In-Situ Win-Situ 4 / Pocket-Situ 4 Operators Manual - Manual (Page 36)

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0031510 rev. 003 11/04
LEVEL/DEPTH CONVERSION INFORMATION
The conversion from pressure in pounds per square inch (psi) to depth or
level in meters or feet requires several conversion factors.
Specific Gravity
A dimensionless specific gravity value may be used for the conversion
from pressure to feet or meters of fluid. A specific gravity of 1.0 (the
specific gravity of pure water at 4°C) is adequate for many groundwater
applications. The value is editable. Specific gravity values equate to liquid
density in g/cm
3 . (See the table in Appendix A.)
Density, Latitude & Elevation
If your software supports it, a more accurate conversion may be applied
whereby pressure in the English unit psi is first converted to the SI unit
Pascal (Pa), and then to meters or feet using two additional values:
• Liquid Density. Pure groundwater at 20°C has a density of 0.998 g/
cm 3 . Refer to Appendix A for a temperature/density table and a method
for experimentally determining liquid density if the working fluid is not
pure water.
• Gravitational Acceleration. The acceleration due to gravity that an
object experiences is location-specific. Given your latitude and
elevation, the software can calculate a value for gravitational accelera-
tion.
TIP: Either specific
gravity or density,
latitude & elevation
may be used to convert
from pressure (psi) to
depth/level (meters or feet).
If your software supports it,
a gain in accuracy may be
realized by selecting the
density, latitude & elevation
option.
SECTION 5: PRESSURE SETUP
TIP: To change
the units for
pressure, depth,
or level readings, select
Preferences from the
Options Menu (Win-Situ) or
select the Home site and
tap Setup in the Command
bar (Pocket-Situ).