AL LP Gas Fitter Contractor Exam
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. What is the primary purpose of a pressure regulator in an LP-gas
system?
a. To increase the volume of gas stored in the tank
b. To reduce and control gas pressure to the required operating level
c. To remove odorant from the gas
d. To convert propane into liquid
Answer: b. To reduce and control gas pressure to the required
operating level
Rationale: A regulator reduces the higher pressure supplied by the
storage container or upstream piping to a controlled pressure suitable
for downstream piping and appliances. Proper regulation is essential for
,safe appliance operation and to prevent excessive pressure from
reaching the system.
2. Which gas is commonly used as the principal fuel in an LP-gas
system?
a. Oxygen
b. Nitrogen
c. Propane
d. Carbon dioxide
Answer: c. Propane
Rationale: Propane is one of the primary liquefied petroleum gases used
for residential, commercial, agricultural, and industrial applications. It is
stored as a liquid under pressure and vaporizes when released into the
fuel system.
3. Why is odorant added to LP gas?
a. To increase its heating value
b. To make leaks easier to detect
c. To reduce vapor pressure
d. To prevent freezing
,Answer: b. To make leaks easier to detect
Rationale: LP gas naturally has little or no detectable odor. An odorant
is added so that people can recognize the characteristic smell
associated with a gas leak and take appropriate action.
4. LP gas stored in a container is primarily in what state?
a. Solid
b. Liquid
c. Plasma
d. Compressed solid
Answer: b. Liquid
Rationale: Propane is stored primarily as a liquid under pressure. When
gas is withdrawn for use, liquid propane vaporizes within the container
to replace the vapor being consumed.
5. What happens to propane when pressure is reduced sufficiently?
a. It can vaporize from liquid to gas
b. It becomes permanently solid
, c. It loses all heating value
d. It becomes oxygen
Answer: a. It can vaporize from liquid to gas
Rationale: Propane has a relatively low boiling point. Under appropriate
temperature and pressure conditions, liquid propane changes into
vapor, allowing it to be delivered through piping to appliances.
6. What is the main hazard created by an accumulation of unburned
LP gas?
a. It produces oxygen
b. It can create a fire or explosion hazard
c. It neutralizes electrical current
d. It automatically extinguishes nearby flames
Answer: b. It can create a fire or explosion hazard
Rationale: Unburned LP-gas vapor can mix with air and form a
combustible mixture. If an ignition source is present, the accumulated
gas can ignite rapidly. Preventing leaks and providing proper ventilation
are therefore critical.
Questions and Correct Answers (Verified
Answers) Plus Rationale 2027 Q&A|
Instant Download Pdf
1. What is the primary purpose of a pressure regulator in an LP-gas
system?
a. To increase the volume of gas stored in the tank
b. To reduce and control gas pressure to the required operating level
c. To remove odorant from the gas
d. To convert propane into liquid
Answer: b. To reduce and control gas pressure to the required
operating level
Rationale: A regulator reduces the higher pressure supplied by the
storage container or upstream piping to a controlled pressure suitable
for downstream piping and appliances. Proper regulation is essential for
,safe appliance operation and to prevent excessive pressure from
reaching the system.
2. Which gas is commonly used as the principal fuel in an LP-gas
system?
a. Oxygen
b. Nitrogen
c. Propane
d. Carbon dioxide
Answer: c. Propane
Rationale: Propane is one of the primary liquefied petroleum gases used
for residential, commercial, agricultural, and industrial applications. It is
stored as a liquid under pressure and vaporizes when released into the
fuel system.
3. Why is odorant added to LP gas?
a. To increase its heating value
b. To make leaks easier to detect
c. To reduce vapor pressure
d. To prevent freezing
,Answer: b. To make leaks easier to detect
Rationale: LP gas naturally has little or no detectable odor. An odorant
is added so that people can recognize the characteristic smell
associated with a gas leak and take appropriate action.
4. LP gas stored in a container is primarily in what state?
a. Solid
b. Liquid
c. Plasma
d. Compressed solid
Answer: b. Liquid
Rationale: Propane is stored primarily as a liquid under pressure. When
gas is withdrawn for use, liquid propane vaporizes within the container
to replace the vapor being consumed.
5. What happens to propane when pressure is reduced sufficiently?
a. It can vaporize from liquid to gas
b. It becomes permanently solid
, c. It loses all heating value
d. It becomes oxygen
Answer: a. It can vaporize from liquid to gas
Rationale: Propane has a relatively low boiling point. Under appropriate
temperature and pressure conditions, liquid propane changes into
vapor, allowing it to be delivered through piping to appliances.
6. What is the main hazard created by an accumulation of unburned
LP gas?
a. It produces oxygen
b. It can create a fire or explosion hazard
c. It neutralizes electrical current
d. It automatically extinguishes nearby flames
Answer: b. It can create a fire or explosion hazard
Rationale: Unburned LP-gas vapor can mix with air and form a
combustible mixture. If an ignition source is present, the accumulated
gas can ignite rapidly. Preventing leaks and providing proper ventilation
are therefore critical.
