Gas Piping Systems Flashcards
7 cards from real Master Plumber 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 Systems flashcards as text
A sediment trap (drip leg) on a gas appliance connection must be installed:
Answer: Immediately upstream of the appliance inlet, after the shutoff valve
The sediment trap must be located immediately upstream of the appliance to catch debris before it enters the appliance valve.
Which gas pressure range is classified as 'intermediate pressure' under NFPA 54?
Answer: 2 psi to 5 psi
Intermediate pressure gas systems operate between 2 psi and 5 psi according to NFPA 54 classifications.
When a gas pipe passes through a concrete floor slab, it must be:
Answer: Sleeved in a conduit sealed at both ends
Gas piping through concrete must be sleeved to protect the pipe from corrosion and allow for movement without cracking.
What is the purpose of a pressure regulator on a gas system?
Answer: To reduce and maintain stable downstream gas pressure
A pressure regulator reduces higher upstream pressure to a stable, lower downstream pressure suitable for appliances.
Under the International Fuel Gas Code, gas piping is NOT permitted to be run through which location?
Answer: Elevator shafts or dumbwaiter shafts
Gas piping is prohibited in elevator shafts, dumbwaiter shafts, and similar enclosed shafts due to the severe fire and explosion risk.
A master plumber is testing a new gas piping system with air before the gas is turned on. The test pressure must be held for a minimum of:
Answer: 10 minutes
NFPA 54 requires the test pressure to be maintained for a minimum of 10 minutes with no measurable pressure drop.
Which of the following best describes the specific gravity of natural gas compared to air?
Answer: Natural gas is lighter than air and rises toward the ceiling
Natural gas (primarily methane) has a specific gravity of about 0.55, making it lighter than air, so it rises and dissipates upward.