🔍 Key Concepts

• Cargo grades B–E definitions and relative hazard levels in 46 CFR (flammability and vapor pressure) • Vent system requirements for grade B and above vs. lower grades (gooseneck vents, flame screens, pressure–vacuum valves) • Why more hazardous cargoes need more protective venting arrangements than just a gooseneck with a flame screen

💭 Think About

• Think about which cargo grades have the highest flash points and lowest vapor pressures and therefore pose the least risk with simple venting arrangements. • Ask yourself: for which grades does the regulation allow only a gooseneck vent and flame screen, and for which grades does it require additional protection (e.g., pressure–vacuum valves, controlled venting systems)? • Compare the regulatory requirements for tanks carrying Grade B versus Grade D or E products: who needs more sophisticated venting and gas–freeing arrangements?

✅ Before You Answer

• Check in 46 CFR Subchapter D (tank barges) which grades are permitted with open or gooseneck vents with flame screens only. • Verify which grades require closed loading/closed gauging and special venting (these will NOT fit the conditions in the question). • Confirm that your choice matches the grades with the least stringent vent requirements among B, C, D, and E.