NFI Exam Review
Combustion Requirements (3) - Answer-Air, Fuel, Heat
Complete Combustion Produces (4) - Answer-Water vapor, carbon dioxide, heat, and non combustible
ashes
incomplete combustion produces (3) - Answer-carbon monoxide, hydrocarbons, and other gases
rate at which fuel burns is controlled by - Answer-the amount of available air
air to fuel ratio is a - Answer-critical factor in obtaining optimum fuel combustion
BTU - Answer-British Thermal Unit, The amount of energy needed to heat one pound of water one
degree Fahrenheit
wood ignites at - Answer-450-550 F
natural gas ignites at - Answer-1,150 F
propane ignites at - Answer-920-1120 F
electric spark temp - Answer-1,700 F
,hot surface igniter temp - Answer-2,400 F
butane lighter temp - Answer-3,200 F
stick match temp - Answer-3,000 F
cigarette temp - Answer-500-800 F
For complete combustion: air is ______ % oxygen + _____ % nitrogen - Answer-20 : 80
for complete combustion, __(QTY)__ molecules of __(PART)___ need to be mixed with ___(QTY)__
molecule of _____(PART)____ in the presence of __(PART)__ - Answer-2 oxygen : 1 fuel : heat
When complete combustion happens __(4 things)___ are released - Answer-heat, carbon dioxide (C02),
water vapor (H20), and nitrogen (N)
Carbon monoxide is dangerous because (other than senseless) - Answer-it mixes with blood and reduces
oxygen carrying capacity
Aldehydes - Answer-chemical compounds that have a strong pungent odor
Carbon monoxide is ________ when aldehydes are present - Answer-present
Aldehydes result from - Answer-flame impingement and through the presence of contaminated air
Efficiency formula - Answer-Heat output divided by heat input (percentage of heat transferred to room)
, 3 Ts of efficiency - Answer-Temperature, turbulence, time
Temperature (efficiency) - Answer-minimum ignition temp
Turbulence (efficiency) - Answer-fuel must collide with oxygen molecules (refers to the degree of fuel
and air mixing that occurs in combustion zone)
Time (efficiency) - Answer-amount of time fuel gases remain in the high temp zone. also known as
"residence time"
Heat Transfer Efficiency - Answer-refers to the percentage of heat generated by combustion actually
transferred to room
High heat transfer efficiency is normally associated with: (5 things) - 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 - Answer-radiating and circulating
Combustion Requirements (3) - Answer-Air, Fuel, Heat
Complete Combustion Produces (4) - Answer-Water vapor, carbon dioxide, heat, and non combustible
ashes
incomplete combustion produces (3) - Answer-carbon monoxide, hydrocarbons, and other gases
rate at which fuel burns is controlled by - Answer-the amount of available air
air to fuel ratio is a - Answer-critical factor in obtaining optimum fuel combustion
BTU - Answer-British Thermal Unit, The amount of energy needed to heat one pound of water one
degree Fahrenheit
wood ignites at - Answer-450-550 F
natural gas ignites at - Answer-1,150 F
propane ignites at - Answer-920-1120 F
electric spark temp - Answer-1,700 F
,hot surface igniter temp - Answer-2,400 F
butane lighter temp - Answer-3,200 F
stick match temp - Answer-3,000 F
cigarette temp - Answer-500-800 F
For complete combustion: air is ______ % oxygen + _____ % nitrogen - Answer-20 : 80
for complete combustion, __(QTY)__ molecules of __(PART)___ need to be mixed with ___(QTY)__
molecule of _____(PART)____ in the presence of __(PART)__ - Answer-2 oxygen : 1 fuel : heat
When complete combustion happens __(4 things)___ are released - Answer-heat, carbon dioxide (C02),
water vapor (H20), and nitrogen (N)
Carbon monoxide is dangerous because (other than senseless) - Answer-it mixes with blood and reduces
oxygen carrying capacity
Aldehydes - Answer-chemical compounds that have a strong pungent odor
Carbon monoxide is ________ when aldehydes are present - Answer-present
Aldehydes result from - Answer-flame impingement and through the presence of contaminated air
Efficiency formula - Answer-Heat output divided by heat input (percentage of heat transferred to room)
, 3 Ts of efficiency - Answer-Temperature, turbulence, time
Temperature (efficiency) - Answer-minimum ignition temp
Turbulence (efficiency) - Answer-fuel must collide with oxygen molecules (refers to the degree of fuel
and air mixing that occurs in combustion zone)
Time (efficiency) - Answer-amount of time fuel gases remain in the high temp zone. also known as
"residence time"
Heat Transfer Efficiency - Answer-refers to the percentage of heat generated by combustion actually
transferred to room
High heat transfer efficiency is normally associated with: (5 things) - 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 - Answer-radiating and circulating
