Which best describes Level 4 Commissioning (Functional Performance Testing)?

• A. It involves only wiring continuity checks.
• B. It ensures equipment performance meets the functional design and client criteria through full testing.
• C. It is the final stage before handover.
• D. It tests only safety interlocks without performance checks.

Answer: (B)

Level 4 Commissioning, or Functional Performance Testing, is about proving that the installed system actually delivers the required functions in real operation. It goes beyond just wiring checks or safety devices and requires full testing of the equipment against the functional design and client criteria under realistic conditions. This means validating control sequences, how subsystems work together, response times, throughput, reliability, and safety integration to ensure the system performs as specified before it’s accepted. The other options fall short because wiring continuity checks focus only on installation details, calling it the final stage before handover emphasizes timing rather than what is tested, and testing only safety interlocks misses the broader performance verification that Level 4 entails.