SAFE DISPENSING OF PROPANE
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS 100%
CORRECT RATED A+
Question 1
What are 3 characteristics of propane?
Answer: Colorless, odorless, and non-toxic
(Note: Pure propane is naturally colorless, odorless, and tasteless; commercial
propane is given a artificial odorant for leak detection).
Question 2
What is the initial boiling point of propane
-44 degree
Question 3
What does one gallon of liquid propane weigh in pounds
4.2 pounds
Question 4
How heavy is propane vapor compared to air? How heavy is liquid propane
compared to water?
Vapor relative to Air: 1.5 times heavier (Specific gravity = 1.50, where
Air = 1.0).
Liquid relative to Water: Half as heavy (Specific gravity = 0.504, where
Water = 1.0).
Question 5
What is the limit of flammability of propane vapor mixed in air (LEL to
UEL)?
Answer: 2.15% to 9.6% (commonly rounded in some texts to 2.3% – 9.5%)
Question 6
What is the most commonly used odorant in LP-gases, and why is it added?
Answer: Ethyl Mercaptan
Explanation: It is added because raw propane is naturally odorless; adding
Ethyl Mercaptan gives it a distinct "rotten egg" smell so leaks can be easily
detected by scent.
Question 7
When liquid propane is released to the atmosphere, what is its expansion
ratio?
Answer: 270 to 1 (or 270:1)
, Correction Note: Standard code specifies that 1 gallon of liquid propane
expands into approximately 270 gallons of gas vapor. (The 20% or 25%
values usually refer to the remaining expansion headspace required inside a
tank to prevent 100% liquid hydrostatic lock).
Question 8
Is pure propane gas non-toxic?
Answer: Yes
Explanation: Propane is non-toxic and non-poisonous to breathe, though
high concentrations in an enclosed space act as a simple asphyxiant by
displacing air/oxygen.
Name several potential sources of ignition? -ANSWER ✔✔Fans, switches, car
ignitions, static, cigs.
When the outside temperature increases, what happens to propane inside a
container? -ANSWER ✔✔Increase pressure
Name THREE types of specifications which propane containers are manufactured
under. -ANSWER ✔✔Container info/ filling connections valves/ product storage
area
What does DOT stand for? ASME? FAA? -ANSWER ✔✔Department of
Transportation, American Society of Mech. Engineering, Federal Aviation Admin.
How long after manufacture may a DOT Steel or Aluminum cylinder be used
before re-certification is required? How many re-certifications are allowed? -
ANSWER ✔✔12 years, every 5, 7, 12 years (as many as you want).
How long after manufacture may a DOT Composite cylinder be used before re-
certification is required? -ANSWER ✔✔5 years and every 5 years after 15 year
max
Where is the identification information found on a DOT cylinder? On an ASME
tank? -ANSWER ✔✔DOT: Collar/ Neck Ring/ Body. ASME: Data Plate
If an ASME container does not have a data plate, but appears to be in good
condition, can it be filled? -ANSWER ✔✔NO
QUESTIONS AND ANSWERS WITH
COMPLETE SOLUTIONS 100%
CORRECT RATED A+
Question 1
What are 3 characteristics of propane?
Answer: Colorless, odorless, and non-toxic
(Note: Pure propane is naturally colorless, odorless, and tasteless; commercial
propane is given a artificial odorant for leak detection).
Question 2
What is the initial boiling point of propane
-44 degree
Question 3
What does one gallon of liquid propane weigh in pounds
4.2 pounds
Question 4
How heavy is propane vapor compared to air? How heavy is liquid propane
compared to water?
Vapor relative to Air: 1.5 times heavier (Specific gravity = 1.50, where
Air = 1.0).
Liquid relative to Water: Half as heavy (Specific gravity = 0.504, where
Water = 1.0).
Question 5
What is the limit of flammability of propane vapor mixed in air (LEL to
UEL)?
Answer: 2.15% to 9.6% (commonly rounded in some texts to 2.3% – 9.5%)
Question 6
What is the most commonly used odorant in LP-gases, and why is it added?
Answer: Ethyl Mercaptan
Explanation: It is added because raw propane is naturally odorless; adding
Ethyl Mercaptan gives it a distinct "rotten egg" smell so leaks can be easily
detected by scent.
Question 7
When liquid propane is released to the atmosphere, what is its expansion
ratio?
Answer: 270 to 1 (or 270:1)
, Correction Note: Standard code specifies that 1 gallon of liquid propane
expands into approximately 270 gallons of gas vapor. (The 20% or 25%
values usually refer to the remaining expansion headspace required inside a
tank to prevent 100% liquid hydrostatic lock).
Question 8
Is pure propane gas non-toxic?
Answer: Yes
Explanation: Propane is non-toxic and non-poisonous to breathe, though
high concentrations in an enclosed space act as a simple asphyxiant by
displacing air/oxygen.
Name several potential sources of ignition? -ANSWER ✔✔Fans, switches, car
ignitions, static, cigs.
When the outside temperature increases, what happens to propane inside a
container? -ANSWER ✔✔Increase pressure
Name THREE types of specifications which propane containers are manufactured
under. -ANSWER ✔✔Container info/ filling connections valves/ product storage
area
What does DOT stand for? ASME? FAA? -ANSWER ✔✔Department of
Transportation, American Society of Mech. Engineering, Federal Aviation Admin.
How long after manufacture may a DOT Steel or Aluminum cylinder be used
before re-certification is required? How many re-certifications are allowed? -
ANSWER ✔✔12 years, every 5, 7, 12 years (as many as you want).
How long after manufacture may a DOT Composite cylinder be used before re-
certification is required? -ANSWER ✔✔5 years and every 5 years after 15 year
max
Where is the identification information found on a DOT cylinder? On an ASME
tank? -ANSWER ✔✔DOT: Collar/ Neck Ring/ Body. ASME: Data Plate
If an ASME container does not have a data plate, but appears to be in good
condition, can it be filled? -ANSWER ✔✔NO
