Review 3 Flashcards
1
Q
- Natural gas and propane are
A
(b is the correct answer) Member of the hydrocarbon (b is correct)
2
Q
- What is the odorant added to natural gas and propane
A
(A is Correct answer) mercaptan
3
Q
- What is the odorant added to natural gas and propane
A
(A is Correct answer) mercaptan
4
Q
- Which of the following statements regarding the odorant added to natural gas is correct?
A
(D is correct answer) the odorant added to natural gas tends to fade and fall out of suspension.
5
Q
- 85 % of natural gas is composed of
A
(B is the correct answer) methane
6
Q
- Identify the chemical formula for the following elements and compounds:
A
a) Methane CH4
b) Propane C3H8
c) Oxygen O2
d) Nitrogen n2
e) Water H2O
f) Carbon Dioxide CO2
g) Carbon monoxide CO
7
Q
- The approximate percentage of oxygen and nitrogen in air is
A
(B is correct) 21 % Oxygen and 79 % Nitrogen
8
Q
- Fill in the values concerning the properties of natural gas
A
a) Lower and upper limit of flammability: 405 % to 15 % of gas in air
b) Approximately ignition temperature: 1200 to 1300 F or 650 to 700 c
c) Heating value: 1000 Btus per cubic foot
d) Relative density or specific gravity as gas 0.6
e) Flame speed: 12inch per second
f) Expansion rate from liquid to gas 600
9
Q
- Fill in the values concerning the properties of propane
A
a) Lower and upper limit of flammability 24 % to 9.5 % of gas in air
b) Expansion rate form liquid to gas 270 %
c) Heating value 2500 Btus per cubic foot
d) Relative density or specific gravity as a gas 1. 52
e) Flame speed 32” / second
10
Q
- Which of the following statements is true concerning propane
A
(a is the correct answer) propane liquid escaping form a container rapidly drops in temperature.
11
Q
- Provide the full wording for the following acronyms:
A
a) L.EL Lower explosive limit
b) U.F.L Upper flammability lime
c) U.E.L Upper explosive limit
d) L.F.L Lower flammability limit
12
Q
- What is L.E.L.?
A
(b is the correct answer) The lowest percent of gas in the air-gas mixture will support combustion.
13
Q
- Odorant is added to natural gas at the:
A
(a is the correct answer) city gate
14
Q
- Pipelines delivering gas to the end user are known as:
A
(b is the correct answer) distribution pipelines
15
Q
- The maximum flame temperature from the combustion of natural gas with air is
A
Answer: 3500 F or 1925 c
16
Q
- This maximum flame temperature will be achieved when the level of oxygen in the
A
flue gases is 0 % and the level of carbon monoxide is 0 % ppm
17
Q
- The two main hydrocarbons which form natural gas are:
A
(a is the correct answer) methane and ethane
18
Q
- What is a “Btu”?
A
(b is the correct answer) British thermal unit
19
Q
A
20
Q
- The boiling point of propane is:
A
(C is the correct answer) -44° F (-42° C)
21
Q
- The boiling point of natural gas is:
A
(c is the correct answer) -44° F (-42° C)
22
Q
- What is the ignition temperature of propane gas compared to natural gas?
A
(b is the correct answer) lower or propane
23
Q
- Which of the following statements is correct concerning the heating value of equal volumes of propane compared to natural gas?
A
(c is the correct answer) Propane has 2 ½ times more heating value than natural gas
24
Q
- Natural Gas is_______ than air and propane is_________ than air
A
(c is the correct answer) lighter, Heav
25
25. One imperial gallon of propane weighs:
(c is the correct answer) 5.1 pounds (2.3 kilograms)
26
26. At 60°F (15.5° C) a pound of propane produces how many cubic feet of gas?
(c is correct) 8.50
27
27. Propane shall have a distinctive odour content to ensure it is readily detectable
(b is correct) 20% of the lower explosive limit.
28
28. When one pound of propane burns, it releases approximately:
(c is correct) 2,500 Btu.
29
29. The relative density of liquid propane as compared to water is approximately
(a is the correct answer) 0.5
30
30. Propane is a:
hydrocarbon
31
31. the propane:
As the temperature of liquid propane in a tank increases, the vapor pressure of
(a is the correct answer) increases
32
32. one boiler horsepower is approximately
(c is the correct answer) 24000 Btu (10 kw)
33
34
35
35. The "specific gravity of a gas (vapor" is:
(b is the correct answer) the weight of the gas as compared to the weight of an equal volume of air.
36
36. Define combustion?
Answer: Rapid oxidization of fuel creating heat and light
37
37. name the three elements required for the combustion of any fuel.
Answer: Fuel, Air, ( or oxygen) initiation heat
38
38. which one of the three elements would be the easiest to control or eliminate in a leak situation (before a fire occurs) and what steps must be taken to safely eliminate this element?
Answer: fuel off the gas supply at a manual valve and ventilate naturally
39
39. perfect combustion is theoretically achieved when the level of oxygen in flue gases is 0 % and the level of carbon monoxide is 0% ppm
40 name the three types of combustion
40
40 name the three types of combustion
Answer: perfect, complete, and incomplete
41
41. the products of perfect combustion of natural gas or propane with oxygen are
(a is the correct answer) water vapor, carbon dioxide, heat, and light
42
42. what air to gas ratio is required for the complete combustion of natural gas
(b is the correct answer) 10 parts of air to 1 part of gas
43
43. what air to gas ratio is required for the complete combustion of propane
(d is the correct answer) 24 parts of air to 1 part of gas
44
44. Air that is mixed with fuel prior to ignition is called
(a is correct answer) Primary air
45
45 Air that is mixed with fuel at the point of combustion and around the flame is called
(b is the correct answer secondary air
46
46. What is excess air
(b is correct answer) air in the combustion zone in addition to that which is required for combustion.
47
47. A long, yellow flame on an atmospheric burner is caused by:
(b is the correct answer) not premixing air and fuel prior to combustion
48
48. smoke in the flue gases may indicate that
(b is the correct answer) incomplete combustion is occurring.
49
49. the flue gases from the complete combustion of natural gas in air are primarily
(c is the correct answer) Carbon dioxide, water vapour, nitrogen, excess air, heat, and light
50
51
52
52. Which of the following is toxic
(d is the correct answer) Carbon monoxide.
53
53. Two undesirable products of incomplete combustion are:
(a is the correct answer) Carbon monoxide and aldehydes
54
54. which one of the following phrases refers to the air found in the products of combustion after the complete combustion of natural gas or propane?
(c is the correct answer) excess air.
55
55 Carbon dioxide and nitrogen are:
(b is the correct answer) inert gases
56
56. which one of the following substances is inert and passes through the combustion zone absorbing heat during the combustion process.
(d is the correct answer) nitrogen
57
57. what is the approximate dew point of the water vapor in combustion gases produced by a properly setup appliance?
(a is the correct answer) 130 F (54 C)
58
58. What problem (if any) occur if the dew point of the water vapour in combustion gases is reached in the appliance or venting system?
Any reasonable and thoughtful answer that recognizes the corrosive.
59
59. Carbon gas which is non- toxic.
(b is correct answer) Hydrocarbon fuels.
60
61. a blue flame is a reliable indicator of complete and efficient combustion
The answer is true.
61
62
62. Air supply to a gas-fired appliance includes:
( d is correct answer) All of the listed choices
63
63. If the air shutters on an atmospheric burner become plugged with dirt, the flame may:
(c is correct answer) appear yellow and long
64
64. A properly set up Bunsen burner flame is
(a is the correct answer) blue
65
65. If an atmospheric burner is supplied with too much primary air, the result may be:
(b is the correct answer) a lifting flame
66
66. What effect could negative pressure in a building have on the venting of an appliance?
(a is the correct answer) It may cause a downdraft condition at appliances.
67
67. Negative pressure in a building is caused by:
(d is the correct answer) lack of makeup air or combustion air
68
(d is the correct answer) 30 parts air to 1 part gas
69
69 What is the approximate total air volume supply required compared to gas input for a natural gas-fired atmospheric burner on an appliance equipped with a draft hood?
(d is the correct answer) 30 parts air to 1 part gas
70
70. How much combustion air is required to burn 10 cubic feet (283 cu. M.) of natural gas?
(a is the correct answer) 100 cu. Ft. (2.83 cu. M)
71
7.1 what is the normal percentage of combustion air to excess air requirements for an atmospheric burner?
The answer is: that excess air is usually an additional 50 % of that required for combustion.
72
72. list four possible causes of incomplete combustion, other than lack of air.
1 may include
2 flam quenching
3 blocked venting, negative building pressure
73
73. Which of the following statements is NOT correct regarding excess air in the combustion process?
(c is the correct answer) excess
74
What is the most common cause of orange flashes in a flame?
(d is the correct answer) dust or dirt
