Sat and Fat?

Your other posts related to water (fluid) levels in vessels.

Does your question relates to Acceptance Tests (Factory vs Site) ?

His question relates to homework.

If FAT is an acronym for Factory Acceptance Test, the purpose of it is verifying that it "does exactly what it says on the tin" in the factory. Non-compliances are easily and cheaply rectified there.

If SAT is an acronym for Site Acceptance Test, the purpose of it is verifying that it still "does exactly what it says on the tin" once installed.

The procedure is given in several documents, one being the approved-for-construction Control Philosophy document written by the Process Engineer, another being the approved-for-construction I/O Schedule, and another being the approved-for-construction Functional Design Specification, both written by the Controls Engineer.

FAT - factory acceptance test - equipment (in my case a process skid) is run through all stages as required by the customer. Usually a customer sends a plant process specialist, and perhaps a DCS specialist to ascertain the device will function as required in the plant. On minor items (tanks with mixers for example) the customer may have a third party who is knowledgeable in this area do the acceptance test. All hookups are temporary and simulated as needed to mimic the final installation. The customer can get as particular as requiring air pressure be set to within 1% of factory, water be of a certain conductance, and so on.

SAT - site acceptance test - equipment has been installed in the plant and all functions checked in real working conditions.