The present document constitutes the deliverable D2.4 and includes the methodology, results and conclusions in the definition of final specifications and requirements of Use case 2 linked to the online monitoring and control technology for ultra clean steel production at the steel plants of SID and VAS. This document contains an updated content of the deliverable D2.3 “Mid requirements & specifications for Use case 2: Smart sensor and model-based decision support system for ultra clean steel production”.