Letters: Life cycle analysis

From Professor E. H Billett Sir: To design objects for long life or for short life is not always obvious ("Recyling becomes a throwaway concept", 29 November). Much depends on the result of life cycle analysis.

There is a class of consumer products where most of the environmental damage occurs in the"use" phase and where technology is changing quite fast. Examples would be washing machines and cars. In these cases, it is important that older products should be scrapped so that they can be replaced with less damaging new products. Design for longevity is important only in those products where the production or disposal phases are most important.

Only life cycle analysis can give guidance to the most environmentally sensitive solutions to the design of consumer products.

Yours faithfully, E. H. BILLETT Dean and Head of Design Brunel University Egham, Surrey 7 December