Coast Guard Exams
Question 92Safety & Environmental - Assistant Engineer70% to pass

Pressure-vacuum relief valves, as used on tank vessels, are usually set to operate at two points, _______________.

AI Explanation
The correct answer is C) 14.2 psia; 2 psig. Pressure-vacuum relief valves on tank vessels are typically set to operate at two specific points: 14.2 psia (pounds per square inch absolute) and 2 psig (pounds per square inch gauge). This is in accordance with the U.S. Coast Guard regulations for pressure-vacuum relief valves on tank vessels. The other options are incorrect because: A) pressure-vacuum relief valves are not set to operate below atmospheric pressure, B) they are set to operate above and below atmospheric pressure, and D) the specified settings of 26 inches of vacuum and 5 psig do not match the standard regulatory requirements.