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ecodesign: practical tools for designers Eric Billett Professor E. H. Billett is
Head of Design, Faculty of Education and Design, Brunel
University. The central role of life cycle analysis The central role played by Life Cycle Analysis (LCA) in the interaction between a product and the environment is by now well known. The great strength of LCA lies in the inclusion of environmental impacts at all the stages in the life cycle from extraction of raw materials through manufacture, transport, use and disposal. In this way it can often be seen that a particular stage of the life cycle is causing most of the environmental damage: for example, washing machines, cars and electric kettles all cause their greatest impact in the use phase. From this information a designer can give this stage of the life cycle priority in the next iteration of the design. LCA can be an expensive tool to apply in depth; if it is done comprehensively it will usually cost upwards of a five figure sum. This presents a difficulty for a designer looking for practical ways to care for the environment in their work. Streamlined life cycle analysis Because of the open ended nature of the extraction and disposal phases as well as the problems of data aggregation and split production, the output from LCA depends quite strongly on a number of judgements made by the user, and the output must be used with considerable caution. The output from Life Cycle Analysis is inherently somewhat ambiguous - despite the impressive apparent level of detail implied by computer printouts from LCA computer packages with their columns and columns of data presented to the 'nth' decimal place. Example of LCA output Because of this complexity, different groups have been able to make a number of simplifications that are often described as streamlined LCA. Typical assumptions that are made to simplify the LCA approach include:
Although the assumptions made to streamline the life cycle analysis must surely reduce the accuracy, one comes to realise that this is probably not all that important because of the somewhat arbitrary nature of LCA in the first place. The simplifying assumptions reduce the cost of analysis considerably. Although, at the present time, even streamlined LCA would probably only be considered after a specific embodiment had been decided. Eco-Design: consideration of wider matters At its best, Life Cycle Analysis quantifies the environmental impact of a particular embodiment of a product - it does not, and cannot, ask the important questions that need to be asked if a sustainable lifestyle is to be our goal. The most revolutionary of these questions, and the hardest to answer, is whether or not the human need in question can be satisfied with less environmental impact by providing a service rather that by selling a product. As an illustration, with broad bandwidth of cable now reaching many dwellings, it may be that the human need for entertainment may be met more effectively by interactive video on demand, from a centrally provided service, rather than by supplying complex video recorders and multimedia workstations to each individual house. There are big lifestyle questions that need to be addressed if a sustainable future is to be established: in transport, in work patterns, in leisure, in agriculture and in housing. At a less revolutionary level, but still with the potential for major progress towards a sustainable future, designers should explore the possibility that there might be a quantum improvement in environmental impact that could result from a revolutionary change in design. For example, electric kettles produce most of their damage during their use associated with the generation of electric power. The adoption of the jug form allowed a very great improvement in the ability to boil small amounts of water without wasting energy. The Dyson vacuum cleaner is a nice example of a revolutionary change in design, although in this case the benefit is likely to be enhanced performance rather than improved environmental behaviour. At a rather more mundane level, designers should put much more effort into excluding toxic materials from designs. In the past engineers and designers have been quite cavalier about including toxics in consumer products with little thought about the problems that this toxic material may cause future generations. Similarly, designers should avoid combining materials that contaminate each other within the mainstream recycling chain. After removal of high value items, this usually involves shredding followed by separation into ferrous metal, aluminium, other non ferrous metal and plastic fluff streams. If possible, the whole product could be made from a single material; for example, polypropylene is a good general purpose engineering plastic that can meet many design needs, including the 'living hinge' and it recycles well. Design environmental review - some simplifying ideas The ideas in the last paragraph are brought together at Brunel into a procedure that can be used at the pre-embodiment stage of the design process - while there are still several ideas in play. The cost of Life Cycle Analysis is minimised, or avoided altogether, by the use of a number of coping strategies. The idea in all cases is not to spend a lot of time nor to abandon the process because of lack of data, but to move forward in a few hours to a rough picture of the environmental problems posed by a new design. The detailed accuracy that is lost in this process is more than made up for by the ability to consider environmental matters at a very early stage in the design process. The most common sticking point in a quick Design Environmental Review of this sort is the failure to find one or more necessary items of data. The first place to look is in one's software packages and data sheets; when these fail to supply the necessary data then one must use detective work to supply an 'engineering estimate' of the missing data. Engineering estimates are not quite guesses, nor are they accurate data; the idea is to use all one's skill and knowledge to end up with a figure in the right ball court. Start by considering whether there is an analogous material that is in the data base that can give a starting point for the estimate. For example, Low Alloy High Tensile Strength Steel is probably very close to normal mild steel; most plastics, apart from a few high performance engineering plastics, will differ only slightly from polythene. It may be that an existing LCA study can be used as a surrogate for the product in question. For example, the PA study on Washing Machines in probably a good basis for thinking about dish washers. If a straight forward analogy cannot be found, then as a last resort, price can be used as a basis for a comparison with a known material. At first sight it is not clear that price is a good substitute for environmental impact but, if the comparator is chosen carefully, then we have found that it can be surprisingly good. Ideally the two materials should have been extracted and processed by similar methods. Consider iron and copper, both come from large holes in the ground, and a great deal of environmental damage results from the operation of the mine. Now, copper ore is much poorer than iron ore, and much of the extra cost of copper is related to this fact. This means that a copper mine makes a much bigger hole in the ground than a similar iron ore mine. Both metals are converted from their ores by pyro-metallurgical processes and so they might be considered reasonable comparisons for each other. Of course, these engineering estimates will not be accurate, but they will give a basis for a rough evaluation of the importance of the different stages of the life cycle, and thus form a basis for detailed design to attack the problem stages. With some idea of the critical LCA stages, the question of whether to design for long life, for fixed life span, for recycling, for shredding and disposal, for landfill, etc. can all begin to be meaningfully addressed. Design environmental review - a practical approach The aim of the review is to identify the critical stages in the life-cycle of a new product and to avoid building in toxics and material incompatibilities at an early stage. Explore the lifestyle and quantum improvement possibilities, "Is this the right product to design?". IF data is available, carry out a streamlined LCA
IF data is missing,
IF some important data cannot be found and there is no appropriate existing parallel study, then use related data that you obtain to make an engineering estimate of the missing data. IF the worst comes to the worst, then use price as a basic metaphor for environmental impact - choose a material whose data you can obtain and which is as similar as possible in its extraction and manufacturing methods to the target substance, then:
Remember that LCA yields data that, at its best, is uncertain and dependent on judgmental factors; well estimated data is a good deal better than no data at all, and probably not much worse than real LCA data. In cases where LCA gives useful design guidance, the differences between the stage that is poor and the other stages is so great that minor errors in the estimates do not affect the overall conclusion. PA LCA conclusions for washing machines The PA study of washing machines showed that around 95 per cent of the environmental damage occurred in the use phase and that this was the phase to concentrate on. This conclusion is so robust that it would remain the same even if the data was substantially in error. So, if you can get good data then use it; if not, then make your best 'engineering estimate' and carry on. Conclusion Designers naturally think in terms of materials, processes and form; by considering the appropriate stages in the life cycle - the LCA method is a natural extension of this approach. Until the time that LCA data is widespread, cheap and complete, the method described can give a designer the confidence to consider environmental matters in a practical, confident way at a stage in the design process where it is still possible to make major changes. The method also prompts explicit consideration of a number of wider eco-design issues .
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