Journeyman Plumbers Exam Gas Piping and Appliances 2

Question 1

What is the minimum clearance required between an unprotected gas appliance vent connector and combustible material?

Accepted Answer

6 inches

Answer

NFPA 54 requires a minimum 6-inch clearance between an unprotected single-wall metal vent connector and combustible materials.

Question 2

Which pipe material is NOT approved for use with natural gas in residential installations under NFPA 54?

Accepted Answer

PVC plastic pipe

Answer

PVC plastic pipe is not permitted for gas piping because it cannot withstand the temperatures and pressures involved and is not listed for gas service.

Question 3

A gas appliance draft hood is designed primarily to:

Accepted Answer

Prevent backdrafting from affecting burner operation

Answer

A draft hood (or draft diverter) protects the appliance burner from downdrafts and pressure fluctuations in the venting system.

Question 4

When sizing a gas piping system, the pressure drop allowed in a low-pressure system (under 2 psi) from the meter to the appliance is typically:

Accepted Answer

0.5 inch WC

Answer

For low-pressure systems, NFPA 54 sizing tables are based on a 0.5 inch WC pressure drop from the meter to the most remote appliance.

Question 5

A gas dryer vent must terminate:

Accepted Answer

At least 3 feet from any opening into the building

Answer

Dryer exhaust vents must terminate outdoors at least 3 feet from any building opening such as windows, doors, or vents to prevent re-entry of combustion products.

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Practice Test

Journeyman Plumbers Exam Gas Piping and Appliances 2