A key challenge facing operators is to optimise their preventive maintenance regimes such that they:
- Maintain the safety of the plant;
- Maximise the availability of the plant; and
- Minimise disruptive corrective maintenance or replacement of equipment.
Traditional preventive maintenance is often initially prescribed by original equipment manufacturers on the basis of generic operating cycles, rather than adjusted for operator specific usage, system location, or online condition monitoring.
The Examination, Maintenance, Inspection and Testing (EMIT) optimisation process seeks to understand the plant or system function, highlight the significant equipment items, review the current EMIT regime, and reduce the associated workload, all while maintaining plant safety and improving plant availability.
WHY CONDUCT AN EMIT OPTIMISATION STUDY?
The total cost of maintenance is the sum of the cost of preventive and corrective maintenance. The optimal maintenance zone is where these two costs are balanced, as illustrated in Figure 1. Locating this balance is an age old problem and this is where an EMIT optimisation study helps. The study aims to establish a cost and plant availability benchmark for the existing maintenance regime, by combining data from current maintenance planning with operating and replacement/repair costs, and then proposing improvements to the maintenance regime to reduce the maintenance burden and improve availability.