Proportional flow control valves can control flow and they are sometimes pressure compensated and temperature compensated. Proportional valves are particularly suitable for applications where it is necessary to vary the output flow, both during the same process and moving from a process to another. The control of these valves can be obtained by many coils (solenoids), this allows a more accurate regulation of flow. Another advantage is that they allow various speeds achievable by changing the electrical signal without any additional hydraulic components. Proportional controls, used with their respective electronic controls, add a variety of machine cycles, operated at higher speeds, in conjunction with controlled start and stop. The regulation of acceleration and deceleration allows improved cycle times, production speeds of the machine and a stable flow is also obtained. These features make proportional valves particularly suitable also for the design of Industry 4.0 systems. Therefore, Inail and the University of Perugia have begun a research activity aimed at studying the main safety and energy efficiency aspects that must be considered in the utilization of proportional valves within hydraulic systems. In this paper relevant application of those components, first for lifting and operating machines and then for machinery tool sector, has been investigated. Main failure modes and safety issues are presented. The complete risk assessment necessary for possible application in the field of machinery will be carried out in future research activities.