ICC Natural Gas Systems and Safety 2

Question 1

What type of pipe is most commonly specified for new natural gas distribution main installations due to its corrosion resistance and ease of installation?

Accepted Answer

Polyethylene (PE)

Answer

Cast iron

Answer

Galvanized steel

Answer

PVC

Question 2

What is the primary function of a pressure regulator station on a natural gas distribution system?

Accepted Answer

To reduce high transmission pressure to safe distribution system pressure

Answer

To measure total gas consumption for billing purposes

Answer

To remove moisture and impurities from natural gas

Answer

To inject odorant into the natural gas stream

Question 3

Per 49 CFR Part 192, at what maximum concentration of natural gas in air must the odorant be detectable by a person with a normal sense of smell?

Accepted Answer

At or below 20% of the lower explosive limit (LEL)

Answer

At 1% gas concentration in air

Answer

At 50% of the lower explosive limit

Answer

At the upper explosive limit (UEL)

Question 4

Which records must an ICC-certified contractor maintain and make available for inspection following any natural gas facility installation?

Accepted Answer

As-built drawings and pressure test records

Answer

Only the original work order and customer invoice

Answer

Customer payment receipts and utility approval letters

Answer

Inspection photographs only

Question 5

When a natural gas leak is discovered during construction or excavation, what is the immediate first action the contractor must take?

Accepted Answer

Evacuate the area and immediately notify the gas utility and emergency services

Answer

Continue work and report the leak at the end of the shift

Answer

Attempt to stop the leak using pipe clamps or repair fittings

Answer

Cover the leak area with soil to prevent potential ignition

Question 6

What is the approximate lower explosive limit (LEL) of natural gas (primarily methane) in air?

Accepted Answer

5%

Answer

2.5%

Answer

10%

Answer

15%

Question 7

What joining method is required when connecting polyethylene natural gas pipe sections in the field?

Accepted Answer

Heat fusion (butt fusion or electrofusion)

Answer

Threaded pipe connections

Answer

Solvent cement (glue) joints

Answer

Compression couplings only