Upstream Compression, Downstream Consequences: A Risk Migration Framework for Engineering Lifecycle Transitions

Commissioning is widely recognised as a critical phase for process safety, yet major incidents and early operational failures consistently reveal commissioning-origin vulnerabilities that were invisible at handover. Existing project risk models assume risk declines immediately after startup, obscuring a fundamental reality: many safety-critical failures originate during commissioning but activate later under normal operating conditions. This temporal disconnect leads to systematic misattribution of commissioning-origin vulnerabilities as operational errors or equipment defects, preventing effective organisational learning. This paper introduces Commissioning Risk Drift (CRD) as a lifecycle framework grounded in established safety science theory. CRD explains how five interdependent mechanisms—commissioning compression, incomplete functional verification, bypass normalisation, knowledge discontinuity at handover, and activation under real loads—create downstream safety vulnerabilities. Operational manifestations include control instability, alarm floods, incompletely validated safety instrumented functions, and eroded safety margins. CRD operates invisibly because rapid demobilisation severs the link between upstream compression decisions and downstream safety consequences, enabling drift toward unsafe states. Managing CRD requires lifecycle governance that extends beyond traditional project boundaries: aligning project and operational KPIs, protecting functional testing windows, retaining commissioning expertise through early operations, and implementing CRD-aware handover protocols. The framework repositions commissioning from a terminal project milestone to a safety-critical lifecycle transition requiring sustained process safety governance.