The gate between a constructed operating room and a clinical operating room is a disciplined commissioning sequence — clean it to a verifiable baseline, prove the air is moving and conditioned exactly as designed, and dry-run the room until it can take its first patient safely. This article covers that final-mile readiness gauntlet for new and renovated surgical and procedural rooms: the construction-to-clinical handover, the terminal-clean protocol, HVAC air-balance and environmental certification, integrated systems commissioning, and the first-case readiness gate. It does not cover the daily turnover and terminal-clean cadence of an operating suite (that is the operational-readiness sibling), the HVAC design parameters themselves (the ASHRAE 170 systems sibling), instrument tray build-out, or the standing infection-prevention and fire/laser safety program — each is its own Article in this Part.

Why first-case commissioning is its own discipline

An operating room is the most environmentally controlled space in a hospital, and the period between substantial completion and first patient is where construction risk and patient-safety risk overlap most dangerously. Three failure modes recur on activation projects:

• Residual construction contamination. Drywall dust, ceiling-plenum debris, sealant off-gassing, and Aspergillus-laden particulate settle into a freshly built room and its supply plenum. If the room is "cleaned" only to a housekeeping standard and opened, the first cases inherit an elevated airborne-fungal and particulate load — a documented driver of surgical-site infection (SSI) and post-construction invasive aspergillosis in immunocompromised patients.
• Air systems that test fine on paper but not in the room. A balancing report can pass at the air handler while the actual room fails on air-changes, pressure relationship, temperature, or humidity because of damper drift, filter loading, door undercuts, or interactions with adjacent rooms once they are also energized.
• Untested integration. Booms, lights, integration video, medical gas alarms, isolated-power monitors, nurse-call, fire alarm, and the room's relationship to the emergency power system each commission cleanly in isolation but fail at the seams when run together under a realistic clinical load.

First-case commissioning exists to close all three before a patient is exposed. It is a planned, evidence-producing process owned jointly by construction, commissioning, infection prevention, facilities/engineering, and surgical services — not a punch-list afterthought. On accredited projects it also generates the documentation surveyors expect: the Infection Control Risk Assessment (ICRA) close-out, the test-and-balance (TAB) certification, and the special-systems acceptance records that feed the building's Statement of Conditions and the surgical service line's activation file.

Where commissioning sits in the delivery sequence

Commissioning of a surgical environment is most reliable when it is sequenced as a defined, gated phase rather than compressed into the days before opening. A typical sequence:

1. Construction substantial completion of the OR shell, finishes, and rough-in — clean, dust-tight, with permanent ceilings, walls, and floor systems in place.
2. Pre-functional / static commissioning — installed-equipment verification, point-to-point checkout, and start-up of HVAC, electrical, medical gas, and low-voltage systems by the responsible contractors.
3. Initial test-and-balance (TAB) of the air system by an independent, certified TAB agency.
4. Rough terminal clean / construction final clean to remove gross construction soil before fine work and before precision air testing.
5. Functional performance testing of systems and inter-system sequences, witnessed by the commissioning authority (CxA).
6. Final (clinical) terminal clean to a healthcare disinfection standard, performed by trained environmental-services (EVS) staff under infection-prevention oversight.
7. Environmental certification — particle counts, air-balance verification, pressure/ACH/temperature/humidity confirmation, and (where required) airborne microbial sampling, on the fully clean, fully assembled room.
8. First-case dry run / mock procedure — a clinical walk-through with full staff and a realistic case setup.
9. First-case readiness sign-off — the documented multidisciplinary go/no-go decision.
10. First live case, followed by a short heightened-monitoring window.

The non-negotiable ordering rule: the room is terminal-cleaned and the environment is certified after all dust-generating and integration work is complete, not before. Re-entering a certified room to chase a punch item resets the clock — the room must be re-cleaned and, depending on the work, re-certified.