Incipient Failures in Exception Handling Devices: Beware the Surprise

Circuit breakers, fire alarms, process monitoring indicator lights, and other such devices are relied upon to prevent additional failures or to mitigate the severity of failure. Ensuring the proper operation of such exception-handling devices is necessary to make reasonable the risk associated with the hazards addressed. Exception-handling devices are intended for intermittent use. As such the presence of incipient failures may not be apparent before the need arises for the device to function. Thus, if the relay that is relied upon to transmit a signal to shut down a critical process is itself inoperable due to disuse, the process may continue operation with additional damage done. Examples of methods for detecting and preventing failures of these devices will be discussed. Case studies will be presented.