Commissioning is where a commercial fit-out becomes a functioning building. HVAC balance, BMS set-point tuning, lighting control programming, fire-alarm cause-and-effect — all happen in the last two weeks before PC. Poor commissioning produces chronic post-handover complaints for the life of the fit-out.
Commissioning is the systematic process of bringing M&E systems from 'installed' to 'operating to specification'. Typical scope for a commercial fit-out:
CIBSE publishes the industry commissioning standards:
Most London commercial CAT B specifications reference CIBSE Code M as the baseline management framework.
All M&E installed and energised. Initial system power-up. Fire alarm cable pulls complete.
Specialist commissioning engineer balances HVAC system to design flows. Typically 3–5 days for 10,000 sqft.
BMS programmed and tuned. Lighting scenes written. Fire alarm cause-and-effect programmed and witnessed.
Systems tested together — fire alarm triggers HVAC shutdown, lighting defaults to emergency, lifts return to ground. Client witness testing.
Commissioning certificates issued for each system. Full O&M pack delivered.
Systems tuned across the seasonal envelope they weren't tested in. Additional balance as occupancy builds.
Installation runs late; commissioning gets compressed from 3 weeks to 1. Systems go live under-tuned. Chronic post-PC complaints follow.
Systems energised before cleaning, purging, pressure-testing. Commissioning engineer can't proceed.
Controls default to manufacturer settings, not specification. Temperature loops oscillate, occupants complain.
DALI addresses mis-mapped at programming. Scene 1 dims the wrong zone. Tuning becomes a 2-day exercise at PC.
Client signs off cause-and-effect at desk rather than walking the floor. Actual behaviour in a real alarm scenario is different from programmed.
A fit-out commissioned in February has HVAC tuned for heating only. In July, the cooling side hasn't been proven. Seasonal commissioning returns to site 3–6 months post-PC to verify all-season performance.
Often included in the 12-month defects period. Budget 2–3 days of engineer time for a 10,000 sqft installation.
Independent commissioning engineer on every fit-out over 5,000 sqft. CIBSE Code M management framework. Full commissioning certificates at PC. Seasonal re-commissioning included in defects cover. See Office Fit-Out, Lighting & Electrical.
No. Testing verifies a system works to spec at a single point. Commissioning tunes the system and proves it works across operating conditions, integrates with others, and handles edge cases.
You can, but you'll get seasonal complaints. Winter fit-outs commissioned without summer tuning produce cooling complaints by May. Budget the re-visit.
Best practice: independent commissioning engineer appointed by client, witnessing contractor's systems. Contractor commissioning alone creates a conflict of interest.
Measured survey and fixed-price quote within 10 working days.