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Truck Company Operations Mittendorf 1998 > Chapter 12 Gas Utilities > Flashcards

Chapter 12 Gas Utilities Flashcards

1
Q

What odorant is commonly added to natural gas?

A

Thiophane

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2
Q

Newer distribution mains of polyethylene are recognizable by what color?

A

Pink or bright orange

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3
Q

What are the primary components of a meter set assembly?

A

Piping, shutoff valve, regulator, and meter

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4
Q

What does a green band on a riser near a stopcock valve indicate?

A

The service line is plastic

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5
Q

Why are rotary meters used?

A

To regulate high pressures and to handle quick surges

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6
Q

To turn off the flow of gas with a stopcock valve, you should turn the tang to what position?

A

Crosswise to the pipe

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7
Q

To eliminate the flow of gas to a multiunit dwelling, which stopcock should you shut off?

A

The stopcock on the common riser

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8
Q

Who should restore the flow of gas to a building when the supply has been shut off?

A

Only a gas company representative

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9
Q

What are the three categories of natural gas emergencies?

A

Inside leaks, outside leaks, and leaks resulting from fires

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10
Q

Normally, what type of gas leak poses the greatest danger?

A

Gas leaks inside structures that present the potential for an explosion

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11
Q

Natural gas supplies approx. ___ of the energy requirements of the U.S.

A

1/3

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12
Q

What hydrocarbons is natural gas generally comprised of?

A

Methane and Ethane

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13
Q

What chemical impurities can be present in natural gas?

A

Nitrogen, carbon dioxide, hydrogen sulfide, helium

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14
Q

What percent of natural gas is methane?

A

97 PERCENT

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15
Q

What may be used in natural gas at 400 parts per million and used for identification? how?

A

Helium
Seepage from underground storage or breaks in gas lines can be differentiated from seepage from natural underground pockets

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16
Q

What concentrations is Thiophane used in natural gas?

A

1 pint per million cubic feet

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17
Q

Natural gas transmission lines have pressures up to what PSI?

A

1000 PSI

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18
Q

How big are transmission lines?

A

12-36 inches

19
Q

What pressure can be found in distribution mains?

A

60 psi

20
Q

What are distribution mains made out of?

A

Older–steel or copper

Newer–polyethylene

21
Q

What color are polyethylene distribution mains?

A

Pink or bright orange

22
Q

What is the pressure inside customer gas lines?

A

1/3 psi

23
Q

How is the pressure in a customer line regulated?

A

regulator and gas meter

24
Q

What is a MSA and what 3 locations can these be found?

A

Meter Set Assembly

Outside sets–outside of structure
underneath sets–underneath structures, stairs..
Curb meter box–vault underneath sidewalk

25
Q

What does a MSA consist of?

A

Piping
shut-off valve
regulator
gas meter

26
Q

What is a riser?

A

pipe rising vertically from the ground close to the exterior wall of a structure

27
Q

What is a shut-off valve called?

A

stopcock or service cock

28
Q

What does a flat washer on the stopcock indicate?

A

service line is plastic pipe inserted inside an older metal pipe

29
Q

What does a ring on the stopcock valve indicate?

A

branch service

30
Q

What does a band (normally green) on the riser near the stopcock indicate?

A

service line is plastic

31
Q

What pressure does the regulator receive? what does it reduce it down to?

A

60 psi–down to 1/3 psi

32
Q

What is an earthquake valve?

A

emergency vibration-sensitive shutoff device

33
Q

What is a Nordstrum valve? How far can the tang be turned?

A

an industrial shutoff valve used for high-pressure applications

The tang can only be turned 1/8th turn

34
Q

When dealing with branch service, what occupancy has the standard service? the others are branch service

A

the occupancy farthest from the supply main

35
Q

Generally, what is the safest and most direct method of eliminating the flow of gas to a structure?

A

turn it off at the stopcock

36
Q

What does a basic stopcock consist of?

A 
Internal core
Casing
Washer
backing nut
circlip
37
Q

What does a G chiseled or painted on the curb indicate?

A

required by OSHA–shows the location where the service line passes beneath the curb and indicates the side of the building on which the MSA is located

38
Q

In an emergency situation where the stopcock wont turn, how might you free it up to turn?

A

Loosen the backing nut up ONE TURN ONLY. tap the backing nut with non-metallic hammer,and turn 1/4 turn

39
Q

What are the 3 primary objectives when dealing with a gas leak emergency?

A

Safety
Protection of Property
Prompt and efficient control of incident

40
Q

What 3 categories can natural gas be divided into?

A

Inside leaks
Outside leaks
Leaks resulting in fires

41
Q

What is a service entrance cock?

A

It is a master valve where the service enters the building

42
Q

What is the best immediate procedure for responding to an outside leak?

A

Call the gas company

43
Q

Of all the decisions to be made, what has the most variables?

A

Where to stop a leak

44
Q

Pipe lines may contain hazardous contaminates known as what?

A

PCBs–Polychlorinated biphenyls

Truck Company Operations Mittendorf 1998 (17 decks)

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