In accordance with 46 CFR 61, what is the interval in years between when boiler drum safety valves must be tested on a fire-tube boiler operating at less than 150 psig as witnessed by a marine inspector?

Correct Answer: Option A — 1

Per 46 CFR 61.10-5, boiler drum safety valves on fire-tube boilers operating at pressures below 150 psig must be tested annually in the presence of a marine inspector. This ensures the pressure relief mechanism remains functional, preventing catastrophic over-pressurization of the boiler shell during normal operations.