Finding a problem after industrial equipment reaches the installation site can lead to expensive delays, travel, rework and disruption to commissioning. Factory Acceptance Testing gives the buyer and manufacturer an opportunity to verify agreed requirements while the product is still at the factory.
However, an effective FAT requires a defined scope, test procedure and acceptance criteria—not simply a final factory visit.
What Is a Factory Acceptance Test?
A Factory Acceptance Test, or FAT, is a planned set of inspections and tests performed at the manufacturer’s facility before shipment. Its purpose is to demonstrate conformity with specified requirements within the agreed test conditions.
IEC 62381:2024 defines requirements and checklists for FAT and related acceptance activities for automation systems in the process industry. It emphasizes agreement among the owner, buyer and vendor regarding scope, activities and responsibilities. Its checklists can be adapted to project-specific test procedures. IEC 62381:2024
Although IEC 62381 is specifically focused on automation systems, the same planning principle is useful for mechanical equipment and fabricated assemblies: all parties should know what will be checked, how it will be checked and what constitutes acceptance.
FAT Is Not the Same as Final Inspection
Final inspection may confirm dimensions, quantity, workmanship, marking and documentation. FAT can include these checks but may extend to assembly verification, operation or performance demonstrations where applicable.
The FAT scope depends on the product. For a fabricated mechanical assembly, it might include:
- Document and drawing review;
- Visual inspection;
- Principal dimensional checks;
- Assembly and interface verification;
- Rotation or movement checks;
- Confirmation of bought-out components;
- Coating and marking inspection;
- Review of manufacturing records;
- Packaging and preservation checks.
For equipment with electrical, instrumentation or control systems, the agreed scope may also cover:
- Component and wiring verification;
- Input and output simulation;
- Alarm and interlock checks;
- Control sequence demonstration;
- Emergency-stop functions;
- Software and parameter review.
A FAT should not be described as a performance test unless the factory setup can reproduce the required operating conditions and the contract defines the method.
Why FAT Matters to Buyers
A properly planned FAT can help identify:
- Incorrect components;
- Missing parts;
- Interface or assembly problems;
- Dimensional nonconformity;
- Incomplete documentation;
- Control logic errors;
- Incorrect labels or nameplates;
- Unresolved deviations;
- Packaging concerns.
Resolving these issues at the factory is usually more practical than correcting them after international shipment.
FAT also creates a shared record of what was inspected and accepted. This can reduce disputes where the buyer and manufacturer otherwise have different interpretations of the specification.
Preparing the FAT Procedure
The FAT procedure should be reviewed before the test date. It should identify:
- Product and project references;
- Applicable drawings and revisions;
- Test scope;
- Test sequence;
- Acceptance criteria;
- Measuring instruments;
- Buyer and manufacturer responsibilities;
- Safety requirements;
- Required records;
- Witness and hold points;
- Treatment of deviations;
- Retest requirements;
- Sign-off authority.
The test procedure should reflect the purchase specification rather than introduce new requirements at the FAT. If the buyer requests an additional test after production is complete, the parties may need to assess technical feasibility, cost and schedule effects.
Documentation Review
FAT often includes review of the manufacturing data book or agreed quality documents. Depending on the project, these may include:
- Approved drawings;
- Material certificates;
- Dimensional inspection reports;
- Welding and NDT records;
- Coating reports;
- Calibration status of test equipment;
- Certificates for purchased components;
- Operation and maintenance information;
- Spare-parts list;
- Packing and preservation procedure.
The exact documentation should be specified during the RFQ and contract review. Some documents require planning from the material procurement stage and cannot reliably be recreated at the end.
Recording Punch-List Items
Not every FAT issue has the same significance. Findings may be classified as:
- A major nonconformity preventing acceptance or shipment;
- A minor item requiring correction before shipment;
- A documentation item;
- An agreed deviation;
- An observation or recommendation.
Each open item should include a description, responsible party, required action, due date and method of closure. Photographic evidence or a follow-up inspection may be sufficient for some items, while others require formal retesting.
“Passed with comments” should not be used without a clear list of what remains open.
FAT, SAT and Performance Testing
FAT occurs before shipment at the manufacturer’s facility. Site Acceptance Testing, or SAT, takes place after installation at the project site.
SAT may verify correct installation, site connections, integration and operation under site conditions. Performance testing may require actual process loads, connected systems or site utilities that are unavailable during FAT.
Therefore, passing FAT does not automatically prove site performance unless the FAT was specifically designed and contractually accepted for that purpose. The contract should distinguish:
- FAT scope;
- SAT scope;
- Commissioning responsibilities;
- Performance guarantee test;
- Final acceptance milestone.
What Buyers Should Include in the RFQ
Buyers planning to witness FAT should specify:
- Applicable test standard or customer procedure;
- Items and functions to be tested;
- Acceptance criteria;
- Required factory test conditions;
- Number of attending representatives;
- Notice period;
- Documentation submission deadline;
- Third-party inspector involvement;
- Language and format of reports;
- Retest and nonconformity arrangements;
- Whether shipment requires written release.
These requirements affect production planning, factory resources and delivery time.
FAT for TOMECO SI Manufacturing Projects
TOMECO SI manufactures custom metal components, fabricated structures and mechanical assemblies based on customer drawings and project specifications. Inspection and pre-shipment verification can be planned according to the agreed product and contract scope.
Where a formal FAT, customer witness point or third-party inspection is required, the procedure, acceptance criteria and documentation should be agreed before production. This helps ensure that the necessary checks are practical, properly recorded and completed before the product leaves the factory.
