Above all, this necessitates the correct specification of the functional unit, such that the performances delivered in practical washing systems are equivalent. Defining such functionality is a specialised undertaking in which all pertinent attributes of the systems and of the products themselves must be considered. Since it is very difficult or misleading to compare inventory data from different studies without knowing and understanding fully the main issues under which an LCI has been performed, the process of comparing and critically reviewing two of the actual Zeolite LCI reports was carried out in a subsequent extension of the study. This has not been included in the Landbank Report. It must be recognised that pre-combustion energy has been excluded for all the systems reported by Landbank and must be stated anytime these data are compared with other LC1s.
Data sources The data for Zeolite A in the studies are from different sources.
Those for STPP were obtained directly from the manufacturing process but those for Zeolite and PCA were taken from the technical literature and patents. The sources are thus inconsistent in terms of quality, age and geography and are therefore disparate. There is obviously a need for further clarification of the Landbank methodology and data sources. Therefore any quotation or comparison of the Landbank-data with any other LC1s needs a careful and transparent interpretation.