FAT and SAT: the acceptance tests that protect your project
Two acceptance milestones decide whether an automation project goes smoothly: the Factory Acceptance Test (FAT) and the Site Acceptance Test (SAT). They exist to catch problems before they become expensive, and for automation systems the process is described in standards such as IEC 62381.
FAT — proving it at the builder
Before the machine ships, it is run and verified at the integrator’s workshop against an agreed checklist: functions, safety, cycle time and sample parts. Fixing an issue here — with the machine still on the builder’s floor and tools at hand — is far cheaper than fixing it after delivery.
SAT — proving it in your plant
After installation, the machine is tested again in real conditions: your power, your air, your materials, your operators. SAT confirms the equipment performs on site and is ready for the production hand-over.
Why both matter
- FAT reduces surprises at delivery and shortens installation.
- SAT confirms real-world performance and defines the moment of acceptance.
- A clear, written test plan protects both buyer and builder — and becomes the basis for the machine’s documentation.
Treat FAT and SAT as part of the contract, not an afterthought. Agree the pass/fail criteria early, and they turn “we hope it works” into “we verified it works”.