The Product Life-Cycle maps the basic stages of a designed product's life from raw materials (recovery or extraction), through manufacturing, distribution, retail and promotion, use and end of life. This mapping is useful in learning that each designed thing has a past and a future as well as being inseparable from numerous processes. It also lays the groundwork for understanding how all of the material 'inputs' and 'outputs' associated with a product are part of the design of that product, and how understanding those inputs and outputs can contribute to more sustainable designing. The Product Life Cycle forms the basis of Life Cycle Assessment (LCA), a methodology that seeks to understand the main impacts associated with each stage of a product's life. LCA is generally used as a tool to compare the relative environmental merits of similar products or services. Some of the key benefits of LCA however, are in the learning potential of the process rather than the outcome, which invariably and necessarily provides a selective picture. For example, LCA entails communication and collaboration between stakeholders and informs the development of an intuitive sense for the dynamics of the product system ('life cycle thinking'). LCA is part of the International Standard Organisations suite of voluntary Environmental Management Systems called the 14000 standards. For further information on this system of environmental management, visit the International Standards Organisation.

Impact Assessment (IA), which makes up a stage of the LCA process (LCIA), is about evaluating life-cycle inputs and outputs in terms of the significance of their environmental impacts (measured in terms of 'impact categories' such as 'global warming potential' or 'human toxicity'). Like all standardised tools that have grown out of the Ecologically Sustainable Development (ESD) charter, there are many problems associated with accounting for situational differences. The attempt to standardise impact measurements along scientific criteria is also thwarted by the inevitable value-choices involved in the selection of impact categories as they apply to any one product system. Furthermore, the impacts associated with one output, say a particular chemical, will likely impact on air, water, land and animals differently and at different rates.

IA is perhaps more effective as a planning tool used to predict the impacts associated with an activity, say a major building development or even the planning of a city. Again, however, while impact assessment looks and sounds scientific, it is always to some degree a work of interpretation, and can (and has) been used to justify projects that are fundamentally unsustainable. Despite these problems, Impact Assessment is one of the most useful concepts we have encountered because it shows that each designed thing always has effects beyond itself and can be used to promote relational thinking. This guide draws on both the practices of LCA and IA.

For further reading on LCA and IA:
The Centre for Design at RMIT is the key locus for LCA activity in Australia.
The UNEP Production and Consumption Unit provides a comprehensive and useful set of resources on the history, processes and application of Environmental Impact Assessment.
For a look at ways the concept of 'impacts' has been employed as a planning tool to promote design for sustainability, visit the publications archive on the Team DES website.

The Relational Product System

The Product Life Cycle offers a very good way of reading products and mapping their impacts, but it does not situate products within their functioning environments, which is where most of their impacts occur and where the greatest opportunities can be created for designing sustainments. By focussing too hard on the product and not enough on the product's environments of use or even cultural meanings, overarching problems, like the far too short lifetimes of products, are not addressed.

A less obvious aspect of relational designing is 'design feedback'. A designer designs an apparently autonomous product but in its making the product also has a small part to play in remaking its maker— informing parameters such as skill, expectation, habit and imagination that flow into other material relations. What we make changes environments but also changes us.