Control Systems / Safety Instrumented Systems

Course Covers Performance Assessment Of Safety Instrumented Systems

By Chemical Processing Staff

Apr 29, 2019

The Mary Kay O'Connor Process Safety Center at Texas A&M University is offering a two-day course covering the verification of safety integrity level (SIL) and spurious trip rate for safety instrumented functions. The course, Performance Assessment of Safety Instrumented Systems, will be held May 7-8 at SIS Tech Solutions. The course is designed for control system specialists, instrumentation and electrical personnel and SIS design specialists

The course covers the performance verification of safety instrumented functions (SIF), including calculation of the probability of failure on demand (PFD) and spurious trip rate (STR). These calculations must take into account the device failure rates, system architecture, subsystem voting configuration, specified diagnostics and testing, and repair times. The PFD calculation must also take into account the susceptibility of the SIF to common mode and common cause failure.

IEC 61511 requires that the PFD be verified by calculation to prove that each SIF meets its target safety integrity level (SIL). The course provides students with an understanding of the fundamentals needed to address this requirement in their workplace. It familiarizes students with failure modes and effects analysis (FMEA), the identification of safe, dangerous, detected, and undetected device failures, the selection of failure rate data, understanding key design parameters, and applying the calculation methodology. The two approaches for approving a device for use in an SIS - certification and prior use - are also explained.

The course presents a series of examples as workshops to illustrate the important concepts and assumptions implicit in the calculations. Students must bring a scientific calculator and notepad to the course.

For more information, visit: