NICET Special Hazard Suppression Systems 3

Question 1

What does the acronym 'AFFF' stand for in fire suppression?

Accepted Answer

Aqueous Film Forming Foam

Answer

AFFF stands for Aqueous Film Forming Foam, named for its ability to form a thin aqueous film over hydrocarbon fuel surfaces to suppress vapors and prevent reignition.

Question 2

Class K fires, as defined by NFPA, involve which type of fuel?

Accepted Answer

Vegetable or animal cooking oils and fats in commercial cooking equipment

Answer

Class K fires involve cooking media (vegetable oils, animal fats) at high temperatures in commercial cooking appliances; they require wet chemical agents for effective suppression.

Question 3

Which inert gas blend, designated IG-541, is marketed under the trade name 'Inergen' and consists of nitrogen, argon, and CO2?

Accepted Answer

IG-541 (52% N₂ / 40% Ar / 8% CO₂)

Answer

IG-541, sold as Inergen, is a blend of 52% nitrogen, 40% argon, and 8% CO2; the CO2 component stimulates breathing to help evacuating personnel maintain oxygen uptake at reduced O2 levels.

Question 4

In a CO2 total flooding system, the 'soaking period' refers to:

Accepted Answer

The duration the design CO2 concentration must be maintained after discharge to ensure complete fire extinguishment

Answer

The soaking period is the post-discharge hold time — typically a minimum specified by NFPA 12 — during which the CO2 concentration must remain at or above the design level to extinguish deep-seated or smoldering fires.

Question 5

Regarding halon 1211 (bromochlorodifluoromethane) systems after the production phase-out under the Clean Air Act:

Accepted Answer

New halon 1211 systems are prohibited, but existing systems may be recharged with recovered or recycled halon

Answer

U.S. EPA regulations prohibit new halon production but allow existing systems to be maintained using recovered, recycled, or reclaimed halon, managed through a halon banking system.

NICET - National Institute for Certification in Engineering Technologies Practice Test

NICET - National Institute for Certification in Engineering Technologies Practice Test

NICET Special Hazard Suppression Systems 3