FE Extinguishing Agent Properties & Chemistry 2

Question 1

Which extinguishing agent is specifically recommended for Class K fires involving cooking oils and fats in commercial kitchens?

Accepted Answer

Wet chemical potassium acetate solution

Answer

ABC dry chemical powder

Answer

Carbon dioxide (CO2)

Answer

AFFF aqueous film-forming foam

Question 2

AFFF (Aqueous Film-Forming Foam) creates a suppression layer on flammable liquid fires by which mechanism?

Accepted Answer

Forming a thin aqueous film that seals the fuel surface

Answer

Chemically reacting with hydrocarbon vapors

Answer

Cooling the fuel below its flash point through water absorption only

Answer

Releasing CO2 gas from the foam bubbles

Question 3

What minimum temperature limitation is a critical operational concern for CO2 extinguishers during discharge?

Accepted Answer

The discharge creates temperatures as low as -110°F (-79°C) at the horn

Answer

The agent freezes in the cylinder below 32°F (0°C)

Answer

CO2 becomes liquid above 87°F (31°C)

Answer

The discharge pressure drops below effective range above 100°F (38°C)

Question 4

Monoammonium phosphate (MAP), the active ingredient in ABC extinguishers, melts on contact with burning Class A materials. Why is this significant?

Accepted Answer

It forms a vitreous coating that seals the fuel surface and prevents re-ignition

Answer

It increases the discharge range of the extinguisher

Answer

It absorbs moisture from the air to dilute combustion

Answer

It lowers the burning point of ordinary combustibles

Question 5

Which clean agent is most widely used as a replacement for Halon 1301 in fixed suppression systems?

Accepted Answer

FM-200 (HFC-227ea)

Answer

Nitrogen (IG-100)

Answer

CO2

Answer

AFFF foam

Question 6

Which dry chemical extinguishing agent is considered the most effective pound-for-pound on Class B flammable liquid fires?

Accepted Answer

Potassium bicarbonate (Purple-K)

Answer

Sodium bicarbonate

Answer

Monoammonium phosphate (ABC)

Answer

Calcium chloride

Question 7

The 'saponification' reaction relevant to Class K extinguisher agents describes which chemical process?

Accepted Answer

Alkaline solution reacting with fatty acid oils to form soap and glycerol

Answer

Oxidation of potassium ions releasing heat

Answer

Reduction of CO2 at high cooking temperatures

Answer

Hydrolysis of foam concentrate in water