1
GAS CFESA TEST ACTUAL EXAM NEWEST 2025 | ALL
100 QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) ALREADY GRADED A+| NEWEST VERSION
Where does natural gas come from? - ...(ANSWERS)....Wells deep in the ground
Where does LP gas come from? - ...(ANSWERS)....byproduct of crude oil, and
some is from natural gas pockets
What are the three different gases often termed as LP gas? -
...(ANSWERS)....butane, ethane, propane
Are LP tanks filled with gas or liquid? - ...(ANSWERS)....Liquid
What happens in a LP tank as gas is drawn off? - ...(ANSWERS)....The liquid boils
off and creates additional gas.
Does natural gas have any odor? - ...(ANSWERS)....No, not when it comes from
the ground and is cleaned
What is meant by the "specific gravity" of as gas? - ...(ANSWERS)....the weight of
gas compared to the weight of air
Is natural gas heavier or lighter than air? - ...(ANSWERS)....Lighter
, 2
Is LP gas heavier or lighter than air? - ...(ANSWERS)....Heavier
Why is LP gas more dangerous to work with than natural gas? - ...(ANSWERS)....LP
is heavier than air so it does not dissipate, and is more volatile
What is the heating value of a cubic foot of natural gas? - ...(ANSWERS)....Approx.
1000 Btu/cu. ft. Varies from 950 to 1150 btus
What is the heating value for LP gas? - ...(ANSWERS)....2500 Btu/cu. ft.
How should you check for gas leaks? - ...(ANSWERS)....Soap bubbles or electronic
leak detector
Which gas is more volatile, natural or LP gas? Why? - ...(ANSWERS)....LP, it has a
higher Btu rating per cubic foot, and is heavier than air so it does not dissipate.
What are 3 things needed for combustion? - ...(ANSWERS)....fuel, oxygen, heat
What are the 3 byproducts of complete combustion? - ...(ANSWERS)....Nitrogen,
carbon dioxide, water vapor
One cubic foot of natural gas requires how much air to burn? -
...(ANSWERS)....minimum of 10
, 3
How much byproducts are left after burning one cubic foot of natural or LP gas? -
...(ANSWERS)....25
What are the dangerous byproducts of that can be left after incomplete
combustion? - ...(ANSWERS)....carbon monoxide, aldehydes, and hydrogen
Why is carbon monoxide so dangerous? - ...(ANSWERS)....colorless and odorless
What are aldehydes? - ...(ANSWERS)....byproducts of incomplete combustion that
has a pungent odor
If carbon monoxide is being produced, will there be aldehydes? -
...(ANSWERS)....No, not always
If there are aldehydes, is there carbon monoxide present? - ...(ANSWERS)....yes
What determines how much carbon dioxide your blood absorbs? -
...(ANSWERS)....the concentration in air, and exposure length
What is primary air? - ...(ANSWERS)....Air that enters through the burner venturi.
What is secondary air? - ...(ANSWERS)....Air surrounding the burner, the air in the
room
, 4
How is primary air controlled? - ...(ANSWERS)....Air shutters at the inlet of the
burner.
What is the hottest part of a flame? - ...(ANSWERS)....light blue outer cone
What causes flames to lift off of a burner and maintain their shape? -
...(ANSWERS)....excessive gas pressure or primary air
What causes flames with yellow tips? - ...(ANSWERS)....Insufficient primary air
What causes an almost totally yellow flame? - ...(ANSWERS)....No primary air
What causes a shapeless flame to flow totally off of the burner? -
...(ANSWERS)....lack of secondary air
In a confined space, combustion air openings must be located where? -
...(ANSWERS)....12in from the floor and 12in from the ceiling
The minimum area allowed for a fresh air opening is what size? -
...(ANSWERS)....100 sq inches
A confined space connected to an unconfined space requires the combustion air
opening of one square inch for every _____ Btus? - ...(ANSWERS)....1000, with a
minimum of 100sq in
GAS CFESA TEST ACTUAL EXAM NEWEST 2025 | ALL
100 QUESTIONS AND CORRECT ANSWERS (VERIFIED
ANSWERS) ALREADY GRADED A+| NEWEST VERSION
Where does natural gas come from? - ...(ANSWERS)....Wells deep in the ground
Where does LP gas come from? - ...(ANSWERS)....byproduct of crude oil, and
some is from natural gas pockets
What are the three different gases often termed as LP gas? -
...(ANSWERS)....butane, ethane, propane
Are LP tanks filled with gas or liquid? - ...(ANSWERS)....Liquid
What happens in a LP tank as gas is drawn off? - ...(ANSWERS)....The liquid boils
off and creates additional gas.
Does natural gas have any odor? - ...(ANSWERS)....No, not when it comes from
the ground and is cleaned
What is meant by the "specific gravity" of as gas? - ...(ANSWERS)....the weight of
gas compared to the weight of air
Is natural gas heavier or lighter than air? - ...(ANSWERS)....Lighter
, 2
Is LP gas heavier or lighter than air? - ...(ANSWERS)....Heavier
Why is LP gas more dangerous to work with than natural gas? - ...(ANSWERS)....LP
is heavier than air so it does not dissipate, and is more volatile
What is the heating value of a cubic foot of natural gas? - ...(ANSWERS)....Approx.
1000 Btu/cu. ft. Varies from 950 to 1150 btus
What is the heating value for LP gas? - ...(ANSWERS)....2500 Btu/cu. ft.
How should you check for gas leaks? - ...(ANSWERS)....Soap bubbles or electronic
leak detector
Which gas is more volatile, natural or LP gas? Why? - ...(ANSWERS)....LP, it has a
higher Btu rating per cubic foot, and is heavier than air so it does not dissipate.
What are 3 things needed for combustion? - ...(ANSWERS)....fuel, oxygen, heat
What are the 3 byproducts of complete combustion? - ...(ANSWERS)....Nitrogen,
carbon dioxide, water vapor
One cubic foot of natural gas requires how much air to burn? -
...(ANSWERS)....minimum of 10
, 3
How much byproducts are left after burning one cubic foot of natural or LP gas? -
...(ANSWERS)....25
What are the dangerous byproducts of that can be left after incomplete
combustion? - ...(ANSWERS)....carbon monoxide, aldehydes, and hydrogen
Why is carbon monoxide so dangerous? - ...(ANSWERS)....colorless and odorless
What are aldehydes? - ...(ANSWERS)....byproducts of incomplete combustion that
has a pungent odor
If carbon monoxide is being produced, will there be aldehydes? -
...(ANSWERS)....No, not always
If there are aldehydes, is there carbon monoxide present? - ...(ANSWERS)....yes
What determines how much carbon dioxide your blood absorbs? -
...(ANSWERS)....the concentration in air, and exposure length
What is primary air? - ...(ANSWERS)....Air that enters through the burner venturi.
What is secondary air? - ...(ANSWERS)....Air surrounding the burner, the air in the
room
, 4
How is primary air controlled? - ...(ANSWERS)....Air shutters at the inlet of the
burner.
What is the hottest part of a flame? - ...(ANSWERS)....light blue outer cone
What causes flames to lift off of a burner and maintain their shape? -
...(ANSWERS)....excessive gas pressure or primary air
What causes flames with yellow tips? - ...(ANSWERS)....Insufficient primary air
What causes an almost totally yellow flame? - ...(ANSWERS)....No primary air
What causes a shapeless flame to flow totally off of the burner? -
...(ANSWERS)....lack of secondary air
In a confined space, combustion air openings must be located where? -
...(ANSWERS)....12in from the floor and 12in from the ceiling
The minimum area allowed for a fresh air opening is what size? -
...(ANSWERS)....100 sq inches
A confined space connected to an unconfined space requires the combustion air
opening of one square inch for every _____ Btus? - ...(ANSWERS)....1000, with a
minimum of 100sq in
