Which of the following describes a safe re-commissioning procedure before re-energizing a B28 system after maintenance?

• A. A documented process including leak checks, detector status, electrical integrity, and authorized re-energization
• B. Visual inspection only
• C. Swapping out detectors without verification
• D. Restart without tests

Answer: (A)

Before re-energizing a B28 system after maintenance, you must follow a documented re-commissioning process that verifies leaks, detector readiness, electrical integrity, and authorized energization. This sequence ensures the system is safe to bring back on line and protects people and equipment from fire or explosion risks associated with flammable refrigerants.

Leak checks confirm there are no residual or new leaks after work, so flammable refrigerant cannot accumulate and pose ignition hazards. Verifying detector status ensures the gas/ flame detection systems are functioning properly and will alarm if a problem recurs. Checking electrical integrity makes sure wiring, interlocks, breakers, and control circuits are sound and will not cause unintended energization or unsafe operation. Authorized re-energization means a qualified person or supervisor approves and signs off, following any permit-to-work or lockout/tagout procedures, to ensure all safety measures are in place.

Relying on visual inspection alone can miss hidden leaks or detector faults. Swapping detectors without proper verification risks having nonfunctional sensors installed. Restarting without tests skips essential safety checks and could reintroduce hazards after maintenance.