Gas - Combustion Duct Sizing and Venting[][][][][][][][][][][][][][][][] Flashcards

1
Q

What are two types of draft?

A

Mechanical draft.

Natural draft[][][][]]

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2
Q

Name two types of draft control devices.

A

Barometric damper.

Draft hood or draft diverter.

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3
Q

What type of draft occurs in the combustion chamber of an appliance equipped with a draft hood?

A

Neutral over-fire draft.

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4
Q

What type of draft occurs in the chamber of an appliance equipped with a barometric damper?

A

Controlled negative over-fire draft.

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5
Q

List the common types of vents used on heating equipment.

A

A Vent

B Vent (Including BW and L)

BH Vent (Plastic)[][][][][][][][][][]]

C Vent[][][][][][][][][][][][][][][][][][][]]

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6
Q

Condensation in a chimney produces ______ acid.

A

Carbonic.

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7
Q

How can condensation in a brick chimney be corrected?

A

By installing a chimney liner.

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8
Q

What gives a manufactured Type A vent better insulating qualities than the Type B vent?

A

Winder seperation (1 in) between the double walls, filled with high-temperature insulating mineral fiber.

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9
Q

On what type of an appliance is a type BW vent used?

A

Recessed wall heaters.

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10
Q

Type L vents are usually used on what type of an appliance?

A

Combination appliances (gas/oil) where corrosion may be a problem.

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11
Q

What type of vent is usually used for high-efficiency furnaces (that allow condensation of the flue gas and very low vent temperatures)?

A

BH vent stainless steel and plastic (pressure).

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12
Q

In some cases a single-walled vent material is used to construct part, or all of a venting system. What is this type of vent called?

A

C Vent.

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13
Q

Type C vent joints are fastened together using __ sheet metal screws, equally spaced around the circumference of the pipe.

A

3.

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14
Q

Venting systems can be broken down into three categories. Name them.

A

Combined vent.

Direct vent[][][][]]

Individual vent[]

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15
Q

Name a double walled venting system that uses space between the vent walls to supply combustion air.

A

Direct vent.

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16
Q

Name a venting system that uses vent connectors and common vents.

A

Combined vent.

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17
Q

If a manifold system is installed with too much slope, the vent connector rise on the lower end may be very short. What problem can this cause?

A

Spillage.

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18
Q

When designing a multi-story venting system, why is it important that all appliances are located away from living areas?

A

So products of combustion cannot enter living areas if vent blockage occurs.

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19
Q

Which category of appliance operates with a non-positive vent static pressure and with a flue loss not less than 17%?

A

Category 1.

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20
Q

Which category of appliance is a condensing appliance operating with a positive vent static pressure and with a flue loss not less than 17%?

A

Category IV.

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21
Q

What is the minimum vent height required if the vent size is reduced from the flue collar size?

A

10 feet.

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22
Q

How many vent connectors are assumed when the vent connector lateral length is greater than zero?

A

Two.

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23
Q

May a fan-assisted appliance be individually vented into a tile-lined, masonry chimney?

A

No.

24
Q

When common vented appliances are located on the same floor, how is the total available height determined?

A

The height is measured from the highest draft hood outlet or the flue collar to the level of the cap or terminal.

25
Q

Is the linear interpolation of table entries allowed when desired values are not listed?

A

Yes.

26
Q

Is the extrapolation beyond the table entires allowed when desired values not listed?

A

No.

27
Q

When the code table shows more than one vent size acceptable, which is preferred?

A

The smallest.

28
Q

An appliance constructed so that all the combustion air is supplied directly from the products of combustion and vented directly to the outdoors by independent enclosed passageways connected directly to the appliance is the definition of?

A

Direct vent appliance.

29
Q

How is the air supply duct to a direct vent sized?

A

Manufacturers specifications.

30
Q

Using a device to regulate the temperature and speed of the flue gases is the definition of?

A

Draft control.

31
Q

What is the difference between an appliance that has draft control and one that does not?

A

The need for dilution air.

32
Q

What’s the first question you should ask yourself when beginning the process to size combustion ducts?

A

Low volume?

High volume?

33
Q

What is the minimum clearance of the combustion air opening above outside grade?

A. 6 inches.

B. 12 inches.

C. 18 inches[]

D. 24 inches.

A

D. 24 inches.

34
Q

Where air supply is provided by mechanical means from the outdoors it shall be based on:

A. 10ft³ per 1000 Btu’s.

B. 15ft³ per 1000 Btu’s.

C. 20ft³ per 1000 Btu’s.

D. 30 ft³ per 1000 Btu’s.

A

D. 30 ft³ per 1000 Btu’s.

35
Q

What type of appliances does the B149.1 codebook deal with when vent sizing using the tables in the appendix?

A. Category 1.

B. Category 2.

C. Category 3.

D. Category 4.

A

A. Category 1.

36
Q

What is the maximum temperature that “B” vent can handle?

A

470°F

37
Q

When would you use “A” vent?

A

Solid and liquid fuels.

38
Q

What type of material is BH venting made of and what are the temperature ratings of that material?

A

PVC - 65°F.

CPVC - 90°F.

39
Q

What does LTVH refer to?

A

Least total vent height.

40
Q

Can a single fan assist appliance be vented into a chimney?

A

No.

41
Q

The height from the top of the highest appliance to the top of the vent is the definition of?

A

Least total vent height.

42
Q

An appliance equipped with an atmospheric burner usually controls the draft with the use of a:

A. Draft exhaust fan.

B. Power venter[][][][]

C. Draft hood[][][][][][][]

D. Barometric draft control.

A

C. Draft hood.

43
Q

An appliance equipped with a type “B” venting system can burn:

A. Natural Gas.

B. Wood[][][][][][]

C. Oil[][][][][][][][][]

D. Coal[][][][][][][]]

A

A. Natural Gas.

44
Q

A high efficiency appliance that produces low temperature flue gases at a positive pressure should use a:

A. Type A vent.

B. Type B vent.

C. Type C vent.

D. Type BH vent s636.

A

D. Type BH vent s636.

45
Q

When a chimney flue serves an appliance which burns a solid-fuelled and gas-fuelled appliance in other than a dwelling unit, the venting of the gas-fuelled appliance shall be:

A. Through a seperate opening below the solid-fuelled appliance.

B. Through a seperate opening above the solid-fuelled appliance.

C. Combined with the solid-fuelled appliance with 30 inches of the flue.

D. Combined with the solid-fuelled appliance as close to the flue as possible.

A

B. Through a seperate opening above the solid-fuelled appliance.

46
Q

The air needed for safe combustion and adequate control of a venting system is the definition of?

A

Air supply requirement.

47
Q

What are two systems used to supply adequate combustion air?

A

Forced air flow.

Natural air flow.

48
Q

What are two methods for bringing in outside air to burners?

A

Ducts.

Hole in the wall.

49
Q

Forced air flow system to supply combustion air is the definition of?

A

Make up air heater method.

50
Q

What are two hazards that can be avoided by providing ventilation air?

A

Build-ups of excessive heat.

Flue gas spillage[][][][][][][][][][]

51
Q

What is the usual location of ventilation air openings?

A

Located as high as possible.

52
Q

Where are ventilation air openings never located?

A

Below the level of the lowest draft hood.

53
Q

True or False?

Allowing the temperature of the flue gases to decrease will decrease the potential for condensation of the flue gases.

A

False.

54
Q

Which type of vent is referred to as an all-fuel vent?

A. Type A.

B. Type B.

C. Type BH.

D. Type C[][]

A

A. Type A.

55
Q

Flue gases begin to condense at a temperature of approximately:

A. 470°F.

B. 250°F.

C. 127°F[]

D. 72°F[]]

A

C. 127°F.

56
Q

Referring to the figure below, it is a:

A. A non-adjustable draft device.

B. A barometric draft control device.

C. A flue gas analyzer[][][][][][][][][][][][][]]

D. An interlocked air damper[][][][][][][]

A

B. A barometric draft control device.

58
Q

True or False?

A barometric draft control device is designed to prevent spillage.

A

False.