10 exam-style questions with answers and explanations, straight from our 1,030-question bank. Tap an answer to check yourself. When you're ready, take the scored version in the free practice test.
The FN exam has 80 questions and runs 2 hours.
These 10 free FN questions are organized by exam domain, so you can see how each part of the Pre-Engineered Industrial Fire Extinguishing System Technician (FN) blueprint is tested. Reveal the answer and explanation under each question.
A machining enclosure protected by a BC dry-chemical system previously cut steel using a combustible cutting oil. The process will change to dry machining of magnesium, with combustible magnesium chips collecting inside the enclosure. What protection basis should now govern agent selection?
Correct answer: D - Select protection specifically suitable for Class D fires involving magnesium chips.
A correctly charged, properly aimed Purple-K system knocks down a solvent fire, but flames return where solvent contacts a hot steel surface. Investigation finds no agent-delivery defect. Which explanation best fits these findings?
Correct answer: B - Flame inhibition can occur without enough cooling to prevent ignition by the hot surface.
A machine has a self-actuating pneumatic indirect-release system with heat-sensitive detection tubing and separate discharge piping. Following a fire-induced rupture of the detection tubing, agent reaches the hazard:
Correct answer: C - Through separate nozzles after detection-tube pressure loss opens the cylinder valve.
A functional test of a local-application dry-chemical system in an open-face spray booth stops coating delivery and electrostatic high voltage but leaves the exhaust running. The listed system's installation instructions and approved control sequence both require exhaust to continue during discharge. A contractor flags the running fan as a failure. How should the fan response be recorded?
Correct answer: C - Acceptable; the fan response matches the approved suppression arrangement.
During the ventilation-failure test of a solvent dip-coating line, extraction airflow falls below the required minimum. The conveyor keeps moving parts through the bath because its stop command is tied only to fire detection. The vapor monitor is not in alarm. What finding belongs in the test report?
Correct answer: B - Record a missing automatic conveyor shutdown on loss of required ventilation.
To clear a newly installed beam, a suppression contractor reroutes a discharge branch and relocates a nozzle. The revised arrangement remains within the listing, the required approval has been obtained, and the altered functions pass acceptance testing. The permit drawing still shows the original route. Before turnover, what needs to change?
Correct answer: C - Revise the as-installed drawing to show the actual route and nozzle location.
The applicable manual for a proposed Firetrace 940502 ABC unit lists maximums of 42.25 ft² for area, 9 ft for height, and 380.25 ft³ for volume. The rectangular enclosure measures 5 ft long, 7 ft wide, and 10 ft high. The reviewer must evaluate these three limits independently. The dimensional review should conclude:
Correct answer: D - Reject the selection because its height exceeds the limit, despite acceptable area and volume.
During a dry-chemical system's scheduled functional test, the technician follows the manufacturer's procedure to prevent agent discharge. The remote manual pull trips the release mechanism. After the mechanism is reset, a test of the fusible-link detection line does not trip it. Both inputs are designed to trip the same mechanism independently. Where should troubleshooting begin?
Correct answer: B - The fusible-link cable, pulleys, and connection to the release
An FK-5-1-12 cylinder arrives for semiannual service with these measurements: required agent charge, 10.0 lb; empty cylinder-and-valve tare, 12.0 lb; current gross weight on the same weighing basis, 21.2 lb. Pressure is correct for temperature. The applicable rule requires refill or replacement for agent loss greater than 5% OR temperature-adjusted pressure loss greater than 10%. The service disposition should be:
Correct answer: A - Refill or replace it; 8.0% of the required agent charge is missing.
An FK-5-1-12 container has stabilized at 40°F and reads 171 psig. Its pressure-temperature chart specifies 171 psig at 40°F and 195 psig at 70°F. There has been no discharge, the required agent mass is confirmed, and the remaining maintenance checks pass. A coworker proposes adding nitrogen to reach 195 psig. What is the appropriate response?
Correct answer: A - Leave the charge unchanged; pressure agrees with the chart at 40°F.
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