Why there is a need for different maintenance philosophies in a process industry specially in energy sector ?

The answers would be :

• To keep the plant equipments functional for the intended service
• To prevent premature failures or break down
• To mitigate the consequences of failure
The different maintenance philosophies should also be technically appropriate, feasible and economically justified.
We must realize that Breakdowns in continuous running process plants e.g. petrochemicals /Energy sector industry can have significant impact on the profitability of a business.No business can sustain for longer time without profit. Whether we are producing or not , our fixed cost of labor /employee remains same. Ratio of fixed costs to product output is negatively affected if plant equipments are not available for production when required.
Frequent  repair of break down equipment is critical to business success.The process of  addressing equipment breakdowns after its occurrence is known as Reactive type Corrective Maintenance.This Reactive approach exists in some form almost in all manufacturing companies. However, when equipment breakdowns occur the cost of repair can go much  beyond the cost of period of repair. The reason is obvious : production process lines require significant run-time after startup to begin producing quality product, and the manufactured products in process at breakdown as well as the products manufactured for a period after breakdown may either be unusable or of less value (off-specs or poor quality). Because of the impact both during and beyond the immediate downtime, modern maintenance business process have sought a methodology  to prevent equipment breakdown by a process known as Preventive Maintenance . With preventative maintenance, equipment is routinely inspected and serviced in an effort to prevent breakdowns from occurring. Such inspections frequency are based on either calendar periods or equipment run time. Corrective Maintenance and Preventive Maintenance  approaches are being adopted  for decades, but each have some important merits/demerits.We all  appreciate that Break down Maintenance or Run to failure maintenance approach shall not be acceptable now days where HSEF (Health,Safety,Environment and Fire) is an issue. Therefore there is need to go for Proactive approach which is feasible by Condition Monitoring (CM)  of equipment for enabling condition based maintenance to get maximum ROI.
Condition based Maintenance (CBM) means to maintain and correct the equipment at the right time.
 Observing the state of the system is known as condition monitoring which will determine the equipment's health, and act only when corrective maintenance is actually needed.
Advancement in recent years have allowed extensive instrumentation of equipment, and together with better tools for analyzing condition data, the maintenance personnel of modern age are more comfortable than in past decades to decide what is the right time to perform maintenance on some piece of equipment. Ideally condition-based maintenance will allow the maintenance personnel to do only the right things, minimizing
spare parts cost, system downtime and time spent on maintenance (MTTR).

The current scenario is that a higher percentage of organizations are practicing reactive maintenance than scheduled maintenance.This unplanned/unscheduled reactive maintenance should not exceed 20 % of total maintenance activities.Condition based maintenance should preferably be up to 60% and scheduled maintenance to 20% as maintenance options.
The objective of maintenance function is to optimize maintenance cost and improve reliability.
A maintenance function is considered to be more effective when it:
•  increases the Mean Time Between Failures (MTBF) of the equipment
•  reduces the consequence of failure
•  reduces the risk of multiple failures