6
3.2.1 Recommended method:
1)
Saturate the filter stone per Section 3.1
Caution: Do not allow the piezometer to freeze once it has been filled with water.
2)
Replace the filter stone.
3)
Hang the piezometer in the borehole at a point just above the water.
4)
Wait until the piezometer reading has stopped changing.
5)
Take the zero and temperature readings.
3.2.2 Alternative method 1:
1)
Place the piezometer under water in a bucket.
2)
Allow 15 to 20 minutes for the temperature of the unit to stabilize.
3)
Lift the piezometer out of the water by the cable only; do not handle the piezometer
housing as body heat from the hand could cause temperature transients.
4)
Immediately take a zero and temperature reading.
3.2.3 Alternative method 2:
1)
Allow 15 to 20 minutes for the temperature of the unit to stabilize.
2)
Lift the piezometer into the air by the cable only; do not handle the piezometer
housing as body heat from the hand could cause temperature transients.
3)
Take a zero and temperature reading.
(If this method is chosen be sure that the piezometer is protected from sunlight or sudden
changes of temperature. Wrapping it in some insulating material is recommended.)
3.2.4 Alternative method 3:
1)
Lower the piezometer to a known depth marked on the piezometer cable. (The
diaphragm inside the piezometer is located approximately 3/4” (15mm), from the tip.)
2)
Use a dip meter to accurately measure the depth to the water surface.
3)
After temperature stabilization, read the piezometer pressure.
4)
Using the factory calibration constants and a knowledge of the pressure of the water
column above the piezometer (height times density), calculate the equivalent zero
pressure reading if linear regression is used, or the factor C if the second order
polynomial is used.
Содержание 4500AL
Страница 2: ......