The major challenge for a maintenance engineer is to implement a maintenance strategy which maximizes availability and
efficiency of the equipment; controls the rate of equipment deterioration; ensures a safe and environmentally friendly operation; and minimizes the total cost of the operation. This can only be achieved by adopting a structured approach to the study of equipment failure and the design of an optimum strategy for inspection and maintenance.Maintenance management techniques have been through a major process of metamorphosis, from focusing on periodic overhauls to the use of condition monitoring, reliability-centered maintenance, and expert systems. Most recently, risk-based maintenance methodologies started to emerge.