Ensure that all material and energy inputs and outputs are inherently as non- hazardous as possible It is better to prevent waste than to treat (or) clean up waste after it has been created Separation and purification operations should be a component of the design framework Systems components should be designed to maximize mass, energy and temporal efficiency System components should be output pulled rather than input pushed through the use of energy and materials Embedded complexity must be viewed as an investment when making design choices on recycle, reuse, or beneficial disposal Targeted durability, not immortality, should be a design goal Design for unnecessary capacity or capacity should be considered a design flaw. This includes engineering "one size fits all" solutions Multi-component products should strive for material unification to promote disassembly and value retention (minimize material diversity) Design of processes and systems must include integration and interconnectivity with available energy and material flows Performance metrics include designing for performance in commercial "after- life" Design should be based on renewable and readily available inputs throughout the life cycle ^^ Anastas, P.T., Zimmerman, J.B., "The twelve principles of green engineering as a foundation for sustainability", Sustainability Science and Engineering, Defining Principles, pp 11-32, Elsevier, 2006.