Six Sigma and chemical process safety

Six Sigma strives toward quantifying defects and reducing them through continuous process improvement, while chemical plant safety methodology works towards reducing the number of risks or hazardous events to a minimum. Hence both the philosophies have several similarities, and incorporating Six Sigma quantification tools into chemical process safety analysis could lead to a powerful safety process. In this paper the uses of tools such as FMEA, Pugh matrix, Fish-bone (cause-effect) diagram, and Z capability metrics in HAZOP studies and hazard and safety analysis are described with examples. In order to achieve ten failures or less (unsafe incidents) in one million years of operation (accepted norm), a safety system in a chemical process should have a Z of at least 7.48.