🔍 Key Concepts

• 46 CFR Subchapter O requirements for dangerous cargoes on tank vessels • Special construction and materials rules for anhydrous ammonia carriage • Differences between gas detection requirements and material compatibility requirements for valves and piping

💭 Think About

• Which of the options deals with material compatibility of metals with anhydrous ammonia, and which deal with more general concepts like certificates, tank location, or gas detection? • Think about whether anhydrous ammonia is treated mainly as a toxic/pressurized gas, a flammable gas, or both for U.S. tankship design rules from around 1980. • For tanks carrying liquefied gases like ammonia, what is more tightly regulated: where tanks can be placed, what they’re made of, or what kind of certificate is issued?

✅ Before You Answer

• Check in 46 CFR Part 154 (Safety Standards for Self-Propelled Vessels Carrying Bulk Liquefied Gases) for any special notes on ammonia and allowed/prohibited construction materials. • Verify whether anhydrous ammonia is specifically regulated as a flammable gas for purposes of pump room gas detection requirements or primarily as a toxic/refrigerated liquefied gas. • Confirm if U.S. regulations rely solely on an IMO Certificate to authorize carriage, or if domestic CFR requirements must also be met regardless of international certificates.