Surveillance Activities

A Reliability Basis Violation occurs when a functional failure occurs on a component that is protected by the reliability basis [5] [6] [11]. Although sometimes the failure may not be directly linked to a failure of the process established by the RBO analysis and implementation, all such failures indicate that the protected component has lost its function. The value obtained in recognizing and documenting all functional failures is the actions driven by the Continuous Improvement Process. In each case, the RBV must be analyzed to determine if there was in fact a failure of the RBO-directed defences that were designed to protect the equipment [11]. If this was the major contributor to the failure, then actions must be taken to correct the failure of the process. If the component failure resulted from events that were omitted from or incorrect in the RB, then the RB must be modified to include new defence mechanisms that will prevent the failure in the future [11]. If the component failure resulted from events that could not have been foreseen or avoided, or would not be economically feasible to prevent, then no modification of the RB would be required. In each of these cases however, some analysis/action must be performed to review the failure causes and determine what course of action should be taken. The responsibility to initiate the analysis/action lies with the System Engineer. Other parties in the organization may be called in to assist in the analysis. Sometimes a formal RCA process is initiated. Other times a simple review by appropriate Subject Matter Experts (SME’s) would establish the actions needed.

Equipment failures resulting directly from an Operator error should still be considered an RBV. The action taken in this case would normally be the development of a

A Case Study on the Development of and Asset Management Process within the Eskom Fossil Fired Power Stations with Emphasis on Reliability Basis Optimisation

57 corrective action describing the event causes. An analysis of these failures should still be performed. Chronic or systemic failures, while not requiring a modification in the RB analysis, should still be addressed through appropriate training and procedural modification.

When determining a RBV the following Integrated Business Improvement (IBI) criteria are used:

• Equipment Performance • Equipment Condition • Inspection and Testing • Maintenance Programme

If the investigation yields any of the above criteria, this is regarded as a Reliability Basis Violation.

The investigation process would typically follow the Power Stations Occurrence Management Process. All maintenance occurrences on components that are protected by the maintenance basis are captured and reported as RBV’s.

When a PM is to be updated, the System Strategy document will also be updated to reflect the PM changes. All changes will also be reported to the Asset Management Department. This is to allow for continuous improvement of the GGCS’s if the GGCS is inadequate.

Reliability Basis violations can typically be initiated by [18]: o Output from the CMMS:

The SAP database is set up to produce reports of PM’s that have surpassed their frequencies by a certain percentage of time. These reports form the basis of RB. Violations, generated electronically and automatically.

o Safety Findings

Safety inspections (or even internal and external safety and health audits) on site or even insurance audit may uncover certain violations of systems. Examples may be fire protection systems that have not been tested as per the RB Strategy or a chemical plant safety shower/conveyor safety trip wire that is not operational, despite confirmed testing as per schedule.

A Case Study on the Development of and Asset Management Process within the Eskom Fossil Fired Power Stations with Emphasis on Reliability Basis Optimisation

58 o Actual Premature Failures:

Despite the fact that a RB Analysis has indicated a specific maintenance strategy regime and this has been followed, premature failures could occur, as a result of:

• Poor workmanship

• Unnecessary maintenance

• Incorrect maintenance procedures • Inadequate training

• Incorrect operation • Inadequate design

• Poor quality manufacturers

• Incorrect installation and commissioning

o Inadequate RB Analysis:

Despite many RB process controls and GGCS’s as guidance, incorrect RB decisions may be taken due to inadequate data, history or relevant plant system experience. These decisions are to be corrected and updated in the Plant System Strategy documents.

o Inadequate PMs/SMP/SOP/WP/BOMs:

The documents developed from the RB Strategy may have flaws in that incorrect interpretations, omissions and replication across units may have taken place.

o Inadequate PM Compliance

Sections required to perform tasks may have wilfully not performed the tasks, due to personnel or other resource constraints.

o Inadequate Work Practices

Despite having done the required task, the quality level of the task may not have been to standard, due to lack of experience, training, misconception, lack of or inadequate documentation.

A Case Study on the Development of and Asset Management Process within the Eskom Fossil Fired Power Stations with Emphasis on Reliability Basis Optimisation

59 Task may have been performed, but due to lack of spares, used parts have been returned to service, has not been carried out or not as yet been returned to service.

o Hidden Failure (testing)

During functional testing or maintenance, hidden failures may be evident, such as a fire pump failing to start or an under-voltage relay not operating.

o Inadequate Configuration Control

Over the years certain deficiencies may have occurred, which have been used during the RB Strategy formulation, which are entirely incorrect. Examples are un-updated drawings, unofficial modifications, incorrect revisions utilised, procedures or PM’s not updated after changes, etc.

5.3.4.2 Work Management Processes