Planning the cable path
OmniTrax Product Guide Page 33
Man-made mediums (concrete, asphalt, crushed stone)
Most of these mediums have light soil characteristics except for new concrete, and concrete that is
regularly exposed to high humidity and significant precipitation.
You must determine the thickness of the hard surface, as installation methods vary according to
thickness. When surveying the site, watch for slab joints and cracks. Mark the location of joints and
cracks on the site survey. Also, you must determine the presence and depth of any metal
reinforcement or screening that may be present in concrete.
New concrete
As newly poured concrete cures, the electrical properties can change dramatically for months
before stabilizing. It is possible that there will be no detection in “green” concrete. Therefore,
Senstar recommends the use of a supplemental sensor during the curing process. In addition, the
OmniTrax sensor’s response must be monitored closely, as the response will change as the
concrete cures.
Concrete > 13 cm (5 in.) thick (no metal reinforcement)
In concrete that is more than 13 cm (5 in.) thick, slots are cut around the perimeter. The sensor
cables are installed in the slots, two backer rods are installed above the cable, and then the slot is
filled with sealant. Avoid routing the sensor cables through existing cracks and expansion joints.
The slots must be modified, as required, to accommodate sensor cable overlaps, ferrite beads,
decouplers, terminators, expansion joints, large cracks and any transitions between hard surface
slots and soil trenches. See Slot dimensions
on page 111.
Concrete < 13 cm thick (no metal reinforcement)
In concrete that is less than 13 cm thick, the cables are buried in trenches similar to asphalt (see
Burial under a narrow strip of asphalt
on page 103). The concrete strip that was removed, is then
restored. The sensor cables are protected by a stone dust bedding.
CAUTION Long straight runs of OC2 cables in slots are NOT recommended due to
the possibility that thermal expansion can force the sensor cables to
pop out of the slots in places.
Note For installations where the sensor cables are buried in both hard
surfaces and soil, a surface test is strongly recommended to estimate
the variance in sensitivity between the hard surface and the soil (see
The surface test on page 185
).
CAUTION Before cutting slots, consider the structural integrity of the concrete
surface given the remaining thickness after the slots are cut, and the
load it must bear.
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