Application of Hazen Williams Equation: Calculating Unit Headloss

What is the unit headloss (ft/1,000 ft) expected in a 16-inch diameter of a PVC pipeline carrying 2700 gpm?

a. 16 b. 4 c. 2 d. 12

The unit headloss expected in a 16-inch diameter PVC pipeline with C=130 and 2700 gpm flow rate is 4 ft/1000 ft.

Option B is correct. Using the Hazen-Williams equation, the unit headloss can be calculated as:

hL = 10.67 * (L/D) * (Q/C)^{1.852}

where:

L = 1000 ft (assumed length)

D = 16 in = 1.333 ft (pipe diameter)

Q = 2700 gpm = 6.439 ft³/s (flow rate)

C = 130 (Hazen-Williams coefficient for PVC)

Substituting in the values and solving for hL, we get:

hL = 10.67 * (1000/1.333) * (6.439/130)^{1.852}

= 4.04 ft/1000 ft

Rounding to two decimal places, the unit headloss is 4 ft/1000 ft, which corresponds to answer choice b.