🔍 Key Concepts
• Portable fire extinguisher size classification on U.S. vessels, including MODUs (Mobile Offshore Drilling Units)
• Relationship between the Roman numeral (I–V) and the physical quantity/size of extinguishing agent
• Difference between size/class (A, B, C, etc.) and type of fire the extinguisher is designed to fight
💭 Think About
• Ask yourself: when regulators label something I, II, III, IV, V by size, in which direction does the size usually change?
• Consider whether an extinguisher’s placement (how easy it is to reach) is normally part of the numbering system or part of the installation requirements instead.
• Think about whether "used for electrical fires only" would be controlled by the class of fire (A/B/C/D/K) or by the size number (I–V).
✅ Before You Answer
• Verify what I–V actually refers to: amount of extinguishing agent / capacity, not fire type.
• Confirm that fire class (A, B, C, etc.) is what determines suitability for electrical fires, not the size numeral.
• Eliminate choices that confuse location or accessibility with regulatory size designation.