Question 998Deck General70% to pass
Open ullage holes in tanks which are not gas-free must be protected by _______________.
AI Explanation
The correct answer is B) flame screens.
Open ullage holes in tanks that are not gas-free must be protected by flame screens. This is a safety requirement to prevent the ignition of flammable vapors that may be present in the tank. Flame screens act as a barrier to prevent open flames or sparks from entering the tank, which could potentially cause an explosion or fire.
The other answer choices are incorrect because:
A) Stop-check valves are used to prevent backflow, not to protect open ullage holes.
C) PV (pressure-vacuum) valves are used to regulate pressure and vacuum in the tank, not to protect open ullage holes.
D) Warning signs alone are not a sufficient safety measure for unprotected open ullage holes in non-gas-free tanks.
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