SENSTAR OmniTrax - Transition from a Slot to a Trench

Preparation of trenches
Page 110 OmniTrax Product Guide
Transition from a slot to a trench
If the cables are routed from concrete to soil or gravel, the last 30 cm (12 in.) of the slot and the
first 3 m (10 ft.) of the trench must be sloped to meet each other. The slope angle of less than 3º
should be gradual and consistent until the trench is at the correct depth for the burial medium. At
the media transition, the junction of the slot and trench should be approximately 7.5 cm (3 in.). A
1 m section of 2 cm (¾ in.) PVC conduit should be installed to protect the sensor cables at the
media transition and where the trench is close to the ground’s surface. Additional cable protection
should be used if the cable may be subject to damage near the hard surface (e.g., longer section
of conduit or pressure treated wood) due to the shallow burial depth. The last 30 cm of the slots
must be widened to accommodate the conduit.
Required equipment and materials
• site plan
• tape measure
• spray paint, grease pen, water-resistant marker, chalk line
• OC2 - concrete saw capable of cutting a slot 14 mm (9/16 in.) wide by 6 cm 2 1/4 in. deep
(ganged blades are recommended for single pass cutting)
• SC2 - concrete saw capable of cutting a slot 1 cm (3/8 in.) wide by 6 cm 2 1/4 in. deep (ganged
blades are recommended for single pass cutting)
• air compressor and hose (the air compressor must have traps to remove moisture and oil from
the air)
Figure 74: Crossing cracks or expansion joints
Figure 75: Slot to trench transition
CAUTION Additional cable protection may be required in the soil or gravel past the
media transition where the cables are close to the surface.
slot
sensor
cable
30 cm
(12 in.)
minimum
greater than 30°
expansion joint
or crack
use backer rod
if crack is more
than 6.5 cm
(2.5 in.) deep
slot
concrete
soil/gravel
trench depth
23 cm (9 in.)
conduit
30 cm (12 in.)
1 m (3.3 ft.)
conduit length depends on required cable protection
7.5 cm (3 in.)
media transition
3 m (10 ft.)
NOT TO SCALE
6 cm (2.3 in.) slot
3º slope