Gas Piping and Appliances Flashcards
7 cards from real Journeyman Plumbers Exam practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Gas Piping and Appliances flashcards as text
Under NFPA 54, what is the required location for the manual gas shutoff valve for a gas appliance?
Answer: Within 6 feet of the appliance in the same room
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.
A gas water heater installed in a garage must have its ignition source elevated at least:
Answer: 18 inches above the floor
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.
Which of the following is the correct way to check for a gas leak at a connection?
Answer: Apply listed leak detection solution and observe for bubbles
Listed leak detection solution (or an electronic gas detector) is the approved method; open flames are dangerous and smell alone may miss small leaks.
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?
Answer: ¾ inch
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.
A Type B gas vent used for a Category I appliance must maintain a minimum clearance to combustible construction of:
Answer: 1 inch
Listed Type B double-wall vents are designed for 1-inch clearance to combustibles, which is their primary advantage over single-wall connectors.
When two or more gas appliances are connected to a common vent, the common vent must be sized based on:
Answer: The combined BTU input of all appliances connected to that common section
The common vent section must handle the combined input from all appliances that can operate simultaneously, so total BTU capacity is used for sizing.
An appliance connector made from aluminum is prohibited for use with:
Answer: LP (propane) gas only
LP gas (propane) contains chemical additives that react with aluminum, causing corrosion and eventual failure; aluminum connectors are prohibited for propane service.