Page 220 - Fair, Geyer, and Okun's Water and wastewater engineering : water supply and wastewater removal

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182 Chapter 5 Water Hydraulics, Transmission, and Appurtenances
ater Hydraulics, T
ransmission, and Appurtenances
Chapter 5
W
Solution 1 (U.S. Customary System):
Day T d , F T d 32 (T d 32)
1 35 3 3
2 37 5 8
3 37 5 13 First maximum positive
4 30 2 11
5 28 4 7
6 25 7 0
7 29 3 3
8 30 2 5
9 24 8 13 First maximum negative
10 36 4 9
11 40 8 1
12 40 8 7
13 42 10 17
14 45 13 30

Figure 5.11 can be plotted for determining F.
The freezing index 13 13 = 26 (U.S. Customary Unit)
The frost depth, d 1.65F 0.468
d 1.65(26) 0.468 7.58 in.
There shall be a minimum of one foot (12 in.) of fill material on the top of a sewer or water main
for freezing protection. Certain U.S. states near Canada require a minimum of 3 ft of fill material.

Solution 2 (SI system):

Day T d , C T d 0 (T d 0)
1 1.67 1.67 1.67
2 2.78 2.78 4.45
3 2.78 2.78 7.22 First maximum positive
4 1.11 1.11 6.11
5 2.22 2.22 3.9
6 3.88 3.88 0.02
7 1.66 1.66 1.64
8 1.11 1.11 2.75
9 4.44 4.44 7.19 First maximum negative
10 2.22 2.22 4.97
11 4.44 4.44 0.53
12 4.44 4.44 3.91
13 5.55 5.55 9.46
14 7.22 7.22 26.68

The freezing index 7.22 7.19 = 14.41 (SI unit)
The frost depth, d 55.18F 0.468
d 55.18(14.41) 0.468 192.33 mm

There shall be a minimum of 305 mm of fill material on the top of a sewer or water main for freezing
protection. Certain U.S. states near Canada require a minimum of 1 m (3 ft) of fill material.