metal components, so that would include mining the ore.”

Material Processing
Raw materials are converted into forms used for manufacturing during this stage. It covers the processes required to make steel, copper, plastic feedstock, paper, gasoline, and the like.

“OK, so the oil for our plastics is then refined into the various hydrocarbon fractions to make the different plastic resins,” said Priscilla, idly sketching a distillation column.

“And the ores are refined into metals by melting or burning off impurities,” added Tom, wondering why Priscilla was sketching a missile silo.

Part Manufacturing
This stage covers single, or at least simple, part manufacturing. Common processes include injection molding, metal stamping and machining, weaving, and milling.

“My cup is made from PET plastic—polyethylene terephthalate. This is where the PET is injection-molded into a cup shape.”

“The plastic that makes up most of my toy is molded, too, but from ABS plastic. The siren sound comes from a little speaker component that I purchase; I’m not sure what’s in it, but I’m sure there’s a lot of copper, so I’ll just model it as a copper part. The spring is made of a steel alloy—probably regular carbon steel.”

In many cases, products need to be assembled using processes that go beyond the creation of individual components. Because this is usually the first stage that brings together a disparate assortment of materials (e.g., a plastic handle and a metal container), environmental impact assessments significantly increase in complexity.

“I don’t really have any assembly steps,” said Priscilla, “since my cup is molded in a single pass from a single material.”

“I do have some assembly steps, but most of the parts just snap together. And of course, the battery is wired up to the siren and the lights.”

Product Use
Any energy used, emissions generated, other resources affected directly by the product during its actual use are counted during this phase. This includes waste that occurs in the context of a product’s use, such as discarded packaging.

“My product is powered by a person picking it up and drinking from it!” laughed Priscilla. “No product impacts there.”

“Mine isn’t,” Tom sighed.  I guess I’ll take a hit for it using energy from the battery. But aren’t most interactive toys like this one battery-powered?”

End of Life
Once a product is no longer used, it has reached its end of life. This usually means that the product is no longer usable, although there are many examples of end of life coming before end of usability (e.g., paper cups). This stage is usually broken down into three resulting streams: the fraction of a product being sent to landfill, to incineration, and to reuse or recycling.

Priscilla knew that recycling was a big issue for her PET plastic cup. “I guess the recycling rate depends on where the product’s being used,” she said. “I’ll bet it’s higher in Europe than in the US.”

“I’m not so sure about that,” Tom said.  We recycle a lot of our steels and aluminums in the US, if not as much of our plastics. We also landfill more of the rest of the materials, rather than incinerate them, which they favor a bit more in Europe.”

Transportation is not typically given as a lifecycle stage, since transportation legs actually occur between each of the lifecycle stages, but it’s an important consideration to account for in the product’s lifecycle impacts. Transportation can be included among the stages according to where it takes place (e.g., the shipping of raw materials to processing centers could be considered a piece of the processing stage). In some cases, transportation may appear as a separate lifecycle component, especially between Assembly and Product Use for consumer products, since there are typically several stops along the way (e.g., wholesaler, retailer, delivery). No matter how it’s handled, it is important to make sure that transportation doesn’t fall through the cracks.

“Most of my components are made in Asia,” Tom jumped in, “but a couple of them aren’t. The speaker comes from Japan, and the acrylic light fixtures come from a little shop in Europe. After the product is assembled in Asia, it’s sent by ship to my main market in the US.”

“Simple for me,” said Priscilla.  The cups are packaged and sent from our factory in Asia and are also sent to the US. I wish we could make them locally,” she added, “I’m sure that would be better for the environment.”

System Boundary
Doing environmental assessments can sometimes be like chasing fractals. Product lifecycles intersect a great many processes, some more directly linked to the product than others. Since an assessment can’t always cover everything, system boundaries clarify what it will include. It’s often helpful to draw a process diagram, and then trace a boundary around what will be measured.

Some of the standard product lifecycle system boundary scopes include:
  • “Cradle to grave” – Usually denotes all phases from raw materials through disposal.
  • “Cradle to cradle” – Like cradle to grave except that it tracks where the product’s elements go after end of use, with special attention to recycling and reuse.
  • “Cradle to gate” – Includes part of the product lifecycle.

Priscilla grabbed a dry-erase marker and sketched out her cup’s process diagram:

“What about packaging?” asked Tom. “You mentioned that the cups are packed into bags of 100 cups, your functional unit.”

“Oh yeah,” said Priscilla. She added the packaging step to the diagram. “I think the bag is pretty minimal compared to the cups, though,” she said. “So until I get a chance to talk to our packaging group about materials and sizes of the packing materials, I’ll exclude that from my system boundary.” Finally, she grabbed a thick orange marker and drew a box for her system boundary.

Her final sketch was as follows:

“Mine’s more complex,” said Tom. He stepped to the whiteboard and began to fill his own process steps into Priscilla’s boxes, and add a few of his own:

“I’ll have to make some more assumptions,” Tom said, stepping back from the diagram. “I include a rechargeable battery with my toy, and I’ll assume the parent recharges the battery ten times before the kid gets bored with the toy, or outgrows it. But since I want to compare this toy to other interactive ones, I’m going to assume the comparisons are also powered by batteries, so I won’t include that in my system boundary.”

With their lifecycle scopes determined—both were versions of a cradle-to-grave assessment, they realized—and their boundaries drawn, Tom and Priscilla were ready to move to the third and final choice.

Choice 3: Metrics

Once you've determined what impacts you want to focus on and how far up and down the product's lifecycle you want to assess, the final decision is how accurately you need to measure your selected impacts across your chosen lifecycle stages. Once you've determined your choice of metrics, you'll be able to identify the types of impact assessment tools and techniques that will be most useful.

Most metrics fall into one of four categories:
  • Comments
  • Checkmarks
  • Scores
  • Measurements

The most qualitative, and usually most subjective, way impacts are expressed is through text alone. People can generally describe what they believe an impact will look like, its severity, and so forth at a high level based on their understanding of the product. Comparisons read more like product reviews than detailed technical analyses. This form might be appropriate for a first-pass assessment or as a basis for narrowing down alternatives to be compared. It is not a useful format if continuity and standardization is important because it's so subjective.

In some cases, evaluations are based on checklists. The assessment will have certain criteria for each of the categories, which are either met, or not. Is mercury present? Is it certified organic? Is it FSC (Forestry Stewardship Council) certified? Does at least 25% of the energy used come from renewable resources? Checklists like this have the advantage of resulting in evaluations that are easy to compare across a wide range of products. They can be used relatively (i.e., seeing which of the products has more checkmarks) or absolutely (i.e., all of the parts we use must meet a certain threshold). While the checkmarks don't reflect many details or degrees of difference (i.e., the product that uses 100% renewable energy gets the same checkmark as the one that uses 25% if that's the threshold), they may provide enough information to support relevant decisions.

Whether in the form of grades, number scales, smiley face icons, or stars, scoring systems have the advantage of the at-a-glance nature of checklists, while also reflecting a more nuanced evaluation of a product's impact. One of the challenges that comes with nuance however is that someone needs to decide whether something gets an A or a B, 3 stars or 4. In many cases, scoring systems lay out guidelines for what qualifies as an A versus a B so that there is some consistency across evaluators and products. Even so, scores can be subjective and, in some cases, political. Still, a balanced and transparent evaluation process can produce a helpful assessment of the scale of a product's environmental impacts. Such scoring systems are especially useful when a quick assessment is needed to initiate the first discussion across a multistakeholder group.

"These are probably beneficial for initial assessment," said Tom, "but that's not what I'm after. I need to get a sense of my actual carbon footprint."

"I agree," said Priscilla. "I've actually used a couple scorecards, where I learned about issues like manufacturing and eventually recycling PET. Now I'd like to put some numbers to this process... you know, some real measurements."

The most precise and objective metrics come in the form of specific numbers representing impact levels. These usually take two forms, one impact-specific and the other a standardized conversion into a single proxy number.

To be continued...

Sources: Dassault Systèmes - SolidWorks Corp, EPA, Berkshire Encyclopedia of Sustainability, Interface Global.

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