What is a Factory Acceptance Test for industrial equipment?

Why must a FAT be defined in the contract?

A Factory Acceptance Test is a defined obligation in the purchase contract: an inspection and test plan agreed between buyer and supplier, naming the tests to be performed, the standards they will follow, the measurement criteria, the equipment to be used, and the witnessing arrangement. The FAT exists in the form the contract defines.

That contractual basis is what gives the FAT its weight. In many contracts, FAT acceptance is tied to a payment, shipment, or documentation milestone; failure gives the buyer specific rights (corrective action, re-test, deferred shipment) without renegotiation. A FAT anchored in the contract becomes one of the procurement’s important control points.

What does a FAT actually check?

A complete FAT verifies the equipment against four classes of contract content:

• The technical specification: dimensions, materials, components, configuration, labelling, and visual condition match the agreed specification.
• Performance requirements: measured performance (capacity, efficiency, accuracy, response, whatever the equipment’s output metric is) meets the contracted values under the test conditions defined.
• Certifications and compliance: certificates, type-test reports, and compliance documentation are present, authentic, and apply to the equipment being shipped.
• Documentation package: manuals, drawings, spare-parts lists, calibration certificates, and any project-specific documentation are complete and match the as-built equipment.

What types of tests can be included in a FAT?

The specific tests depend on the equipment and the applicable standard. Some common categories:

• Routine tests: required by the relevant standard for every unit produced (insulation resistance for transformers, hydrostatic test for pressure vessels, polarity and continuity for wiring assemblies).
• Type tests: performed once per design to validate the design itself (short-circuit tests for switchgear, temperature-rise tests for transformers). Often already done by the manufacturer with reports referenced rather than repeated for each contract.
• Performance tests: measured against the contract’s performance values (efficiency curves, throughput, accuracy under load).
• Functional tests: operational sequences, control system behaviour, interlocks, alarms, and emergency stops, run end-to-end.
• Visual and dimensional inspection: final check of fit, finish, labelling, marking, and packing.

For HV equipment — transformers, switchgear, HV cables — see how partial discharge (PD) testing at FAT is specified, witnessed and accepted.

What a FAT actually catches when the works is in China

The definition is the easy part. What makes a FAT worth attending is the gap between what a supplier demonstrates and what the contract requires, and that gap is widest when the buyer is on another continent and the works is in China. A FAT catches the failures that survive a supplier’s own QC because they are matters of contract interpretation, not workmanship:

• A type-test or material report that applies to a different design revision, batch or model than the unit being shipped.
• Calibration certificates for the test instruments that do not trace to a recognised, accredited laboratory.
• Nameplate, tag and marking that do not match the contract specification or the approved drawings.
• A documentation set delivered only in Chinese, or missing the certificates a regulated application such as EU-GMP requires.
• A monitoring, alarm or safety feature quietly dropped, with a plausible-sounding reason for why it is not needed.

That last one is the most common, and the most expensive to concede.

For a regulated application the documentation package is part of the equipment’s qualification, not an afterthought. A unit that performs well on the factory floor can still fail acceptance on documentation alone, which is why a FAT verifies the certificates and records as rigorously as the function.

Who should attend a FAT, and what are their roles?

A typical attended FAT involves the supplier’s testing team running the tests, the supplier’s QC representative confirming results against the procedure, the buyer or buyer’s representative observing and signing off, and, for lender- or end-client-monitored projects, a third-party inspector with authority to accept or refuse on behalf of the absent party. Each role is named in the inspection and test plan, and each signature on the FAT report carries a specific meaning.

How does FAT differ from the supplier’s internal QC?

Internal QC is the supplier’s own quality control during and after manufacturing. It is independent of the buyer’s presence, follows the supplier’s procedures, and produces internal records. FAT is the buyer-facing acceptance event that draws on the QC results but adds witnessed verification, contract-anchored test scope, and signed buyer acceptance. The strength of a supplier’s internal QC largely determines how readily it passes FAT.

How does FAT differ from SAT and commissioning?

FAT happens at the manufacturer’s premises before shipment. SAT, the Site Acceptance Test, happens at the buyer’s installation site after delivery, verifying that the equipment performs under operating conditions and in its installed configuration. Commissioning is the broader handover phase that brings the equipment into operational service (including SAT, training, calibration of on-site references, and warranty start). FAT is the earliest of the three acceptance points; SAT and commissioning depend on the FAT having been done properly. For the full comparison, what each test covers, what each signature commits the buyer to, and why passing FAT is no guarantee of passing SAT, see FAT vs SAT: the difference between a factory acceptance test and a site acceptance test.

For the working document applied on the day, the readiness, identity, witnessing and release steps of the factory test itself, see the factory acceptance test checklist.

Frequently asked questions