An interval version of PROMETHEE for the comparison of building products' design with ill-defined data on environmental quality

Life Cycle Assessment (LCA) is a powerful technique used to calculate total input and output flows of materials and energy from and to the environment during every step of a product life. A measure of a product Environmental Quality (EQ) can then be derived and help in the selection and in the design of more environmentally friendly design alternatives. EQ is a multicriteria measurement. In the construction field, LCA flows cannot be known with precision without loss of realism. Hence intervals have been introduced to model them. Thus, different designs are characterized by interval multicriteria measures. Manipulation of such environmental performances calls for a MCDA method which (1) does not allow for trade-offs between criteria, (2) preserves as much information as possible and (3) is simple enough to be understood by non-specialist users. PROMETHEE was identified as a suitable method according to the previous criteria, but it is not able to handle interval performances so far. We discuss the necessary changes to devise an interval version, called ‘PROMETHEE I’.