🔍 Key Concepts

• 46 CFR requirements for tank barge cargo tank venting • Differences between grade A/B vs grade C/D petroleum vapor hazards • Purpose of pressure-vacuum (P/V) relief and flame screens on cargo vents

💭 Think About

• Which grades of petroleum have the highest vapor hazard and are more likely to require controlled, pressure‑type venting rather than open gooseneck or straight vents? • How do pressure‑vacuum relief devices protect tanks during loading/unloading and temperature changes compared to simple open vents? • Which options provide BOTH over/under‑pressure protection AND flame protection for a flammable cargo vapor space?

✅ Before You Answer

• Verify in 46 CFR which venting arrangements are specified for grade B petroleum on tank barges • Check which answer choices include both a flame arresting feature and a pressure‑vacuum control feature • Confirm that the selected vent type is suitable for flammable, higher‑hazard cargoes (not just for low‑hazard or non‑volatile products)