Plumbing & Mechanical Inspection Flashcards
6 cards from real CBI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Plumbing & Mechanical Inspection flashcards as text
What is the purpose of a plumbing trap?
Answer: To hold water that creates a seal preventing sewer gases from entering the building through drain openings
P-traps and S-traps hold a water seal (2-4 inches) in the curved pipe section, blocking toxic and flammable sewer gases from entering habitable spaces through drain openings.
What is the minimum slope required for horizontal drain pipes?
Answer: 1/4 inch per foot for pipes 3 inches or smaller; 1/8 inch per foot for pipes larger than 3 inches
Proper slope ensures wastewater flows by gravity without flowing too fast (which leaves solids behind) or too slow (which causes clogs). Quarter-inch per foot is standard for most residential drain pipes.
What is a plumbing vent and why is it necessary?
Answer: A pipe extending to the roof that allows air into the drainage system to maintain proper flow and prevent siphoning of traps
Plumbing vents allow air to enter the drainage system, equalizing pressure so waste flows freely and preventing the vacuum effect that would siphon water from traps, allowing sewer gases to enter.
What should an inspector verify during an HVAC rough-in inspection?
Answer: Correct ductwork sizing, proper support, sealed connections, refrigerant line insulation, and compliance with mechanical code
HVAC rough-in inspections verify duct sizing for adequate airflow, proper hanging/support, sealed joints, fire dampers at penetrations, refrigerant line specifications, condensate drainage, and code-required clearances.
What is the purpose of a water heater temperature and pressure (T&P) relief valve?
Answer: To release water and pressure if the tank overheats or becomes over-pressurized, preventing a tank explosion
The T&P valve is a critical safety device that opens automatically if water temperature exceeds 210°F or pressure exceeds 150 PSI, preventing the catastrophic failure (explosion) of the water heater tank.
Where must a water heater T&P relief valve discharge line terminate?
Answer: To the exterior of the building or to an approved indirect waste receptor, within 6 inches of the floor
The discharge pipe must terminate where released hot water will not cause injury or damage: typically outside the building or to an approved drain, within 6 inches of the floor, and without being threaded, reduced, or trapped.