FE Extinguishing Agent Properties & Chemistry 3

Question 1

Why are halon extinguishing agents (Halon 1211 and 1301) now heavily regulated under the Clean Air Act?

Accepted Answer

They have high ozone depletion potential (ODP) due to bromine content

Answer

Halons contain bromine, which has an extremely high ozone depletion potential (ODP); Halon 1211 has an ODP of 3.0 and Halon 1301 has an ODP of 10, leading to their phase-out under the Montreal Protocol.

Question 2

Which factor most significantly reduces the effective discharge range of a CO2 extinguisher in outdoor environments?

Accepted Answer

Wind dispersing the CO2 cloud before it reaches the fire

Answer

CO2 is a gas that disperses easily in open air, and wind can carry the CO2 cloud away from the fire before adequate concentrations can be achieved to extinguish the flames.

Question 3

What is the primary reason dry chemical extinguishing agents can cause corrosion damage to metals and sensitive electronics?

Accepted Answer

They absorb moisture from the air and form corrosive solutions after discharge

Answer

After discharge, dry chemical powders are hygroscopic and absorb moisture from the air, forming corrosive compounds (e.g., carbonic acid from sodium bicarbonate) that attack metals and electronics.

Question 4

FM-200 (HFC-227ea) clean agent primarily extinguishes fires through which mechanism at design concentrations of approximately 6.25%?

Accepted Answer

Chemical flame inhibition combined with heat absorption

Answer

FM-200 extinguishes fire through a combination of physical heat absorption (about 20%) and chemical flame inhibition via radical scavenging (about 80%) at its design concentration.

Question 5

Which extinguishing agent must NEVER be used on Class D combustible metal fires such as magnesium, lithium, or titanium?

Accepted Answer

Both water-based agents and CO2

Answer

Both water and CO2 can react violently with burning Class D metals — water can dissociate into hydrogen gas causing explosions, and CO2 can be reduced by some metals to release carbon and intensify burning.

(FE) Certified Portable Fire Extinguisher Technician Practice Test

(FE) Certified Portable Fire Extinguisher Technician Practice Test

FE Extinguishing Agent Properties & Chemistry 3