Halon cannot be used on fires of which class?

Halon cannot be used on fires of which class?

• A. Class A
• B. Class B
• C. Class C
• D. Class D

Answer: (D)

Halon extinguishes by interfering with the chemical reactions occurring in the flame and by displacing some of the oxygen locally. That makes it effective for ordinary combustibles, flammable liquids, and energized electrical fires. But fires involving reactive metals (the metal fire category) behave very differently: the metal itself can keep reacting at extremely high temperatures, and Halon doesn’t provide the cooling or the proper separation of fuel and oxidizer that these fires need. For metal fires, special dry powder extinguishing agents (and sometimes water cooling in certain cases) are required. So Halon cannot be used on Class D fires.

Halon extinguishes by interfering with the chemical reactions occurring in the flame and by displacing some of the oxygen locally. That makes it effective for ordinary combustibles, flammable liquids, and energized electrical fires. But fires involving reactive metals (the metal fire category) behave very differently: the metal itself can keep reacting at extremely high temperatures, and Halon doesn’t provide the cooling or the proper separation of fuel and oxidizer that these fires need. For metal fires, special dry powder extinguishing agents (and sometimes water cooling in certain cases) are required. So Halon cannot be used on Class D fires.