Maintenance strategies


Corrective maintenance (CM)

This is maintenance management in which plant system or equipment item are allow to breakdown before being fixed. It is generally applied to low cost and low risk equipment.

Scheduled overhaul (SOH)

A maintenance approach in which equipment overhaul or repair is carried out at a specified interval basis. This policy is suitable for equipment or machinery with identifiable age when failure rate function rapidly increases and large elements of the equipment or machine must survive to that age and also where reworking can restore the machine to an acceptable operational condition [17] .

Scheduled replacement (SRP)

This refers to maintenance techniques in which equipment or a unit of it is replaced on a scheduled basis. This is usually ideal when equipment or machines are exposed to critical failure; large units of the equipment or machines must survive to the least the replacement time and the failure type must be of major economic consequences [17] .

Continuous on-condition task

The continuous on-condition task is also referred to as online condition based maintenance (ONCBM) in this paper and is the approach in which the condition of an equipment item is monitored uninterruptedly using diagnostics devices. The major disadvantage of this type of approach is that it is expensive [18] .

Scheduled on-condition task

The scheduled on-condition task is referred to as offline condition based maintenance (OFCBM) in this paper and is an inspection performed on an equipment item at regular interval with the aim of detecting potential failure [6] . The check carried out on equipment items is performed by maintenance practitioners or operators with or without the use of diagnostic tools. This approach is effective and yet more cost effective than the continuous on-condition task and as such more attractive to most industries and the maritime industry inclusive. However the major challenge of the scheduled on-condition task is the problem of determining the appropriate interval for performing inspection task [18] .