NFI EXAM REVIEW WITH ALL CORRECT & 100%
VERIFIED ANSWERS|ACTUAL COMPLETE EXAM|
LATEST UPDATE
Combustion Requirements (3) ✔Correct Answer-Air, Fuel, Heat
Complete Combustion Produces (4) ✔Correct Answer-Water vapor, carbon dioxide, heat, and non combustible
ashes
incomplete combustion produces (3) ✔Correct Answer-carbon monoxide, hydrocarbons, and other gases
rate at which fuel burns is controlled by ✔Correct Answer-the amount of available air
air to fuel ratio is a ✔Correct Answer-critical factor in obtaining optimum fuel combustion
BTU ✔Correct Answer-British Thermal Unit, The amount of energy needed to heat one pound of water one
degree Fahrenheit
wood ignites at ✔Correct Answer-450-550 F
natural gas ignites at ✔Correct Answer-1,150 F
propane ignites at ✔Correct Answer-920-1120 F
electric spark temp ✔Correct Answer-1,700 F
hot surface igniter temp ✔Correct Answer-2,400 F
butane lighter temp ✔Correct Answer-3,200 F
stick match temp ✔Correct Answer-3,000 F
cigarette temp ✔Correct Answer-500-800 F
For complete combustion: air is ______ % oxygen + _____ % nitrogen ✔Correct Answer-20 : 80
for complete combustion, __(QTY)__ molecules of __(PART)___ need to be mixed with ___(QTY)__ molecule of
_____(PART)____ in the presence of __(PART)__ ✔Correct Answer-2 oxygen : 1 fuel : heat
When complete combustion happens __(4 things)___ are released ✔Correct Answer-heat, carbon dioxide
(C02), water vapor (H20), and nitrogen (N)
Carbon monoxide is dangerous because (other than senseless) ✔Correct Answer-it mixes with blood and
reduces oxygen carrying capacity
Aldehydes ✔Correct Answer-chemical compounds that have a strong pungent odor
Carbon monoxide is ________ when aldehydes are present ✔Correct Answer-present
Aldehydes result from ✔Correct Answer-flame impingement and through the presence of contaminated air
, Efficiency formula ✔Correct Answer-Heat output divided by heat input (percentage of heat transferred to
room)
3 Ts of efficiency ✔Correct Answer-Temperature, turbulence, time
Temperature (efficiency) ✔Correct Answer-minimum ignition temp
Turbulence (efficiency) ✔Correct Answer-fuel must collide with oxygen molecules (refers to the degree of fuel
and air mixing that occurs in combustion zone)
Time (efficiency) ✔Correct Answer-amount of time fuel gases remain in the high temp zone. also known as
"residence time"
Heat Transfer Efficiency ✔Correct Answer-refers to the percentage of heat generated by combustion actually
transferred to room
High heat transfer efficiency is normally associated with: (5 things) ✔Correct Answer-Appliance having
proportionally large exterior surfaces with good heat radiating properties
Long residence time of the hot gases in the Appliance
Adequate turbulence inside the appliance to property transfer heat from the fire chamber to appliance walls
Rapid heat transfer through the walls of the appliance
Adequate air movement (convection) outside
2 types of factory built fireplaces ✔Correct Answer-radiating and circulating
Radiant design ✔Correct Answer-transmits heat energy from firebox opening by direct radiation to the space
in front of it. (do not have grills or louvers on the face, heat moving blowers not avail.)
circulating design ✔Correct Answer-adds function of heat transfer via heated air convection by circulating air
around the fire chamber and releasing into space to be heated through grills and louvers
Built-in, high efficiency fireplaces ✔Correct Answer-contain efficient combustion and convection champers
that are enclosed in an insulated metal cabinet. Can be enclosed in close proximity to combustibles
Fireplace inserts and hearth stoves are ✔Correct Answer-designed to improve the efficiency of an open
fireplace and retain the general appearance of the fireplace while improving its efficiency
Hearth appliance construction ✔Correct Answer-modern solid fuel appliance designed to introduce
combustion air through specific and controllable air inlets and are controlled by the user
Most controlled combustion devices are made of (metals) ✔Correct Answer-cast iron or steel
Cast Iron (fireplace) ✔Correct Answer-made from molds, can be decorative
Steel (fireplace) ✔Correct Answer-welded joints that need no service, some use steel fireboxes inside
decorative cast iron
Soapstone (fireplace) ✔Correct Answer-lower thermal conductivity, delivers heat slowly but retain and
delivers heat longer
VERIFIED ANSWERS|ACTUAL COMPLETE EXAM|
LATEST UPDATE
Combustion Requirements (3) ✔Correct Answer-Air, Fuel, Heat
Complete Combustion Produces (4) ✔Correct Answer-Water vapor, carbon dioxide, heat, and non combustible
ashes
incomplete combustion produces (3) ✔Correct Answer-carbon monoxide, hydrocarbons, and other gases
rate at which fuel burns is controlled by ✔Correct Answer-the amount of available air
air to fuel ratio is a ✔Correct Answer-critical factor in obtaining optimum fuel combustion
BTU ✔Correct Answer-British Thermal Unit, The amount of energy needed to heat one pound of water one
degree Fahrenheit
wood ignites at ✔Correct Answer-450-550 F
natural gas ignites at ✔Correct Answer-1,150 F
propane ignites at ✔Correct Answer-920-1120 F
electric spark temp ✔Correct Answer-1,700 F
hot surface igniter temp ✔Correct Answer-2,400 F
butane lighter temp ✔Correct Answer-3,200 F
stick match temp ✔Correct Answer-3,000 F
cigarette temp ✔Correct Answer-500-800 F
For complete combustion: air is ______ % oxygen + _____ % nitrogen ✔Correct Answer-20 : 80
for complete combustion, __(QTY)__ molecules of __(PART)___ need to be mixed with ___(QTY)__ molecule of
_____(PART)____ in the presence of __(PART)__ ✔Correct Answer-2 oxygen : 1 fuel : heat
When complete combustion happens __(4 things)___ are released ✔Correct Answer-heat, carbon dioxide
(C02), water vapor (H20), and nitrogen (N)
Carbon monoxide is dangerous because (other than senseless) ✔Correct Answer-it mixes with blood and
reduces oxygen carrying capacity
Aldehydes ✔Correct Answer-chemical compounds that have a strong pungent odor
Carbon monoxide is ________ when aldehydes are present ✔Correct Answer-present
Aldehydes result from ✔Correct Answer-flame impingement and through the presence of contaminated air
, Efficiency formula ✔Correct Answer-Heat output divided by heat input (percentage of heat transferred to
room)
3 Ts of efficiency ✔Correct Answer-Temperature, turbulence, time
Temperature (efficiency) ✔Correct Answer-minimum ignition temp
Turbulence (efficiency) ✔Correct Answer-fuel must collide with oxygen molecules (refers to the degree of fuel
and air mixing that occurs in combustion zone)
Time (efficiency) ✔Correct Answer-amount of time fuel gases remain in the high temp zone. also known as
"residence time"
Heat Transfer Efficiency ✔Correct Answer-refers to the percentage of heat generated by combustion actually
transferred to room
High heat transfer efficiency is normally associated with: (5 things) ✔Correct Answer-Appliance having
proportionally large exterior surfaces with good heat radiating properties
Long residence time of the hot gases in the Appliance
Adequate turbulence inside the appliance to property transfer heat from the fire chamber to appliance walls
Rapid heat transfer through the walls of the appliance
Adequate air movement (convection) outside
2 types of factory built fireplaces ✔Correct Answer-radiating and circulating
Radiant design ✔Correct Answer-transmits heat energy from firebox opening by direct radiation to the space
in front of it. (do not have grills or louvers on the face, heat moving blowers not avail.)
circulating design ✔Correct Answer-adds function of heat transfer via heated air convection by circulating air
around the fire chamber and releasing into space to be heated through grills and louvers
Built-in, high efficiency fireplaces ✔Correct Answer-contain efficient combustion and convection champers
that are enclosed in an insulated metal cabinet. Can be enclosed in close proximity to combustibles
Fireplace inserts and hearth stoves are ✔Correct Answer-designed to improve the efficiency of an open
fireplace and retain the general appearance of the fireplace while improving its efficiency
Hearth appliance construction ✔Correct Answer-modern solid fuel appliance designed to introduce
combustion air through specific and controllable air inlets and are controlled by the user
Most controlled combustion devices are made of (metals) ✔Correct Answer-cast iron or steel
Cast Iron (fireplace) ✔Correct Answer-made from molds, can be decorative
Steel (fireplace) ✔Correct Answer-welded joints that need no service, some use steel fireboxes inside
decorative cast iron
Soapstone (fireplace) ✔Correct Answer-lower thermal conductivity, delivers heat slowly but retain and
delivers heat longer
