PAL-AT Installation Manual
37
8. If a synthetic liner is not installed under the slotted pipe, a compacted clay/silt base layer should be
used under the pipe to minimize the vertical migration of a leak. The slotted pipe should be covered
with backfill material of sand or soil.
9. It is recommended to have 12” [300 mm] inches of backfill installed and compacted with hand tampers
above the slotted pipe before mechanical compactors are used, to prevent crushing the pipe.
10. During the storage and installation of TFH cable, the ends of the cable must be protected to keep water
from entering. The cable is shipped with shrink tube caps on the ends. Additional caps are supplied
with TFH connectors to be installed on the cable temporarily until the connectors are installed. The
caps should be installed over the jacket, but under the outer plastic overbraid of the cable. The cable
ends should not be immersed in water at any time, even with the shrink caps installed. After the
connectors are installed, if there is any possibility of water contacting the connectors, they should be
sealed with non-corrosive RTV and shrink tubing immediately. If the connector needs to be reopened
later for calibration, slit open the outer shrink tubing. Replace it with a new shrink tube immediately
after calibration. Shrink tube caps are not required for TFH-Gold.
11. The sensor cable must be protected from damage when it is in the trench before backfilling. The cable
must be protected when pipes are being welded or other work is occurring nearby. The cable should
not be stepped on.
12. All connectors of sensor cable must be located in junction boxes at or above grade. A vertical riser of
PVC conduit or other material suitable for the project must be installed to provide protection to the
cable through the backfill and into the junction box (see figure 6-1). Follow the instructions for installing
cable connectors using shrink tubing and RTV sealant to insure a watertight assembly.
CAUTION: It is extremely important to prevent damage to the TFH cable jacket. A damaged
cable must be replaced.
6.2 Installing the Sensor Cable
1. After all other work is completed and the area is free and clear of all activities that can cause damage,
the sensor cable should be installed.
Care must be taken during installation of sensor cable to avoid contact with potential
contaminants such as oil, hydrocarbon liquid, soap or other material that may contain
surfactants. Contamination by any of these liquids will destroy the water repellency of the
cable and it will need to be replaced.
2. When the construction schedule allows, the PAL-AT panel should be permanently mounted and
connected with electrical power before installing jumper or sensor cable. This will allow the system's
setup and calibration procedures to proceed efficiently. For additional information on calibration points,
refer to the PAL-AT Operating Manual.
3. Slowly play out the cable by hand rotating the spool. Never pull loose coils of cable off the end of the
spool. When loose coils are pulled taut, kinks form in the cable that could prevent bringing the system
on-line. Protect open ends of the cable from damage, contaminants and moisture.
4. Starting from the panel, connect a minimum of 50' [15 m] of jumper cable before connecting the sensor
cable. Route the sensor cable as shown on the contract drawings. Refer to table 1 (see section 3) for
amount of jumper cable to be connected to the end of the sensing string.
5. Make sure all TFH cable ends are sealed with shrink tubing after installation.
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