Water Supply Systems Flashcards
6 cards from real 306A practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Water Supply Systems flashcards as text
When using the fixture unit method to size water supply piping, what does the conversion to litres per second account for?
Answer: The probability that not all fixtures will be used simultaneously
The fixture unit method uses probability theory to account for the fact that in most buildings, not all fixtures operate at the same time. This diversity factor allows smaller pipe sizes than if every fixture were assumed to run simultaneously.
What is the standard test pressure for a water supply system in a residential building?
Answer: 150 psi (1034 kPa) for a minimum of 2 hours
The water supply system is typically tested at 100 psi (690 kPa) or 1.5 times the working pressure, whichever is greater, and held for a minimum of 2 hours with no visible leaks or pressure drop.
What is the purpose of an expansion tank on a closed-loop domestic hot water system?
Answer: To absorb the volume increase when water is heated and the system has a backflow preventer
When a backflow preventer creates a closed system, heated water expands with nowhere to go, causing dangerous pressure increases. An expansion tank absorbs this thermal expansion safely.
What is the minimum size of an individual fixture supply pipe for a lavatory?
Answer: ⅜ inch
A ⅜-inch supply pipe is the minimum size for a lavatory faucet, providing adequate flow for handwashing while conserving water.
What is the effect of installing a water softener on the hot water supply only?
Answer: Reduced scale buildup in the water heater and hot water pipes
Installing a softener on the hot water supply reduces scale buildup (calcium and magnesium deposits) in the water heater and hot water piping, improving efficiency and extending equipment life.
What valve type is NOT acceptable as an isolation valve on a water supply branch because it restricts flow?
Answer: Globe valve
A globe valve creates significant flow restriction due to its internal design, which forces water to change direction through the valve body. Ball and gate valves provide full-port (unrestricted) flow and are preferred for isolation.