MIL-HDBK-1004/10

The formula for a horizontally oriented anode is:

EQUATION:

R

=

0.0052 P/L x ln{[4L + 4L(S + L) ]/ds} + s/L - (s + L) -1

(10)

h

where

R

=

electrolyte-to-anode resistance for a single vertical

v

anode to a remote reference (ohms)

R

=

electrolyte-to-anode resistance for a single horizontal

h

anode to a remote reference (ohms)

P

=

electrolyte resistivity (ohms-cm) at the location and

depth of the anode

L

=

anode length or backfill column length if backfill is

used (feet)

d

=

effective diameter of anode or backfill column (feet)

s

=

twice depth of anode (feet)

Simplified Expressions for Common Situations. For many common

6.2.1.4

situations, the Dwight formulae have been simplified by combining terms and

eliminating terms that have insignificant values in most cases. Some of these

simplified formulae have been given in para. 4.2.6. In addition to these

simplified formulae, the following simplified formula is often used:

a)

Resistance of a Single Vertical Anode

EQUATION:

R

=

(P/L)K

(11)

v

where

R

=

electrolyte-to-anode resistance for a single vertical

v

anode to remote reference (ohms)

P

=

electrolyte resistivity (ohms-cm) at the location and

depth of the anode

L

=

anode length (feet) or backfill column length if backfill

is used

K

=

shape function from table below where:

L/d =

ratio of length-to-diameter of anode

K

L/d

K

L/d

1

0.008

16

0.0201

2

0.010

18

0.0207

3

0.012

20

0.0213

4

0.013

25

0.0224

5

0.0140

30

0.0234

6

0.0150

35

0.0242

7

0.0158

40

0.0249

8

0.0165

45

0.0255

9

0.0171

50

0.0261

10

0.0177

55

0.0266

12

0.0186

60

0.0270

14

0.0194

55

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