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2nd year sheet metal > Gas Fundamentals > Flashcards

Gas Fundamentals Flashcards

1
Q

At what point is primary air supplied to the combustion zone?

A

Upstream from point of combustion

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2
Q

What does theoretical air consist of?

A

Primary and secondary air

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3
Q

Excess air + theoretical air =

A

Total combustion air

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4
Q

What is another name for calorific value?

A

Heating value

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5
Q

Propane in a tank will build from liquid to vapour and expands _________ times its original volume?

A

270

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6
Q

Standard temperature and pressure?

A

60 degrees F and 14.7 psia

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7
Q

Three constituents of fire?

A

Heat, fuel and oxygen

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8
Q

Incomplete combustion can produce harmful products, name 2?

A

Aldehydes and carbon monoxide

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9
Q

Water vapour, carbon dioxide and nitrogen are produced when all fuel gas is burned and what takes place?

A

Complete combustion

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10
Q

Appliance output divided by appliance input gives you?

A

Appliance efficiency

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11
Q

When sizing combustion air and the input falls between 2 figures, what should you do on the chart?

A

Round up

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12
Q

What is the difference between tight and loose construction?

A

Tight has vapour barrier, loose does not

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13
Q

Where are combustion air terminals fastened?

A

To the appliance having the largest BTU input

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14
Q

If height for grade cannot be adhered to, what can be installed?

A

A gooseneck

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15
Q

Automatic dampers can be installed on combustion air, where will they be wired?

A

Interlocked to the main burner. In case of fail, the damper will be in the open position.

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16
Q

What is added to gas from the transmission company to ensure safe handling? And at what rate is it added?

A

Mercaptan
1 lb/1,000,000 cubic feet

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17
Q

Ambient air admitted to a venting system at a draft control device is known as what type of air?

A

Dilution air

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18
Q

What temperature is water most dense?

A

4 degrees C or 39 degrees F

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19
Q

Density x Volume =

A

Mass

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20
Q

When water changes to steam, its volume increases approximately ________ times?

A

1700

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21
Q

Fusion is the transformation from solid to ____________?

A

Liquid

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22
Q

Condensation is the transformation from ___________ to liquid?

A

Gas

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23
Q

In heat transfer, what type is through direct contact?

A

Conduction

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24
Q

What type of heat transfer takes place because of differences in density?

A

Convection

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25
Q

Transmission of heat energy by means of electromagnetic infrared rays is what type of heat transfer?

A

Radiation

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26
Q

Substances expand and contract at different rate, what is this known as?

A

The coefficient of linear expansion

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27
Q

According to the principles of hydrostatics, what will happen to the pressure on a horizontal pipe if the length of the pipe is increased?

A

Horizontal runs do not increase pressure so it will stay the same

28
Q

What is the heating value of Propane?

A

2500

29
Q

Propane cylinder may be filled to?

A

80% of the volume or 42% of the water capacity

30
Q

What is the minimum pressure rating for a propane cylinder?

A

240 psig

31
Q

Name 3 types of draft when referring to venting appliances

A

Forced, natural and induced

32
Q

How high must vents extend above a roof that is flat?

A

Minimum 2’ and 2’ higher than any portion of a building within 10’

33
Q

Type B vent clearance to combustibles?

A

1”

34
Q

Type BW vent clearance to combustibles?

A

1/2”

35
Q

For each additional 90 degree change of direction over 2, how must the table be derated for draft hood appliances?

A

10% or derate by multiplying by .90

36
Q

What is a concern for venting a single mid efficient into a masonry chimney?

A

Condensation

37
Q

Where must a vent terminal be located in regards to a mechanical air supply?

A

Not within 6’

38
Q

What is ROT and what does it mean with respect to sizing vents?

A

Rule of Thumb sizing and it means to simply size the vent connector and common vent the same size as the draft hood or flue collar outlet

39
Q

All piping and equipment before and including the meter is the ownership of?

A

The utility company

40
Q

How many inches of water column is a low pressure natural gas line system?

A

7” to 14” WC

41
Q

Low pressure propane gas line system?

A

11” WC

42
Q

What is the smallest diameter of threaded pipe that can be used for natural gas unless it is schedule 80?

A

1/2”

43
Q

What type of gas line fitting cannot be nested?

A

Bushings

44
Q

When pipe protrudes through a ceiling or wall, how much pipe must be exposed? Through a floor?

A

Ceiling or wall-1” unthreaded pipe exposed
Floor-2” unthreaded pipe exposed

45
Q

How deep must gas lines be buried in a commercial installation?

A

24”

46
Q

What is the first thing that must be determined prior to sizing a gas line?

A

Longest run (total furthest distance)

47
Q

Pressure taken in a gas line with only the pilot burning is what type of test?

A

Standing pressure test

48
Q

Pressure taken in a gas line with the appliances main burner operating is what type of test?

A

Operating pressure test

49
Q

What is the minimum size face on a test gauge?

A

3” in diameter

50
Q

Maximum working pressure of propane in a single family dwelling?

A

2 psig

51
Q

Gas law that states the pressure will increase, volume will decrease if the temperature remains constant?

A

Boyles Law

52
Q

Gas law that states if the temperature increases and the volume increases, the pressure will remain constant?

A

Charles Law

53
Q

Two ways of removing water from natural gas?

A

Adsorption and absorption

54
Q

Who is responsible for setting gas line pressures inside or outside of a building?

A

The installer

55
Q

Define matter?

A

Anything that has mass and occupies space

56
Q

What are 2 factors that affect the state in which matter exists?

A

Pressure and temperature

57
Q

What type of heat is the energy absorbed or released when a substance undergoes a phase change?

A

Latent heat

58
Q

When you say that liquid propane is lighter than water, you are referring to its?

A

Relative density

59
Q

What is used to allow a single wall vent connector to pass through a floor or a ceiling?

A

A ventilated metal thimble

60
Q

Clearance to combustibles for “C” vent?

A

6”

61
Q

When a chimney liner is used, how much must the tables be derated?

A

20%

62
Q

What type of venting is used on a high efficient oil burning appliance?

A

Type L

63
Q

What do you call support hangers for vertical pipe?

A

Riser clamps

64
Q

What is the function of pipe dope?

A

Lubricant

65
Q

What is the maximum volume of gas released from a vent?
Natural gas
Propane

A

Natural gas-2.5 cu.ft
Propane-1cu.ft

66
Q

How are gaskets for grooved joints identified?

A

By color

67
Q

What can happen if a malleable iron fitting has been over tightened onto a carbon iron pipe?

A

Creeping

2nd year sheet metal (5 decks)

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