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Site Acceptance Test (SAT): What It Verifies, and How It Differs from a FAT
A site acceptance test, or SAT, proves equipment still performs to spec once it’s installed and running on your site, on real utilities and real load. It repeats the factory acceptance test, which happened earlier at the vendor’s works. The reason it’s worth doing twice: transit and installation break things a factory test can’t catch.
What does a SAT verify?
A SAT re-proves the kit where it will actually earn its keep. It usually covers:
- Installation – mounting, alignment and connections match the drawings.
- Site utilities – real power, air, water or feedstock, connected and correct.
- Function re-test – the operating modes re-run, in case transit shook something loose.
- Integration – it talks to the systems up and down the line.
- Load – output confirmed against the contract figure, on site.
- Punch closure – any FAT carry-over verified as actually fixed.
SAT or FAT – where’s the split?
Where and when. A factory acceptance test runs at the vendor’s works before shipment. A SAT runs on your site after installation, with real utilities and real load behind it. The FAT catches build faults early; the SAT catches what transit, installation and integration break before commissioning goes further.
Where does the SAT sit in commissioning?
It follows pre-commissioning and formally accepts the installed system, which opens the rest of the commissioning process. In most contracts a passed SAT is the trigger for handover and the money that comes with it.
SAT vs FAT at a glance
The same split, read from the site side.
| Aspect | Site Acceptance Test (SAT) | Factory Acceptance Test (FAT) |
|---|---|---|
| Where | Your installation site | Vendor / maker's works |
| When | After installation | Before shipment |
| Conditions | Real utilities and load | Simulated / test utilities |
| Approves it for | Commissioning | Shipping |
| You walk away with | Signed SAT protocol | Signed FAT protocol |
Free SAT sign-off pack
It brings the on-site checks, the FAT carry-over and the final acceptance into one signed record you can hand over. Download the checklist (PDF). You can also complete the checklist digitally in flowdit on your phone, tablet or PC.
Related Terms
- Functional Testing – confirms each function works on site.
- Operational Readiness – the state a passed SAT unlocks.
- Punch List – the open-items log to close.
- Equipment Commissioning – bringing installed kit into service.
- Project Handover – usually triggered by a passed SAT.
Further Reading
- Site Acceptance Test (SAT) in Commissioning – Simply Explained
- Commissioning-Software – commissioning end to end
