System‐level validation of safe operating limits in major hazard installations using integrated process modelling

Safe operating limits (SOLs) define critical operating boundaries for preventing loss of containment in major hazard installations. However, their validation is often limited to equipment‐level thresholds, without systematic assessment of plant‐wide process interactions. This study develops a system‐level validation framework that integrates steady‐state modelling with dynamic simulation to quantify enforceable operating envelopes under interacting unit constraints. The methodology combines process safety time (PST) analysis, escalation pathway evaluation, and control‐system response assessment under representative upset scenarios. Inter‐unit thermal, pressure, and inventory couplings are explicitly considered to evaluate deviation propagation across the process network. Application to a representative distillation system demonstrates that plant‐wide modelling reveals constraint interactions not evident from isolated unit analyses, resulting in a system‐constrained operating envelope aligned with safeguard performance and control response. The proposed methodology provides a reproducible engineering framework for validating operating limits in interconnected chemical process systems. By integrating dynamic simulation, system‐level constraint analysis, and lifecycle feedback, the approach strengthens operating‐envelope robustness under realistic disturbance conditions.