Jungbluth, Niels; Meili, Christoph

The ISO 14040/44 standard was developed for the comparison of products or services. A critical issue in this framework is the “functional unit” which is defined as the “quantified performance of a product system for use as a reference unit”. Furthermore, ISO says “Comparisons between systems shall be made based on the same function(s), quantified by the same functional unit(s) in the form of their reference flows. Today life cycle thinking is often applied in broader sense. Especially in the field of consumer choices questions arise, for which environmentally sound choices go beyond the limitations of the ISO standard. Such questions are e.g. • What do you like to drink? • What do we eat for lunch? • Which pet animal should we keep in our family? • Which topping do you like for the sandwich? From the single persons point of view, even options with distinct functions might be taken as comparable in a specific situation. Life cycle thinking should be used to guide such decisions. In former studies answering such questions there is no strict comparability, but they can certainly help to guide personal lifestyle decisions. An expanded use of the instrument and the idea of life cycle assessment is reflected in the developments for the organizational LCA. Here, too, comparability is generally not possible. Therefore, the calculations are carried out for a “reporting unit” instead of a functional unit. The method of LCA nevertheless provides important inputs for improvement of such a unit. To make the difference to a comparative product life cycle assessment clear, we propose to speak about a “decisional unit” instead of a functional unit. In addition, we propose talking about a juxtaposition of different consumer choices and instead of a comparison. We think it is important to further develop relevant standards in this sense. Otherwise, the strict definitions in the ISO standard lead to e.g. rejections of such case studies just due to formal issues.