Journeyman Plumbers Exam Gas Piping and Appliances 4

Question 1

Under NFPA 54, what is the required location for the manual gas shutoff valve for a gas appliance?

Accepted Answer

Within 6 feet of the appliance in the same room

Answer

NFPA 54 requires an accessible shutoff valve within 6 feet of each appliance and in the same room so it can be reached quickly in an emergency.

Question 2

A gas water heater installed in a garage must have its ignition source elevated at least:

Accepted Answer

18 inches above the floor

Answer

To prevent ignition of heavier-than-air flammable vapors that settle near the floor, ignition sources in garages must be 18 inches above floor level.

Question 3

Which of the following is the correct way to check for a gas leak at a connection?

Accepted Answer

Apply listed leak detection solution and observe for bubbles

Answer

Listed leak detection solution (or an electronic gas detector) is the approved method; open flames are dangerous and smell alone may miss small leaks.

Question 4

What is the minimum pipe size for a gas supply line serving a residential furnace rated at 100,000 BTU/hr at 100 feet from the meter with ½ inch WC pressure drop?

Accepted Answer

¾ inch

Answer

Using NFPA 54 sizing tables for natural gas at low pressure (0.5 in WC drop), a 100-ft run at 100,000 BTU/hr typically requires ¾-inch pipe.

Question 5

A Type B gas vent used for a Category I appliance must maintain a minimum clearance to combustible construction of:

Accepted Answer

1 inch

Answer

Listed Type B double-wall vents are designed for 1-inch clearance to combustibles, which is their primary advantage over single-wall connectors.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Gas Piping and Appliances 4