For buyers of industrial ozone generators, the contract does not end when the equipment ships — it ends when the system is commissioned, tested, and formally accepted at your site. Yet commissioning is the phase where most disputes, performance shortfalls, and warranty arguments originate. A structured FAT (Factory Acceptance Test) and SAT (Site Acceptance Test) process protects both parties: you get documented proof that the system meets specification, and the manufacturer gets a clear acceptance boundary that closes the project cleanly. This guide explains what to test, when, and how — so your next ozone system starts up on time and performs as quoted.

Why FAT and SAT Matter for Ozone Systems

An ozone system is not a single machine; it is a chain of subsystems — feed gas preparation, discharge cells, power supply, cooling, dissolution, off-gas destruction, and controls. A defect in any link (for example, a undersized chiller or a poorly sealed oxygen line) may only appear after weeks of operation, when ozone output drifts below specification. FAT and SAT testing push those defects to the surface before they become your problem:

• FAT (at the factory): verifies performance under controlled conditions before shipment, when corrections are cheap and fast.
• SAT (at your site): verifies that transport, installation, utilities, and integration have not degraded performance, and confirms guaranteed values under real process conditions.
• Acceptance documentation: the signed test records become the baseline for warranty claims, spare-part planning, and future capacity audits.

Practical rule: If a performance parameter is not measured and signed for during FAT and SAT, it does not exist as a guarantee. Oral assurances about "typical output" or "stable concentration" carry no weight in a dispute. Put every guaranteed number into the test protocol.

Phase 1: The Factory Acceptance Test (FAT)

The FAT is best conducted at the manufacturer's facility with your inspector present (in person or via live video). The manufacturer should provide the test bench, calibrated instruments, and a written procedure in advance. Key items:

1. Performance Testing at Rated Conditions

Run the unit at 100% and (if guaranteed) at partial loads such as 50% and 25%. Record ozone output, concentration, feed gas flow, power consumption, and cooling water data simultaneously. All results must be normalized to the reference conditions stated in your contract — temperature, pressure, and feed gas composition. A unit that produces 100 g/h at 15 °C cooling water may deliver noticeably less at 30 °C; if your site's summer water temperature is 30 °C, that is the condition that must be tested or derated in the contract.

2. Run-In and Stability

Request a continuous run of at least 4–8 hours at rated load before the formal measurement window. New discharge cells and power electronics can drift slightly during the first hours of operation; measuring too early can hide a defect or create a false failure. During the run-in, watch for cooling water temperature stability, abnormal noise from the power supply, and any ozone smell around enclosures.

3. Documentation Review

Before signing the FAT report, verify the document package: general arrangement drawings, electrical schematics, P&IDs, I/O list, instrument calibration certificates, material certificates for wetted parts, and the complete spare parts list with part numbers. This is also the right time to witness packing — ozone generators and oxygen equipment must be shipped with inert-gas-purged, moisture-protected internals and shock indicators on the crate.

Phase 2: Installation Checks Before SAT

Many SAT failures are actually installation failures. Before the manufacturer's engineer leaves the site (or before the SAT is scheduled if you self-install), close out these checkpoints:

• Utilities match the drawings: power supply voltage and phasing, cooling water flow/pressure/quality, and compressed air or oxygen supply purity all match the interface list.
• Piping is clean: oxygen piping must be degreased and blow-down clean; contamination in oxygen service is a genuine fire risk, not a formality.
• Instrumentation is calibrated: ambient ozone monitors in the generator room and at occupied areas are installed at breathing height and tested with a calibration gas.
• Emergency provisions work: the room ventilation system, ozone alarm linkage (ventilation start on alarm), and the emergency stop chain are function-tested.

Phase 3: The Site Acceptance Test (SAT)

The SAT confirms guaranteed performance integrated with your process. Duration is typically 3–7 days of continuous operation for water treatment systems, because dissolution performance and downstream water quality need time to stabilize. Core elements:

1. Repeat the Performance Guarantee Under Site Conditions

Measure output and concentration with an independent (third-party or owner-supplied) analyzer where possible — not only the unit's built-in display. Built-in readings are convenient for daily operation, but the acceptance measurement should use a calibrated external UV analyzer, and the two readings should be compared and the deviation recorded. If the contract states a dissolved-ozone or treated-water target, sample at the contract-defined points after the contact system has reached steady state.

2. Control and Integration Testing

• Verify automatic output control against process signals (flow pacing, residual control, or ORP setpoint, as specified).
• Test communication to your SCADA/DCS: all agreed points, alarm priorities, and failure modes.
• Simulate failures — cooling water loss, feed gas failure, power dip — and confirm the system shuts down safely and restarts per the specified sequence.

3. Training and Handover

The SAT is also the last structured opportunity for knowledge transfer. Require the manufacturer to train your operators on daily checks, alarm handling, dielectric inspection intervals, and long-term shutdown procedures — and record attendance. A signed training record belongs in the acceptance package together with the SAT report, as-built drawings, O&M manual, and updated spare parts recommendations.

Common Acceptance Disputes and How to Avoid Them

In export projects, most disputes trace back to a handful of avoidable causes:

• Unstated reference conditions. Output guaranteed "at standard conditions" that nobody defined. Always write the reference temperature, pressure, and feed gas (air / 93% O₂ / 99.5% O₂) into the contract.
• Instrument disagreement. Buyer's analyzer and vendor's analyzer differ by 8%. Agree in advance which instrument class is authoritative and how deviations are handled.
• Site utility shortfalls. Cooling water at 35 °C instead of the assumed 28 °C derates the unit — and the vendor is blamed. Confirm utility data during design, not during SAT.
• Mixed responsibilities. The dissolution system is supplied by a third party, but ozone output "into water" is guaranteed. Split the guarantee clearly: generator output is the vendor's; dissolution efficiency is a system-level figure requiring the whole train to be defined.

Checklist discipline: Professional buyers treat the FAT/SAT protocol as a contract annex, drafted and agreed before the purchase order is signed. If your supplier cannot produce a FAT procedure when you ask for it during tendering, treat that as a supplier-selection signal, not a paperwork detail.

A Practical Timeline

For a typical 10–100 g/h oxygen-fed system, a realistic schedule looks like this: FAT procedure agreed at contract stage; FAT performed 2–3 weeks before shipment; installation supervision at delivery; SAT with 3–7 days of continuous operation after mechanical completion; and final acceptance with retention payment released upon signing. Building this sequence into the payment milestones is the simplest way to keep everyone aligned — the manufacturer is motivated to test well, and you are never asked to accept an untested system.

A disciplined acceptance process costs a few days of effort and protects years of operation. Tonglin Ozone supports international buyers with complete FAT/SAT protocols, third-party instrument cooperation, remote or on-site commissioning supervision, and operator training in English. If you are planning an ozone water treatment project and want an acceptance process that leaves no gray areas, talk to our engineering team.