Factory Acceptance Testing (FAT) describes the final checks performed on packaged equipment (major and minor) prior to delivery to the construction site. It is often debated as to whether FATs should be attended to and verified by the engineering team, responsible for the design of the equipment, or the commissioning team responsible for energizing and function-checking the equipment. In most well-funded capital projects, the FAT is led by and signed off by the engineering team, however, the commissioning (and often operations team) will also attend and witness the testing and provide a combination of final sign-off.
The importance of adequate factory acceptance testing cannot be understated, as many site commissioning hours can be spent rectifying issues that would have been easily remedied in the supplier’s factory (and under the supplier’s budget). The cost to resolve these issues on-site, especially in high labor cost markets such as Australia, can increase project costs by many times as well as lead to unnecessary start-up schedule delays and contingency drawdown.
Although the specific details for Factory Acceptance Testing differ for each discipline, it is critical to ensure the correct and competent personnel are utilized to witness and sign off equipment at the FAT. It is quite common in today’s industry (due to resource constraints) for companies to send inexperienced or irrelevant personnel to witness FATs of critical systems, often resulting in sign-off and client acceptance of inferior delivery.
Typical Factory Acceptance Testing activities include:
- General construction checks, tagging, bill of material verification, location, and material quality.
- Control System hardware and software function checks, alarming, interlocks, sequencing, drive control, process control, and emergency shutdown systems.
- Electrical checks such as protection checks, point-to-point testing, insulation resistance checks, and polarity checks, motor bump tests.
- Instrumentation checks, calibration verification, certification, and initial loop checks.
- Mechanical and piping checks such as flange verification, pressure, leak tests, etc.
- Transportation readiness and preservation requirements.
- Spare parts, maintenance, and commissioning procedures.
Of all the FAT activities, often the most complex and time-consuming is the control system software verification checks. These verification activities can often span months of duration and are required to ensure the functionality of the process control system is met. This includes alarming and interlocks functionality, as well as drive logic, sequencing, and overall process control. Sufficient testing of these systems is critical in optimizing on-site commissioning activities and minimizing the need for time-consuming re-work.
As the nature of project delivery becomes more “package” focussed, with specialized equipment from various suppliers, it is critical that interface testing between various skids and packages is also accounted for in the commissioning budget and schedule. Failure to do so often results in significant delays during the start-up process, as many systems may “pass” their individual FATs, whilst failing to meet the requirements of the overall integrated system.
Care should be taken to ensure all factory acceptance testing documentation is handed over to the commissioning team to form part of the overall commissioning dossier. Often this is missed and results in the requirement to re-test functions that may have already been verified at a previous stage.