For a machine manufacturer, acceptance is where the deal is really settled. A factory acceptance test (FAT) signs the machine off before it ships; a site acceptance test (SAT) signs it off once it is installed and running at the customer's plant. Between and around those two gates sit staged payments, warranty positions, and the reputation you carry into the next order. All of it rests on one thing: the documentation the acceptance produces.
And that documentation is often the weakest part of an otherwise rigorous process. Test results live on paper and get transcribed later; photos sit scattered across engineers' phones; the acceptance package is assembled from memory days after the machine has left the floor. For equipment worth six or seven figures shipping across borders, that is a genuine exposure. This guide sets out what FAT and SAT documentation should capture, how the two tests differ, and why a photo- and video-first record is a better fit for machine acceptance than the paper-and-PDF status quo.
A Factory Acceptance Test is the inspection and functional testing of a machine or system at the manufacturer's own facility, before it ships to the customer. It proves that the equipment meets the agreed specification — function, safety, build quality — in a controlled setting where problems are cheap to fix. The FAT is usually witnessed by the customer or their representative, and it produces an acceptance record: the test protocol, the results measured against acceptance criteria, any deviations or open punch-list items, and the evidence that backs each result.
The point of a FAT is leverage over risk while the machine is still in your hands. A fault found on your own floor is a morning's work; the same fault found after the machine has crossed a continent is flights, delays, and a held payment.
A Site Acceptance Test is the equivalent test performed after the machine has been installed at the customer's site. It confirms the equipment performs correctly under real operating conditions — integrated with the customer's utilities, feedstock, and surrounding systems, under genuine loads that cannot be reproduced on the manufacturer's floor. The SAT re-verifies the core functions covered at FAT and adds everything only the live environment can reveal.
In most contracts the SAT is the gate for final acceptance, and often for the final payment milestone. Commissioning and operator handover happen around it, which makes the SAT record the document a customer returns to for years whenever a question about the installation arises.
The two tests differ in timing, location and purpose. The FAT happens at the manufacturer's facility before shipment; the SAT happens at the customer's site after installation. The FAT exists to catch problems before international logistics makes them expensive; the SAT exists to confirm real-world performance and integration once the machine is in place.
They are not independent. The SAT builds directly on the FAT record — the same protocol, re-run in a harder environment. A gap at FAT becomes a far costlier gap at SAT: a test that was never properly documented, or a deviation that was noted but not photographed, turns into a dispute at the exact moment the machine is furthest from your factory and closest to a withheld payment. The stronger the FAT package, the smoother the SAT.
It is tempting to treat FAT and SAT records as engineering paperwork. In practice they are commercial instruments. Sign-off releases staged payments, so weak or slow documentation delays cash, not just filing. When a machine ships worldwide, "was this scratch there at FAT, or did it happen in transit?" is a question worth real money — and the only thing that answers it is a dated, unambiguous record from before the machine was crated. And a clean, professional acceptance package is itself a signal: it tells a customer they are dealing with a manufacturer who takes handover as seriously as engineering.
This is the same logic that turns quality control from a cost into a protection, covered in our piece on outgoing quality control — the acceptance test is simply the high-value, high-stakes version of the same idea.
A defensible FAT record has five layers. The protocol and acceptance criteria — what was agreed, so results have something to be measured against. Build-quality evidence — the overall machine, key assemblies, nameplates and serial numbers, safety devices, the control cabinet. Functional results — each test with its pass or fail against criteria and the actual readings (speed, pressure, temperature, cycle time). The punch list — every open item photographed, described, assigned to an owner and tracked to closure. And sign-off — who witnessed, when, with signatures.
This is where video earns its place. A machine completing a cycle, a safety-stop responding, an alignment holding under load — these are far better shown in a ten-second clip than described in a sentence. A photo proves a state; a short video proves behaviour. An acceptance record that can hold both, against the right test, is worth more than either alone.
The SAT record starts before the machine is even powered on, with its condition on arrival. Recording how the equipment turned up — ideally against how it was packed and shipped — is what separates transit damage from installation issues later. It is the same handover discipline as a photo proof of delivery, applied to a machine rather than a pallet, and it connects directly to how the crate was documented leaving the factory (documenting outgoing goods) and loaded for transport (container loading inspections).
From there the SAT record covers installation and integration evidence, the functional tests re-run under real conditions with readings against criteria, the commissioning steps, operator training captured as photos or short clips, and the final acceptance protocol with sign-off. Done well, it closes the loop that the FAT opened — the same principle behind joining incoming and outgoing quality control into one continuous record.
Three failure points recur. Paper and PDF forms, filled by hand and transcribed later, with the photos living somewhere separate from the form they belong to. Personal phones, where images are scattered, private, and lost the moment a commissioning engineer or contractor moves on. And the assembly problem — the acceptance package built days afterward from memory and an unsorted folder of images, which is slow, error-prone, and a poor look on a serious deal.
Most tools aimed at this problem are checklist-first: they digitise the form well but treat the visual evidence as an attachment bolted on afterwards. For machine acceptance, where the condition and behaviour of the equipment is the evidence, that is the wrong way round. The record should be visual-first — photos and video as the spine, with the checklist and readings structured around them.
The most useful way to think about acceptance documentation is not as two isolated events but as one unbroken evidence trail that follows a high-value machine through its whole journey: assembly and in-process checks, FAT on your floor, packing and export, transport, installation, SAT and commissioning, handover. Each stage answers the same question — what condition, in whose custody — and each hands a clean baseline to the next.
That thread is exactly where machine manufacturing meets the discipline your logistics counterparts already know. The difference between incoming and outgoing quality control is the same distinction as FAT versus SAT, one level up: prove the state of the goods at every point they change hands, and liability is never ambiguous.
A workflow that survives contact with a busy factory floor has four properties. Standard templates per machine type, so every acceptance captures the same checklist and the same required photos and clips. Capture on a shared device rather than personal phones, with each image and video filed automatically against the machine and order. One record that holds structured photos, video, checklist and readings together — and produces a clean acceptance report on demand rather than days later. And offline capture, because factory floors and remote installation sites both tend to have poor connectivity exactly where the work happens.
That is the approach Blimp is built for: visual-first capture, structured data attached, filed against the job, available as a report the moment the test ends.
What is the difference between FAT and SAT?
A Factory Acceptance Test (FAT) is performed at the manufacturer's facility before shipment; a Site Acceptance Test (SAT) is performed at the customer's site after installation. FAT catches problems while the machine is still on your floor; SAT confirms real-world performance and integration once it is installed.
What should a FAT report include?
The agreed test protocol and acceptance criteria, build-quality evidence (machine, assemblies, nameplates, safety devices), functional test results with readings against criteria, a punch list of open items with owners, and witnessed sign-off with signatures — with photos and video attached to each relevant result.
Who witnesses a Factory Acceptance Test?
The customer or their appointed representative typically witnesses the FAT, alongside the manufacturer's engineering and quality staff. The witnessed results and sign-off form the acceptance record that authorises shipment.
What is an acceptance protocol?
An acceptance protocol (in German, an Abnahmeprotokoll) is the formal record documenting a machine's condition, tests, deviations and sign-off at the point of acceptance — the legally relevant proof that the equipment was delivered and accepted as agreed.
Can FAT and SAT be documented with photos and video?
Yes, and increasingly they should be. Timestamped photos prove condition and build quality; short videos prove behaviour such as a machine cycle or a safety-stop test. A visual-first record filed against the machine is faster to produce and harder to dispute than a paper protocol with images attached separately.
Blimp captures machine acceptance the way it actually happens — photo- and video-first, on a shared device, filed against the machine and produced as a clean report on demand, online or off. See Blimp for manufacturing or get started.
Blimp lets you easily capture, organise and share photo documentation and professional photo reports. Available on mobile and web, Blimp simplifies reporting, reduces manual work and streamlines claims handling across industries.
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