Don't Skip the Factory Acceptance Test (FAT)
- May 31, 2021
- 4 min read
A Factory Acceptance Test (FAT) confirms that your CEMS or DAS equipment and software work correctly before it ever leaves the shop. FATs aren't required by regulation, but skipping one is one of the easiest ways to turn a straightforward installation into a costly field repair.
What Is a Factory Acceptance Test (FAT)?
A FAT is a structured test of a system's hardware and software, run in a controlled environment before the equipment ships to your site. The goal is simple: catch problems on the shop floor, where they're cheap and fast to fix, instead of in the field, where they're neither.
No regulation mandates a FAT. But for CEMS and DAS projects, that testing window is often the last chance to verify configuration, logic, and calculations before installation crews start pulling cable and analyzers go into racks. Skip it, and issues that would have taken an hour to correct in the shop can turn into days of field troubleshooting, change orders, and schedule slips.
Why a FAT Is Worth the Time
The cost math is straightforward. A configuration error found during a FAT gets fixed by an integrator sitting at a bench with the full system in front of them. The same error found after installation means a technician on-site, a system that may need to come back down, and a customer waiting on a system that isn't fully operational yet.
A FAT also gives you a real look at the system before you're depending on it for compliance reporting. You see the dashboards, run through alarms, and confirm the reports before go-live, not after.
Types of CEMS and DAS Factory Acceptance Tests
The scope of a FAT depends on what's being delivered. Two types come up most often on CEMS and DAS projects: a DAS FAT and a Hardware/Full FAT.
DAS FAT (Software and Data Acquisition System)
A DAS FAT covers the DAS software (the server) and DAS hardware (the data controller or PLC) — nothing else. It's the right scope when the DAS is being installed against existing or third-party analyzers and sample systems. Typical items covered:
• I/O details (analog ranges, digital trigger states, base digital logic)
• Calculations (unit conversions, base calculations)
• Complex digital logic
• Validation methodology
• Calibration logic
• Alarm methodology
• Compliance calculations
• Reports
• Dashboards
Hardware / Full FAT
A Hardware or Full FAT covers the complete package: analyzers, DCS connection points, sample systems, CEMS rack equipment, and the DAS and data controller/PLC that tie it all together. This is the right scope for projects where ATG is supplying the full CEMS system alongside the DAS. Typical items covered:
• Analyzer readings checked against known reference values
• Analyzer faults triggering the correct alarms at the analyzer
• Analyzer-to-PLC/data-controller readings matching (no scaling or unit-of-measure mismatches), with alarms matching as well
• Sample system valving following the correct logic, sample pump de-energizing on specified faults, and calibrations passing
What to Expect During a FAT
FATs typically run at the integrator's facility, with the customer's project team, engineers, and often the site operators who'll run the system day to day invited to attend. Plan for a few things going in:
A written test plan. You should see the FAT checklist ahead of time, not during the test. It gives you a chance to flag anything specific to your site or permit conditions before the clock starts.
Time for questions, not just checkmarks. A good FAT is also a working session. Use it to ask about alarm thresholds, report formats, or anything about the system you're not sure you understand yet.
Documented results. Every item tested should be logged, along with any deficiencies found and how they were resolved. That record becomes part of your project file and your reference point if a question comes up after startup.
A punch list, if needed. It's normal for a FAT to surface a few items that need correction. What matters is that they're tracked to closure before the system ships, not carried into the field.
How Alliance Approaches Every FAT
Alliance Technical Group treats the FAT as a checkpoint, not a formality, on every CEMS and DAS project.
We show up prepared. Before the client arrives, our integrators run their own internal FAT to verify the system and correct anything they find, so the time you spend with us is spent on your questions, not on catching our mistakes.
We test for satisfaction, not just specs. Meeting the functional spec is the baseline. We also use the FAT to walk you through the system so you leave confident in how it operates, not just confident that it passed.
We document everything. Our FAT checklist covers every component of the system, and we track results against it so there's a clear record of what was tested and confirmed.
A FAT is one of the best opportunities you'll get to review the system with your engineer before it's running your compliance data. Don't skip it.
Alliance Technical Group provides CEMS shelters, data acquisition systems, and the full range of stack testing, LDAR, and ambient air services that keep facilities compliant.
FAQ
Is a Factory Acceptance Test required for a CEMS or DAS project?
No. A FAT isn't required by regulation. It's a best practice that catches configuration and equipment issues before installation, when they're far less expensive to fix.
What's the difference between a DAS FAT and a Full FAT?
A DAS FAT tests only the DAS software and data controller/PLC. A Full FAT (also called a Hardware FAT) tests the entire CEMS package, including analyzers, sample systems, and DCS connection points, in addition to the DAS.
Who should attend a factory acceptance test?
Your project engineer, and ideally the operators who'll run the system day to day. Attending the FAT gives your team a working knowledge of the system before it's installed, not after.
What happens if an issue is found during a FAT?
It gets added to a punch list and corrected before the system ships. That's the whole point of testing at the shop instead of the field: problems get fixed while they're still cheap and easy to fix.