Partial stroke system meets SIL 3

An FMEDA report has shown the NETHERLOCKS partial stoke system FAITH (Fail Action Integrity Test Handling) to be very reliable, with 0 Fail Safe Detected, Fail Safe Undetected and Fail Dangerous Detected conditions recorded from the tests. For most cases, the FAITH is suitable for use in SIL3 applications.

The FAITH system makes it possible to carry out a manuallyinitiated partial stroke test on ESD (Emergency Shut Down) valves during normal operation, without interrupting process flow. It limits, with mechanical stops, the angle of the stroke of the valve-actuator combination to a set percentage - ensuring the ESD valve 'works', without actually shutting down the operation. By operating mechanically rather than relying on electronic contacts or signals, reliability and simplicity is maximised.

An FMEDA (Failure Modes, Effects, and Diagnostic Analysis) assessment has been carried out by Exida on NETHERLOCKS' FAITH system.