MIL-HDBK-1004/10

(1) However, the L/d ratio of two 1-1/2-inch diameter by

60-inch long anodes in tandem is less than 100 and thus the fringe factor

must be used.

L/d = (2 x 60)/1.5

L/d = 80 < 100

(2) The fringe factor from curve Figure 101 corresponding to

L/d ratio is 0.95.

R (adjusted) = 3.19 x 0.95

R = 3.03 ohms

k)

Stub anodes:

(1) In the design of an elevated water tank, the need for stu

anodes must be justified. The main anode radius has been calculated to b

22 feet. The main anodes are spaced to provide approximately the same

distance from the sides and the bottom of the tank. The main anodes will

protect a length along the tank bottom equal to 1-1/2 times the spacing o

the anode from the bottom.

(2) The anode suspension arrangement for the tank under

consideration is shown in Figure 99. Thus, it can be seen that stub anod

are required for this design. Ten stub anodes are arranged equally space

on a circumference that has a radius of 8 feet in a manner illustrated in

Figure 98. For smaller diameter tanks, stub anodes may not be required.

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