Most mitigating schedule risks in data center projects starts before construction. They start when testing should begin but the site still isn’t ready.
I’d sum the article up like this: a project can look 95% complete and still be far from ready for startup, system testing, and handoff. The main trouble spots are broken handoffs, bad test sequence, weak readiness checks, open defects that roll from FAT to SAT to IST, and PM hiring that leans too hard on build experience instead of startup and systems knowledge.
Here’s the short version:
A simple way I’d read the article is this: installed does not mean ready. If you want the schedule to hold, you need readiness gates, named owners, test scripts, deficiency logs, and PMs who can manage startup under pressure.
| Area | Where teams get stuck | What the article says to do |
|---|---|---|
| Handoffs | No clear owner | Assign owners and acceptance criteria early |
| Sequence | TAB, controls, and startup out of order | Lock test prerequisites into the CPM schedule |
| Testing | FAT/SAT/IST issues roll forward | Use signed readiness checks before each phase |
| Defects | Open items pile up | Track them by severity, owner, and close date |
| Turnover | Docs and training come late | Build packages during commissioning |
| Staffing | PMs are build-focused only | Hire for FAT, SAT, IST, and MEP/controls depth |
If I were reading this as a PM, my takeaway would be simple: the job is not close to done just because the equipment is in place. The schedule is won or lost in the gap between install and test-ready.
Data Center Commissioning: Where Project Managers Get Stuck & How to Fix It
Most commissioning delays begin before testing starts. The first cracks usually show up in team handoffs, then in sequence planning, and later in test readiness.
The most common weak spot is also the one people miss the most: no one owns the handoff.
Owners, GCs, and subcontractors often assume someone else is tracking readiness. So the work gets shared, but ownership doesn’t. Everyone has a hand in it, and no one is on the hook.
Commissioning tends to expose gaps that started earlier. Construction wraps up and moves on, then the commissioning team shows up to a site that looks finished but isn’t ready. As-builts are incomplete. O&M manuals are late. Operations still hasn’t set turnover acceptance criteria. That missing owner is what turns small readiness problems into schedule delays.
Sequence mistakes drive a large share of commissioning delays. Poor trade coordination shows up in more than 60% of commercial HVAC commissioning schedule failures.[1] And the pattern is usually the same: TAB starts before controls are stable, or OEM startup begins before point-to-point checks are done.
That leaves controls contractors holding the bag. Instead of running a clean startup, they end up troubleshooting in real time - chasing untuned control loops, unverified sequences of operation, and sensors that still haven’t been calibrated. None of that time was built into the plan, and it cuts straight into the commissioning schedule.
Controls loops need to be tuned, verified, and stable before TAB starts. Teams should require 48 hours of uninterrupted automatic operation with no manual overrides or active alarms before functional testing.[3]
Once the sequence slips, formal testing starts late, and open defects come along for the ride.
Testing breaks down when teams treat readiness like a calendar date instead of a field condition.
FAT findings that aren’t formally closed before equipment ships move straight into SAT. SAT deficiencies that aren’t categorized and closed hold up IST. And IST - which already needs a fixed 6- to 12-week window[5] - gets blocked by incomplete BAS and fire-life-safety interfaces, unmapped alarm points, or missing load bank access.
FAT, SAT, IST, and turnover tend to fail in the same way: unresolved issues roll from one phase into the next. Status reports do not prove field readiness.[2] The answer is simple, but it takes discipline:
That’s why project managers need controls that track readiness before testing starts.
Once FAT, SAT, and IST start slipping, the schedule doesn’t bounce back on its own. It only recovers when the team puts tight control around readiness gates. That means moving past broad status updates and using measurable checks that show whether a system is ready to test, not just whether it looks finished on paper.
If commissioning sits in the schedule as one big line item, the team loses sight of what’s actually driving the work. A better move is to split it into separate, logic-linked activities in the master CPM schedule: equipment startup, controls program review, loop tuning, TAB, and functional performance testing. Each one needs its own predecessor and successor, with those logic ties built straight into the CPM schedule.
A commissioning RACI or witness and sign-off matrix helps close the ownership gap. It spells out the commissioning owner, vendor attendance duties, and who from the PMO, commissioning agency, OEM vendors, and operations must witness and sign off on each test.
The readiness review also needs to happen early enough to matter. Run it 3 to 4 weeks before startup mobilization, not the day before. At that point, the team should verify:
Once that schedule logic is in place, the next control point is a live deficiency log.
A deficiency log doesn’t help much if it’s loose or inconsistent. Each entry should include a unique ID, system category, severity level, assigned owner, root cause, corrective action, target close date, and retest requirement.
Severity levels are what give the log real bite:
| Deficiency Severity | Meaning | Turnover Impact |
|---|---|---|
| Critical | Unsafe condition or failure of a critical function | Blocks turnover |
| High | Affects redundancy, reliability, or maintainability | Usually blocks turnover unless risk-accepted |
| Medium | Operational inconvenience; non-critical function | May allow conditional turnover |
| Low | Documentation, labeling, or cosmetic issues | Closed post-turnover if tracked |
Test scripts need that same level of control. Each script should spell out pass/fail criteria, required measurements, vendor attendance duties, and key scenarios like utility loss, UPS ride-through, and chiller failure. It also helps to standardize disposition tags for every test result: Passed with no exception, Passed with documented exception, Failed and retested, or Deferred to IST. [4]
When tests are under control, turnover work can’t wait until the finish line.
Turnover packages for electrical, mechanical, controls, fire alarm, and security systems should be built during commissioning, not during the last week. Each package should include as-builts, O&M manuals, training records, warranties, and SOP/EOP/MOP documents.
Ownership should be assigned before testing begins. The PMO manages the schedule and repository. The commissioning agent prepares and witnesses scripts. Operations witnesses maintainability. OEM vendors support SAT and IST.
Operations training needs to sit inside that turnover package before go-live. The team has to close the gap between construction complete and operations-ready before substantial completion, not after.
Matrices, deficiency logs, and turnover packages only help if the team is hired to commission, not just to build. At this point, schedule risk turns into a staffing issue.
A PM can be great at trade stacking, concrete, and steel. That’s a real skill. But it doesn’t automatically mean they can manage an integrated test sequence where power, cooling, and controls all have to work together under live conditions.
Standard construction PMs track progress by what’s installed. Commissioning-ready PMs track progress by what can be tested and validated. That one shift changes a lot. It affects how they read the schedule, how they run vendor meetings, and what they do when a controls sequence breaks during startup.
You can see that gap in the results. Poor coordination between trades is cited in over 60% of commercial HVAC commissioning schedule failures [1]. That usually means the team was staffed for construction admin, not systems startup.
So the hiring screen has to look for key skills for data center construction managers like commissioning judgment, not just delivery on a construction schedule.
A commissioning-ready PM or Cx manager should be able to explain their direct role in FAT, SAT, and IST sequences. Not just say they attended. They should also have handled FAT, SAT, IST, deficiency closure, and operations handoffs.
Electrical and mechanical literacy is non-negotiable. The candidate needs to read design documents, understand BMS/EPMS integration points, and spot a bad controls sequence before it turns into a failed test. Without that level of depth, a weekly status report can look fine while commissioning is quietly sliding.
| Screening Area | What to Look For |
|---|---|
| Testing experience | Direct role in FAT, SAT, and IST - not just project-level exposure |
| MEP literacy | Ability to understand design documents and electrical/mechanical interfaces |
| Deficiency management | Experience running severity-tiered deficiency logs through closure |
| Vendor coordination | Track record managing OEM vendors and controls contractors under schedule pressure |
| Turnover documentation | Ownership of O&M packages, MOPs, and training records before substantial completion |
A few red flags tend to show up fast:
When those skills aren’t there, the schedule usually breaks at startup, not during install.
Finding people like this is tougher than it sounds. In 2024, 51% of data center operators struggled to find qualified candidates for operations and commissioning roles, only about 15% of applicants for commissioning positions meet minimum technical qualifications, and specialized Cx roles often take more than 2 months to fill [8].
That’s where iRecruit.co fits in. The firm focuses on mission-critical construction recruiting for project management, MEP systems, commissioning, and field roles. Its process centers on pre-qualified candidates who can show real commissioning experience, not just a PM title on a résumé. iRecruit.co also supports recruitment, RPO, and consulting for mission-critical project management, MEP, commissioning, and field roles.
Construction progress is easy to see. Commissioning readiness isn't. And that blind spot is exactly where data center schedules start to slide.
The pattern is familiar: broken handoffs, out-of-sequence startup, failed tests, and incomplete turnover packages. Those issues don't appear by accident. They show up when commissioning is treated like a closeout task instead of a separate delivery phase with its own plan, tools, and staffing. On a 50 MW hyperscale campus, a three-month delay in reaching operational readiness can cost $30 million to $150 million in lost revenue, stranded capital, and penalties.[6] That's not just a paperwork issue. It's a planning and execution issue. And those delays stay under control only when readiness is managed before testing starts.
That means putting readiness reviews, deficiency logs, and turnover packages in place before functional testing begins. Hard readiness gates matter for a reason. Requiring 48 hours of continuous automatic operation before testing begins helps stop teams from finding integration failures during the most time-pressed part of the job.[3] But those controls only work when the team is set up for commissioning, not only construction.
A PM who is strong in construction sequencing may still not have the judgment that commissioning calls for. That's where many projects get into trouble. Staffing often gets ignored until the schedule is already under strain. The right team is what turns commissioning control into on-time turnover.
Projects that finish on time don't treat commissioning like a final ceremony at the end of construction. They treat it as a phase that starts during design, runs alongside construction, and ends only when operational readiness is verified and documented.
Commissioning delays projects because it exposes small, hidden execution gaps after schedule slack is already gone. It doesn’t create the problems. It reveals them.
Most delays come from a few familiar trouble spots: unclear ownership for readiness, messy handoffs, sites that aren’t ready, and controls, integration, or documentation issues that show up too late during testing. And here’s the hard part: integrated systems testing can’t just be squeezed into a smaller window. When those issues surface late, teams often end up doing rework, and final delivery slips.
A system is ready for Integrated Systems Testing only when that readiness is proven and documented - not just because the equipment is sitting in place.
That means the pre-functional checklists are complete, point-to-point controls integration has been verified, asset startup has finished, and permanent power is stable.
It also means the sensors have been calibrated, the control loops have been tuned, and the system has run for 48 hours of continuous automatic operation with no overrides, no bypasses, and no alarms.
On top of that, TAB reports must be submitted, labeling must be finalized, and test records must be signed.
A commissioning-ready project manager needs technical depth and strong coordination skills.
They should understand:
But technical know-how alone isn’t enough.
They also need to lead with readiness-focused governance. That means spotting risks early, coordinating across teams, managing complex workflows, and using tools like readiness checklists, deficiency logs, and commissioning matrices to turn “construction complete” into verified, testable system performance.
