Home Health Case Studies in Maintenance and Reliability: A Wealth of Best Practices
Technical Integrity (TI)
TI is the absence of foreseeable risk of failure that could endanger the safety of personnel, environment, or asset value. Loss of TI will harm the long-term viability of the facility, sometimes destroying the business itself. For example, after the Bhopal disaster i, Union Carbide had to close down their operations in India. In the UK, Rail Track ii closed down after the Hatfield disaster and Ansett Airlines iii in Australia suffered a similar fate. In all these cases, the company involved lost TI. It is, therefore, very important to manage TI effectively. Hidden failures can seriously impair TI, so one of the things we have to do is to detect hidden failures and ensure that faults are rectified promptly.
Testing for Hidden Failures
In order to detect hidden failures, we have to test the items in a real or simulated situation. Such tests are also called detective or failure-finding tasks. Testing the sensing elements and logic units can be done during operation by defeating the signal to the actuators. This is what we call function testing. In such a test, the final element, such as an actuator or valve, does not get a signal, so it does not move. The advantage of doing function tests is that production is not interrupted, and there is no loss associated with such tests.
The alternative is to do a full test where the equipment, system, or plant shuts down. Such complete tests can cause large production losses. As a result, there is considerable reluctance to do them. Such a decision is often based on a limited understanding of the TI issues involved and of the resulting risks to the facility
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