Conversions. The equation for converting feet of head to pounds per

square inch is:

P = H x SPGR

or

H = 2.31 x P

2.31

SPGR

Where:

P = pressure in PSI

H = Head (in feet of fluid)

SPGR = Specific gravity

2.31 = Conversion constant

We found out in the first part of this class that all products produce a

different pressure at different heights. In the equation, the specific

gravity compensates for the different products and the constant 2.31 takes

care of the feet of head (hd)or the PSI.

Example: SPGR =.8448

Head = 250 ft

P = 250 x .8448 =91 PSI

2.31

H = 2.31 X 91 =249 ft/hd

844

motor gasoline, JP-4, and diesel fuel. Properties of these fuels will be

found in MIL-HDBK-200 (Federal specifications) and gravity range in Table 6-

1. With such a wide variation, specific gravity becomes an important factor

in the design of military pipelines. The heaviest fuel making up 24 percent

or more of the total requirement will be taken as the design fuel.

which a liquid can be made to flow. It is the internal force (resistance)

or opposition to flow. Viscosity can be expressed as kinematic viscosity or

dynamic viscosity. For our purposes in the U.S. Army we will use kinematic

viscosity. The units of kinematic viscosity are centistokes and feet

squared per second. The viscosity, in units of centistokes (cs), is found

by using Figure 1-1. If the units of feet squared per second are desired,

then the conversion factor of 92,900 cs equals one foot squared per second

is used.

To convert 20 cs to cubic ft/sec use, the following formula:

y

=

Kinetic

=

20

=

0.000215285

92,900

92,900

12-8

QM 5099