Before any transformer hums, turbine spins, or control system switches to “ON,” one decisive moment determines whether design has truly become reality — the acceptance test.
For infrastructure built under FIDIC, EPC, or lender-financed frameworks, Factory Acceptance Tests (FAT) and Site Acceptance Tests (SAT) are the formal checkpoints where engineering, quality, and finance intersect.
They are not mere technical rituals; they are contractual milestones that certify readiness, release payments, and validate warranties.
In essence, FAT and SAT are the final exams of the engineering process — and failure is not an option.
Factory Acceptance Test (FAT): Proving the product before it ships
The FAT is performed at the manufacturer’s facility, before equipment leaves the factory floor.
It’s the first line of defense against non-conformance, ensuring that costly or mission-critical components — such as switchgear, transformers, turbines, or control cabinets — meet design intent and contract requirements.
Key objectives of FAT
- Verify that design specifications, electrical ratings, and mechanical tolerances comply with the approved drawings and datasheets.
- Validate protection logic, automation sequences, and interlocks.
- Confirm calibration of instruments and metering devices.
- Review quality documentation: material certificates, test reports, and calibration records.
- Witness functional tests with the OE, client, and sometimes the lender’s technical adviser present.
A successful FAT produces a signed certificate of conformity, allowing the manufacturer to proceed with packing, shipping, and insurance formalities.
For lenders, it is often the trigger for partial equipment payment — effectively translating technical compliance into financial release.
Typical FAT package
| Document | Purpose |
|---|---|
| FAT Procedure & Test Checklist | Defines scope, parameters, and sequence of testing |
| Drawings & Design References | Verified against contract technical specs |
| Calibration Certificates | Confirms accuracy of test instruments |
| Test Data Sheets | Recorded results for all measurements |
| Non-Conformance & Corrective Actions | Logged and closed before dispatch |
| FAT Certificate | Formal approval for shipment |
Site Acceptance Test (SAT): Performance in the real world
Once equipment is installed and energized, Site Acceptance Tests (SAT) verify integration, performance, and safety under actual operating conditions.
SAT is the moment where multiple engineering disciplines — civil, mechanical, electrical, and automation — converge.
Core elements of SAT
- Visual inspection for transport and installation damage.
- Functional verification under live conditions (voltage, load, temperature).
- Interface testing with SCADA, PLC, or DCS systems.
- Grounding, insulation-resistance, and protection-relay checks.
- Verification of alarms, interlocks, and fail-safe operations.
- Validation of performance against the Employer’s Requirements and FIDIC Clause 9 (Tests on Completion).
When the OE and the contractor jointly sign the SAT certificate, the asset is deemed technically accepted — paving the way for Taking-Over Certificates, performance guarantees, and start of the Defects Notification Period.
FAT vs SAT — A comparison
| Feature | FAT | SAT |
|---|---|---|
| Location | Manufacturer’s facility | Project site |
| Objective | Verify manufacturing and functionality before shipment | Confirm installation and integration on site |
| Witnessed by | OE, contractor, client, sometimes lender | OE, client, grid operator, safety inspector |
| Risk managed | Manufacturing defects, design errors | Installation, interface, and commissioning faults |
| Output | FAT certificate, release for delivery | SAT certificate, approval for operation |
The Owner’s Engineer: Neutral witness, technical referee
Under FIDIC supervision, the Owner’s Engineer plays the central role in both FAT and SAT.
They review test procedures, approve setups, witness results, and issue formal acceptance reports.
Their signature signifies that the equipment meets both technical specifications and contractual quality standards — a declaration that carries legal, operational, and financial weight.
The OE also ensures traceability: linking each test to the QA/QC plan, the relevant Inspection & Test Plan (ITP), and the specific purchase order or submittal.
This traceability transforms testing into a verifiable audit trail — a prerequisite for lender confidence and for future maintenance planning.
FAT/SAT and ESG Assurance
While primarily technical, FAT and SAT have become instruments of ESG accountability as well.
Testing protocols increasingly include:
- Environmental compliance checks (noise, oil containment, emission levels).
- Worker safety and HSE practices during live testing.
- Governance transparency, with independent observers and documented procedures.
These steps assure investors and regulators that commissioning is conducted safely, ethically, and transparently — values now embedded in most modern project finance conditions.
Digital testing: From clipboards to cloud
Today, FAT and SAT are entering the digital era.
Using IoT sensors, mobile apps, and cloud dashboards, OEs and contractors can record live readings, photos, and signatures directly into centralized QA/QC systems.
This eliminates data loss, speeds up report approval, and provides real-time visibility for clients and financiers anywhere in the world.
Digital testing also integrates with BIM and asset-management software, meaning every test result becomes part of the digital twin — accessible throughout the asset’s lifecycle.
Proof before power
In engineering, nothing speaks louder than a test passed and a certificate signed.
Factory and Site Acceptance Tests are the final checkpoints of credibility — where blueprints, workmanship, and governance converge into measurable proof.
For owners and lenders, FAT and SAT are not just technical exercises; they are the ultimate reassurance that what was designed, funded, and promised is now built, compliant, and ready to perform.
In the world of energy and infrastructure, that signed test report is more than paperwork — it is the passport of trust that connects design ambition to operational reality.
Elevated by www.clarion.engineer