and the third column the headloss per

storage to a point on the main where a

1,000 feet of pipe.

Knowing any two

branch is connected, is subtracted

of these, the third can be found by

from the allowable headloss to the

drawing a straight line through the

service connection at the end of the

two knowns.

As an example, assume

branch.

This will give the allowable

100gpm is flowing through a 1,000 foot

headloss

in

the

branch.

Then,

long pipe of 4-inch diameter.

Draw a

entering

the

nomograph

with

this

line passing through 100 gpm on the

headloss and the peak demand (flow) at

left column and 4 inches on the second

the service connection, the diameter

column.

Extending

the

line,

a

of pipe required can be obtained.

As

headloss of about 12-1/4 feet per

stated before, the nomograph gives

1,000 feet of pipe is obtained.

This

headloss per 1,000 feet of pipe, so

compares

very

well

with

values

conversions between the actual length

obtained by calculation.

of pipe and these values must be made.

If the pipe size obtained is one which

c. Headloss by use of figure 15.

is not available, use the next larger

Figure 15 gives the headloss per 1,000

size

which

is

available.

Then,

feet of pipe for any C from 70 to 160.

entering the nomograph with the flow

The left column is the coefficient of

rate and the selected pipe size, find

the

second

column

is

the actual headloss per 1,000 feet.

headloss per 1,000 feet of pipe, the

Convert this loss to the loss for the

third column is a pivot line, the

length of the branch. The headloss in

fourth column gives the pipe diameter,

the branch, plus the headloss in mains

and the right column gives the flow

to the point where the branch connects

rate.

The chart is used by drawing

to the main, will give the cumulative

two straight lines intersecting at the

headloss from storage to the service

pivot

line.

One

of

the

lines

connection.

This cumulative headloss

intersects the two columns to the left

must

not

exceed

the

allowable

of the pivot line, while the other

headloss.

intersects the two columns to the

right. The same example will be used.

100 gpm flows in a 1,000 foot long

pipe

of

4

inch

diameter.

The

To illustrate the application of the

coefficient of friction is 100.

The

design steps explained above, a sample

values of the two right columns are

water distribution system will be

known, so a straight line is drawn

designed for the following situation:

through 100 gpm and 4-inch diameter

A QM depot in a theater of operations

pipe.

This line is extended to

must have a water distribution system.

intersect the pivot line.

The second

Preliminary

studies

indicate

the

line must pass through this point, so

following:

the second line is drawn through the

intersection point on the pivot line

a. A troop strength of 50 officers

and through C = 100 on the left

and 700 EM.

column.

The headloss per 1,000 feet

of

pipe

can

be

read

at

the

b. Average

water

demand:

25

intersection of the second line with

gpd/man.

the headloss column.

A value of 12-

1/4 is obtained. This is shown by the

c. Laundry

water

requirements:

solid line on the figure.

A second

47,000 gpd.

example of the use of this nomograph

is given with the figure.

The

d. Sketch of system layout is shown

headloss in the mains can be found by

in figure 16.

use of any one of the above methods.

After having determined the actual

Numbers underlined are lengths of lines,

headlosses in the various sections of

numbers in parentheses ( ) are service

the mains, the actual headloss, from

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