NFI Core Knowledge || ACTUAL QUESTIONS WITH
CORRECT ANSWERS!!
HPBEF correct answers Hearth, Patio & Barbecue Education Foudation
Energy Content correct answers Measure of the available chemical energy per pound of wood
or cubic foot of gas of fuel. Normally expressed in BTUs.
Heating Value correct answers The amount of heat actually available from a fuel (also
expressed in BTUs)
BTUs correct answers British Thermal Units
Combustion triangle correct answers oxygen, heat, fuel
Stages of Wood Combustion correct answers 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 answers Wood: 450°-550°F
Natural Gas: About 1,150°F
Propane Gas: 920°-1,120°F
Aldehydes correct answers Chemical compounds that have a strong pungent odor, are
produced in incomplete or interrupted combustion.
Flame Impingement correct answers 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 answers Heat output divided by heat input
Byproducts of Combustion correct answers Water vapor, carbon dioxide, and non-
combustible ashes.
Combustion correct answers A rapid reaction between oxygen and fuel that results in fire
Fuel correct answers A substance that provides energy as the result of a chemical change
OR
A material that releases energy as it burns
Combustion Efficiency correct answers A measurement or percentage of the fuel's energy
that is converted to heat
Heat Transfer Efficiency correct answers A measurement or percentage of heat generated by
combustion actually transferred into the interior space or room.
, Radiant Design Factory-Built Fireplaces correct answers Transmits heat energy from the
firebox opening by direct radiation to the space right in front of it
Circulating Design Factory-Built Fireplaces correct answers Adds the function of heat
transfer via heated air convection by circulating air around the fire chamber and releasing it
to the space to be heated through grills or louvers.
Conduction correct answers The direct transfer of heat from one substance to another
substance that it is touching
Convection correct answers The transfer of heat through a gas or liquid, including air.
Radiation correct answers The emission of waves of infrared energy, which is converted to
heat on contact with solid surfaces (people, furniture, walls)
Definition of UL correct answers Underwriters Laboratories, recognized as a leader in
developing safety standards
UL127 correct answers Safety standard for factory built fireplaces (solid fuel like wood or
coal burning). Either subjected to a 1700°F or 2100°F test, manufacturers choice.
UL1482 correct answers Standard for solid-fuel type room heaters. Include freestanding
stoves, fireplace inserts, and some built-in high efficiency fireplaces; also known as
controlled combustion appliances. These appliances are designed with tight fitting, gasketed
doors that are closed during operation. Vented with either a masonry chimney or a factory-
built chimney tested to 2100°F (HL103-HT)
UL103 correct answers Standard for factory-built chimneys for residential type and building
heating appliances. Factory-built chimneys approved for use with wood stoves and some
factory-built fireplaces. Subjects to a 1000°F test, then to a 10 minute high temperature test to
either 1700° or 2100°, manufacturers choice.
UL641 correct answers Standard for Type-L low temperature venting systems. Originally
covered factory-built vent piping and fitting for use with gas and oil appliances, is know the
basis for testing pellet venting products. Two tests are conducted: 570°F flue gases and
1700°F flue gases.
UL1618 correct answers Standard for wall protectors, floor protectors and hearth extensions
for intended use with heat producing devices (fireplaces, FP stoves, FP inserts, and solid-fuel
type room heaters).
A floor protector is defined in the UL1618 standard as... correct answers A noncombustible
surfacing applied to the floor area underneath and extending in front, to the sides, and to the
rear of a heat producing appliance.
A hearth extension is defined in the UL1618 standard as... correct answers A noncombustible
surfacing applied to the floor area extending in front of and at the sides of the hearth opening
of a fireplace or fireplace insert.
CORRECT ANSWERS!!
HPBEF correct answers Hearth, Patio & Barbecue Education Foudation
Energy Content correct answers Measure of the available chemical energy per pound of wood
or cubic foot of gas of fuel. Normally expressed in BTUs.
Heating Value correct answers The amount of heat actually available from a fuel (also
expressed in BTUs)
BTUs correct answers British Thermal Units
Combustion triangle correct answers oxygen, heat, fuel
Stages of Wood Combustion correct answers 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 answers Wood: 450°-550°F
Natural Gas: About 1,150°F
Propane Gas: 920°-1,120°F
Aldehydes correct answers Chemical compounds that have a strong pungent odor, are
produced in incomplete or interrupted combustion.
Flame Impingement correct answers 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 answers Heat output divided by heat input
Byproducts of Combustion correct answers Water vapor, carbon dioxide, and non-
combustible ashes.
Combustion correct answers A rapid reaction between oxygen and fuel that results in fire
Fuel correct answers A substance that provides energy as the result of a chemical change
OR
A material that releases energy as it burns
Combustion Efficiency correct answers A measurement or percentage of the fuel's energy
that is converted to heat
Heat Transfer Efficiency correct answers A measurement or percentage of heat generated by
combustion actually transferred into the interior space or room.
, Radiant Design Factory-Built Fireplaces correct answers Transmits heat energy from the
firebox opening by direct radiation to the space right in front of it
Circulating Design Factory-Built Fireplaces correct answers Adds the function of heat
transfer via heated air convection by circulating air around the fire chamber and releasing it
to the space to be heated through grills or louvers.
Conduction correct answers The direct transfer of heat from one substance to another
substance that it is touching
Convection correct answers The transfer of heat through a gas or liquid, including air.
Radiation correct answers The emission of waves of infrared energy, which is converted to
heat on contact with solid surfaces (people, furniture, walls)
Definition of UL correct answers Underwriters Laboratories, recognized as a leader in
developing safety standards
UL127 correct answers Safety standard for factory built fireplaces (solid fuel like wood or
coal burning). Either subjected to a 1700°F or 2100°F test, manufacturers choice.
UL1482 correct answers Standard for solid-fuel type room heaters. Include freestanding
stoves, fireplace inserts, and some built-in high efficiency fireplaces; also known as
controlled combustion appliances. These appliances are designed with tight fitting, gasketed
doors that are closed during operation. Vented with either a masonry chimney or a factory-
built chimney tested to 2100°F (HL103-HT)
UL103 correct answers Standard for factory-built chimneys for residential type and building
heating appliances. Factory-built chimneys approved for use with wood stoves and some
factory-built fireplaces. Subjects to a 1000°F test, then to a 10 minute high temperature test to
either 1700° or 2100°, manufacturers choice.
UL641 correct answers Standard for Type-L low temperature venting systems. Originally
covered factory-built vent piping and fitting for use with gas and oil appliances, is know the
basis for testing pellet venting products. Two tests are conducted: 570°F flue gases and
1700°F flue gases.
UL1618 correct answers Standard for wall protectors, floor protectors and hearth extensions
for intended use with heat producing devices (fireplaces, FP stoves, FP inserts, and solid-fuel
type room heaters).
A floor protector is defined in the UL1618 standard as... correct answers A noncombustible
surfacing applied to the floor area underneath and extending in front, to the sides, and to the
rear of a heat producing appliance.
A hearth extension is defined in the UL1618 standard as... correct answers A noncombustible
surfacing applied to the floor area extending in front of and at the sides of the hearth opening
of a fireplace or fireplace insert.
