NGA-WE-CT20D-COURSE Classifying
Gas Leaks Exam Questions And
Correct Answers | Passed
Building - Answer- The structure which is normally or occasionally entered by humans
for business, residential or other purposes, and which gas could accumulate
Combustible Gas Indicator (CGI) - Answer- A device capable of detecting and
measuring gas concentration (of the gas being transported) in the atmosphere
Confined Space - Answer- Any subsurface structure (such as vaults, tunnels, catch
basins or manholes) of sufficient size to accommodate a person, and in which gas could
accumulate.
Dispersion Area - Answer- Where a leak can be detected; as opposed to where a leak
is actually occurring.
Gas Associated Substructure - Answer- A device or facility utilized by a gas company
(Such as a valve box, vault, test box or vented casing pipe) which is not intended for
storing, transmitting or distributing gas.
Gas Migration - Answer- The movement of natural gas through from one medium or
area to another.
Grade 1 Leak - Answer- A leak which represents and existing or probable hazard to
persons or property, and requires immediate repair or continuous action until the
conditions are no longer hazardous.
Grade 2 Leak - Answer- A leak which is recognized as being non-hazardous at the time
of detection, but justifies scheduled repair based on probable future hazard.
Grade 3 Leak - Answer- A leak which is non-hazardous at the time of detection and can
be reasonably expected to remain non-hazardous.
Leak Location - Answer- Where a leak is occurring; as opposed to where it is detected.
Lower Explosive Level - Answer- The lowest ratio of gas in air mixture that could
combust. The LEL for natural gas is approximately 5% gas-in-air.
Natural Gas - Answer- A mixture of gases primarily methane, that is lighter than air.
Gas Leaks Exam Questions And
Correct Answers | Passed
Building - Answer- The structure which is normally or occasionally entered by humans
for business, residential or other purposes, and which gas could accumulate
Combustible Gas Indicator (CGI) - Answer- A device capable of detecting and
measuring gas concentration (of the gas being transported) in the atmosphere
Confined Space - Answer- Any subsurface structure (such as vaults, tunnels, catch
basins or manholes) of sufficient size to accommodate a person, and in which gas could
accumulate.
Dispersion Area - Answer- Where a leak can be detected; as opposed to where a leak
is actually occurring.
Gas Associated Substructure - Answer- A device or facility utilized by a gas company
(Such as a valve box, vault, test box or vented casing pipe) which is not intended for
storing, transmitting or distributing gas.
Gas Migration - Answer- The movement of natural gas through from one medium or
area to another.
Grade 1 Leak - Answer- A leak which represents and existing or probable hazard to
persons or property, and requires immediate repair or continuous action until the
conditions are no longer hazardous.
Grade 2 Leak - Answer- A leak which is recognized as being non-hazardous at the time
of detection, but justifies scheduled repair based on probable future hazard.
Grade 3 Leak - Answer- A leak which is non-hazardous at the time of detection and can
be reasonably expected to remain non-hazardous.
Leak Location - Answer- Where a leak is occurring; as opposed to where it is detected.
Lower Explosive Level - Answer- The lowest ratio of gas in air mixture that could
combust. The LEL for natural gas is approximately 5% gas-in-air.
Natural Gas - Answer- A mixture of gases primarily methane, that is lighter than air.
