Inspection, Testing, and Maintenance
NFPA 72 separates inspection (visual check), testing (functional verification), and maintenance (servicing to keep it working). Know that testing frequencies depend on device and system type, and that records must be kept.
Key concepts: acceptance testing at installation, periodic testing thereafter, sensitivity testing of smoke detectors, and battery testing. Know that testing must verify alarm, supervisory, and trouble signals, notification appliances, and off-premises transmission. Documentation of tests and results is required and is often the answer to a question about what must follow a test.
Traps: confusing inspection with testing; assuming all devices are tested at the same interval; forgetting that records must be retained and made available to the AHJ; forgetting that a system modification requires re-testing.
Rule of thumb: inspection = look, testing = operate, maintenance = fix. Any change to the system triggers re-testing of affected portions. Always document.
Worked example: After replacing a smoke detector, the technician must test the device and the affected circuit and record the results, not simply install and leave.