Chapter 12 Gas Utilities

Question 1

What odorant is commonly added to natural gas?

Answer 1

Thiophane

Question 2

Newer distribution mains of polyethylene are recognizable by what color?

Answer 2

Pink or bright orange

Question 3

What are the primary components of a meter set assembly?

Answer 3

Piping, shutoff valve, regulator, and meter

Question 4

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

Answer 4

The service line is plastic

Question 5

Why are rotary meters used?

Answer 5

To regulate high pressures and to handle quick surges

Question 6

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

Answer 6

Crosswise to the pipe

Question 7

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

Answer 7

The stopcock on the common riser

Question 8

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

Answer 8

Only a gas company representative

Question 9

What are the three categories of natural gas emergencies?

Answer 9

Inside leaks, outside leaks, and leaks resulting from fires

Question 10

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

Answer 10

Gas leaks inside structures that present the potential for an explosion

Question 11

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

Answer 11

1/3

Question 12

What hydrocarbons is natural gas generally comprised of?

Answer 12

Methane and Ethane

Question 13

What chemical impurities can be present in natural gas?

Answer 13

Nitrogen, carbon dioxide, hydrogen sulfide, helium

Question 14

What percent of natural gas is methane?

Answer 14

97 PERCENT

Question 15

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

Answer 15

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

Question 16

What concentrations is Thiophane used in natural gas?

Answer 16

1 pint per million cubic feet

Question 17

Natural gas transmission lines have pressures up to what PSI?

Answer 17

1000 PSI

Question 18

How big are transmission lines?

Answer 18

12-36 inches

Question 19

What pressure can be found in distribution mains?

Answer 19

60 psi

Question 20

What are distribution mains made out of?

Answer 20

Older–steel or copper

Newer–polyethylene

Question 21

What color are polyethylene distribution mains?

Answer 21

Pink or bright orange

Question 22

What is the pressure inside customer gas lines?

Answer 22

1/3 psi

Question 23

How is the pressure in a customer line regulated?

Answer 23

regulator and gas meter

Question 24

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

Answer 24

Meter Set Assembly

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

Question 25

What does a MSA consist of?

Answer 25

Piping shut-off valve regulator gas meter

Question 26

What is a riser?

Answer 26

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

Question 27

What is a shut-off valve called?

Answer 27

stopcock or service cock

Question 28

What does a flat washer on the stopcock indicate?

Answer 28

service line is plastic pipe inserted inside an older metal pipe

Question 29

What does a ring on the stopcock valve indicate?

Answer 29

branch service

Question 30

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

Answer 30

service line is plastic

Question 31

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

Answer 31

60 psi--down to 1/3 psi

Question 32

What is an earthquake valve?

Answer 32

emergency vibration-sensitive shutoff device

Question 33

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

Answer 33

an industrial shutoff valve used for high-pressure applications The tang can only be turned 1/8th turn

Question 34

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

Answer 34

the occupancy farthest from the supply main

Question 35

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

Answer 35

turn it off at the stopcock

Question 36

What does a basic stopcock consist of?

Answer 36

``` Internal core Casing Washer backing nut circlip ```

Question 37

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

Answer 37

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

Question 38

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

Answer 38

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

Question 39

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

Answer 39

Safety Protection of Property Prompt and efficient control of incident

Question 40

What 3 categories can natural gas be divided into?

Answer 40

Inside leaks Outside leaks Leaks resulting in fires

Question 41

What is a service entrance cock?

Answer 41

It is a master valve where the service enters the building

Question 42

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

Answer 42

Call the gas company

Question 43

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

Answer 43

Where to stop a leak

Question 44

Pipe lines may contain hazardous contaminates known as what?

Answer 44

PCBs--Polychlorinated biphenyls