OQ (Operational Qualification)

The OQ demonstrates through structured tests that automated equipment functions correctly across all operational ranges defined in the URS. We test each sequence (start, normal stop, emergency stop, restart), all recipes, the boundaries of process parameters (temperatures, pressures, flows, times), all alarms with acknowledgment and recording in the audit trail, safety interlocks, degraded modes (loss of communication, loss of power), 21 CFR Part 11 requirements, and batch report generation. It is typically the longest qualification phase, between three and eight weeks for a complex line. A good ISA-88 architecture drastically reduces OQ duration because phases run independently, without code recompilation or redeployment.