Reliability, Availability, Maintainability and Safety:
these aspects are mutually correlated, and related through a specific evaluation aimed at maximizing the efficiency of a plant, ensuring, for a given time interval and for each element, the performance of the expected function in the absence of unacceptable risks.

• Reliability: the ability of a system or component to perform its required functions under stated conditions for a specified period of time (mission time);
• Availability: the degree to which a system, subsystem or equipment is in a specified operable and committable state at the start of a mission, when the mission is called for at an unknown, i.e. a random, time;
• Maintainability: attitude of the entity in assigned conditions of utilization to be maintained or returned to a state of correct operation for the required function;
• Safety: absence of untolerable risks.

It is noteworthy that the IIS Group, and particularly IIS SERVICE, is not only able to make a RAMS assessment for a specific plant, being it new or operating, but especially is able to ensure that its services are harmonized to the RAMS methodology, or conforming with the approach for efficiency optimization and the relating cost control.