Gas Utilities Ch.(6) Flashcards
The common odorant is a_____/_______mix, which is used in solution of ________ per _____ cubic feet of gas.
Mercapitan/Thiophane mix
One pint per million
Natural gas also has an ignition temperature of ______degrees, and has a flammable range between ___and ___percent.
1100 degrees
4 and 14%
Transmission lines maintain pressures up to ____ psi
1000
Transmission lines vary in diameter from ___ to ___ inches.
12 to 36
The gas carried by service lines as medium pressure, which normally does not exceed ____ psi
60
At the service meter pressure is reduced to low pressure (approximately ___ psi)
1/3 psi
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.
Yellow
Older installations of plastic pipe can be ___ (________), or ______in color.
Pink( salmon beige)
Orange
Above gas lines must be made of ____
Steel
MSA’s can be found in the following locations
Outside set
Underneath set
Curb meter box
Cabinet set
MSA’s can be categorized as follows x3
Residential
Industrial
Multiple gas meter
Tracing the riser up from the ground , the first fitting is the shut off valve call a ____ or ____
Stopcock or service cock
A ring on stopcock ;
A flat washer ;
A band;
Ring = branch service
A flat washer = plastic pipe inside metal pipe
A band = plastic pipe
_____ pipes will have a wire running the length of pipe, for locating
Polyethylene
look for a “____” that is either chiseled or painted on the curb. A “___”, required by ________, marks the location where the service line passes beneath the curb and indicates which side of the building the MSA is ocated
G
Cal- OSHA
Industrial shut off valves , known as _____ valves, are used for high pressure applications
Nordstrom
Meters under sidewalks call ____ meters, are common in commercial areas
Curb meters
Who to notify if the identification as to which unit or building an MSA’s serves is worn away
Gas company
Stuck tang during emergency;
Use two wrenches, one on the tang and the other on the backing nut. Holding the tang steady, loosen the backing nut _______turn only!
One quarter
If backing nut is loosened to far, the core can fly out, leaking medium pressure gas ___ to ___
40 to 60
The tang on a Nordstrom valve can only be turned _____ turn in either direction
One quarter turn
Curb valves , also referred to as an _______
Located near property line by side walk ___ to ___ ft underground
Emergency shut off valve
2 to 3 ft
Natural gas leaks can be divided into 3 categories .
*which is greatest danger
Inside
Outside
Leaks with fire
Leaks outside structures;
The fire department role at the site is _______
To maintain public safety
Type of mallet that should be used to drive plug into the end of a broken pipe. X 4
Wooden, rubber, plastic or brass
