AM-08-25 Reliability and Availability: Lifecycle Lessons from Functional Safety

Description:

With the adoption of the international functional safety standards IEC 61508 [1], IEC 61511 [2], and the US version, ANSI/ISA 84.00.01-2004 [3], many process plant operations are being challenged with determining if they are in compliance. These new international and national standards have two basic purposes. First, to define the Safety Lifecycle which is a practical methodology that defines the steps necessary to ensure overall plant safety for process plants. Second, to define how to determine the required level of risk reduction, necessary to reduce plant hazards, and the achieved level of risk reduction of the safety instrumented equipment. These levels of risk reduction are expressed in the Safety Integrity Level (SIL) parameter. The safety lifecycle process can be overwhelming at first and one can argue that there is a tremendous emphasis on upfront engineering work. There are however many reasons why upfront engineering work will not only provide adequate risk reduction where necessary, but also assist in overall cost reduction for the mplementation of functional safety. This paper will discuss several aspects of cost reduction and improvement in overall plant reliability and availability.