Coast Guard Regulations, 46 CFR Part 54, require steam safety and relief valves to be provided with a substantial lifting device, capable of lifting the disc from its seat at what percentage of the set pressure?

Correct Answer: Option C — 75%

46 CFR Part 54 mandates that all steam safety and relief valves feature a substantial manual lifting device. This mechanism must be capable of lifting the valve disc fully off its seat against the spring pressure at a minimum of 75 percent of the set pressure.