RMGA Emergency Response Procedures 2

Question 1

What concentration of natural gas in air (expressed as % LEL) typically triggers evacuation procedures?

Accepted Answer

25% LEL

Answer

Most standard operating procedures require evacuation and emergency response actions when gas concentrations reach or exceed 25% LEL to provide a safety margin below the explosive range.

Question 2

What agency must a natural gas operator notify if a gas incident causes a death or injury requiring hospitalization?

Accepted Answer

PHMSA National Response Center

Answer

49 CFR Part 191 requires operators to notify the PHMSA National Response Center by telephone for incidents involving death, injury requiring hospitalization, or significant property damage.

Question 3

What is 'backfilling and compaction' important for after a gas main repair?

Accepted Answer

Restoring original soil conditions to protect the pipe and prevent future settlement

Answer

Proper backfilling and compaction restore soil support around the repaired pipe, prevent ground settlement, and protect the pipe from future damage.

Question 4

Who is typically responsible for shutting off gas service during a structure fire when the fire department requests it?

Accepted Answer

The gas utility upon request from fire department or emergency responders

Answer

The gas utility is responsible for safely shutting off service when requested by fire or emergency personnel during a structure fire.

Question 5

What is the purpose of 'purging with inert gas' before restarting a gas main?

Accepted Answer

To displace oxygen from the piping before introducing flammable gas, preventing a combustible mixture

Answer

Purging with nitrogen or another inert gas displaces air (oxygen) from the piping so that when natural gas is introduced, no flammable mixture can form.

RMGA - Rocky Mountain Gas Association Practice Test

RMGA - Rocky Mountain Gas Association Practice Test

RMGA Emergency Response Procedures 2