1
For Expert help and assignment solutions, +254707240657
CFESA Gas Questions and Answers (100%
Correct Answers) Already Graded A+
Where does natural gas come from?—Ans: Wells deep in the
ground
Where does LP gas come from?—Ans: byproduct of crude oil,
and some is from natural gas pockets
What are the three different gases often termed as LP gas?—Ans:
© 2025 Assignment Expert
butane, ethane, propane
Are LP tanks filled with gas or liquid?—Ans: Liquid
What happens in a LP tank as gas is drawn off?—Ans: The liquid
Guru01 - Stuvia
boils off and creates additional gas.
Does natural gas have any odor?—Ans: No, not when it comes
from the ground and is cleaned
What is meant by the "specific gravity" of as gas?—Ans: the
weight of gas compared to the weight of air
Is natural gas heavier or lighter than air?—Ans: Lighter
Is LP gas heavier or lighter than air?—Ans: Heavier
Why is LP gas more dangerous to work with than natural gas?—
Ans: 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?—Ans:
Approx. 1000 Btu/cu. ft. Varies from 950 to 1150 btus
What is the heating value for LP gas?—Ans: 2500 Btu/cu. ft.
How should you check for gas leaks?—Ans: Soap bubbles or
electronic leak detector
, 2
For Expert help and assignment solutions, +254707240657
Which gas is more volatile, natural or LP gas? Why?—Ans: 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?—Ans: fuel, oxygen,
heat
What are the 3 byproducts of complete combustion?—Ans:
Nitrogen, carbon dioxide, water vapor
One cubic foot of natural gas requires how much air to burn?—
Ans: minimum of 10
How much byproducts are left after burning one cubic foot of
natural or LP gas?—Ans: 25
© 2025 Assignment Expert
What are the dangerous byproducts of that can be left after
incomplete combustion?—Ans: carbon monoxide, aldehydes,
and hydrogen
Guru01 - Stuvia
Why is carbon monoxide so dangerous?—Ans: colorless and
odorless
What are aldehydes?—Ans: byproducts of incomplete
combustion that has a pungent odor
If carbon monoxide is being produced, will there be aldehydes?—
Ans: No, not always
If there are aldehydes, is there carbon monoxide present?—Ans:
yes
What determines how much carbon dioxide your blood
absorbs?—Ans: the concentration in air, and exposure length
What is primary air?—Ans: Air that enters through the burner
venturi.
What is secondary air?—Ans: Air surrounding the burner, the air in
the room
How is primary air controlled?—Ans: Air shutters at the inlet of the
burner.
What is the hottest part of a flame?—Ans: light blue outer cone
, 3
For Expert help and assignment solutions, +254707240657
What causes flames to lift off of a burner and maintain their
shape?—Ans: excessive gas pressure or primary air
What causes flames with yellow tips?—Ans: Insufficient primary air
What causes an almost totally yellow flame?—Ans: No primary air
What causes a shapeless flame to flow totally off of the burner?—
Ans: lack of secondary air
In a confined space, combustion air openings must be located
where?—Ans: 12in from the floor and 12in from the ceiling
The minimum area allowed for a fresh air opening is what size?—
Ans: 100 sq inches
© 2025 Assignment Expert
A confined space connected to an unconfined space requires
the combustion air opening of one square inch for every _____
Btus?—Ans: 1000, with a minimum of 100sq in
A combustion air opening to the outside must be one square inch
Guru01 - Stuvia
for every _____ Btus if open directly to the outside, or by vertical
duct?—Ans: 4000
If horizontal ducts are used to bring in fresh air, the size must be
one square inch for every _____ Btus?—Ans: 2000
All outside combustion air opening must be protected with
what?—Ans: Screen, not smaller than 1/4mesh
What is the difference between a vent and a flue?—Ans: A flue
removes byproducts from the combustion chamber, a vent
removes byproducts from the room to the outdoors
What are the two primary functions of the flue?—Ans: Remove
combustion byproducts, and create a draft to pull in secondary
air
How critical is the sizing of the flue? Why?—Ans: Very, too small
and it will not remove all the byproducts, too large and the vapors
condense
Can a vent pipe be connected directly to the flue on a piece of
gas equipment?—Ans: NO
For Expert help and assignment solutions, +254707240657
CFESA Gas Questions and Answers (100%
Correct Answers) Already Graded A+
Where does natural gas come from?—Ans: Wells deep in the
ground
Where does LP gas come from?—Ans: byproduct of crude oil,
and some is from natural gas pockets
What are the three different gases often termed as LP gas?—Ans:
© 2025 Assignment Expert
butane, ethane, propane
Are LP tanks filled with gas or liquid?—Ans: Liquid
What happens in a LP tank as gas is drawn off?—Ans: The liquid
Guru01 - Stuvia
boils off and creates additional gas.
Does natural gas have any odor?—Ans: No, not when it comes
from the ground and is cleaned
What is meant by the "specific gravity" of as gas?—Ans: the
weight of gas compared to the weight of air
Is natural gas heavier or lighter than air?—Ans: Lighter
Is LP gas heavier or lighter than air?—Ans: Heavier
Why is LP gas more dangerous to work with than natural gas?—
Ans: 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?—Ans:
Approx. 1000 Btu/cu. ft. Varies from 950 to 1150 btus
What is the heating value for LP gas?—Ans: 2500 Btu/cu. ft.
How should you check for gas leaks?—Ans: Soap bubbles or
electronic leak detector
, 2
For Expert help and assignment solutions, +254707240657
Which gas is more volatile, natural or LP gas? Why?—Ans: 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?—Ans: fuel, oxygen,
heat
What are the 3 byproducts of complete combustion?—Ans:
Nitrogen, carbon dioxide, water vapor
One cubic foot of natural gas requires how much air to burn?—
Ans: minimum of 10
How much byproducts are left after burning one cubic foot of
natural or LP gas?—Ans: 25
© 2025 Assignment Expert
What are the dangerous byproducts of that can be left after
incomplete combustion?—Ans: carbon monoxide, aldehydes,
and hydrogen
Guru01 - Stuvia
Why is carbon monoxide so dangerous?—Ans: colorless and
odorless
What are aldehydes?—Ans: byproducts of incomplete
combustion that has a pungent odor
If carbon monoxide is being produced, will there be aldehydes?—
Ans: No, not always
If there are aldehydes, is there carbon monoxide present?—Ans:
yes
What determines how much carbon dioxide your blood
absorbs?—Ans: the concentration in air, and exposure length
What is primary air?—Ans: Air that enters through the burner
venturi.
What is secondary air?—Ans: Air surrounding the burner, the air in
the room
How is primary air controlled?—Ans: Air shutters at the inlet of the
burner.
What is the hottest part of a flame?—Ans: light blue outer cone
, 3
For Expert help and assignment solutions, +254707240657
What causes flames to lift off of a burner and maintain their
shape?—Ans: excessive gas pressure or primary air
What causes flames with yellow tips?—Ans: Insufficient primary air
What causes an almost totally yellow flame?—Ans: No primary air
What causes a shapeless flame to flow totally off of the burner?—
Ans: lack of secondary air
In a confined space, combustion air openings must be located
where?—Ans: 12in from the floor and 12in from the ceiling
The minimum area allowed for a fresh air opening is what size?—
Ans: 100 sq inches
© 2025 Assignment Expert
A confined space connected to an unconfined space requires
the combustion air opening of one square inch for every _____
Btus?—Ans: 1000, with a minimum of 100sq in
A combustion air opening to the outside must be one square inch
Guru01 - Stuvia
for every _____ Btus if open directly to the outside, or by vertical
duct?—Ans: 4000
If horizontal ducts are used to bring in fresh air, the size must be
one square inch for every _____ Btus?—Ans: 2000
All outside combustion air opening must be protected with
what?—Ans: Screen, not smaller than 1/4mesh
What is the difference between a vent and a flue?—Ans: A flue
removes byproducts from the combustion chamber, a vent
removes byproducts from the room to the outdoors
What are the two primary functions of the flue?—Ans: Remove
combustion byproducts, and create a draft to pull in secondary
air
How critical is the sizing of the flue? Why?—Ans: Very, too small
and it will not remove all the byproducts, too large and the vapors
condense
Can a vent pipe be connected directly to the flue on a piece of
gas equipment?—Ans: NO
