Question 1306 Deck General

The correct answer is D) all of the above. Cargo tank safety valves on vessels must meet the following requirements: 1) They are not held closed by tank pressure, which means they can open if the pressure in the tank gets too high, preventing a tank rupture. 2) They can be opened by pilot valves, which are smaller valves that can activate the main safety valve. 3) They are not to be "popped" or tested in port, as this could release cargo vapors and create a hazardous situation. Testing should only be done at sea or in a safe environment. The other answer choices are incorrect because they do not fully encompass all the requirements for cargo tank safety valves on vessels.