Question 56 ONC01 - Master/Chief Mate Unlimited Tonnage

The Correct Answer is C ### Why Option C (16 and 36) is Correct: Class "B" fires involve flammable liquids (such as grease, oil, or gasoline). The most effective agents or devices for extinguishing Class B fires are those that smother the fuel source, interrupt the chemical chain reaction, or cool the fuel below its ignition temperature, without spreading the liquid fuel. In standard fire control plans (like those often referenced in maritime or industrial settings): * **Symbol 16** typically represents a **Dry Chemical (ABC/BC) Fire Extinguisher**. Dry chemicals are highly effective Class B (flammable liquid) fire suppressants because they rapidly interrupt the chemical chain reaction. * **Symbol 36** typically represents a **Foam Fire Extinguisher or Foam System**. Foam works by creating a blanket over the liquid fuel, cutting off the oxygen supply and providing cooling, making it ideal for Class B fires. Therefore, both devices represented by symbols 16 (Dry Chemical) and 36 (Foam) are best suited for extinguishing Class B fires. ### Why Other Options Are Incorrect: * **A) 26:** Symbol 26 usually represents a **Water Hose/Hydrant** or a **Water Fire Extinguisher (sometimes called Stored Pressure Water)**. Water is generally ineffective on Class B fires, and can often worsen them by splashing and spreading the burning liquid. * **B) 47:** Symbol 47 typically represents a **CO2 (Carbon Dioxide) Fire Extinguisher**. While CO2 *is* effective on Class B fires (by displacing oxygen), the question asks for the *best suited* agents. Dry chemical (16) and Foam (36) are often preferred for larger Class B incidents, and CO2 is primarily known for Class C (electrical) fires and smaller Class B fires where residue is a concern. However, compared to the combination in C, 47 alone is incomplete. * **D) 16 and 47:** This option includes Dry Chemical (16, effective) and CO2 (47, effective). While both 16 and 47 are effective, symbol 36 (Foam) represents another primary and highly suitable agent for Class B fires, especially for bulk liquids or large surface areas. Standard classification often pairs Dry Chemical (16) and Foam (36) as the most universally recognized effective Class B suppression combination, making C the more comprehensive and technically accurate answer regarding the *best suited* agents on a fire control plan.