EMG
 Consultation 

Address:
E . M. George,
EARALIL
40/6564 Market Road,
Convent Jn, Ernakulam,
Kochi 682 011
Kerala, India

When we have not only to build but also to operate, the spectrum of work really widens. Over all economics, such as, whether it is better to save on capital costs and incur increased operational costs, become very important for the builder himself. Of course this is actually an opportunity for over all cost saving, because, now the risks on a wider area is under the same mangement control. This situation brings in the need for in depth scientific analysis of reliability and availability risks and such other actions.

Reliabilty is the ability of the system to continue to operate without failure for a certain time. This is important when interruptions of the operation is not convenient. If we cannot tolerate stoppage of the operation even for a short time, reliability becomes very important. A typical example would be a stand alone power generation turbine. If the turbine has to work for a long time uninterrupted the reliability has to be very high. Is it less expensive to build in very high reliabilty or is it better to have a stand-by turbine? What is better in the long run?

Availabilty on the other hand measures the total time the system would operate irrespective of interruptions. For example, If grid power is available as stand-by, the total time the local power generation turbine runs is what matters irrespective of the number of interruptions, provided of course the change over time is tolerable. Here, high availabilty is important when compared to reliabilty.

Optimisation between Capital Cost, Running Cost and Cost of Maintenance including the Spares Stocking Cost can be done by studying the statistical probabilities of the number and extent of failures of equipment. In a competitive environment this optimisation is critical to survival. How many times can we expect an equipment to fail this year? Where and how can we spread the risk? These are questions which need and can be asked and answered.

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