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Site Acceptance Test (SAT)

A SAT proves the machine performs on the buyer's site, on the buyer's utilities and product, integrated into the line. This page covers what to test after installation, how to write the protocol, and the site-specific failures a factory test cannot catch.

By Global Machinery Hub · Published November 2, 2026 · Updated November 2, 2026 · 6 min read
Site Acceptance Test (SAT)

The core idea of this page: the site acceptance test answers a different question from the factory test. The FAT asked "does this machine meet its specification?"; the SAT asks "does this machine, on this site, with these utilities and this product, in this line, produce good packs at the required rate?" Those are not the same question, which is why a machine that passed a factory test can fail on site.

What the SAT adds that the FAT cannot

Real utilities

Compressed-air quality and pressure stability, power quality, steam and chilled-water capacity, water hardness, and extraction. A sealing machine that held temperature in a supplier's stable plant can struggle on a site with a weak air supply or a voltage dip at shift start.

Real product and material

Product from actual production, with the real variation in viscosity, particle size, fill temperature and film lot. Film lot variation alone explains a large share of on-site seal problems.

Real integration

Handshakes with the upstream filler and downstream case packer, conveyor height and gap, accumulation logic, line control and MES/SCADA interfaces. Integration faults are the most common reason a SAT slips.

Test the unhappy paths as well as the happy ones: blocked downstream, starved upstream, an operator pressing stop mid-cycle, a power dip and recovery, and a product change while the line is running. These are the states where handshakes fail, and they are exactly the states a factory test cannot reproduce because the factory line around the machine is not the buyer's line.

Real environment

Ambient temperature, humidity, dust, washdown and vibration. These affect adhesive behaviour, sensor reliability and fill accuracy.

Writing the SAT protocol

The protocol should be written before installation, not after. It needs: scope per machine and per format; the utilities to be verified with their acceptable ranges; the product and material lots to be used; the performance run length; pack-quality tests with sample sizes and pass limits; the integration tests; and the documentation to be handed over.

Where the FAT already proved a criterion, the SAT can reduce sample size but should not skip it — the point is to prove the result transfers.

Sequence of a well-run SAT

Installation verification

Level, alignment, guarding, anchorage, and that the as-built machine matches the drawings and the FAT configuration. Photograph the installation before commissioning.

Utility verification

Measure, do not assume: air pressure and dew point at the machine inlet, supply voltage and phase balance, seal-jaw heat-up time and stability, water flow and temperature. Record the values.

Dry commissioning

Run the sequence with no product, then with dummy product, checking every sensor, interlock and stop category. Confirm safety functions before anyone runs production.

Performance run

Run at rated speed for the agreed duration on the buyer's product, with the stop and reject log attached. Count small stops, not just stoppages over a threshold.

Pack quality and handover

Run the agreed pack tests, retain samples, then hand over documentation, spares, training records and the signed protocol with the punch list.

Training and competency

Acceptance is not complete while only the supplier's engineer can run the machine. The SAT should include operator training on the actual formats, a demonstrated changeover by the buyer's crew, a cleaning cycle performed by the buyer, and a basic fault-finding walkthrough of the alarm list. Record who was trained and on which date; auditors ask for it later.

Documentation package

Handover documentation should include as-built drawings, electrical schematics, pneumatic diagrams, spare-parts list with recommended spares, PLC and HMI backups, calibration certificates, material certificates, the validated parameter set per format, and the signed protocol with its punch list. A machine without a parameter backup loses its validated settings the first time someone replaces a controller.

Closing the punch list

Any item that cannot be fixed during the visit is recorded with an owner, a date and an agreed interim control — for example a manual check that substitutes for a missing sensor. Interim controls must be written into the operating procedure, not remembered by whoever was in the room, otherwise they quietly disappear at the first shift change.

Site-specific failure modes

The recurring ones: utilities out of specification discovered after the supplier has left; product that behaves differently from the sample used at the factory; film lot variation causing seal failures that appear only after hours of running; conveyor interface faults; and operators trained on a machine that then gets re-parameterised during commissioning without retraining.

Ramp-up after acceptance

Acceptance and ramp-up are different phases, and conflating them is how lines end up "accepted" while running at seventy percent of target. Plan a ramp-up window with a daily output target, a defined support presence from the supplier, and a review point where the punch list and the OEE baseline are revisited. The SAT proves the machine can perform; the ramp-up proves the organisation can run it.

Verification checklist

Before signing: utilities measured and within range and recorded against the machine inlet rather than the plant header; performance run duration met with stop log attached; pack tests passed with retained samples; integration handshakes demonstrated; documentation and spares handed over; operators trained and records kept; punch list closed or scheduled with owners and dates.

Source: Acceptance testing — Wikipedia

"In engineering and its various subdisciplines, acceptance testing is a test conducted to determine if the requirements of a specification or contract are met."

Frequently asked questions

Can the SAT be combined with the FAT?

No. They test different things: factory conditions versus site conditions. Combining them hides utility and integration problems until after acceptance.

What if the product is not available on site yet?

Use the closest available substitute, document the difference, and plan a retest with real product. Do not close the SAT on a substitute without written risk acceptance.

How long after installation should the SAT run?

Long enough to include a real start-up, a shift change and a cleaning cycle — typically several days of production, not a single afternoon.

Related reading: FAT and SAT guide, factory acceptance test, OEE, and the end-of-line packaging category.

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