🔍 Key Concepts

• 46 CFR requirements for pressure-vacuum (P/V) relief valves on cargo tanks • Material requirements for valve components (what MUST be corrosion resistant vs what is just good practice) • Design/size requirements such as minimum nominal pipe size and protections against vent blockage

💭 Think About

• Look at the exact wording typically used in 46 CFR: does it usually require one specific metal (like bronze), or does it more often say something broader like "corrosion resistant" for certain parts? • Ask yourself which statements sound like a precise regulatory requirement and which sound more like general good-maintenance advice that would not usually be written as a hard rule. • Consider which features are critical to safe operation during normal service (e.g., exposure to cargo vapors, risk of sticking) versus during maintenance periods when valves might be removed.

✅ Before You Answer

• Verify in 46 CFR whether the rule specifies bronze by name for all major parts, or if that sounds too restrictive to be a regulation. • Check if there is a stated minimum valve size for P/V valves on cargo tanks and whether “2 inches nominal pipe size” is actually written in the regulation. • Confirm whether 46 CFR explicitly requires valve springs to be plated or corrosion resistant, and whether it says anything about having to remove the valve for overhauling as a rule.