Introduction
If you want a vertical startup, the fastest way to miss it is by “saving time” during Factory Acceptance Testing (FAT).
Across food, beverage, personal care, and household goods, painful commissioning rarely comes from bad machines. It comes from risk deliberately deferred out of FAT and into the plant.
So which FAT shortcuts most reliably predict a rough start-up — and why?
In this article, you’ll learn which compromises are survivable, which almost guarantee pain, and where that risk will surface once the equipment hits your floor.
FAT is the lowest-cost environment to find defects in function, reliability, controls, and human interaction. A shallow FAT doesn’t eliminate problems – it relocates them to commissioning, under production pressure.
Some shortcuts are manageable. The ones below are not.
Why FAT Shortcuts Show Up So Loudly During Commissioning
Commissioning and start-up are inherently high-risk periods. They are the first time the machine is exposed to:
When latent issues arrive unresolved, the downstream pattern is predictable:
Industry guidance around FAT exists largely because misalignment on scope, criteria, and responsibility creates unbudgeted cost, schedule slip, and finger-pointing between OEMs and CPGs. Shortcuts amplify that misalignment.
If you’ve ever struggled to explain why a rushed FAT caused months of pain, this is the reason: Risk didn’t disappear—it just changed locations.
The FAT Shortcuts That Most Reliably Predict a Non-Vertical Startup
1. “Demo FAT” Instead of an Endurance + Performance FAT
Intermittent issues do not show up in a 30-90 minute demo:
A demo FAT proves the machine can run. An endurance FAT proves the machine can keep running.
If you’re being pushed to accept a demo FAT, the real question to ask is: “Where will reliability discovery happen instead—and how expensive will that be?”
2. No Clear, Measurable FAT Acceptance Criteria
If acceptance criteria aren’t defined, measurable, and agreed upfront, you can’t:
Ambiguity at FAT almost guarantees conflict at start-up—usually when time and patience are gone.
3. Running “Convenient” Materials Instead of Production-Intent Material
Most secondary packaging machines are material-handling disguised as automation.
Corrugate and carton variability—recycled content, warp, scoring quality, humidity exposure—drives:
If you don’t test the real operating envelope, you don’t know where the edges are.
You may not be able to replicate all site conditions at the OEM-that’s what the SAT is for. But using non-representative materials at FAT almost guarantees a machine-versus-material blame loop later.
4. Skipping Abnormal-Condition Testing and Recovery Behavior
Normal operation is not what kills vertical startup. Recovery behavior does.
If operators discover on site that recovery is unsafe, unclear, or requires engineering intervention, they will bypass, wedge, or run manual to keep production moving.
That behavior becomes permanent long before the machine is “fixed.”
5. No Changeover, Wear-Part, or Standard-Work Validation
Vertical startup isn’t “first SKU at rate.” It’s the operating system being stable:
If those aren’t proven, you’re vertical for one SKU—and fragile for months.
6. The Wrong People Attend FAT (or Aren’t Empowered)
The people who will live with the machine must:
Training gaps—not mechanical capability—are often the real bottleneck in ramp-up.
7. Shipping With Open Action Items to Hit a Date
Anything unresolved at ship almost always gets resolved:
Start-up becomes a construction project—and reliability suffers permanently.
8. Incomplete Controls and Safety Verification
Controls issues consume commissioning time disproportionately because they masquerade as mechanical problems.
Undisciplined logic changes and unverified safety behavior elevate both downtime and incident risk.
9. No Integration-Minded Testing
Vertical startup is a system outcome, not a machine outcome.
Many “machine problems” are actually interface problems that only surface when the line runs as a system.
10. Thin Virtual FAT or “Video Sign-Off”
Virtual FAT is not inherently bad. Thin evidence is.
Without structure and data, you can’t verify acceptance—or spot marginal behavior that will matter later.
A Practical Way
Use this table as a pre-FAT risk screen before agreeing to scope reductions.
FAT Shortcut
Risk Deferred to Site
Short endurance
→
Reliability / ‘infant mortality’*
Non-production materials
→
Material-handling instability
No failure scripts
→
Unsafe or slow recovery
No changeover testing
→
Human-system fragility
Incomplete controls checkout
→
Commissioning drag + safety risk
No integration testing
→
System-level instability
* Infant mortality is when a machine technically “works,” but starts failing repeatedly in its first weeks or months because it was never run long enough, hard enough, or realistically enough before shipment.
When you see a shortcut, ask: “What risk bucket am I buying—and where will it surface?”
Assumptions and Context to Keep in Mind
A few clarifications:
The Bottom Line
If FAT feels rushed, shallow, or overly polite, it’s not being efficient—it’s exporting risk.
The machines that commission cleanly are rarely perfect at FATs. They’re the ones where defects were surfaced early, argued through, and closed before steel hit the floor.
If you want vertical startup, FAT isn’t where you save time. It’s where you decide where the pain will live—at the OEM, or on your line.
