Layer of protection analysis for reactive chemical risk assessment.

Reactive chemical hazards have been a significant concern for the chemical process industries (CPI). Without sufficient control and mitigation of chemical reaction hazards, reactive incidents have led to severe consequences, such as release of flammable and toxic materials, fires and explosions, and threats to human lives, properties, and the environment. Consequence of reactive hazards can be well understood through calorimetric testing and computational techniques. However, risks of incidents caused by reactive chemicals have not been well addressed due partly to sparse failure frequency data. In this paper, the semi-quantitative layer of protection analysis (LOPA) approach is used to estimate reactive chemical risk, and the probabilities or frequencies of failure scenarios are addressed. Using LOPA, reactive risks can be evaluated with respect to predefined criteria, and the effectiveness of risk reduction measures can be assessed. The hydroxylamine (HA) production system is employed as a case study to demonstrate the application of LOPA to reactive chemical risk assessment.