• Smith Flow Control - Halma India

Partial Stroke System for Fail Safe Detection

An FMEDA (Failure Modes, Effects, and Diagnostic Analysis) report, carried out by Exida, has shown that 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 was subject to a thorough examination according to IEC 61508 to determine Probability of Failure on Demand (PFD) statistics for this device. The failure rates of the FAITH System must be added to the failure rates of the valve-actuator combination when determining the PFD AVG and Safe Failure Fraction (SFF) for the final element. FAITH makes it possible to carry out a manually-initiated 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. Based in the Netherlands, Netherlocks is a leading supplier of safety and valve control systems for major industrial operations as well as smaller firms. The company's mechanically enforced procedures minimise the risk of human error in production and maintenance processes, which could otherwise be dangerous and costly. Over 15 years of experience in protecting personnel and equipment means the company has been at the forefront of many design innovations which have helped to make industrial safety easier to implement and more effective than ever before.