On the basis of the elements collected, the first stage of the study can start. This first step fixes the trend of the project structure. The co-operation between SAP s.r.l. and the customer allows to reach an optimal guide line through information exchange. Any feed-back from the customer is also kept for future projects. An intensive use of CAD/CAE programs (computer-assisted engineering and design) during plant design and construction makes it possible the co-operation among specialists from different branches, working on the same project at the same time, thus improving the project co-ordination, reducing mistakes and increasing productivity.