BOOK 29 TRUCK OPERATIONS MANUAL CHAPTER 6 GAS UTILITIES Flashcards
Pure natural gas is completely
Odorless
For the purpose of leak detection, odorant is added so that as little as ___-percent of natural gas in the air can be detected.
One percent
The common odorant is a ______/______ mix, which is used in solution of one pint per million cubic feet of gas.
Mercapitan/thiophane
Natural gas is lighter than
Air
Natural gas also has an ignition temperature of _____ degrees, and has a flammable range between _ and __ percent.
1100 degrees
4 and 14%
Most natural gas is initially distributed through over ______ miles of transmission lines from Texas, Kansas, New Mexico, Oklahoma, Arizona, and the Rocky Mountain area.
30,000
Transmission lines maintain pressures up to ____ psi and use pressure booster compressor stations, at specific intervals, to maintain appropriate flow and pressures.
1000 psi
Natural gas is generally distributed by a combination of
Transmission lines and distribution mains
Transmission lines bring natural gas into the Southern California area and vary in diameter from __ to __ inches.
12-36’’
The gas is carried by service lines, as medium pressure, which normally does not exceed
60 psi
At the service meter (Meter Set Assembly), the pressure is reduced to a low pressure (approximately __ psi.).
1/3
Distribution mains are generally _______ and account for a high percentage of the mains in use today.
Polyethylene
Older existing distribution mains are made of ____ or _____, but are rare to find.
Steel or copper
Polyethylene mains are color coded to identify the pipe as transporting natural gas. These pipes are ______, which is the national color code for newer installations. Older installations of plastic pipe can be ___ (salmon beige), or ______ in color.
Yellow
Pink
Orange
Polyethylene will have a ___ running the length of the pipe, for locating plastic gas lines, below ground.
Wire
Above ground gas lines must be made of _____ and cannot be plastic.
Steel
are normally located underneath city streets, parallel to curbs, under grassy parkways, between the curb and sidewalk, and occasionally in alleys.
Distribution mains
Service lines run from distribution mains to structures, via an outside riser, where ______ ______ and ______ are located.
Pressure regulators and meters
Gas companies refer to gas meters as
Meter set assemblies
MSA’s can be found in the following locations:
Outside set
Underneath set
Curb meter box
Cabinet set
Additionally, MSA’s can be categorized as follows:
Residential
Industrial
Multiple Gas Meter
The pipe rising vertically from the ground, close to the exterior wall of a structure is called a
Riser
Tracing the riser up from the ground, the first fitting is the shut- off valve called a
stopcock or service cock.
A ring on the stopcock valve indicates a
Branch service
A ____ _____ on the stopcock valve indicates that the service line is a plastic pipe inserted inside an older metal pipe.
Flat washer
A ____ on the stopcock valve indicates the service line is plastic.
Band
Next, up the riser, is a flat circular device called a “_______” that reduces medium gas pressure (up to 60 psi) to a relatively low level of approximately 1/3 psi.
Regulator
A “_”, required by Cal-OSHA, marks the location where the service line passes beneath the curb and indicates which side of the building the MSA is located.
G
Some MSA’s may be equipped with an emergency vibration-sensitive shut off device known as an
EARTHQUAKE VALVE
Earthquake valves are marketed by private industry and are normally mounted on the ______ side, right side as you face the meter, of an MSA.
Discharge
Personnel should recognize and understand that a ____-____ may possibly shut off the flow of gas,
Swift kick
Turning a reset button, ___ turn, completes reset of this device.
One quarter
INDUSTRIAL METER SET ASSEMBLIES
Industrial shut-off valves, known as ______ valves, are used for high pressure applications.
Nordstrom valves
INDUSTRIAL METER SET ASSEMBLIES
Industrial applications that are high pressure can use two regulators in _____ to regulate the gas pressure.
In series
INDUSTRIAL METER SET ASSEMBLIES
A _____ meter is used, instead of a conventional MSA, to regulate the high pressure and handle quick surges.
Rotary
INDUSTRIAL METER SET ASSEMBLIES
The lid over the curb meter space is made of lightweight _____, or _____ set in a metal frame, and is easily identified by its gas company markings.
Concrete or fiberglass
MULTIPLE METER SET ASSEMBLIES
____ _________ shut off the entire building and individual meters/stopcocks can control the flow of gas to individual occupancies in one structure.
Master stopcocks
The occupancy that is further from the supply main is a _____ _____, and the other occupancies are ____ _____.
Standard service
Branch service
If tang on shut off valve is stuck Use two _______, one on the tang and the other on the backing nut. Holding the tang steady, loosen the backing nut ____-_____ turn only!
Wrenches
One-quarter
NOTE
Newer stopcocks have a ___ driven into the backing nut, and bolt, and cannot be loosened.
Pin
The ______ _____ is a larger version of a residential stopcock.
Nordstrom valve
The tang on a Nordstrum valve can only be turned __-____ turn, in either direction, ensuring the “ON” and “OFF” positions are easy to locate.
One quarter
Some industrial meters are equipped with a ____ ____ that has a wheel handle (similar to an OS&Y).
Gate valve
Curb valves are ___ to ____ feet underground and under a small metal, concrete or fiberglass lid; with “Gas Company” markings in raised letters.
Two to three
Curb valves
If the lid is stuck, and additional leverage is necessary, insert the point of a _____ _____ in the hole and apply the proper leverage.
Pickhead axe
Curb valves
This valve is an ordinary gate valve with a “_____” type handle. Turn the handle ______ to stop the flow of gas.
Faucet
Clockwise
Curb valves
If the valve is too deep to reach with the hand, a ____ ___ can be used for extra reach.
Sprinkler key
Natural gas emergencies can be divided into the three following categories:
Inside leaks
Outside leaks
Leaks resulting in fires
While each leak has its own dangers and concerns, the greatest danger results from gas leaks _____ ______, due to the potential for ignition and explosion.
Inside structures
For faint odors, always check the condition of _____ ____- as a first action.
Piglet lights
there will be a “master” valve called the _______ valve stopcock; which stops the flow to all tenants in the building on the service pipe.
Isolation valve stopcock
Previously, The Gas Company used to teach its members a technique, known as the ____-____method, for controlling the flow of gas in small diameter pipes. (Now against gas company policy)
Bend back
______plastic pipe is acceptable as long as all tools used to work on plastic pipe are grounded.
Crimping
_____ _____ can be driven into various diameter steel pipes with a rubber mallet.
Redwood plugs
Be aware that, on rare occasions, pipelines may contain hazardous contaminants such as _______ ______.
Polychlorinated biphenyls
Fog down the plastic pipe with a wetting agent such as __ ___ to prevent ignition from static electricity. Water alone tends to bead up and run off of polyethylene pipe, thus reducing the effectiveness of water
Wet water
Small fires may be extinguished with __ _____ or ___ if necessary, to approach a shut off valve
Dry chemical or C02
