Master Plumber Exam Gas Piping Systems 4

Question 1

Propane (LP gas) differs from natural gas in a critical safety way because propane:

Accepted Answer

Is heavier than air and can accumulate in low areas

Answer

Propane has a specific gravity of about 1.5, meaning it is heavier than air and will settle in basements, pits, and low spots creating explosion hazards.

Question 2

What is the required BTU content used to size natural gas piping when the specific BTU rating of appliances is unknown?

Accepted Answer

1,000 BTU per cubic foot

Answer

Natural gas is typically rated at approximately 1,000 BTU per cubic foot for standard piping sizing calculations.

Question 3

Which type of fitting is NOT approved for use in a gas piping system?

Accepted Answer

Cast iron fittings

Answer

Cast iron fittings are not approved for gas piping because they are brittle and can crack under pressure or mechanical stress.

Question 4

When installing a gas meter, what is the minimum required clearance from an electrical meter?

Accepted Answer

3 feet

Answer

Gas meters must be installed at least 3 feet away from electrical meters to reduce ignition risk from electrical sparks.

Question 5

A gas appliance connector (flexible connector) used to connect a range to the gas supply line may be a maximum of:

Accepted Answer

4 feet

Answer

Flexible gas appliance connectors are limited to a maximum length of 6 feet to prevent kinking, stress, and concealed installation.

Master Plumber Exam Practice Test

Master Plumber Exam Practice Test

Master Plumber Exam Gas Piping Systems 4