🔍 Key Concepts

• 46 CFR requirements for cargo tank venting on barges carrying Grade A flammable liquids • Purpose of pressure-vacuum (P/V) valves and vent headers on tank barges • Distinguishing between general safety principles (vents on each tank, adequate height) and very specific dimensional requirements

💭 Think About

• Ask yourself which options clearly relate to preventing overpressure, vacuum, or vapor accumulation hazards on a tank barge carrying highly flammable cargo. • Consider whether the regulations usually specify exact minimum vent diameters, or whether they more often require vents to be "adequate" or "suitable" for the service. • Think about which one choice sounds like a very specific engineering number that might not appear as a universal requirement in the regulations.

✅ Before You Answer

• Check 46 CFR for any explicit statement about minimum vent diameter for Grade A cargo tank vents. • Verify that a pressure-vacuum valve on a vent header is indeed tied to controlling pressure and vapors on flammable liquid cargoes. • Confirm that each cargo tank must have some means of venting and that vents are required to reach a safe height above the deck to disperse vapors.