NFI Core Knowledge Exam Questions
and Answers Graded A+
HPBEF - Correct answer-Hearth, Patio & Barbecue Education Foudation
Energy Content - Correct answer-Measure of the available chemical energy per
pound of wood or cubic foot of gas of fuel. Normally expressed in BTUs.
Heating Value - Correct answer-The amount of heat actually available from a fuel
(also expressed in BTUs)
BTUs - Correct answer-British Thermal Units
Combustion triangle - Correct answer-oxygen, heat, fuel
Stages of Wood Combustion - Correct answer-1. Moisture Evaporation (heat is
absorbed, not given off)
2. Vaporization of Hydrocarbon Compounds
3. Gas Vapor Ignition and Combustion
4. Char Burning
Ignition rates per fuel - Correct answer-Wood: 450°-550°F
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, Natural Gas: About 1,150°F
Propane Gas: 920°-1,120°F
Aldehydes - Correct answer-Chemical compounds that have a strong pungent odor,
are produced in incomplete or interrupted combustion.
Flame Impingement - Correct answer-Flames improperly touching the logs per a
gas unit, or cooling of the flame by a poorly built fire in a wood burner.
Efficiency is best defined as - Correct answer-Heat output divided by heat input
Byproducts of Combustion - Correct answer-Water vapor, carbon dioxide, and non-
combustible ashes.
Combustion - Correct answer-A rapid reaction between oxygen and fuel that
results in fire
Fuel - Correct answer-A substance that provides energy as the result of a chemical
change
OR
A material that releases energy as it burns
Combustion Efficiency - Correct answer-A measurement or percentage of the fuel's
energy that is converted to heat
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
and Answers Graded A+
HPBEF - Correct answer-Hearth, Patio & Barbecue Education Foudation
Energy Content - Correct answer-Measure of the available chemical energy per
pound of wood or cubic foot of gas of fuel. Normally expressed in BTUs.
Heating Value - Correct answer-The amount of heat actually available from a fuel
(also expressed in BTUs)
BTUs - Correct answer-British Thermal Units
Combustion triangle - Correct answer-oxygen, heat, fuel
Stages of Wood Combustion - Correct answer-1. Moisture Evaporation (heat is
absorbed, not given off)
2. Vaporization of Hydrocarbon Compounds
3. Gas Vapor Ignition and Combustion
4. Char Burning
Ignition rates per fuel - Correct answer-Wood: 450°-550°F
©COPYRIGHT 2025, ALL RIGHTS RESERVED 1
, Natural Gas: About 1,150°F
Propane Gas: 920°-1,120°F
Aldehydes - Correct answer-Chemical compounds that have a strong pungent odor,
are produced in incomplete or interrupted combustion.
Flame Impingement - Correct answer-Flames improperly touching the logs per a
gas unit, or cooling of the flame by a poorly built fire in a wood burner.
Efficiency is best defined as - Correct answer-Heat output divided by heat input
Byproducts of Combustion - Correct answer-Water vapor, carbon dioxide, and non-
combustible ashes.
Combustion - Correct answer-A rapid reaction between oxygen and fuel that
results in fire
Fuel - Correct answer-A substance that provides energy as the result of a chemical
change
OR
A material that releases energy as it burns
Combustion Efficiency - Correct answer-A measurement or percentage of the fuel's
energy that is converted to heat
©COPYRIGHT 2025, ALL RIGHTS RESERVED 2
