FAT

What is a FAT?

The Factory Acceptance Test (FAT) refers to a structured acceptance test carried out at the manufacturer's or system integrator's site — before the system is transported to the future operator. The goal is to demonstrate, under controlled conditions, that the delivered solution meets the contractually agreed requirements. In intralogistics, the FAT is particularly relevant when procuring conveyor systems, automated storage systems, sorters, or WMS implementations.

At its core, the FAT documents the transition point from manufacturer responsibility to joint acceptance: the client and the manufacturer work through a predefined test plan together to verify that functions, interfaces, and performance parameters have been implemented as agreed. Deviations are recorded, classified, and documented in a defect report.

How does a FAT work in practice?

A FAT is typically structured in several phases. First, a test plan is created that defines all scenarios to be tested, acceptance criteria, and test responsibilities. Ideally, this plan should be anchored in the contract to avoid disputes at a later stage.

During execution, test cases are worked through step by step. Common test items in intralogistics include:

• Functional testing of individual components (e.g. conveyor technology, warehouse management software, scanners)
• Simulation of operational scenarios and exception situations (e.g. fault conditions, emergency shutdown)
• Testing of interfaces to ERP or WMS systems
• Verification of throughput and performance parameters
• Documentation review (manuals, circuit diagrams, safety certifications)

Identified deviations are classified — commonly by severity (e.g. critical, major, minor). The FAT is only considered passed once agreed minimum requirements have been met. Open items are recorded in a punch list and must be resolved before or at the latest during the SAT (Site Acceptance Test) at the operator's site.

What matters when planning a FAT?

A common mistake is defining the test plan only shortly before the FAT date. The earlier acceptance criteria are fixed in writing, the less room for interpretation remains during the acceptance process. In addition, all relevant stakeholders — logistics planning, IT, procurement, and any external consultants — should be involved in the FAT, as decisions on deviations often need to be made on the spot.

Whether a FAT is mandatory depends on the contract. For complex or safety-critical systems, however, it is standard industry practice and significantly reduces the risk of costly rework after commissioning. The scope and degree of formalization vary greatly depending on the vendor — which is why precise contractual specification is recommended.