Safety study evaluation, HAZOP

Step 1 - Complete the LOPA without taking any credit for the SIF. First, determine the initiating events from HAZOP/What-if/EMEA study. Next, evaluate frequencies of all initiating events from company database and industry experience. Then, determine the probability that each IPL will function successfully from an industrial database. PFO yg of some typical protection layers are (CCPS, 2000) BPCS control loop = 0.10 Operator s response to alarm = 0.10 Rehef safety valve = 0.01 to 0.001 and vessel failure probability at maximum design pressure = 10 ". Finally, compare the calculated risk with the tolerable risk target... 

This chapter briefly described the use and application of both the HAZOP study and what-if analysis, when each can and should be performed during the various phases of the product or project life cycle, and how each can be used to evaluate the viability of a new or (more commonly) an existing system. The occupational safety and health practitioner should seriously consider using these techniques to ensure a more comprehensive analysis and overall understanding of the inherent safety of any system or process. 

In the previous chapter, it was established that in industry, plant hazards can cause harm to property (plant—machinery, asset), people, or the environment. So, it is important to develop some means of analyzing these and come up with a solution. Unfortunately, it is not as straightforward as it sounds. There are plenty of plant hazard analysis (PHA) techniques and each of them has certain strengths and weaknesses. Also each specific plant and associated hazard has specific requirements to be matched so that hazard analysis will be effective. In this chapter, various hazards (in generic terms) will be examined to judge their importance, conditions, quality, etc. so that out of so many techniques available for PHA it is possible to select which one is better (not the best because that needs to be done by experts specifically for the concerned plant) suited for the type of plant. So, discussion will be more toward evaluation of PHA techniques. Some PHA is more suited for process safety management (PSM) and is sometimes more applicable for internal fault effects [e.g., hazard and operability study (HAZOP)]. In contrast, hazard identification (HAZID) is applicable for other plants, especially for the identification of external effects and maj or incidents. HAZID is also covered in this chapter. As a continuation of the same discussion, it will be better to look at various aspects of risk analysis with preliminary ideas already developed in the previous chapter. In risk analysis risk assessment, control measures for safety management systems (SMSs) will be discussed to complete the topic. 

ABSTRACT In recent years, serious accidents in chemical plants occurred frequently in Japan. Also in order to prevent deserters ccidents caused by natural disasters, it is needed to re-evaluate risks which consider reliability of existed safety guards system in chemical plants. In order to identify hazards in chemical plants, HAZOP (Hazard and Operability Study) is used as one of effective measures. In this paper, we propose the method to calculate the probability of occurrence of hazards in chemical plants by considering of existed safety guards system. The method is based on the HAZOP information and reliability of safety equipment arrangement. 

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