Managing Equipment Reliability During its Installed Life

Once a piece of equipment is installed into a functional location, there are two reliability priorities:

1. Know the condition of the equipment at all times in order to prevent failures in service.

2. Eliminate the root causes of failure for the specific equipment and functional location to make the equipment’s installed life (MTBF) as long as possible.

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Eliminating Unexpected Failures

The plant’s first requirement for equipment management is the elimination of in-service failures. Predictive Maintenance (PdM) technologies provide information about the current status of equipment health. These technologies include:

•Vibration Analysis
•Infrared Thermography
•Motor Circuit Evaluation
•Current Signature
•Bearing/Winding Temperature
•Ultrasonic Inspection

From the trending and analysis of these tests, a set of standards can be established which when exceeded cause the equipment to be removed for repair and prevent failures in service. The difficulty in tracking a component’s condition occurs because multiple condition technologies must be applied and there are no effective standards in place to facilitate integration of reporting.



The management of equipment condition monitoring results involves the following:

1. Assure that there is a strategy for identifying critical equipment which cannot be allowed to fail in service.

2. Assure that critical, functional locations are monitored adequately to detect possible degradation and pending failures.

3. Set a monitoring schedule for each piece of equipment based on its criticality and failure rate.

4. Assure that equipment is monitored as required and if it is not measured during routine inspections, that it is assessed on a special task to prevent missing its required interval.

5. Assure that all condition problems are easily visible to managers and maintenance staff.

6. Track the time period that a condition problem has bee open to prevent equipment problems from being overlooked.

7. Track work orders assigned to each machine condition problem and know when that work order is closed. Once the work order has been closed, validate the quality and results of the maintenance work with a condition survey of applicable technologies.

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Extending Installed Life (MTBF)

As condition problems are found and equipment is repaired, it is critical to identify the most probable root case or causes of failure. Typical root causes of failure include;

• Over/Under Greasing
• Contaminated Lubricant
• Dirty Cooling Passages
• Overload
• Power Quality
• Imbalance
• Over/Under Tightening
• Abrasive Wear
• Lightening Strike
• Internal Moisture
• Excessive Starts
• Loss of Lubrication
• Misalignment
• Inappropriate Design
• Process Contamination
• High Ambient Temperature

Once the plant analyzes hundreds of failures by equipment type and plant location, patterns of root cause of failures are likely to emerge. For all critical equipment, the equipment should receive a precision installation, validation of an acceptable baseline and a countermeasures plan to offset the top equipment type and location of root causes of failure. When this reliability management strategy is put into place, careful tracking of both equipment and location MTBF is needed to identify poor reliability equipment or locations.

Another method of tracking a plant’s reliability maturity is to tabulate the number of assets with faults each month. Typically a plant just starting predictive monitoring will see about 10% of assets monitored with degradation. As a program of prescribed maintenance is implemented and equipment faults are fixed prior to failure, the failure rate declines to about 5% of total monitored assts. With the elimination of top root causes of failure, the failure rate declines to about 2.5% of total assets.