SMMS Workshop (Targeted Strategy Application)

Trevor Kletz set out four inherent safer design strategies. Substitute replaces the hazardous material, Minimise reduces inventory, Moderate operates at less severe conditions, and Simplify eliminates complexity. They originated at ICI in the 1970s following the Flixborough disaster of 1974 with twenty eight fatalities, and they were codified into CCPS Inherently Safer Chemical Processes, first in 1996 and then in its 2nd Edition of 2009, and into the EPSC inherent safer design guidance. The approach remains the most cost effective way to reduce hazards in the chemical industry, because a hazard eliminated at the concept or FEED stage typically costs one to ten percent of the equivalent control layer retrofit and avoids the cumulative reliability burden of safeguards. Our SMMS workshops matter most at three points. These are conceptual design where substitution and process route selection are open, the FEED stage where minimise, moderate, and simplify are most actionable, and post incident redesign where the most aggressive options finally surface. We also bring in the Heikkila Inherent Safety Index for quantitative scoring and use inherent safer design to reduce the later SIL allocation burden. A SIL 2 SIF on a hazard with a one hundred kilogram inventory can become a SIL 1 requirement, or be eliminated entirely, once the inventory drops to ten kilograms, which is often achievable through continuous flow conversion or feedstock substitution.