NGA 70 REVIEW NEWEST ACTUAL EXAMS WITH COMPLETE
QUESTIONS AND ANSWERS //VERIFIED//GRADED A+//
Components of natural gas
Methane, Ethane, Inert gases, propane/heavy hydrocarbons.
Ethane
Distinguishing feature of pipeline nautural gas
Gas temp will drop X F for every XXX psig reduction
7 degrees for 100 psig
Temperature at which natural gas can form a "frost ball"
32 F
Elements of combustion
Fuel, oxygen, ignition
Page 1 of 7
, Dig-In
Third party damage. #1 avoidable cause of pipeline damage.
Causes of emergency situation
third party damage, overpressure, accumulation in lines,
component failure, vandalism, excavation
Low pressure leaks may move
slowly, and spread over a wider area
High pressure leaks may move
more directly through the path of least resistance
Moist soil effect on underground leak
creates a barrier to traveling upwards, accumulating
underground may cause horizontal migration
Dry soil effect on underground leak
gas moves freely, may absorb odorants
Page 2 of 7
QUESTIONS AND ANSWERS //VERIFIED//GRADED A+//
Components of natural gas
Methane, Ethane, Inert gases, propane/heavy hydrocarbons.
Ethane
Distinguishing feature of pipeline nautural gas
Gas temp will drop X F for every XXX psig reduction
7 degrees for 100 psig
Temperature at which natural gas can form a "frost ball"
32 F
Elements of combustion
Fuel, oxygen, ignition
Page 1 of 7
, Dig-In
Third party damage. #1 avoidable cause of pipeline damage.
Causes of emergency situation
third party damage, overpressure, accumulation in lines,
component failure, vandalism, excavation
Low pressure leaks may move
slowly, and spread over a wider area
High pressure leaks may move
more directly through the path of least resistance
Moist soil effect on underground leak
creates a barrier to traveling upwards, accumulating
underground may cause horizontal migration
Dry soil effect on underground leak
gas moves freely, may absorb odorants
Page 2 of 7
