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Red Seal Prep > GAS > Flashcards

GAS Flashcards

1
Q

How far past a finished floor must the unthreaded portion of a gas pipe extend?

A

2”

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2
Q

What is the largest diameter of gas pipe that can have threaded joints?

A

2”

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3
Q

What is the minimum height above a roof penetration for a vent terminal?

A

2’

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4
Q

When can a manual vent damper be installed?

A

Only in a commercial application on appliances without a draft hood

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5
Q

What is the maximum length of a connector for a clothes dryer?

A

6’

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6
Q

What is the minimum clearance between a single wall vent connector and a combustible material?

A

6”

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7
Q

What is the minimum distance away from an openable window for a direct vent appliance with an input of 75,000 BTU?

A

12”

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8
Q

How is a direct vent appliance identified?

A

Always has an exhaust and an intake piped to outdoors

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9
Q

In what two states can propane be stored?

A

Liquid and vapour

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10
Q

Why can a fan assist appliance use a smaller air supply than a draft hood appliance with the same input?

A

Fan assist appliances do not require dilution air

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11
Q

What is the maximum length of a 4” single wall vent connector with two 90° elbows installed on a Category 1 appliance?

A

6’

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12
Q

What joining method is not permitted for gas lines?

A

Soldering

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13
Q

What is the minimum test pressure when pressure testing a low pressure gas installation?

A

15 psi

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14
Q

How much combustion air is required to burn 100,000 Btu’s of CH4?

A

1000 cubic feet

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15
Q

Why must a masonry chimney be lined when connecting a gas fueled appliance?

A

Condensation in the chimney will ruin mortar joints

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16
Q

What is the calorific value of propane as a liquid?

A

109560 BTU/imperial gallon

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17
Q

What shall be done with used fittings before re-using them on a new gas installation?

A

The must be inspected and ascertained to be as good as new

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18
Q

What marking is important for a decorative appliance designed to be installed in a fireplace?

A

FOR USE IN NONCOMBUSTIBLE FIREPLACES

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19
Q

How much of the thermocouple tip should be in the pilot flame?

A

3/8” to 1/2” of the tip

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20
Q

What is the minimum distance between a vent terminal and a mechanical air intake?

A

6’

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21
Q

What protection is required when a single wall venting material passes through a combustible ceiling?

A

6” clearance all the way around

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22
Q

What is the minimum bury depth of a gasline in a residential installation?

A

15”

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23
Q

What must be done to an appliance that has been involved in a fire or flood before it can be returned to service?

A

The appliance must be inspected

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24
Q

What does the abbreviation LPG mean?

A

Liquefied petroleum gas

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25
Q

What is the importance of a drop-out test?

A

To determine the lowest mV that will keep the power unit energized

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26
Q

How many BTU’s are available in 10 ft3 of propane gas?

A

25000 BTU

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27
Q

Hydrocarbons are made up of?

A

Hydrogen and carbon

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28
Q

What is the maximum length and operating pressure of an addition to the gasline that would be exempt from a standard air pressure test?

A

20’ and 0.5psi

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29
Q

What is the maximum BTU capacity of a vent terminal installed 12” from an openable window or door?

A

100 MBH

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30
Q

True or False

It is permissible to attach ductwork to any space heater

A

False

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31
Q

Where would you find the amount of gas the appliance should consume?

A

Rating plate

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32
Q

What is the maximum hanger spacing for copper tubing?

A

6’

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33
Q

What is the purpose of a response time test?

A

To confirm that the gas will shut off to the main burner within a specified time

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34
Q

Which gas fired appliance must be connected with a hose?

A

Infra-red tube heater

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35
Q

What minimum dimension is required for a clear and unobstructed passageway for an appliance?

A

36” x 36”

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36
Q

What is the minimum clearance above a horizontal furnace?

A

6”

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37
Q

When passing thorough a combustible wall or partition with a single wall vent connector, how are the combustibles protected?

A

A ventilated thimble is used

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38
Q

What would happen to the pressure drop if the length of the gas line were increased?

A

Pressure drop increases

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39
Q

What is the minimum clearance to combustibles for type B vent?

A

1”

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40
Q

What is the minimum wall thickness for copper tubing used in a low pressure gas installation?

A

Type G

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41
Q

How must a suspended unit heater be supported?

A

Mounted firmly with metal hangers or brackets

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42
Q

What is the minimum required height clearance from the floor for an infrared heater that is installed in either a repair or a shop area that communicates with an aircraft hanger?

A

8’

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43
Q

True or False

A horizontal furnace installed in an attic must have a walkway

A

True

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44
Q

What is the minimum gauge of a single wall vent connector?

A

28 GSG

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45
Q

How is an undersized gas line determined?

A

The pressure drop will exceed 1” WC

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46
Q

What is the closed circuit range for a thermocouple?

A

8-17mV

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47
Q

What is true in regard to propane burning appliances and safe hook up?

A

Propane can only be used for 100% safe hook-up

48
Q

What type of vent is approved for venting a solid fuel appliance?

A

Factory built chimney

49
Q

The range of flammability for CH4 is?

A

5-15%

50
Q

Where in a gas system is it allowable to use aluminum tubing?

A

To supply gas to a pilot burner only

51
Q

What is the smallest round pipe size used for venting a Category I appliance?

A

3”

52
Q

When sizing a gas line, to determine length, what would you take into consideration?

A

Distance from the meter to the furthest appliance

53
Q

What is the range of flammability for propane gas?

A

2.3-9.5%

54
Q

What is the pressure test requirement for welded natural gas pipe?

A

The greater of 50 psig or 1.5 times operating pressure for 3 hrs

55
Q

What is the required clearance from the edge of a roof or other hazard for an appliance?

A

6’

56
Q

What is the pressure test requirement for natural gas piping with a working pressure of 10 psi and a total length of 150ft?

A

50 psig for 60 minutes

57
Q

When vent connectors enter the common vent, which one is the lowest?

A

The largest size

58
Q

What type of appliance may be vented into a type B vent?

A

Any Category I appliance

59
Q

Why is it important to have a conversion burner correctly positioned and firmly secured?

A

To eliminate direct flame impingement on any surface other than a flame spreader

60
Q

What is the primary/secondary air requirement for natural gas?

A

10 cubic feet of air/cubic foot of gas

61
Q

What is the maximum equivalent length of an air supply duct before increasing the size?

A

20’

62
Q

Does thermostat location affect a millivolt gas valve powered by a thermopile?

A

Yes, wire thickness will increase as installation distance increases

63
Q

How is a venting system serving a single draft hood equipped appliance sized using rule of thumb?

A

The vent connector and the vent are the same size as the appliance outlet

64
Q

Except where permitted by Clause 4.13.2, what minimum clearance to combustible material is needed for a domestic type clothes dryer front?

A

24”

65
Q

How many table size reductions are permitted on a vent connection to a 5” draft hood?

A

1 size reduction is allowed

66
Q

What is the pressure in the vent when a power venter is connected to the B-vent wall termination?

A

Non-positive

67
Q

Natural Gas must never exceed _______ under any circumstance in any building.

A

65 psi

68
Q

Using “rule of thumb sizing”, what size is a common vent with a 6”, a 4”, and a 3” vent connector attached?

A

7”

69
Q

What is the difference between a safe hook up and 100% safe hookup?

A

A 100% safe hook-up will shut off the gas to the main burner and the pilot burner if the pilot flame is extinguished

70
Q

What kind of flame would be present on a pilot burner if an appliance was converted to propane without replacing the pilot orifice?

A

Pilot flame would be carbonizing

71
Q

What size is the vent serving a single gas appliance?

A

Same size as the draft hood

72
Q

What is the minimum rated working pressure for gas hose and fittings?

A

350 psi

73
Q

What important requirement is necessary for a return air duct of an air handling unit located where a spillage susceptible appliance is located?

A

That the return air duct connection to the air handler and duct joints are sealed

74
Q

What is the minimum clearance between a single wall vent connector and combustible material if the combustible material is protected with 28 ga heat sheild spaced 1” apart?

A

2” (refer to table 8.7)

75
Q

Which meter dial is used to determine the consumption of a gas appliance?

A

Proving dial

76
Q

When is it permissible to block an air supply for Category 1 appliances?

A

Never

77
Q

Two draft hood boilers each with an input of 1.5 MMBH are installed in a mechanical room. What size air supply is required?

A

285.7 in squared

78
Q

True or false

A radiant type room heater can be installed in a fireplace as long as a permanent stop is installed on the damper control to prevent complete closure of the flue outlet.

A

True

79
Q

True or false

A boiler can be installed on a combustible floor provided it is installed with a manufacturer’s certified special base.

A

True

80
Q

How is a vent serving two or more draft hood appliances sized using rule of thumb?

A

It will be 100% of the diameter of the largest outlet, plus 50% of the diameter of the other outlets

81
Q

What is required whenever air supply is provided to appliances by mechanical means?

A

Airflow sensing device

82
Q

If a propane appliance will burn 75,000 BTU/hr at an elevation of 0-2000 ft, what would the input be adjusted to if the appliance was installed at an elevation of 8100 ft?

A

56,700 BTU/hr

83
Q

What is the minimum side clearance for a bracket or pendant fixture from combustible materials?

A

5”

84
Q

What is the maximum length of a 3”single wall vent connector with two 90° elbows installed on a Category 1 appliance?

A

5’

85
Q

A chimney must terminate _____ feet higher than any obstruction within 10 feet.

A

2’

86
Q

What is the minimum above clearance from combustible material for a free standing circulating or radiant type room heater?

A

36”

87
Q

What determines the amount of air supply required by a gas appliance?

A

Venting method and input rating

88
Q

What is the smallest dimension allowed for a rectangular air supply duct?

A

3”

89
Q

What is the minimum height of an air supply inlet above grade level?

A

12”

90
Q

True or False

It is permissible to attach ductwork to any space heater?

A

False

91
Q

What protection is required when a single wall vent connector passes through a combustible wall?

A

A ventilated thimble

92
Q

What item does the thermocouple energize?

A

Power unit in a safety gas valve or safety switch

93
Q

The gas orifice determines the _________ of the gas delivered to the burner.

A

Volume

94
Q

Where is the best place to connect a manometer while measuring standing and operating pressures on a gas line?

A

At the dirt pocket of the farthest appliance from the gas meter

95
Q

According to the Code, when searching for a gas leak, what classification of electrical illumination is required for hazardous locations?

A

Class 1, Group 11A

96
Q

In a storage garage any component of an appliance capable of igniting a flammable vapor must be located at what minimum distance above the floor?

A

18”

97
Q

The underground portion of the gasline between a propane storage tank and the building it serves will have propane in what state?

A

May carry propane in it’s gaseous or liquid state

98
Q

True or False

A

When a downflow furnace is located in an enclosure, the circulating air and combustion air shall be taken from the same space.

99
Q

What is the equivalent length of a 90° change of direction in an air supply pipe?

A

10’

100
Q

What is the minimum gauge of a single wall vent connector for an incinerator?

A

20 GSG

101
Q

What is the normal pressure setting for a Natural Gas service regulator?

A

7” w.c.

102
Q

True or False

A decorative appliance can be installed in a bathroom or bedroom if it is a direct vent type.

A

True

103
Q

An increase in pressure will cause the boiling point of a liquid to?

A

Increase

104
Q

What size is the vent serving a single gas appliance?

A

Same size as the draft hood

105
Q

True or False

A vent connector should never be attached to a range

A

False

106
Q

What is the above clearance to combustible material for a hot plate?

A

30”

107
Q

Why can a fan assist appliance use a smaller air supply than a draft hood appliance with the same input?

A

Fan assist appliances do not require dilution air

108
Q

What method of joining underground piping or tubing is prohibited?

A

Threaded

109
Q

The main burner flame of a furnace should be?

A

Slightly carbonizing

110
Q

True or False

A conversion range burner with controls at the rear of the range is acceptable provided the valves are readily accessible

A

True

111
Q

What would happen to the pressure drop if the number of fittings on the gas line are reduced?

A

Pressure drop decreases

112
Q

What important requirement is necessary for the installation of gas appliances where combustible dust or fibers are present in a building?

A

The appliance must be certified or approved for such an installation

113
Q

What is the pressure test requirement for natural gas piping with a working pressure of 10 psi and a total length of 150ft?

A

50 psi for 60 minutes

114
Q

True or False

A furnace installed parallel to a refrigeration coil must be equipped with a damper to prevent the circulation of cool air through the furnace or of heated air over the refrigeration coil.

A

True

115
Q

When does the gas code allow for the Rule of Thumb method for vent sizing?

A

Only on draft hood appliances

116
Q

What is coaxial pipe?

A

Vent piping system which uses an oversized intake pipe with a smaller diameter exhaust pipe through the center

117
Q

What is the smallest size of a rectangular chimney?

A

12in squared

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