Plant Hazard Analysis and Safety Instrumentation Systems

Section 1: IEC 61508/61511 Implementation

Introduction: People all over the world are working very hard to obtain optimum solutions toward implementation of design, installation, commissioning, and operation and maintenance (O&M). Here, the word “optimum” is very important. Unless proper planning is done right from the beginning there is every possibility that the system could be under- or overdesigned. In the former case, basic safety might be compromised, whereas in the latter case it will be costlier. Another issue is that many people believe that by increasing redundancy, greater safety will be achievable. It is true that the greater the safety requirements, the greater the availability should be. However, the reverse may not be true. This ...