Factory acceptance testing (FAT) — witnessed functional and quality testing of equipment and controls at the works before despatch to site.
Commissioning, FAT & SAT — in depth
FAT catches problems where they are cheapest to fix. Before despatch, equipment and control systems are functionally tested at the works against an agreed protocol — mechanical, electrical and software — with the client witnessing hold points, so what arrives on site is already proven and documented.
What matters in practice
Build quality, alignment, rotation.
Wiring, continuity, energisation.
Simulated I/O and control logic.
Client sign-off of key tests.
| Element | Checks | Note |
|---|---|---|
| Mechanical | Build/align | Pre-despatch |
| Electrical | Wiring/energise | Safe |
| Software | Logic/I/O | Simulated |
| Sign-off | Witnessed | Documented |
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Read MoreReynolds & Bauhm designs and delivers commissioning, fat & sat solutions backed by process engineering and performance guarantees.
Fundamentals, design drivers and practical guidance
Factory acceptance testing (FAT) — witnessed functional and quality testing of equipment and controls at the works before despatch to site.
Reynolds & Bauhm runs structured FAT and SAT regimes, full loop-check documentation and witnessed performance tests, so plants are handed over proven against specification with a complete, auditable commissioning record — not signed off on optimism.
Commissioning is the disciplined transition from a constructed plant to a proven, operating one, and it is split into clear stages: Factory Acceptance Test (FAT), Site Acceptance Test (SAT), loop checking, and performance testing. Each stage de-risks the next — faults caught at FAT in the supplier's works are an order of magnitude cheaper to fix than the same fault found during live process commissioning on site.
A Factory Acceptance Test verifies the panel, PLC and software against the functional design specification before it leaves the factory: I/O is simulated, interlocks and trips are forced, alarms and sequences are demonstrated, and the client witnesses and signs off. Site Acceptance Test then repeats the critical checks in situ, confirming that field wiring, instruments and final elements behave as the tested logic expects once connected to real plant.
What our engineers assess on every scope of this type
| Parameter | Typical basis | Why it matters |
|---|---|---|
| Interlocks | Cause-and-effect tested | Safety functions proven before run |
| Performance test | Against guaranteed duty | Demonstrates the contract is met |
| Documentation | Signed records per stage | Auditable basis for handover |
| FAT | Witnessed at supplier works | Catches logic/panel faults early and cheap |
| SAT | Repeated on site | Proves field wiring and instruments |
| Loop check | Every signal, point by point | Confirms path, direction and scaling |
Common questions on installation and commissioning
That each instrument's signal reaches the control system at the correct value, and each output drives the correct final element in the correct direction with the correct scaling. It is the foundation that performance testing relies on.
Through a witnessed performance test running the process against its guaranteed duty — flow, removal efficiency and energy — over an agreed period. Meeting the targets over that run is the basis for acceptance and handover.
A complete commissioning pack: FAT and SAT records, loop-check sheets, interlock cause-and-effect results, the performance-test report and a closed punch list — an auditable trail that the plant was proven, not assumed.
Because a fault found in the supplier's works during Factory Acceptance Testing (FAT)-type checks is far cheaper and faster to correct than the same fault discovered during live commissioning on site. FAT proves the panel, logic and sequences against specification before anything ships.
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