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1
Q
A
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2
Q

In order to increase regulator accuracy, the pitot tube senses pressure at what point?

A

Lowest outlet pressure point

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3
Q

Which regulator will have the least amount of droop under flow conditions?

A

A pilot operated regulator

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4
Q

Critical flow in a regulator occurs when the velocity of the gas reaches what threshold?

A

Sonic Velocity

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5
Q

What does a double-ported balance regulator use to sense downstream pressure?

A

A downstream sense line

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6
Q

Where is the sense line connected on a proportional regulator?

A

To the top of the diaphragm

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7
Q

When zero governor regulators are used for burners that are to be operated under positive or negative combustion chamber conditions, how can the combustion chamber pressure be counterbalanced?

A

Connecting a pressure reference line from the combustion chamber to the top diaphragm chamber of the zero governor

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8
Q

What type of regulator is pictured below?

A

Double-ported balanced regulator

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9
Q

In the above image what is the purpose of connecting the sense line?

A

To sense outlet pressure

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10
Q

In the above image at what point is the sense line connected to the main supply piping?

A

Downstream to the top of the piping

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11
Q

What type of regulator is pictured below?

A

Atmospheric regulator

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12
Q

What type of regulator is pictured below?

A

Pilot operated regulator

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13
Q

What would happen if the regulator shown below was installed backwards?

A

It will pass no flow

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14
Q

What would happen if the above regulator was installed upside down?

A

It would provide lower downstream pressure

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15
Q

When selecting a regulator for a gas piping system, what regulator inlet pressure should you assume there to be when the system is under no flow?

A

Static pressure (system setting)

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16
Q

For a direct-operated regulator, what amount of droop can be expected?

A

10-20%, but by code should be no more than 10%

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17
Q

When you need extreme accuracy in high-pressure gas system applications, what type of regulator is best suited for this application?

A

Pilot-operated

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18
Q

If two or more available regulator springs have published pressure ranges that include the desired pressure setting, for more accuracy you would select the spring with the lower pressure range.

TRUE / FALSE

A

TRUE

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19
Q

What factors make it beneficial to select a regulator orifice size in the smallest diameter that will handle the desired flow?

A

Avoids instability and premature wear, Allows for smaller relief valves, Reduces lockup pressure

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20
Q

What is used to determine the required flow of relief valves for a gas system?

A

The wide-open flow rates of the upstream regulator

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21
Q

What is the maximum droop allowed from a regulator in a gas piping system?

A

10%

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22
Q

What four factors affect the flow of gas through a piping system?

A

Type of gas, diameter of pipe, length of pipe, pressure drop

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23
Q

What factor determines which of the two formulas are used to develop the code tables?

A

System Pressure

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24
Q

Pipe sizing tables in the B149.1 used to size low pressure piping systems make an allowance for a reasonable number of fittings. How is this accomplished?

A

By adding a hidden 20% to the displayed code zone lengths (as noted in the formula in the code book)

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25
Q

Plastic pipe is approved for use in a liquid propane system.

TRUE / FALSE

A

FALSE (B149.1.20, 6.2.16)

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26
Q

In what two ways can the volume of gas required for an appliance be determined?

A

The appliance rating plate, or the appliance manufacturer when the rating is not shown on the appliance (B149.1.20, 6.4.2)

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27
Q

What shall not be done if piping or tubing is located in an area where a corrosive chemical is used?

A

It must not be concealed (B149.1.20, 6.7.3)

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28
Q

In British Columbia, piping of NPS 2 ½” and over shall have welded pipe joints.

TRUE / FALSE

A

FALSE. BC Gas Safety Regulations - 2.3 Clause 6.9.2 of CSA B149.1-20 is repealed and the following substituted: 6.9.2 Piping of NPS 2-1/2 to 4 shall be either press-connect fittings certified to CSA 6.32(ANSI LC-4) or welded pipe joints. Piping greater than NPS 4 shall be welded pipe joints.

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29
Q

If a gas piping system requires welding, who can perform this welding?

A

Welding of gas piping systems shall be performed in accordance with a procedure and by an operator registered under the applicable provincial or territorial legislation.
(B149.1.20, 6.9.3).

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30
Q

When can piping or tubing enter a building below grade?

A

Only when permitted by the Authority Having Jurisdiction (good luck) (B149.1.20, 6.15.8)

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31
Q

What are the three ways that piping or tubing can be identified by in a care, detention occupancy, commercial, industrial or assembly building?

A

The entire piping or tubing system shall be painted yellow, The piping or tubing system shall be provided with yellow banding that has a minimum width of 1” and is marked at intervals not exceeding 20’, or the piping or tubing system shall be labelled “GAS” or “PROPANE” utilizing yellow label s or markings.
(B149.1.20, 7.17.1)

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32
Q

Can a quick disconnect device be used instead of a manual shut off valve?

A

NO (B149.1.20, 6.18.7)

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33
Q

When is an overpressure protection device required by code?

A

When the inlet pressure to a main pressure regulator exceeds the pressure rating of any downstream component or accessory

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34
Q

What method of overpressure protection will interrupt flow of gas in the event of an over pressurization?

A

Automatic shut-off system

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35
Q

Which type of over pressure protection system must be manually reset after it has been activated?

A

Automatic shut-off

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36
Q

Referring to the figure below, if the main diaphragm ruptures, what is the likely result?

A

The relief valve will provide reduced flow rates

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37
Q

Referring to the figure below, this is an example of which type of over-pressure protection?

A

Pressure relief

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38
Q

Referring to the figure below, what method of overpressure protection is represented?

A

Upstream monitor system

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39
Q

Referring to the figure below, how can we easily change which regulator is the worker and which is the monitor?

A

Switch the set points on the regulators

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40
Q

A separate line relief valve shall be installed where in relationship to the regulator?

A

As close as possible downstream from the regulator

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41
Q

Why do air requirements differ for appliances with and without draft control?

A

Units with draft control require dilution air

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42
Q

An atmospheric gas appliance has an input of 390 Mbh and is equipped with a draft hood. It is to be installed in a building that complies with code clause 8.2.1. A or B. What size duct is required to provide air to this appliance?

A

9”

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43
Q

A furnace room complies with code clause 8.2.1. (a) or (b). It contains a 260 Mbh furnace without draft control and a 120 Mbh hot water heater with a draft hood.

Size the combustion air duct based on a length of 21’

A

7”

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44
Q

A boiler room contains the following five pieces of equipment:

  • one 3500 Mbh boiler with draft control
  • two 450 Mbh hot water heaters with draft hoods
  • two 750 Mbh duct heaters without draft control.

Calculate the required free area of the combustion air duct.

A

436 in2

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45
Q

The following gas appliances are installed in a mechanical room:

  • one 1400 Mbh steam boiler with a barometric damper
  • one 550 Mbh hot water heater with draft hood
  • two 600 Mbh direct fired make-up air units

Select a square grill for the combustion air opening in the boiler room wall that will meet the minimum requirements of the B149.1 gas code (grills rated at 67% free area).

A

18” x 18” (314.507 in2)

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46
Q

The air supply to a 20,000 Mbh boiler, using a force draft burner, is provided by mechanical means through a horizontal duct 42 feet in length. What is the quantity of air required to be supplied to the boiler?

A

600,000 ft3 (30 ft3 for every 1,000 btu/h)

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47
Q

A 2,752 Mbh forced draft natural gas boiler is operating in a mechanical room, excess air set at 40%. What is the required free area for the combustion air duct?

A

92 in2

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48
Q

A structure is equipped with a boiler rated at 5,300 MBH and a hot water tank rated at 400,000 Btu/h. Both pieces of equipment are equipped with draft controls and the air supply is ducted from outdoors. What is the size of the free ventilation air opening?

A

47.9 in2

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49
Q

A structure is equipped with a boiler rated at 750 kW and a barometric draft control. What is the free area of the combustion air supply opening in mm?

A

162,750 mm2

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50
Q

A structure has a mechanical room into which air must be ducted from outdoors. It contains the following appliances:

  • One boiler rated at 3,000 MBH, equipped with a barometric damper
  • Two duct heaters without draft controls rated at 950,000 Btu/h each
  • Two hot water tanks rated at 250,000 Btu/h each. Both tanks are equipped with draft hoods

What is the free area of the combustion air supply opening?

A

385 in2

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51
Q

A structure is equipped with appliances rated at 1,900 MBH. None of the appliances is equipped with draft control devices and the air supply is ducted from outdoors. What is the free area of the ventilation air opening?

A

10 in2

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52
Q

A structure has a mechanical room into which air must be ducted from outdoors. It contains the following appliances:

  • One boiler with no draft control rated at 500 kW
  • One boiler with draft control rated at 4,000 MBH
  • One duct heater with no draft control rated at 125 kW
  • One hot water heater with a draft hood rated at 800,000 Btu/h

What is the free area of the combustion air supply opening?

A

485.37 in2

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53
Q

A mechanical room is equipped with gas appliances with a total input of 3,200 Mbh. All appliances are equipped with draft control devices. The louvre specified for the combustion air opening has a free area of 70%. What is the size of the opening required to fit the louvre?

A

428.58 in2

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54
Q

What is the minimum opening size on a screen used on a combustion air-supply opening?

A

1/4”

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55
Q

On a combustion air louvre with dampers the dampers must be controlled in what way?

A

Automatically

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56
Q

What interlock is required for an automatically adjustable combustion air louvre?

A

Normally Open contact interlocked with burner control

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57
Q

What two fan styles are commonly used for mechanical air supply systems?

A

Axial and Centrifugal

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58
Q

When air is provided by mechanical means what type of switch must be used?

A

The code does not specify the type. Air proving switch (sail or differential)

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59
Q

What three factors would lead you to want to pre heat combustion air?

A

Prevent the freezing of pipes, prevent thermal shock of the boiler, maintain appliance efficiency

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60
Q

What do ICI Appliance manufacturers do for high altitude installations? (above 4500 feet)

A

Increase blower motor horse power

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61
Q

What is the relationship between static pressure and air flow?

A

As static pressure goes up air flow goes down

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62
Q

What three factors have the greatest affect the static pressure in ducting?

A

Cross sectional area, length, number of fittings

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63
Q

What is the static pressure ranges of the following combustion supply-air ducting systems?

a. Low Pressure:

b. Medium Pressure:

c. High Pressure:

A

a. less that 3” w.c.
b. 3” to 6” w.c.
c. 6” to 10” w.c.

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64
Q

What advantage does a direct contact water heater have?

A

No loss out the stack, no lost condensation, no lost radiant heat.

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65
Q

Describe how an immersion burner works.

A

A submerged radiant tube heat exchanger is used to heat large volumes of liquid.

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66
Q

Describe how an indirect bath heater works.

A

It uses two separate, submerged heat exchangers to heat a fluid with one heat exchanger and transfer that heat from the fluid to the second heat exchanger.

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67
Q

What are three of the potential hazards of using a direct fired construction heater?

A
  • Being too close to combustibles can lead to a fire
  • The possibility of fire if used in a wood frame structure
  • There is the potential for dangerous levels of carbon monoxide
68
Q

What is a curing oven used for?

A

Used to generate some form of chemical reactions once a temperature setpoint is reached by a particular substance.

69
Q

What is a drying oven used for?

A

It is used to remove moisture from materials.

70
Q

What is a baking oven used for?

A

It is used to remove moisture from materials and to generate some form of chemical reactions once a temperature setpoint is reached by a particular substance.

71
Q

What is the typical temperature range of an industrial furnaces?

A

750 to 3,275 °F

72
Q

What is the purpose of a CO2 generator?

A

To produce carbon dioxide required by plants in commercial green houses.

73
Q

What is the purpose of an exothermic generator?

A

To produce cover gasses as a non-oxidizing atmosphere for the heat treating of bright metals.

74
Q

What is the purpose of an endothermic generator?

A

To provide a positive pressure in a heat-treating furnace, and a platform on which a carburizing or decarburizing environment can be formulated.

75
Q

A direct fired make-up air unit is designed for temperatures ranging from -5⁰F to 85⁰F. At what outdoor temperature (within design parameters) will the velocity across the burners be the greatest?

A

85⁰F

76
Q

A direct fired makeup air heater has the same function as an RTU.
TRUE / FALSE

A

FALSE

77
Q

What is the main benefit of a DFMAH?

A

No efficiency lost to a heat exchange

78
Q

Referring to the B149.1 under what conditions can a DFMAH be used?

A

A DFMAH shall not be installed unless it is necessary to exhaust air and replace it with preheated air

79
Q

What must be proved before the DFMAH can start?

A

Any inlet or discharge air louvres must be proved open through an interlock with the control the exhaust system is operating

80
Q

What is the purpose of makeup air?

A

To replace the air exhausted by large exhaust appliances which, when properly designed, installed and maintained ensure a neutral pressure in the building

81
Q

When a DFMAH is used in a kitchen it must be interlocked with the kitchen exhaust fan so that neither fan can operate without the other operating?
TRUE / FALSE

A

TRUE

82
Q

List three things that could affect the external static pressure placed on a DFMAH.

A

Filters, Grilles, Ductwork

83
Q

When the DFMAH is in operation the burner is always firing?
TRUE / FALSE

A

FALSE

84
Q

What are the two modes of operation for a spray booth DFMAH?

A

Spray Mode, Bake Mode

85
Q

In a DFMAH what is adjusted to control air velocity?

A

Profile plates

86
Q

Other than make up air for a kitchen or spray booth list three other applications for DFMAH.

A

Shaft pressurization (stairwell or elevator), storage garage, mine shaft

87
Q

What is the purpose of tertiary air in the combustion process?

A

To add air to control emissions and flame shape

88
Q

What type of heat transfer does an infrared burner utilize?

A

Direct radiation

89
Q

What type of heat transfer does a low temperature indirect heating burner use?

A

It uses a fan to transport the heated air to the work

90
Q

What type of heat transfer does a direct-fired burner use?

A

It uses a mix of radiation and hot gas convection

91
Q

What type of heat transfer does a high temperature indirect-heated burner utilize?

A

Tubes or enclosed walls are heated and radiate heat to the work

92
Q

Identify the type of flame represented in the following image:

A

Figure 1 type A

93
Q

Identify the type of flame represented in the following image:

A

Figure 2 type C

94
Q

Identify the type of flame represented in the following image:

A

Figure 3 type E

95
Q

Identify the type of flame represented in the following image:

A

Figure 4 type F

96
Q

Identify the type of flame represented in the following image:

A

Figure 5 type H

97
Q

A propane fired boiler has a low-fire input of 1,700,000 BTUH and a high-fire input of 22,100,000 BTUH. What is its turndown ratio?

A

13:1

98
Q

What ratio of air/natural gas are most premix burners limited to for acceptable, normal operation?

A

10:1

99
Q

What are three characteristics of a nozzle mix burner?

A
  • Its ability to operate over a wide range of air/gas ratios
  • To control the mixing of the gas and air without sacrificing clean combustion or flame stability
  • To allow the ability to vary the flame shape
100
Q

What methods can be used to atomize oil in an oil fired burner?

A
  • Air atomizing
  • Pressure atomizing
  • Steam atomizing
101
Q

How can the flame length of an oil-fired burner be modified?

A

Changing the oil nozzle spray angle

102
Q

The main burner flame shall be proven at the furthest point(s) along its base from the source of ignition when the burner flame width is in excess of how many feet?

A

3 feet

103
Q

What style of burner is represented by the following image:

A

a. Gun burner

104
Q

What style of burner is represented by the following image:

A

Lance burner

105
Q

What style of burner is represented by the following image:

A

Cane burner

106
Q

What style of burner is represented by the following image:

A

Immersion burner

107
Q

What can be the results of an improperly selected, sized and/or installed venting system?

A

Efficiency loss, Appliance damage, Increased appliance maintenance, damage to breeching & stack, Production downtime, Increased operating costs.

108
Q

Define forced draft:

A

A mechanical draft produced by a device upstream from the combustion zone of an appliance

109
Q

What is the draft source for a natural draft appliance? Explain how this draft source moves the products of combustion through the appliance and the venting.

A

Gravity is the source. It moves the products of combustion through the appliance and venting because the hot flue gases are lighter and naturally rise (buoyancy).

110
Q

Define induced draft:

A

A mechanical draft produced by a device downstream from the combustion zone of an appliance

111
Q

Describe the three general variations of Burner inlet blowers and the different pressures associated with each.

A

a. Blowers which operate with enough pressure to overcome the burner alone. The combustion chamber, appliance outlet and venting will all be under negative pressure
b. Blowers which operate with enough pressure to overcome the burner and combustion chamber. The combustion chamber will be under positive pressure, appliance outlet will be neutral or negative and the appliance venting will be under negative pressure
c. Blower which operates with enough pressure to overcome the burner, combustion chamber and part or all of the venting. All parts of the system past the burner are under positive pressure.

112
Q

What is the pressure upstream of the blower when it is located on the outlet of the appliance?

A

Negative

113
Q

What is the pressure downstream of the inducer blower located on the outlet of the appliance?

A

It will be positive immediately downstream but could be either negative, neutral or positive on the downstream side depending on the blower’s power and the venting system

114
Q

In a venting or chimney system with mechanical draft what two types of draft can be present and what type of pressure is associated with each?

A

Forced draft – static pressure in the venting is positive
Induced draft – static pressure is the venting is negative

115
Q

When a venting system was originally installed as a gravity system where is the best location for the blower to be located? Why?

A

Forced draft – static pressure in the venting is positive
Induced draft – static pressure is the venting is negative

116
Q

What must be done when a power venter is used in place of a natural draft venting system.

A

Gas flow to the main burner must be prevented in the event of power venter failure

117
Q

When must design registration take place when you are designing or modifying complex, technical, and regulated equipment in BC?

A

Before the construction and installation of the equipment

118
Q

When are parallel blade damper used?

A

For open/closed operation

119
Q

When are opposed blade dampers used?

A

For modulating operation

120
Q

What must be done when an automatic flue damper is installed on an appliance with a continuous pilot?

A

Must have a fixed minimum opening of 20% of the flue area and be interlocked with the burner control system so the that damper is proved fully open before ignition of main burner and The fuel supply to the appliance will be shut off in the event of failure except where the damper will fail fully open.

121
Q

What are three common ways to prove draft in an appliance or venting system?

A

A pressure switch, An integrated proven draft switch, A pressure transducer

122
Q

What type of boiler is generally considered to be not limited in its energy output and operating pressure?

A

Water tube boiler

123
Q

Referring to Figure 1, what type of boiler is shown?

A

Horizontal Fire tube boiler

124
Q

Referring to Figure 1, how would this boiler be identified for passes?

A

2-pass

125
Q

Referring to Figure 1, what is the first pass that the burner is firing into referred to as?

A

Morrison tube

126
Q

What can be done in a firetube boiler to maintain a consistent velocity of the flue products through the boiler?

A

Decrease the amount of tubes at each consecutive pass

127
Q

What type of firetube boiler has a reversal chamber surrounded by water?

A

Wet back

128
Q

Referring to Figure 2, what is the portion of tubes called in a water tube boiler in which the cooler water flows down to the steam drum?

A

Downcomers

129
Q

What type of firetube boiler has a reversal chamber that is not surrounded by water?

A

Dry back

130
Q

Referring to Figure 2, what is the portion of tubes called in a water tube boiler in which the hot water flows up the portion of the tubes connected between the lower and upper drums?

A

Risers

131
Q

Referring to Figure 3, what is the part of the water tube boiler identified within the red circle?

A

Mud drum

132
Q

Referring to Figure 4, what is the part of the water tube boiler identified within the red circle?

A

Steam drum

133
Q

Referring to Figure 5, what is the design type called for this water tube boiler?

A

A type

134
Q

Referring to Figure 6, what is the design type called for this water tube boiler?

A

D type

135
Q

Referring to Figure 7, what is the design type called for this water tube boiler?

A

O type

136
Q

What is the input of an 80% efficient steam boiler with an EDR rating of 11,500 ft2?

A
137
Q

What is the BHP rating of a hot water boiler with an output rating of 3,400 MBH?

A
138
Q

What Btu output would be required from a steam boiler to supply 8300 ft2 of exposed radiation?

A
139
Q

The input of a 75% efficient steam boiler is 1,000 MBH. How many pounds of 212°F water could be generated into 212°F Steam in 90 min?

A
140
Q

A hot water boiler is 80% efficient and operates at 170°F. How many ft3 of C3H8 would be consumed each hour to heat a building which contains 7100 ft2 of gross EDR?

A
141
Q

A propane boiler with an input of 5,000 MBH is 75% efficient. How many ft2 of net EDR will it satisfy when operating with 170 o F water?

A
142
Q

A building with a net EDR of 15,500 ft2 is heated with a 100 BHP steam boiler. By what percentage would the boiler have to be over fired in order to satisfy the required output?

A
143
Q

If a steam boiler was fired at 140% of its rated output of 60 BHP, how many ft2 of net EDR could the boiler service?

A
144
Q

A boiler with rating of 109 BHP is to be fired on CH4 what would you suggest is the input? Assume 75% efficiency.

A
145
Q

Modern burner controls do not need to be continuously powered.

A

FALSE

146
Q

What initiates the burner cycle?

A

The Control Circuit switches being completed

147
Q

List some of the typical switches that could be found on the limit circuit of a boiler.

A

Manual switch, operating Aquastat, high limit Aquastat, low water cut-off, thermostat, DDC contacts, Pressuretrol, flow switch, aux-low water cut-off.

148
Q

What is the purpose of an interlock?

A

To stop the burner from firing to prevent an appliance from damaging itself if a condition fails to be satisfied.

149
Q

What must be done when a non-recycling interlock opens?

A

It must be reset manually

150
Q

What feature shall be included on a low water cut-off that is an interlock for a water boiler that is located above the hot-water circulating system?

A

It must have a manual reset feature.

151
Q

Define Permissive:

A

Conditions that need to be satisfied before you can start the equipment cycle.

152
Q

Define Interlock:

A

Prevents an appliance from damaging itself if a condition fails to be satisfied.

153
Q

List the common run interlocks:

A

Combustion Air Proving Switch (CAPS), Mag Starter Aux Switch, Low gas Pressure Switch (LGPS), High Gas Pressure Switch (HGPS), Oil Temp Switch, Low Oil Pressure Switch, Low Atomizing Media Switch

154
Q

What type of interlock is required when combustion air is supplied by mechanical means?

A

A combustion air proving switch

155
Q

What is the “normal” position of a combustion air proving switch?

A

Open (NO)

156
Q

What is the purpose of the purge interlock:

A

To prove adequate air supply before the start of the pre-purge countdown timer and during the purge period.

157
Q

What is the purpose of a low fire start interlock?

A

To prove combustion air damper and fuel valve are in low fire position before ignition.

158
Q

How many air changes of the combustion zone and flue passages must take place during the pre-purge period prior to the ignition cycle?

A

4

159
Q

When shall a proven low fire start be required?

A

On a variable input appliance that has an input in excess of 1,000,000 BTUH, unless otherwise approved.

160
Q

List 4 types of pre-ignition interlocks:

A

Start interlock, fuel valve switch, proof of closure switch, overtravel proof of closure switch

161
Q

Define proof of closure switch:

A

A factory sealed switch incorporated into a safety shut-off valve that includes at least one set of contacts, which close only after the valve port is closed and which open prior to the opening of the valve port.

162
Q

What type of switch is pictured below?

A

Over Travel Proof of Closure Switch

163
Q

For a PID controller, what does the proportional do?

A

It produces an output value that is proportional to the current error value

164
Q

For a PID controller, what does the derivative do?

A

It sums the error over time

165
Q

For a PID controller, what does the proportional gain do?

A

It determines the ratio of output response to the error signal

166
Q

For a PID controller, what does the integral do?

A

It acts as a brake or dampener on the control effort

Line D (13 decks)

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