Data Center Commissioning Checklist: What to Inspect Before Handover, Trade by Trade

• Most data center projects commission in five levels, often with a design review in front, and each level assumes the one before it was clean.
• Levels 2 and 3 are the installation and pre functional checks: mostly visual, item by item, and still mostly done on a clipboard or tablet.
• Electrical checks include labels against the panel schedule, busway joints that show they were tightened, arc flash labels, clear working space and A and B feeds on separate paths.
• A thermal scan during load bank tests catches hot breakers, busway joints and connections before the IT load arrives.
• On liquid cooled halls, record every leak from the first pressure test, and flush the loop so it starts clean.
• Firestopping and sprinkler clearance are easy to undo in the last weeks of a build, so they belong on the same checklist.
• A verified handover package on day one, with punch list items closed by photo, is worth millions on an AI hall that goes live sooner.

Short answer: Most projects use five levels, often with a design review in front: factory tests, installation checks, startup and pre functional checks, system tests and an integrated systems test. Each level has to pass before the next begins, and the names vary from owner to owner.

Commissioning moves a data center from drawings to a proven facility in stages. A DCD explainer with Kirby Group Engineering walks through the levels, and the Uptime Institute Journal describes the same ladder.

Commissioning levels at a glance

1. 1. Level 0, design review: the design is checked against the owner's requirements and local codes before anything is bought.
2. 2. Level 1, factory tests: major equipment is tested and witnessed at the factory before it ships.
3. 3. Level 2, installation checks: installed equipment is inspected on site against the drawings and the contractor's checklists.
4. 4. Level 3, startup and pre functional checks: each system is started and checked on its own: installed right, labeled and matching the plan.
5. 5. Level 4, system tests: each system is tested at full performance, including load bank tests of generators, UPS systems and batteries.
6. 6. Level 5, integrated systems test: everything runs together under failure scenarios, up to a full blackout test.

Names and scope change from owner to owner, and some firms split the ladder into more levels. What stays constant is the order: each level depends on the one before it being clean.

The commissioning agent runs the tests and signs them off. The ACG commissioning guideline describes that agent as independent of the designers, contractors and suppliers, because it is hard for anyone to test their own work objectively.

Every later test assumes the earlier checks were right. This checklist is about making sure they were.

Short answer: Level 2 confirms that equipment arrived undamaged and was installed according to the drawings. Level 3 starts each system and confirms it is installed right, labeled and matching the plan, before any system is tested at full load.

At Level 2, contractors complete post installation checklists against the record drawings, and the whole commissioning team reviews them. At Level 3, manufacturers and the commissioning agent work through startup and functional checklists, item by item.

Almost all of it is visual. Someone walks the hall with a clipboard or a tablet, looks at each item and ticks a box, often days after the crew that installed it has moved on.

These checks decide how the rest of commissioning goes. When Levels 2 and 3 are clean, fewer Level 4 and 5 tests fail, fewer tests are rerun, and the commissioning agent's time goes to testing instead of chasing installation defects.

The technicians, contractors and commissioning engineers we interviewed were clear about what makes these checks worth trusting. Positive confirmation, where every item is recorded as checked and passed, beats a report where silence counts as a pass.

At Level 2, a defect costs the crew a few minutes. At Level 5, it costs a rerun.

Short answer: Check that labels match the panel schedule, busway joints show they were tightened, IR windows and arc flash labels are in place, working space is clear, cords and whips run to plan, and the A and B feeds really land on separate paths.

Electrical defects are the most expensive kind to find late, because fixing them usually means a shutdown. Before anything is energized, walk every electrical room and every row with this list.

The electrical checklist

• Panel and breaker labels: every circuit identified and matching the panel schedule. Schedules start drifting the day they are written, as our guide to NEC panel schedules explains.
• Busway joints: joint bolts tightened and showing it, with covers on.
• IR windows and arc flash labels: windows installed where the design calls for them, and warning labels present and readable on every piece of gear that needs one.
• Working space: the floor in front of electrical equipment kept clear of boxes, carts and cable reels.
• PDU whips and power cords: run to plan, supported and fully seated.
• A and B feeds: each supply of a dual corded device on its own feed, not both on one strip.

Why busway joints are easy to verify

Many busway systems join sections with a torque indicating bolt that has two heads. In Eaton's installation instructions, the upper head shears off when the joint reaches the right torque, so a joint that still has both heads was never fully tightened.

That turns a torque check into a visual one. Nobody has to put a wrench on the joint to know it was tightened; they only have to see it.

Labels and clearances

The NEC and NFPA 70E expect electrical equipment to carry arc flash warning labels, so qualified people know the hazard before they open anything. OSHA's construction rules keep the working space around electrical equipment free of stored material, and on a busy build that space fills up fast.

Both are easy to fix at Level 2 and easy to miss when they are checked by sample. Both also come back after handover, which is why the same walk belongs on every operating round.

A sheared bolt head, a readable label and a clear floor are all facts you can see.

Short answer: Because a loose or undertightened connection looks fine cold and only shows itself as heat under load. A load bank puts the design load on the hall, and a thermal scan while it runs catches hot breakers, busway joints and connections before the IT load arrives.

Load banks stand in for the IT equipment that is not there yet. As 7x24 Exchange explains, they add load to simulate design conditions, and for cooling tests they reproduce the heat that IT equipment would give off.

That load is the best chance to find a bad connection before it matters. In the DCD explainer, busbars are load tested with resistive load banks while thermal imaging checks the joints, and Keentel Engineering gives the example of an untorqued bus joint found by its heat at Level 4 (vendor).

The scan works because heat follows resistance. A connection that is loose, undertightened or corroded resists the current and warms up, which thermal imaging shows long before the connection fails.

Scan the whole hall, not only the switchgear room. Breakers, busway joints, whips and the connections at each PDU all carry the test load, and each is a place where a joint can run hot.

A load bank test without a thermal scan proves the system carried the load. It does not prove every joint did.

Short answer: Check that quick disconnect couplers are latched, hoses and fittings are sound from several angles, drip trays are in place and dry, valves are tagged and set right, and insulation is intact. On liquid cooled halls, record every leak from the first pressure test onward.

AI halls are bringing liquid to the rack, and the build is where its connections are cheapest to fix. Walk every row and every plant room with this list.

The mechanical and liquid cooling checklist

• Quick disconnect couplers: fully latched, not strained or pulled sideways.
• Hoses and fittings: no kinks, strain or damage, checked from several angles because a weep often shows from only one side.
• Drip trays: present under connections and dry.
• Valves: tagged, and in the position the sequence calls for.
• Insulation: intact on chilled pipework, with no gaps where condensation can form.
• Leaks: every leak recorded with the time, the exact location and photos, starting with the pressure test.

Pressure tests and flushing

Before a loop is filled, it is pressure tested. OCP guidance on connecting liquid cooled equipment says commissioning should include a pressure test of the entire system, with liquid or with gas at low pressure, using a method set by the design engineer and the commissioning agent.

After the test comes flushing and filtration, so the loop starts clean. OCP's row manifold guideline covers that preparation step by step, because whatever is left in the pipework at handover stays in the loop.

Every leak found during these tests deserves its own record: when, where and what it looked like. That record becomes the first page of the loop's history, so a weep that returns months later can be compared with the day it was first fixed.

On a liquid cooled hall, the leak history starts at the pressure test, not at the first alarm.

Short answer: Sprinkler heads blocked by new trays and equipment, firestopping missing or damaged where cables and pipes pass through walls and floors, extinguishers missing or out of date, blocked exits, and cardboard and packaging left in racks.

Fire and life safety items sit outside most commissioning checklists, yet inspectors and insurers look at them closely. They are also the items most easily undone in the last weeks of a build, when trades are working on top of each other.

The fire and life safety checklist

• Sprinkler heads: clear of new cable trays, ducts and equipment, as our guide to sprinklers between inspections explains.
• Firestopping: in place and intact at every cable and pipe penetration through a rated wall or floor.
• Extinguishers: present, mounted and in date.
• Exits and egress paths: clear, with doors that close and latch.
• Combustibles: cardboard, packaging and pallets out of racks and rooms.

Why firestopping deserves its own walk

Firestopping is installed late, by a different trade, and then disturbed by everyone who adds a cable afterward. A paper published by the International Firestop Council lists the most common firestop deficiencies, from overfilled penetrations to the wrong gap around a pipe, and warns that weak inspection wastes the last chance to catch them.

For some buildings, such as high rises and buildings in higher risk categories, the International Building Code calls for special inspection of firestopping by an approved agency. Either way, check every penetration at handover and again after any cable work through it.

The same items carry on into operations, where the International Fire Code sets the rules for exits, doors and extinguishers. A closed door during the walk should be recorded as not inspected, never as a pass.

A penetration nobody looked at is not a pass. It is a gap in the record.

Short answer: Because closing an item usually means a contractor marked it done in a tracking tool, so senior people walk the hall again to confirm. Confirming each item at its location with a dated photo removes that second walk and settles disputes.

Near the end of a build, every unfinished or wrong item goes on the punch list, often hundreds of them on a single hall. Each has an owner, a location and a status, and the status is usually set by the person who made the fix.

That is where time leaks. The commissioning agent or the owner's rep cannot sign off on a status alone, so the senior people on the project walk the hall again to see each item, the same problem as proving an inspection round was really completed.

Closing items with proof changes that. When each item is confirmed at its location with a dated photo, the second walk becomes a review at a desk, and a dispute about who fixed what has an answer.

It is one lever on the path to go live, not the whole path. Punch list closure works alongside the tests, the paperwork and the handover meeting.

Closed should mean seen, not marked.

Short answer: The verified as built, an asset register captured from the floor, a scope record for every connection, punch list closure with dated photos, leak and thermal records from commissioning, and the commissioning agent's signed test records.

The handover package is what the owner keeps after the contractor leaves. The technicians, contractors and commissioning engineers we interviewed said as built drawings and commissioning records are the items most often missing at handover, and that records go stale within about a month as equipment moves.

The pattern is not new. In the FMI and CMAA survey of owners, 70% said they frequently or sometimes saw incomplete documentation for systems and equipment during commissioning, and that survey dates from 2011.

What goes in a verified handover package

• Verified as built: drawings and a 3D record that match the floor on the day of handover, with a photo of every port, as our guide to fiber as built records explains.
• Asset register: every asset with its location and label, captured from the floor rather than typed from a list.
• Scope record per connection: each fiber end face result tied to its exact port.
• Punch list closure: every item with a dated photo of the fix.
• Leak and thermal records: every leak from the pressure tests and every hot spot from the load bank tests, with location and date.
• Test records: the commissioning agent's signed results for every level.

Owners should ask for the same record on sites they do not run. Colocation halls, leased space and partner builds can all be required to hand over the same package, written into the contract, so every site in the portfolio meets one standard.

The handover package should exist on day one, not arrive in pieces over the following quarter.

Short answer: Far more than the liquidated damages. Late handover typically costs $20,000 to $50,000 a day in damages, and by our calculation a 100 rack AI hall forgoes $1.8 million to $4.7 million of GPU time for every day it is not live.

Schedules are under pressure everywhere. Currence, as reported by Network World in July 2026, expects 30% to 50% of the large scale capacity due online in 2026 to be delayed, after more than a quarter of the capacity expected in 2025 missed its completion date.

The people who catch defects are scarce too. Turner and Townsend's 2026 market report, covered by Data Center Knowledge, found nearly 90% of respondents citing shortages of mechanical, electrical and plumbing trades, and CSIS estimates that AI data centers could need roughly 140,000 extra skilled trades workers by 2030 in its high case.

What a late week costs

The technicians, contractors and commissioning engineers we interviewed put commissioning at about $25,000 per MW, within a range of $15,000 to $50,000, and late handover liquidated damages typically at $20,000 to $50,000 a day. Those are the costs written into the contract.

• One AI rack idle for a day: roughly $18,000 to $47,000 of forgone GPU time.
• A 100 rack hall, one day late: $1.8 million to $4.7 million.
• The same hall, one week late: $12.6 million to $32.9 million.

These are our calculations from published GPU rental rates, and they dwarf the cost of checking. A defect caught at Level 2 costs the crew a few minutes, while the same defect found at Level 5 can cost the hall a day.

On an AI build, every day between crew complete and go live has a price.

Short answer: A FacilityOps robot walks the hall after each crew finishes and runs the trade by trade checklist on every round, with a photo and a location for every item. The result is one record across every trade and a verified handover package on day one.

FacilityOps AI (RoboSkill Inc.) builds an autonomous inspection platform for data centers. On a build, our goal is every inspection a commissioning agent or owner's rep walks, across every trade, with one robot, one record and one verified handover package.

Our inspection robots run fully autonomously, and a technician can take manual control at any time. The platform is hardware agnostic: inspection robots and sensor hubs are the most common way we capture data, but it works with any capture source.

What the robot checks

• Every trade on the same round: a FacilityOps robot works through the electrical, mechanical and liquid cooling, fire and life safety, and fiber checks in this guide on the same pass.
• Heat under test load: during load bank tests, thermal scans across the hall flag hot breakers, busway joints and connections, with switchgear read through its IR windows.
• Leaks from the first test: every leak during pressure tests is recorded with date, time, exact location on the image (for example Data Hall 3, CDU 7) and photos from several angles per fitting.
• Punch list closure: items are imported with their locations, and the robot visits each one and confirms it closed with a dated photo, or flags it still open.
• Defect rates per installer and crew: so you can see who needs help without anyone standing over them.
• The handover package: the verified as built in our 3D digital twin, the asset register, a scope record per connection, punch list closure evidence, and leak and heat records, ready on day one.

Built to be trusted

• We check the work. We never do the work. We never run, sequence or sign off tests: that stays with the commissioning agent, and the robot gives the agent the evidence. We never open energized gear, as our answer on robots and electrical panels explains.
• Positive confirmation: every item in scope is recorded as checked, with a photo and its location, and nothing is reported clear unless every point was seen.
• People stay in the loop: anything the robot cannot read clearly goes to a person, a closed door is recorded as not inspected, and a person reviews every finding before it reaches you.
• Everything runs on site: detection and the 3D model run on the robot's onboard computer, and you own every image and record. Patent pending.

Where it stands today

Whole facility rounds, the 3D digital twin and change detection run in a production data center today. Since July 28, 2026, a FacilityOps robot has run inspection rounds at the CRSC Data Center, powered by Solutions IS, in Houston, completing 19 autonomous inspection runs and more than 1,600 observations in its first three weeks.

A build trial starts with one row: the robot runs the trade checks on your own floor after your crews finish, and you judge the result on your own data. It takes the checking walk off your senior technicians and commissioning agents, so they spend their time where only they can.

• Commissioning agent: the independent party who plans, witnesses and signs off commissioning for the owner.
• Owner's rep: the person who represents the owner on site and accepts the work.
• Level 2: installation checks of equipment on site, before startup.
• Level 3: startup and pre functional checks of each system on its own.
• Pre functional check: confirmation that a system is installed, labeled and ready to test.
• Load bank: equipment that draws power and gives off heat to simulate the IT load.
• Integrated systems test: the Level 5 test of every system together under failure scenarios.
• Punch list: the list of unfinished or wrong items to close before handover.
• Firestopping: the materials that seal a penetration so fire and smoke cannot pass through a rated wall or floor.
• Torque indicating bolt: a bolt whose head shears off at the right torque, so tightening can be seen.
• Handover package: the records the owner receives at handover.
• Positive confirmation: a record that each item was checked and passed, rather than silence counting as a pass.

What are the five levels of data center commissioning?

Level 1 is factory testing, Level 2 checks delivery and installation, Level 3 starts each system and runs pre functional checks, Level 4 tests each system at full performance, and Level 5 tests everything together under failure scenarios. Many projects add a Level 0 design review, and the names and scope vary from owner to owner.

What is the difference between Level 2 and Level 3 commissioning?

Level 2 confirms equipment arrived undamaged and was installed according to the drawings, before it is powered. Level 3 starts each system for the first time and checks it on its own: installed right, labeled and matching the plan. Both are mostly visual, item by item checks, and both decide how smoothly Levels 4 and 5 go.

What is the difference between pre functional and functional testing?

Pre functional checks confirm a system is ready to test: installed correctly, labeled, connected and started. Functional testing then proves the system performs as designed, under load and in failure scenarios. A failed functional test often traces back to something a pre functional check should have caught, such as a loose joint or a valve in the wrong position.

What is checked during Level 2 commissioning?

Installed equipment is checked against the drawings: labels and panel schedules, busway joints, clearances, cords and whips, couplers, hoses, valves, insulation, firestopping, sprinkler heads, exits and every fiber port. Contractors usually complete post installation checklists, and the commissioning team reviews them before any system is started.

What does a commissioning agent do on a data center project?

The commissioning agent plans and runs commissioning for the owner. They write or review the checklists and test scripts, witness and sign off tests at each level, track issues to closure and confirm the facility performs as the owner required. On a data center they also lead the integrated systems test, including failure and blackout scenarios.

Why must the commissioning agent be independent of the contractor?

Because it is hard for anyone to test their own work objectively. Commissioning guidance such as the ACG guideline describes the agent as independent of designers, contractors and suppliers, so the party that installed the equipment is not the one certifying it. Owners hire an independent agent for exactly that reason.

What is load bank testing in a data center?

A load bank is equipment that draws power and gives off heat like the IT equipment that is not there yet. During commissioning, load banks put the design load on generators, UPS systems, power distribution and cooling, so each can be tested at full capacity before the servers arrive.

Why do thermal scans during load bank tests matter?

A loose, undertightened or corroded connection looks normal when cold and only shows itself as heat under load. Scanning breakers, busway joints and connections while the load bank runs finds those joints before the IT load arrives, when fixing them still means a planned outage rather than an emergency.

How is a liquid cooling loop tested before it is filled?

It is pressure tested as a whole system, with liquid or with gas at low pressure, using a method set by the design engineer and the commissioning agent. The pressure is watched over time for any drop, leaks are fixed and the test is repeated, and the loop is then flushed and filtered so it starts clean.

What fire and life safety items should be checked before handover?

Sprinkler heads clear of new trays and equipment, firestopping intact at every cable and pipe penetration, extinguishers present and in date, exits and egress paths clear, doors that close and latch, and cardboard and packaging out of racks and rooms. Check firestopping again after any late cable work through a penetration.

What is in a data center handover package?

The verified as built, an asset register captured from the floor, a scope record for every connection, punch list closure with dated photos, leak and thermal records from commissioning, the commissioning agent's signed test records and the manufacturer documents for every system. As built drawings and commissioning records are the items most often missing.

Can a robot inspect a data center during construction?

Yes. A FacilityOps robot walks the hall after each crew finishes and checks electrical, mechanical and liquid cooling, fire and life safety and fiber items on the same round, with a photo and a location for every item. It never runs or signs off tests and never opens energized gear; it gives the commissioning agent the evidence.

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A commissioning checklist earns its keep at Levels 2 and 3, trade by trade, while every defect is still a few minutes of a crew's time. Electrical, mechanical, liquid cooling, fire and life safety and fiber each have checks you can see, and each leaves a record worth keeping.

Load bank thermal scans, leak records from the first pressure test and punch list items closed with photos turn those checks into a handover package the owner can trust on day one. That package is also the first page of the facility's operating record.

Find it the day it was installed, and keep the photo that proves it.

• Graeme Burton, DCD: Working back to front, September 29, 2023 (sponsored, Kirby Group Engineering)
• Orr, Brown and Rafter, Uptime Institute Journal: Improve project success through mission critical commissioning, May 4, 2015
• AABC Commissioning Group: ACG Commissioning Guideline, 2005
• 7x24 Exchange: Load bank testing in data centers (industry magazine)
• Keentel Engineering: L1 to L5 data center commissioning, August 28, 2026 (vendor)
• Eaton: Busway installation instructions, IB01701001E, 2009 (vendor)
• OSHA: Construction electrical standard, general requirements
• Open Compute Project: Guidelines for connection of liquid cooled IT equipment, April 2022
• Open Compute Project: Pre commission preparation of technology cooling system row manifolds, March 2025
• Valiulis and Phillips, published by the International Firestop Council: Top 12 firestop deficiencies, 2006
• International Firestop Council: Special inspector qualifications, March 20, 2025
• FMI and CMAA: Twelfth Annual Survey of Owners, 2011
• Network World: Up to 50% of data center capacity slated for 2026 could be delayed, July 27, 2026
• Data Center Knowledge: AI data center boom strains global construction capacity, July 22, 2026
• Girishankar and Smith, CSIS: GenAI's human infrastructure challenge, September 16, 2025
• Field figures: FacilityOps interviews with data center technicians, contractors and commissioning engineers, October 2026; rack and hall idle costs are our calculation from published GPU rental rates

• Reducing Fiber Commissioning Rework With Robotics: Catch Defects Before Turn Up, Not After
• Why Fiber Cabling Errors Survive Data Center Commissioning, and How to Catch Them Before Power On
• Fiber Infrastructure Digital Twins: Keeping As Built Cabling Records True After Handover
• A and B Power Feeds: How to Prove Data Center Redundancy Is Physically Independent
• Liquid Cooling Leak Detection: What Sensors Miss and Inspection Catches
• Data Center Robotics: Who Checks the Robot's Work?