When a new tablet press, blender, coating machine or packing line is bought, two tests decide how smooth the rest of the project will be: the factory acceptance test (FAT) and the site acceptance test (SAT). They sound similar and are often written in the same project plan, so people mix them up. They answer different questions, and skipping or rushing either one is a common reason why new equipment starts production late.
What is a FAT?
A factory acceptance test is carried out at the supplier’s premises, before the equipment is packed and shipped. Its purpose is to confirm that what has been built matches the user requirement specification (URS) and the agreed design, and that it works properly while it is still inexpensive to correct.
The test is run by the supplier’s engineers, with representatives of the buyer present as witnesses. It is done against a written, pre-approved protocol, and every test result is recorded, signed and kept with the project file.
What is a SAT?
A site acceptance test is carried out at your own plant after the equipment has been delivered and installed. It confirms that the machine survived transport, is installed correctly, and works with the real utilities, building systems and other equipment around it. A machine that passed its FAT on the supplier’s test floor can still behave differently on your floor, because the power quality, the compressed air, the room conditions and the connected systems are different.
FAT and SAT side by side
| FAT | SAT | |
|---|---|---|
| Where it happens | At the supplier's factory | At your own site, in the installed location |
| When | Before the equipment is shipped | After delivery and installation, before qualification |
| Main question | Was the equipment built and does it work as specified? | Did it arrive intact and does it work with our utilities and surroundings? |
| Utilities used | The supplier's, often simulated | Your real power, air, water, steam and HVAC |
| Cost of fixing a problem | Lower, because the machine is still with the supplier | Higher, because the machine is installed and the project clock is running |
| Who attends | Supplier engineers plus your engineering, production and QA representatives | Your engineering, production and QA team, with supplier support |
What to check during a FAT
A good FAT protocol follows the URS, point by point. These are the areas most teams cover:
- Documents. Drawings, P&IDs, material and surface finish certificates for product-contact parts, calibration certificates for the instruments, manuals, the software and PLC version list, and the supplier’s own test records.
- Visual and dimensional inspection. Build quality, welds, surface finish, labelling, guarding, access for cleaning, and agreement with the approved drawings.
- Functional tests. Every operating mode, start and stop, speed and rate ranges, and the rated capacity. Compare the rated working volume or output with what you planned. For a blender or granulator, the Mixer Capacity Calculator helps confirm that the planned batch size fits.
- Controls and software. Screen navigation, recipe handling, user levels and passwords, audit trail, data backup, alarms and what happens on a power loss or a restart.
- Safety and interlocks. Emergency stops, door and guard interlocks, over-pressure and over-temperature protection, and the machine’s response to each fault.
- Performance with a representative load. If possible, use placebo or a suitable test material, not an empty machine, and include the challenging conditions the URS describes.
Every test should have an expected result written before the test, not after it. Anything that does not meet it goes onto a deviation list (often called a punch list), with an owner and a due date.
What to check during a SAT
- Condition on arrival. Check the packing, look for transport damage, and compare what arrived against the delivery list and the FAT release record.
- Installation. Position, levelling, anchoring, clearances, connections for each utility, piping and cable routing, and agreement with the as-built drawings.
- Utilities. Voltage and phase, earthing, compressed air quality and pressure, water and steam supply, drainage, and the extraction or HVAC connection.
- Functional re-checks. Repeat the key FAT functions, especially the safety functions, interlocks and alarms, on the installed machine.
- Integration. Communication with other equipment, the building management system, the line controller or the data system, and any signals that tie the machine to an airlock or room status.
- Open items. Confirm that each FAT punch-list item has been closed, with evidence.
How FAT and SAT connect to IQ, OQ and PQ
FAT and SAT are commissioning activities. Qualification (IQ, OQ and PQ) is the formal GMP demonstration that the equipment is installed correctly, operates as intended across its range, and performs consistently with the real product. In a risk-based approach, well-documented FAT and SAT results can be used as evidence in qualification, so that tests are not repeated for no reason. This only works if the FAT and SAT were done to approved protocols, by trained people, with good documentation, and if the quality unit has agreed in advance which results will be leveraged.
FAT and SAT do not replace qualification. They make it faster and lower risk, because the obvious problems have already been found.
Where acceptance testing goes wrong
- Starting the FAT without an approved protocol, and writing the results from memory afterwards.
- Letting the supplier test alone, with no witness from the buyer.
- Testing only the easy conditions and leaving out the worst case from the URS.
- Shipping the machine with open punch-list items and no plan to close them.
- Treating a passed FAT as a reason to skip or shorten the SAT.
- Failing to record the software and firmware versions, so that later changes cannot be traced.
- Missing documents at handover, such as calibration certificates and material certificates, which are slow to chase after the supplier’s project team has moved on.
A short practical checklist
- Write the URS first, and build the FAT protocol from it.
- Agree the FAT and SAT scope, the acceptance criteria and who signs, before the order is placed.
- Send QA the protocols for approval, and get the documents ahead of the test date.
- Bring a witness team with production, engineering and QA experience to the FAT.
- Close or formally accept every punch-list item before shipping.
- Run the SAT on installed equipment with real utilities, and keep the results ready for the IQ.
Questions on acceptance testing
Is a FAT required by regulators?
Regulations do not use the term, but they expect that equipment is shown to be suitable for its purpose before use. A FAT is a widely used, practical way to find problems early, so most companies include it for major equipment.
Can a FAT replace IQ and OQ?
No. It can support them, and some results can be reused if the protocol and records meet the quality unit’s requirements, but qualification still has to happen on the installed equipment at your site.
What happens if the equipment fails the FAT?
The failure is recorded, the supplier corrects it, and the affected tests are repeated. The equipment should not ship until the open items are closed or formally accepted by the buyer.
What is the difference between SAT and IQ?
The SAT is a commissioning test that checks the installed machine works with your site. The IQ is the formal qualification record that documents that it was installed according to the approved design and specifications.