Integration
Why FAT Matters Before a Skid Ships
A factory acceptance test verifies the interfaces between mechanical, instrumentation, control and documentation in one controlled stage.
A skid is a system, not a collection of items
A metering skid is assembled from items that each arrive with their own vendor and their own paperwork: the meter runs and valves, the instrumentation, the flow computer, the panel and its cabling, and the control logic that stitches them together. What the client takes delivery of, though, is not that list — it is a single system that has to work as one.
That is why the riskiest part of a skid is usually none of its items, but the interfaces between them: where instrumentation meets the panel, the panel meets the control logic, and the control logic meets what the documentation says it does.
FAT tests the interfaces under the most controlled conditions available
A factory acceptance test verifies exactly those interfaces in one controlled stage, against an inspection and test plan approved by the client, while the skid is still in the shop and every part of it is easy to reach.
The difference is the cost of correction. Fixing incorrect wiring or a wrong signal mapping in the shop is a job of a few hours. The same correction after shipping, on site, needs access, a work permit, and time that usually sits on the critical path of commissioning.