Hazard analysis techniques take on many forms, with some being uniquely developed to assess specific systems, processes, or scenarios. There are also a number of well-known methods that are used on a wide variety of systems, such as What-if/Checklist Analysis, Hazard and Operability Analysis (HazOp), and Failure Modes and Effects Analysis (FMEA). Unfortunately, these generalized methods tend to work well on only a part of the risk assessment spectrum, such as failure mode identification, causal factor determination, or risk prioritization, with few of them effectively addressing all aspects of risk evaluation. In this paper, we discuss a hybrid methodology that utilizes the strengths of HazOp and FMEA for failure mode identification and risk prioritization, and Layers of Protection Analysis for evaluation and application of effective controls. As part of the hybridized methodology development, a completely new risk prioritization chart was prepared that allows consideration of risks to the environment, people and business, from both engineered processes and personnel operations.

Background

Effective manufacturing processes are generally viewed as those that create high-quality products efficiently, while protecting the workers, the community, the customers, and the physical and environmental assets. In today's global economy, it has also become ever more important for these operations to run as efficiently as possible to provide effective competition to prevent relocation or closure of manufacturing facilities. These competitive manufacturing pressures create conflicts among the differing goals, especially in the areas of responsible manufacturing and profitability. However, with proper system evaluation techniques and the associated management of identified risks, an equitable balance can be attained that ultimately addresses the issue of competitiveness.

In this paper, we focus on two main manufacturing methods - continuous (direct delivery) and batch processes - to which we apply our risk management concepts. Of these two types, continuous processes receive the most attention, because it is this type of system to which we have most frequently applied our integrated hazards analysis approach. We only briefly address piece-part manufacturing (such as assembly line processes) for which process failures and resulting product defectivity are generally predicted via techniques such as statistical process control (SPC). This paper also discusses the advantages of using an integrated hazards analysis approach to determining and evaluating system risk, focusing primarily on engineered systems. This represents only a part of the risk spectrum for an operating system; additional risk evaluation techniques should be considered to capture the big picture of system risk. These might include design for environment, health, and safety concepts integrated into the process/product development phase, and life-cycle analysis to determine potential impacts of chemical use, product disposal, and eventual system decommissioning.

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