Water Supply & DistributionQuestion 27 of 360
Converting demand: a building has an estimated 46 WSFU load served predominantly by flush tanks. Using a typical Hunter-curve conversion, the demand is about 30 gpm. If you must maintain roughly 8 fps maximum velocity, why can you not simply pick the smallest pipe that carries 30 gpm at any velocity?
a.Because gpm cannot be converted to velocity
b.Because smaller pipe always costs more
c.Because a pipe too small would exceed the velocity limit, causing noise, erosion, and water hammer
d.Because velocity has no effect on pipe life
Explanation
Forcing 30 gpm through an undersized pipe raises velocity above the roughly 8 fps guideline, causing noise, erosion, and water hammer, so pipe size is limited by velocity as well as flow. gpm and velocity are directly related through pipe area, smaller pipe is not more expensive, and velocity strongly affects pipe life.
Law Reference: 2022 California Plumbing Code (CPC) §610.0Practice all 360 questions free — no signup required.
Related questions on this topic
- Which standard applies to cross-linked polyethylene (PEX) tubing used in potable water distribution?
- A residential water heater is 55 feet of developed pipe run from the farthest bathroom. Using standard practice, which change would most directly reduce the long wait for hot water without adding a recirculation pump?
- An air gap and a reduced pressure principle assembly (RP) are both acceptable for high-hazard protection. What is one key advantage of an air gap over an RP assembly?
- Which standard covers seamless copper water tube types K, L, and M?
- On which fixtures does the code most specifically require water hammer arrestors?
- A pressure vacuum breaker (PVB) is selected for a landscape irrigation system. What is the minimum installation height for a PVB relative to the highest downstream head or outlet?
Last reviewed: · editorial process
PrepPass Editorial Team · Verified against California CSLB C-36 Plumbing Trade Examination · How we review