Perimeter layout guidelines
FlexZone Product Guide Page 17
Fence corners and heavier gauge posts (flexible fences)
Corner posts and heavier gauge support posts tend to dampen the fence’s vibration transmission
characteristics. Therefore, use cable loops at corner posts and heavy gauge support posts, to
increase the sensitivity. Each sensitivity loop requires approximately 3 m (10 ft.) of sensor cable
(see Figure 23:
).
Zone demarcation loops (flexible fences)
Zone demarcation loops may be used at software defined zone boundaries for improved location
accuracy. It is possible that an alarm that occurs very close to a software defined zone boundary
could be reported in the adjacent zone (± 3 m). Zone demarcation loops add extra sensor cable at
zone boundaries to help ensure that an alarm is reported in the zone in which it occurs. Allot 3 m
(10 ft.) for each zone to adjacent zone boundary (see Figure 24:
). Rather than using extra cable
for zone demarcation loops, overlapping CCTV coverage can provide visual assessment to verify
alarms and alarm location. When setting up the camera views, ensure that there is at least 6 m
(20 ft.) of overlapping coverage at each zone boundary.
Service loops (flexible fences)
Service loops provide extra sensor cable along the fence to make cable repairs. Allot 75 cm
(30 in.) of cable each 50 m (164 ft.) for a service loop. Locate the U-shaped service loops at fence
posts (see Figure 25:
).
Drip loops (flexible fences)
Drip loops raise the connector above the sensor cable to prevent water from running along the
cable and accumulating in the enclosure. Drip loops also relieve strain resulting from temperature
changes that cause the cable to expand and contract. Form the drip loop by raising the connector
15 cm (6 in.) above the level of the cable run. Allot 50 cm (20 in.) of cable for each splice or
termination (see Figure 26:
).
Termination loops (flexible fences)
Termination loops provide extra sensor cable at the end of the protected section of the fence (at
the terminator) to make cable repairs or future sensor cable layout changes. The amount of cable
that can be used for a termination loop depends on the length of sensor cable (plus lead-in cable if
used) connected to the processor (side A or side B, maximum 300 m). Termination loops are
typically comprised of up to 5 coiled loops of sensor cable with a 60 cm (2 ft.) diameter.
Termination loops also include the length of 1 fence panel as the cable uses a double pass on the
final protected panel (see Figure 27:
).
Splice loops (flexible fences)
If there is extra sensor cable at the location of a cable splice, you can save the cable for cable
repairs or future sensor cable layout changes by forming a splice loop instead of cutting the cable
to length (see Figure 28:
). The maximum length of cable per side (300 m) cannot be exceeded,
but up to 10 m of cable can be coiled and attached to the fence at each side of a cable splice. A
10 m splice loop is comprised of 5 coiled loops of sensor cable with a 60 cm (2 ft.) diameter. Each
60 cm diameter coil of sensor cable contains approximately 2 m of cable.
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