Design & SizingQuestion 3 of 110
Cold-water piping is commonly limited to a maximum velocity of about 8 ft/s. Using v = 0.408 x Q / d^2, what is the approximate maximum flow a pipe with a 1.025 in inside diameter (nominal 1 in type L copper) can carry without exceeding 8 ft/s?
a.12 gpm
b.17 gpm
c.21 gpm
d.28 gpm
Explanation
Rearrange to Q = v x d^2 / 0.408 = 8 x (1.025)^2 / 0.408 = 8 x 1.051 / 0.408 = 20.6 gpm, about 21 gpm. Above this flow the velocity exceeds 8 ft/s and erosion-corrosion and noise become a concern. Hot water is usually held to an even lower 5 ft/s.
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