Preventive Maintenance ApproachThewhole process of Maintaining Infrastructure assets has evolved and improved markedlyin the last couple of decades. This development in the Infrastructure Industryis due to a variety of factors, such as vast rise in the number and heterogeneityof infrastructure assets that need to be maintained, complexity in theirdesigns & structure, new and upcoming maintenance tools & methods, heightenedsafety standards and the ever changing global outlook on maintenance strategies.The advent of Reliability-Centered Maintenance (RCM) has played a pivotal rolein this evolution.Inthe past decades, preventive maintenance was the most widely used maintenancetechnique. It was deemed to be the most advanced and effective maintenancetechnique at disposal to the construction & infrastructure industry. ThisPreventive Maintenance strategy was established on the assumption of a cause-and-effect co-relation betweenscheduled maintenance and functional reliability.
In turn, this assumption wasbased on the hypothesis that since mechanical parts are subjected to wear andtear, the reliability of any equipment or component within a system is directlyassociated to its operational lifetime. Hence, it was conjectured, that themore routinely an equipment was serviced or overhauled, the more secure it wasagainst the possibility of failure. However, this strategy of preventivemaintenance comes with a lot of limitations :· Costof system downtime:Shutting down of a system, results in loss of productive time and thereforeloss of revenue.· Costof system maintenance:Utilization of resources to routinely perform inessential scheduled maintenanceis exorbitant.· Probabilityof grave safety or environmental ramifications: Shutting down and starting-up afacility is one of the high-risk operations, thus intrusive preventivemaintenance practice tends to increase the risk of environmental damage.· Complexityof systems: Themore complex the systems are, the more strenuous it is to perform planned/Preventive Maintenance Reliability Centered Maintenance(RCM)IntroductionTheintent of an efficient maintenance strategy is to avert or assuage theconsequences of failure, not to avert the failure itself.
In other words: ifthe ramifications of any failure do not have deleterious consequences onsafety, operations, environment or cost, then there is no exigency to proceedwith the scheduled maintenance.Reliabilitycentered maintenance (RCM) is the maintenance strategy implemented whenfollowing a procedure that evaluates equipment condition and formulates themaintenance specifications of a physical asset in its operating context. RCM accentuates the practice ofPredictive maintenance, in addition to conventional preventive methods. “A reliability-centered maintenance program includes only those taskswhich satisfy the criteria for both applicability and effectiveness. Theapplicability of a task is determined by the characteristics of the item, andits effectiveness is defined in terms of the consequences the task is designedto prevent.” (Source: Nowlan and Heap,1978)Thisstrategy provides a framework for exploring the various functions and likelyfailures for an asset, with an emphasis on safeguarding the system’s functions,rather than equipment itself.