Plant Hazard Analysis and Safety Instrumentation Systems

2.0. SIL Policy and Programmable Systems

Safety in process plants, production plants, and in machinery industries is mainly governed by the following:

• Moral obligation: Avoidance of any harm to personnel and environment

• Laws: Local and international legislations and regulations

• Sound economic reasons

These safety needs are to be kept in mind from conceptual design stage through all stages of the safety life cycle already discussed. As mentioned at the beginning of the chapter, the logic solver has nearly 15% of the total PFD demands, yet these need special attention because these are Type B devices where both hardware and software need proper consideration. When people talk of programmable systems, naturally logic solvers come to mind! However, ...