DiTemp ATTS – Statistical evaluation of confidence levels

The system is set to reproduce a temperature rise or drop of the same magnitude as the one expected in the case of an anomaly, e.g. a leakage.

These two sections of fiber are placed at the beginning and at the end of the real sensing cable to test the detection of a simulated event at both extremities and therefore predict the ability to detect real events over the whole length of the sensing cable. The simulated temperature rise or drop events are typically generated every hour. The DiTemp ATTS records the timing of the simulation start and of the received alert from a dedicated zone in a DiTemp Relay Module controlled by the DiView software. If no alert is received after a predefined timeout, the DiTemp ATTS can generate an alert, indicating that the system might be unavailable.

A signal is also available during the heating or cooling cycle, to allow recording by a plant control system. The DiTemp system will detect real leakages also during a simulated test, since the two events take place in different zones. Alerts from the test zone are typically not transmitted to the plant controller and do not initiate any further action.

The system records all timing results, so that a report can be periodically generated to summarize the availability score and the average and maximum reaction times, providing a periodic evaluation of the SIL level (Safety Integrity Level proven by experience).