FBII OMNI-408EU User Manual page 27

System Limitations (cont'd)
electrical circuits, children playing with matches, or arson.
Depending on the nature of the fire and/or the location of the
smoke detectors, the detector, even if it operates as anticipated,
may not provide sufficient warning to allow all occupants to escape
in time to prevent injury or death.
A passive infrared motion detector can detect intrusion only within
the designed ranges as diagrammed in its installation manual.
Passive infrared detectors do not provide volumetric area
protection. They do create multiple beams of protection, and
intrusion can be detected only in unobstructed areas covered by
the beams. They cannot detect motion or intrusion that takes
place behind walls, ceilings, floors, closed doors, glass partitions,
glass doors, or windows. Mechanical tampering, masking,
painting, or spraying of any material on the mirrors, windows, or
any part of the optical system can reduce their detection ability.
Passive infrared detectors sense changes in temperature; however,
as the ambient temperature of the protected area approaches the
temperature range of 90º to 104º Fahrenheit (32º to 40º Celsius),
the detection performance can decrease.
Alarm warning devices such as sirens, bells, or horns may not alert
people or wake up sleepers who are located on the other side of
closed or partly open doors. If warning devices sound on a
different level of the residence from the bedrooms, then they are
less likely to waken or alert people inside the bedrooms. Even
persons who are awake may not hear the warning if the alarm is
muffled by noise from a stereo, radio, air conditioner, other
appliances, or by passing traffic. Finally, alarm warning devices,
however loud, may not warn hearing-impaired people or waken
deep sleepers.
Telephone lines needed to transmit alarm signals from a premises
to a central monitoring station may be out of service. Telephone
lines are also subject to compromise by sophisticated intruders.
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