Title: Safety Instrumented Systems – Avoidance and Control of Systematic Failures
Date: February 5, 2019
Location: 110-12AV SW
Safety Instrument Systems (SIS) intend to control risk of hazards to a tolerable boundary by reducing dangerous failures rate. There are two types of failures; random and systematic. Random failures occur at random times and result from one or more degradation mechanisms. Systematic failures, however, are related to a deterministic way to a certain cause, which can only be eliminated by a modification of the design or manufacturing process, operational procedures, documentation or other relevant factors. Both systematic safety integrity (to avoid systematic failures) and hardware safety Integrity (to avoid random failures) are needed to meet the required risk reduction target for a SIS. Thus, if systematic integrity is missed, much is neglected. Studies show that many catastrophic accidents occurring in process industries address multiple systematic failures. Unlike random failures, systematic failures cannot be analyzed straightforwardly. The author’s experiences in automation field of process industries shows avoidance and control of systematic failures in SIS are not being highlighted as much as random hardware failures. This talk focuses on systematic failures and discusses procedures, techniques and measures to be used for avoidance and control of systematic failures.